UNIVERSITY  FARM 


RICHTER'S  ORGANIC  CHEMISTRY 


ORGANIC    CHEMISTRY 

OR 

CHEMISTRY    OF    THE    CARBON    COMPOUNDS 


BY 

VICTOR    VON    RICHTER 

EDITED  EY  PROF.  R.  ANSCHUTZ  AND  DR  H.  MEERWEIN 


VOLUME  II 

CHEMISTRY   OF   THE   CARBOCYCLIC   COMPOUNDS 


TRANSLATED    FROM    THE    I1TH    GERMAN    EDITION 
BY 

E.  E.  FOURNIER  D'ALBE,  D.Sc.,  A.R.C.Sc. 

AUTHOR  OF  "CONTEMPORARY  CHEMISTRY,"  "THE  ELECTRON  THEORY,"  ETC. 


LONDON 
KEGAN  PAUL,  TRENCH,  TRUBNER  &  CO.  LTD. 

PHILADELPHIA :    P.  BLAKISTON'S  SON  &  CO. 
1922 


PREFACE    TO    THE    ELEVENTH 
GERMAN    EDITION 


THE  second  volume  of  the  present  work  was  published  in  its  last 
edition  in  1905  by  me  in  collaboration  with  Professor  Georg  Schroeter. 
Dr  Schroeter,  who  had  also  rendered  extremely  able  assistance  in  the 
production  of  the  seventh  and  succeeding  editions,  was  appointed  a 
year  ago  to  the  distinguished  position  of  Professor  of  Chemistry  at  the 
Veterinary  College  in  Berlin.  Collaboration  in  the  preparation  of  the 
present  second  volume  of  the  treatise  was  then  undertaken  by  his 
successor  at  the  Chemical  Institute,  Dr  Hans  Meerwein,  Assistant 
Instructor  in  Organic  Chemistry. 

RICHARD  ANSCHUTZ. 


Since  the  publication  of  the  second  volume  seven  years  have 
elapsed,  during  the  last  few  of  which  the  book  was  out  of  print.  In 
the  course  of  these  latter  years  the  amount  of  new  subject-matter  has 
undergone  a  remarkable  increase.  Consequently,  the  present  volume, 
in  comparison  with  the  last  edition,  has  had  to  be  enlarged  by  more 
than  nine  sheets,  in  spite  of  the  adoption  of  a  larger  size  of  page,  as 
otherwise  the  whole  character  of  the  edition  would  have  been  altered. 

As  in  previous  editions,  a  list  of  the  most  important  interpolations 
and  additions  is  given  below. 

Tri-,  tetra-,  penta-,  hepta-,  octo-,  and  nonocyclic  compounds. — Special 
attention  is  called  to  the  ring  expansion  by  the  action  of  nitric  acid 
on  cyclo-alkyl  methylamine  as  a  new  general  reaction.  The  tetra- 
methylene  group  has  been  supplemented  principally  by  the  inclusion 
of  the  simplest  examples :  cyclobutane,  cyclobutene,  and  cyclo- 
butanone.  The  simplest  saturated,  and  unsaturated,  carbohydrates, 
with  eight-membered  carbon  rings,  are  obtained  by  the  transformation 
of  pseudo-pelletierin,  and  have  been  very  closely  examined.  By  the 
recognition  of  the  constitution  of  india-rubber  as  a  polymeric  dimethyl, 
cyclo-octadiene,  the  group  of  octocarbocyclic  compounds  has  gained 
considerably  in  interest. 

The  class  of  nonocarbocyclic  compounds  has  had  to  be  added. 

Single-nucleus  aromatic  substances. — The  historical  account  of  the 
theory  of  the  aromatic  compounds  has  been  supplemented  at  essential 
points  (p.  28). 

Special  attention  is  directed  to  the  extremely  consistent  splitting 
up  of  benzene  and  its  homologues  by  the  oxidising  action  of  ozone. 

Halogen  derivatives  of  benzene  carbohydrates. — Recognition  of  the 
fact  that  the  capacity  for  reaction  of  aromatically  combined  halogens 


vi  PREFACE 

can  be  very  considerably  increased  by  the  addition  of  finely  divided 
copper  or  copper  salts,  has  proved  of  great  practical  importance. 

Nitrogenous  derivatives  of  benzene  carbohydrates. — The  preparation 
of  optically  active  dialkyl  anilin  oxides  is  worthy  of  attention. 

The  behaviour  of  nitro-diphenylamines  in  the  formation  of  salts  has 
been  more  closely  examined,  and  more  satisfactory  reasons  have  been 
given  for  regarding  them  as  pseudo-acids.  As  regards  new  investiga- 
tions on  the  diazo-amido-compounds,  the  preparation  of  diazo-benzene 
amide  is  particularly  important.  New  methods  of  obtaining  diazo- 
amido-compounds  have  been  discovered.  The  discovery  of  two 
isomeric,  differently  coloured,  series  of  salts  is  important,  as  regards 
the  constitution  of  amido-azo-compounds,  and  their  salts.  Attention 
is  directed  to  the  production  of  tetraphenyl-hydrazin  and  its  interesting 
resolving  reactions  ;  see  also  diphenyl-dihydro-phenazin.  The  process 
of  reaction  in  the  formation  of  phenyl-hydrazones,  by  the  action  of 
diazo-benzene  salts  on  aliphatic  compounds  with  easily  replaceable 
hydrogen  atoms,  has  been  experimentally  elucidated  in  its  individual 
phases. 

The  group  of  aromatic  compounds  of  arsenic  has  attained  greater 
importance,  through  the  discovery  of  pharmaceutically  valuable 
substances,  such  as  salvarsan. 

Phenols. — The  consideration  of  the  nitro-phenols  as  pseudo-acids 
has  gained  in  interest  by  the  discovery  of  a  red  ester  of  picric  acid. 
The  question  of  the  constitution  of  the  oxy-azo-benzenes  has  been 
finally  decided  in  favour  of  the  azo-formula.  Reference  may  also  be 
made  to  the  discovery  of  cyclic  double  esters  of  the  phenol-sulpho- 
acids  :  sulphonylides. 

Quinones. — The  discovery  of  the  long- sought  o-benzo-quinone 
should  be  mentioned  in  the  first  place.  The  nitrogenous  derivatives 
of  the  quinones  have  been  thoroughly  discussed.  The  investigation 
of  the  reactions  and  constitution  of  anilin-black  by  the  oxidation  of 
anilin  is  of  the  highest  importance.  Attention  may  also  be  called  to 
the  remarkable  researches  regarding  the  so-called  two-nucleus  quinones 
of  the  diphenyl,  naphthalin,  and  anthracene  series. 

The  nitrogenous  derivatives  of  the  oxy-phenyl-paraffin  alcohols  have 
been  thoroughly  discussed,  owing  to  their  marked  physiological  action. 
Special  attention  is  directed  to  the  analysis  and  synthesis  of  adrenalin 

(P-  370). 

Aromatic  aldehydes  and  ketones. — In  this  group  a  series  of  new 
and,  in  some  cases,  easily  effected  syntheses  should  be  noted.  Special 
attention  should  be  given  to  the  atom  displacements  in  the  trans- 
formation of  the  aromatic  ethylene  glycols,  the  halogen  hydrines,  and 
the  ethylene  oxides. 

Aromatic  carbo-acids. — Benzoyl  nitrate,  benzo-nitrosol  acid,  benzo- 
nitrol  acid,  and  benzo-nitrile  oxide  figure  as  new  carboxyl  derivatives 
of  benzoic  acid.  With  reference  to  the  constitution  of  anthranile,  the 
so-called  dianthranilides  must  be  mentioned,  as  the  true  bimolecular 
anhydrides  of  the  anthranile  acids.  Thiosalicylic  acid  and  its  progeny 
have  been  much  used  as  the  basic  products  for  preparing  thio- 
indigo  red. 

The  discovery  of  di-iodo-tyrosin  in  certain  species  of  coral  is  of 
physiological  importance. 


PREFACE  vii 

Single-nucleus  aromatic  substances  with  unsaturated  side  chains. — 
The  discovery  of  the  tri-morphism  of  allo-cinnamic  acid,  whereby  the 
previously  vague  isometry  of  the  cinnamic  acids  may  be  regarded  as 
explained,  is  of  principal  interest  in  this  field. 

Hydro-aromatic  substances. — Inasmuch  as  by  the  smooth  method 
of  reduction  of  aromatic  compounds,  by  means  of  hydrogen  and  finely 
divided  nickel,  the  hydro-aromatic  substances  have  become  an  easily 
accessible  primary  material,  this  field  of  research  has  made  remarkable 
progress,  mainly  by  the  use  of  Grignard's  reaction.  For  determina- 
tions of  constitution,  especially  as  regards  terpenes,  the  elegant  method 
of  oxidation  by  means  of  ozone  has  proved  of  great  service.  For 
terpene  chemistry  the  synthesis  of  unsaturated  hydrocarbons,  with 
semi-cyclic  double  linking,  is  of  importance.  The  tetra-  and  dihydro- 
benzenes  were  subjected  to  a  fresh  critical  study.  Extended  synthetic 
investigations  with  regard  to  the  cyclo-nitrales  have  finally  led  to  a 
synthesis  of  irone,  which,  however,  is  not  technically  valuable.  A 
curious  method  for  the  synthesis  of  different  hydro-aromatic  substances 
was  discovered  in  the  action  of  chloroform  and  alkali  on  o-  and 
p-alkaline  phenols.  The  production  of  the  optically  active  forms  of 
4-methyl-cyclo-hexilidene-acetic  acid,  in  which  the  asymmetry  of  the 
molecule  is  not  caused  by  the  presence  of  an  asymmetric  carbon  atom, 
is  of  technical  interest. 

Attention  might  also  be  directed  to  the  splitting  of  cyclic  ketones 
by  means  of  sunlight. 

Terpenes. — The  exceedingly  numerous  researches  made  in  the  entire 
field  of  terpene  chemistry  have  necessitated  •  an  almost  complete  re- 
working, and  a  partial  re-division,  in  particular  of  the  di-cyclic  terpenes. 
The  olefinic  terpene  group  has  been  enriched  by  the  discovery  of 
ocimene  and  nerol.  The  constitutional  determinations  of  the  mono- 
cyclic  terpenes,  which  may  now  be  regarded  as  concluded,  have  been 
confirmed  by  numerous  syntheses.  Thus,  dipentene,  terpinene, 
a-phellandrene,  sylvestrene,  and  carvestrene  have  been  obtained  in  a 
synthetic  manner.  A  number  of  analogously  composed  combinations 
derived  from  the  terpenes,  such  as  terpinene,  terpene,  terpinene-cineol, 
and  terpinenol,  have  ranged  themselves  alongside  of  terpin,  cineol,  and 
the  terpineols.  Sabinene  and  thuyene  were  associated,  by  numerous 
transformations,  with  terpinene  and  the  terpinenoles.  Eucarvone  has 
been  examined  again,  and  has  been  recognised  as  a  heptacarbocyclic 
combination.  The  pinene  separated  from  the  turpentine  oils,  has  been 
recognised  as  a  mixture  of  two  linkage-isomeric  terpenes,  and  from  these 
a  number  of  new  derived  and  transformation  products  are  obtained. 
The  transformation  of  pinene  into  borneol  and  isoborneol,  or  their 
esters,  has  been  converted  into  a  technically  realisable  method  for  the 
artificial  production  of  camphor  from  turpentine  oil.  A  fresh  and  very 
thorough  treatment  of  camphene  has  confirmed  the  Wagner  camphene 
formula  ;  nevertheless,  this  has  raised  doubts  as  to  the  unity  of  this 
terpene.  Bornylene,  camphane,  isocamphane,  and  santene  were  the 
subjects  of  new  and  fruitful  researches.  A  series  of  articles  on  the 
behaviour  of  borneol  and  isoborneol  towards  each  other,  and  towards 
pinene  or  camphene  -  chlorohydrate,  appear  to  prove  the  stereo- 
isomerism  of  these  combinations.  The  constitution  of  fenchone  could 
be  accurately  ascertained  by  a  series  of  splitting  reactions. 


viii  PREFACE 

Phenyl-benzenes  and  phenylfat  carbohydrates. — A  series  of  naturally 
occurring  substances  have  been  recognised  as  oxybenzo-phenones,  and 
oxybenzylidene-acetophenones,  which  have  hitherto  been  regarded  as 
phenol  esters  of  protocatechu  acid  and  oxy-cinnamic  acid. 

Important  new  observations  have  been  made  in  favour  of  regarding 
the  coloured  salts  of  triphenyl-carbinole  as  quinoid  combinations  ; 
see  also  dibenzylidene-acetone. 

The  benzein,  rosamin,  and  phthalein  classes  have  been  increased 
by  further  research. 

Prominence  should  be  given  to  diphenylketene,  the  most  easily 
accessible,  and  consequently  the  most  thoroughly  examined,  factor  in 
this  class,  rich  in  reactions. 

Amongst  the  most  theoretically  important  researches  which  have 
been  made  in  various  directions  with  excellent  results,  we  may  mention 
those  relating  to  hexaphenyl-ethane,  and  similar  combinations,  and 
their  dissociation  into  the  corresponding  triaryl-methyls. 

The  diphenyl-butane  group  has  been  enriched  by  notable  papers 
relating  to  diphenyl-butadiene  and  diphenyl-butenin. 

Condensed  nuclei. — Notice  should  be  taken  of  the  virtual  tautomery 
of  anthranol  and  anthrones,  as  well  as  of  anthra-hydrokinone  and 
oxanthrone.  The  amido-anthrakinones  have  repeatedly  shown  them- 
selves to  be  excellent  intermediaries  for  the  production  of  new  vat  dyes, 
and  so  have  the  dianthrakinonyls  and  the  benzo-anthrones. 

Glucosides. — There  have  been  new  investigations  on  certain  gluco- 
sides  related  to  amygdalin  (p.  719). 

Natural  dye-stuffs. — Much  light  has  been  thrown  on  the  complex 

constitution  of  cochineal  dye. 

• 

The  above  brief  review,  in  the  course  of  which  we  have  only  been 
able  to  refer  to  some  of  the  most  important  recent  developments,  shows 
that,  in  the  time  which  has  elapsed,  notable  progress  has  been  made  in 
nearly  all  classes  of  carbocyclic  compounds. 

RICHARD  ANSCHtJTZ. 

HANS  MEERWEIN. 
BONN,  October  1912. 


CONTENTS 

CARBOCYCLIC   COMPOUNDS 

PAGE 

Ring  Formation  in  Cyclo-paraffin  Bodies  ......          3 

I.—TRI-,  TETRA-,  PENTA-,  HEPTA-,  OCTO-, 
AND  NONOCARBOCYCLIC  COMPOUNDS   .   6 

A.  Trimethylene  Group. — Trimethylene,  Trimethylene-carboxylic  Acid        .          7 

B.  Tetramethylene  Group. — Tetramethylene,  Cyclobutene,  Cyclobutanine    .        10 

C.  Pentacarbo cyclic  Compounds. — Camphor,  Pentamethylene,  Cyclopentene, 

Cyclopentadiene,  Alcohols,  Ring  Ketones,  Adipin  Ketones,  Diketo- 
pentamethylene,  Aldehydes  and  Extra-cyclic  Ketones,  Carboxylic 
Acids,  Alcohol-carboxylic  Acids,  Keto-carboxylic  Acids,  Bicyclo- 
pentane  ...........  13 

D.  Heptacarbocyclic    Compounds. — Suberane,    Suberene,    Cycloheptadiene, 

Tropilidene,  Oxy-suberane-carboxylic  Acid     .....        22 

E.  Octocarbocyclic  Compounds. — Cyclo-octane,  Azelane     ....       25 

F.  Nonocarbocyclic  Compounds        ........       26 

II.— HEXACARBOCYCLIC   COMPOUNDS        .      27 

A.    MONONUCLEAR   AROMATIC   SUBSTANCES   OR 
BENZENE   DERIVATIVES 

History.  General  Survey.  Isomerism  of  Benzene  Derivatives.  Principles 
of  Location  for  Benzene  Substitution  Products.  Location  of  the  Di- 
derivatives.  Isomerism  of  the  Poly-substitution  Products.  Constitu- 
tion of  the  Benzene  Nucleus.  Benzene  Ring  Formations.  Benzene 
Ring  Splittings.  Splitting  by  Feeble  Oxidation.  Splitting  by 
simultaneous  Chlorination  and  Oxidation.  Splitting  by  Reduction 
in  Alkaline  Solutions  .  .  .  .  .  .  .  .  .27 

1.  SINGLE-NUCLEUS  BENZENE  DERIVATIVES  : 

Benzol.  Coal-tar.  Working  of  Coal-tar  for  Aromatic  Hydrocarbons. 
Alkyl-benzols.  Allylene.  Isomerism  and  Constitution  of 
Alkyl-benzols.  Xylol.  Ethyl-benzol,  Mesitylene,  Cymol, 
Toluol  ..........  49 

2.  HALOGEN  DERIVATIVES  OF  THE  BENZENE  HYDROCARBONS  : 

A.  Halogen     Substitution     Products     of    Benzene.  —  Fluoro-benzols, 

Bromo-,  Chloro-,  and  lodo-benzols        .....       60 

B.  Halogen  Derivatives  of  the  Alkyl-benzols. — Benzyl  and  Benzal  Com- 

pounds.    Chloro-,  Bromo-,  lodo-,  and  Fluoro-toluol         .          .       64 

3.  NITROGEN  DERIVATIVES  OF  BENZENE  HYDROCARBONS         ...       67 

(1)  Nitro-derivatives  of  Benzene  and  the  Alkyl-benzols. — Nitro-benzols, 

Nitro-toluols.  Nitro-products  of  the  Alkyl-benzols.  Nitro- 
halogen  Derivatives  of  the  Alkyl-benzols  ....  68 

(2)  Nitroso-derivatives   of  Benzene   and   the   Alkyl-benzols. — Nitroso- 

benzols,  Nitroso-toluols       .......        75 

(3)  fi-Alphyl-  or  Aryl-hydroxylamines. — Formyl-  and  Phenyl-hydro- 

xylamines.  Chloro-  and  Nitro-compounds.  Nitroso-diphenyl- 
hydroxylamines  .  .  .  .  .  .  .  •  77 

(4)  fi-Alphyl-nitroso-hydroxylamines       ......        79 

(5)  Amido-derivatives  or  Anilines. — (a)  Primary  Phenyl-amines.  Their 

Reduction  and  Exchange  Reactions.  Their  Properties  and 
Transformations,  (b)  Secondary  and  Tertiary  Phenyl-amines 
and  Phenyl-ammonium  Bases.  Phenyl-alkylamine.  Separa- 
tion of  Primary,  Secondary,  and  Tertiary  Bases.  Di-alkyl- 
aniline  Oxides.  Methyl-anilines.  (c)  Poly-phenyl-amines. 
(d)  Aniline  Derivatives  of  Inorganic  Acids.  (e)  Carboxylic 


x  CONTENTS 

PACE 

Derivatives  of  the  Aromatic  Primary  and  Secondary  Bases. 
(/)  Phenylated  Amidins  of  Formic  Acid  and  Acetic  Acid. 
Carbylamines,  Ureas,  and  Phenyl-ureas,  Thio-ureas,  and 
Hydrazin  Derivatives,  (g)  Phenylated  Nitriles  and  Imides  of 
Carbonic  Acid.  Phenyl  Isocyanate.  Phenyl  Sulpho-cyanide. 
Cyanamide  Derivatives.  Phenyl-amine  Derivatives  of  Oxalic 
Acid.  Anilides  of  Dicarbpxylic  Acid.  Anilido-carboxylic 
Acids.  Aniline  Substitution  Products.  Aniline  Haloids. 
Nitranilines.  Nitro-diphenyl-amines.  (h)  Nitroso- derivatives 
of  the  Primary,  Secondary,  and  Tertiary  Amines ...  79 
(5«)  Diamines. — Phenylene-diamines.  Toluene-  and  Xylene-di- 
amines.  Condensation  of  o-Diamines.  Differences  between 
o-,  m-,  and  p-Diamines.  Triamines  and  Tetramines  .  .  113 

(6)  Phenyl-nitrosamines. — Nitrosanilides.     Nitroso-formanilides         .      119 

(7)  Phenyl-nitr  amines. — Diazo-benzoic  Acids  .  .  .          .120 

(8)  Diazo-compounds.  —  Aromatic     Diazo-derivatives.        Diazonium 

Salts.  Diazo-perhalides.  Iso-diazo-hydrate.  Diazo-benzol- 
sulphonic  Acids.  Diazo-benzol  Cyanide.  Chief  Decomposi- 
tions of  Diazo-benzol  Salts  .  .  .  .  .  .121 

(9)  Diazo-amido-compounds  .          .          .          .          .          .          .132 

(10)  Dis-diazo-amido-compounds. — Reactions  and  Formations.    Diazo- 
amido-compounds   from   Primary   Aromatic   Bases.       Mixed 
Fatty-aromatic  Compounds.     Phenyl- triazones.     Re-arrange- 
ments of  Diazo-amido-compounds       .          .          .          .          .132 

(n)  Diazo-oxy-amido-compounds. — Diazo-oxy-amido-benzol        .          .      137 

(12)  Diazo-amido-compounds. — Diazo-benzol-imides.        Their     trans- 

formations.    Tetrazones     .          .          .          .          .          .          .137 

(13)  Azoxy-compounds. — Their   Formation   and    Behaviour.     Azoxy- 

benzol      .          .          .          .          .          .          .          .          .  139 

(14)  Azo-compounds. — Their  Classification,  Nomenclature,  Formation, 

and  Properties.  Indifferent  Symmetrical  Azo-compounds. 
Azo-benzols  and  Azo-toluols.  Amido-azo-compounds  .  .140 

(15)  Hydrazin  Compounds. — Hydrazo-compounds.      Hydrazo-benzols 

and  -toluols.  The  Benzidin  and  Semidin  Transformations 
of  the  Hydrazo-compounds.  The  Phenyl-hydrazin  Group. 
Phenyl-alkyl-hydrazins.  Hetero-ring  Formations  of  Sub- 
stituted Phenyl-hydrazins.  Phenyl-hydrazone  and  Osazone. 
Phenyl-hydrazone  Transformations.  Phenyl-hydrazin  Deri- 
vatives of  the  Inorganic  Acids.  Carboxylic  Derivatives  of 
Phenyl-hydrazin.  Fatty  Acid  Derivatives.  Alcoholic  Acid 
Derivatives.  Phenyl-hydrazin  Derivatives  of  Mono-ketonic 
Carbonic  Acid.  Dicarboxylic  Acids.  Olefin-  and  Oxy- 
dicarboxylic  Acids.  Hetero-ring  Formation  of  Phenyl- 
hydrazin  Derivatives  of  Dicarboxylic  Acids.  .  .  .145 

(16)  Hydrazins  or  Amidrazones. — Nitrazones.     Phenyl-hydrazo-  and 

Phenyl  -  azo  -  aldoximes.  Formazyl  Compounds.  Phenyl- 
nitroso-hydrazin.  Tetrazones.  Hydro-tetrazones  .  .163 

4.  AROMATIC  COMPOUNDS  OF  PHOSPHORUS,  ARSENIC,  ANTIMONY,  BISMUTH, 

BORON,  SILICON,  AND  TIN  : 
Phenyl-phosphene.     Phenyl-arsenic  Compounds.     Phenyl-boron  and 

-silicon  Compounds   .          .          .          .          .          .          .          .168 

5.  PHENYL  METAL  DERIVATIVES  : 

Magnesium  -  diphenyl.        Aryl  -  magnesium     Haloids.         Mercury- 

diphenyls  .......  .     171 

6.  SULPHONIC  ACIDS  : 

Formation.  Properties  and  Transformations.  Monosulphonic 
Acids.  Benzo-sulphonic  Acids.  Benzo-sulpho-compounds. 
Xylol-sulphonic  Acids.  Poly-sulphonic  Acids.  Chloro-, 
Bromo-,  lodp-,  lodoso-,  Nitro-,  Nitroso-,  and  Amido-benzol- 
sulphonic  Acids.  Sulphanilic  Acid.  Amido-azo-benzol  Acids . 
Sulphinic  Acids.  Sulphones  and  Sulphoxides  .  .  .172 

7.  PHENOLS  : 

Monohydric  Phenols.  Their  Formation  and  Behaviour.  Their 
Colour  Reactions,  and  Nuclear  Syntheses.  Phenolates. 
Cresols.  Ethyl-  and  Propyl-phenols.  Thymol.  Carvacrol. 


CONTENTS  xi 

PAGE 

Derivatives  of  Monohydric  Phenols.  Phenol-alcohol  Ethers. 
Phenoxalkylamines.  Phenol  Ethers.  Acid  Esters  of  Phenol. 
Phenyl  Esters  of  the  Phosphoric  Acids.  Phenyl  Carbonates. 
Phenol  Substitution  Products.  Phenol  Haloids.  Mono-  and 
Poly-haloid  Phenols.  Nitro-phenols.  Mono-,  Di-,  Tri-,  and 
Tetra-nitro-phenols.  Picric  Acid.  Haloid  Nitro-phenols. 
Nitroso  -  compounds.  Nitroso  -  phenol.  Nitroso  -  cresol. 
Amido-phenols.  Their  Condensations.  Diamido-phenols. 
Diazo-phenols.  Azoxy-phenols.  Azo-phenols.  Hydrazo- 
phenols.  Thio-derivatives.  Mercaptans.  Condensation  of 
o-Amido-thio-phenols.  Phenyl  Sulphides.  Amido-phenyl- 
Sulphides.  Dihydric  Phenols.  Pyro-catechin.  Hetero-ring 
Formations  from  Pyro-catechol.  Homologous  Pyro-catechols. 
The  Resorcin  Group.  Resorcin.  Its  Ethers  and  Esters. 
Nitro-  and  Thio-resorcin.  Homologous  Resorcins.  Orcin. 
Hydroquinone  Group.  Hydroquinone.  Homologous  Hydro- 
quinones.  Substituted  Hydroquinones.  Trihydric  Phenols. 
Pyrogallol.  Phloro-glucin.  Tetrahydric  Phenols.  Penta- 
and  Hexahydro-phenols  .  .  .  .  .  .  .183 

8.  QUINONES  : 

Ortho-quinones.  Para-quinones.  Phenol  Addition  Products  of 
Quinones.  Homologous  p-Quinones.  Quinone  Haloids.  Oxy- 
quinones  and  Polyquinoyls.  Croconic  and  Leuconic  Acid. 
Nitrogen  Derivatives  of  Quinone.  Quinone  Dioximes, 
Imines,  and  Azines.  Indo-phenols.  Indo-anilines.  Quinone 
Phenyl-di-imines.  Aniline  Black.  Indamines  .  .  .  224 

9.  PHENYL-PARAFFIN  ALCOHOLS  AND  THEIR  OXIDATION  PRODUCTS   .          .     239 

(a)  MONOHYDRIC  PHENYL-PARAFFIN  ALCOHOLS  AND  THEIR  OXIDA- 
TION PRODUCTS  :  240 

(1)  Monohydric    Phenyl-paraffin    Alcohols. — Benzyl    Alcohol. 

Homologous  Phenyl-paraffin  Alcohols.  Derivatives  of 
the  Phenyl-paraffin  Alcohols.  Homologous  Phenyl- 
alkyl  Chlorides.  Esters  of  Carboxylic  Acid.  Nitrogen 
Derivatives  of  the  Phenyl-paraffin  Alcohols.  Benzyl- 
amines.  Benzyl-anilines.  Benzyl-diazo-compounds, 
Triazenes,  and  Azides.  Benzyl-hydroxylamines.  Sub- 
stituted Benzyl  Alcohols.  Formation  of  Hetero-rings 
from  Derivatives  of  o-Amido-benzyl  Alcohol  .  .  240 

(2)  Aromatic     Monaldehydes.  —  Benzaldoximes.        Pyrones. 

Benzaldehyde.  Homologous  Benzaldehydes.  Deri- 
vatives of  Benzaldehyde.  Benzaldehyde  Haloids. 
Nitro-,  Nitroso-,  Hydroxylamino-,  Azoxy-,  Azo-,  and 
Amido-benzaldehydes.  Hetero-ring  Formations  of 
Benzaldehyde  .......  252 

(3)  Aromatic    Monoketones. — Aceto  -  phenone.       Its    Homo- 

logues.  Homo-benzolated  Paraffins.  Nitro-aceto- 
phenones.  Amido-aceto-phenones.  Hetero-ring  For- 
mation of  the  Aromatic  o-Amido-ketones  .  .  .  264 

(4)  Aromatic  Monocarboxylic  Acids. — Their  Formation.     Oxi- 

dation   with    Chromic    and    Nitric    Acids.     Nuclear 
Syntheses  and  Reactions.     Benzoic  Acid.     Its  Homo- 
logues.       Alkyl-benzoic  Acids.       Ethyl-benzoic  Acids. 
Propyl-benzoic  Acids.      Phenyl-fatty  Acids.      Hydra- 
tropic  Acid      ........     269 

(6)  DERIVATIVES  OF  THE  AROMATIC  MONOCARBOXYLIC  ACIDS: 

(1)  Esters  of  the  Monobasic  Aromatic  Acids  ....      277 

(2)  Aromatic  Acid  Haloids. — Benzoyl  Chloride,  Bromide,  and 

Nitrate 278 

(3)  Acid  Anhydrides. — Benzoic  and  Aceto-benzoic  Anhydrides     279 

(4)  Acid  Peroxides     .          .          .          .          .          .          .          .280 

(5)  Thio-acids  and  Bi-thio-acids  .          .          .          .          .          .280 

(6)  Acid  Amides. — Benzamide.     Benzanilide.     Hippuric  Acid. 

Its  Salts,  Esters,  and  Nitriles 280 

(7)  Acid  Hydrazides. — Benzoyl-hydrazin       ....      283 

(8)  Acidyl-azides. — Benzoyl-azide.     Hippurazide  .          .          .     284 


xii  CONTENTS 

PAGE 

(9)  Nitrites   of  the  Aromatic   Monocarboxylic   Acids, — Benzo- 
nitrile.     Alphyl  Cyanides.     Nitriles  of  the  Phenyl-fatty 
Acids.     Benzyl  Cyanide    ......      285 

(10)  Amido-haloids      ........      287 

(n)  Imido-chlorides     ........      287 

(12)  Phenyl-hydrazide  Imido-chlorides    .          .          .          .  .287 

(13)  Imido-ethers  of  the  Aromatic  Acids  ....      288 

(14)  Thiamides     of    the     Aromatic     Acids.  —  Thio-benzamide. 

Selenium-benzamide          .          .  .          .          .  .288 

(15)  Imido-thio-ethers  of  the  Aromatic  Carboxylic  Acids     .          .      289 

(16)  Amidines  of  the  Aromatic  Carboxylic  Acids. — Benzamidine. 

Phenyl-benzamidine  .          .          .  .          .          .289 

(17)  Dioxy-tetrazotic  Acids   .......      290 

(18)  Hydrazidins  or  Amidrazones. — Benzenyl-hydrazidin  .          .      291 

(19)  Nitrazones,  Nitrosazones,  and  Phenyl-azoximes  .          .      291 

(20)  Formazyl  Derivatives. — Formazyl-  and  Guanazyl-benzol    .      292 

(21)  Hydroxamic  Acids,  their  Ethers  and  Esters. — Benzo-hydro- 

xamic  Acid.     Tribenzoyl-hydroxylamme    .  .  .      293 

(22)  Haloids  of  Benzo-hydroxamic  Acid  ....      294 

(23)  Benzo-nitrolic  Acid        .......      294 

(24)  Benzo-nitrosolic  Acid     .......      295 

(25)  Nitrile  Oxides       .          .          .-         .  .          .          .          .      295 

(26)  Amidoximes. — Benzenyl-amidoxime         ....      295 

(27)  Hydrazidoximes    .          .  .          .          .  .          .  .296 

(28)  Hydroxamoximes  .          .          .          .          .          .          .297 

(29)  Ethyl-orthobenzoic  Esters         .          .          .  .          .          .297 

(30)  Benzo-trichlorides  and  -trifluorides    .....      297 

(31)  Orthobenzoic  Acid  Piperidide.          .....      297 

(c)  SUBSTITUTED  AROMATIC  MONOCARBOXYLIC  ACIDS  : 

(1)  Halogen  Benzole  Acids  .          .          .          .          .          .297 

(2)  lodoso-  and  lodo-benzoic  Acids        .          .          .  .  .298 

(3)  Nitro-monocarboxylic  Acids. — Nitro-benzoic  Acids.    Nitro- 

haloid  and  Nitro-phenyl-benzoic  Acids         .          .  .298 

(4)  Nitroso-monocarboxylic  Acids. — Nitroso-benzoic  Acid         .      300 

(5)  Hydroxylamino-carboxylic  Acids      .....      300 

(6)  Aromatic  Amido-monocarboxylic  Acids. — Anthranilic  Acid. 

Anthranile.  Acetyl-anthranile.  Dimolecular  Anhy- 
drides of  Anthranilic  Acid.  Kynuric  Acid.  Di- 
cyanamino  -  benzoyl.  Methyl  -  anthranilic  Acid. 
Hetero-ring  Formations  of  Anthranilic  Acid.  Arnido- 
benzoic  Acids.  Amido-phenyl-fatty  Acids.  Atroxindol  301 

(7)  Diazo-benzoic  Acids       .          .          .          .  .          .  .311 

(8)  Diazo-amido-benzoic  Acids      .          .  .          .  .          .311 

(9)  Diazo-imido-benzoic  Acids      .          .          .  .  .          .311 

(10)  Azoxy-benzoic  Acids      .          .          .  .          .          .          .311 

(u)  Azo-benzoic  Acids  .          .          .          .          .          .  .311 

(12)  Hydrazin-benzoic  Acids  ......      312 

(13)  Phosphine-benzoic  Acids         .          .  .          .  .          .312 

(14)  Sulpho-benzoic  Acids. — Saccharin  .          .          .          .          .312 

(d)  MONOHYDRIC     OXY-PHENYL-PARAFFIN     ALCOHOLS     AND     THEIR 

OXIDATION  PRODUCTS  : 

(1)  Monohydric     Oxy-phenyl-paraffin     Alcohols,      or     Phenyl 

Alcohols. — Saligenin.  Anisyl  Alcohol.  Pseudo-phenol 
Haloids.  Methylene-quinones.  Quinols  .  .  .314 

(2)  Aromatic  Oxy '-mono-aldehydes,  Phenol-aldehydes. — Salicylic 

Aldehyde.  Anisaldoxime.  Homologous  Monoxy- 
benzaldehydes.  Proto-catechuic  Aldehyde.  Vanillin. 
Piperonal.  Tri- and  Tetra-oxy-benzaldehydes  .  .321 

(3)  Phenol  Ketones     ........      325 

(4)  Phenol-monocarboxylic     Acids. — Salicylic    Acid.          Sali- 

cylates.  Anisic  Acid.  Oxy-toluic  and  Cresotinic 
Acids.  Oxy-mesitylenic  Acids.  Phloretic  Acid. 
Phloretin.  Vanillic  Acid.  Luteolin.  Catechin. 
Gentisinic,  Orsellinic,  and  Gallic  Acids.  Tannin  and 
Tannic  Acids  ........  327 


CONTENTS  xiii 

(e)    POLYHYDRIC  AROMATIC  ALCOHOLS  IN  WHICH  ONLY  ONE  HYDROXYL 
IS    PRESENT    IN    EACH     SlDE     CHAIN,     AND     THEIR     OXIDATION 

PRODUCTS  :  PAGE 

(1)  Di-    and    Trihydric    Aromatic    Alcohols. — Phthalyl    and 

Xylylene  Alcohols    .  -344 

(2)  Aldehyde  Alcohols          .......      345 

(3)  Aromatic  Dialdehydes    .          .  .      346 

(4)  Di-  and  Triketones         ...  ...      347 

(5)  Alcohol-carboxylic  Acids. — Phthalide.     Meconin         .          .      347 

(6)  Aldehyde  Acids. — Phthal-aldehyde  Acids.     Opianic  Acid.      350 

(7)  Ketone-carboxylic  Acids  .          .          .          .          .          -353 

(8)  Dicarboxylic     Acids.  —  Phthalic     Acids     and     Chlorides. 

Phthalylene  tetrachlorides.  Phthalimide.  Iso- 
phthalic  Acid.  Uvitinic  Acid.  Terephthalic  Acid. 
Aromatic  Dicarboxylic  Acids  with  one  molecule  of 
Carboxyl  in  the  Nucleus  and  in  the  Side  Chain.  Homo- 
phthalimide.  Aromatic  Dicarboxylic  Acids  having 
both  Carboxyls  in  different  Side  Groups  .  .  .  354 

(9)  Aldehydo-dicarboxylic  Acids  .....      364 
(10)   Tricarboxylic  Acids. — Trimellitic  and  Hemi-mellitic  Acids. 

Trimesic  Acid  .......      364 

(n)  Aromatic      Tetracarboxylic     Acids. — Pyro-mellitic     Acid. 

Prehnitic  and  Mellophanic  Acids         ....      365 

)   Aromatic  Pentacarboxy lie  Acid  .  .          .     365 

(13)  Aromatic  Hexacarboxylic   Acid. — Mellitic   and   Euchronic 

Acids      .........      366 

(/)  AROMATIC  POLY  ALCOHOLS  CONTAINING  MORE  THAN  ONE  HYDROXYL 
GROUP  IN  THE  SAME  SlDE  CHAIN,  AND  THEIR  OXIDATION 
PRODUCTS : 

(1)  Phenyl-glycols  and  Phenyl-glycerin. — Stycerine.        Haloid 

Esters  of  the  Phenyl-glycols.  Dihaloids.  Ephedrin. 
Adrenalin  .  .....  367 

(2)  Phenyl-alcohol  Aldehydes. — Phenyl-tetrose        .          .          .      370 

(3)  Phenyl   Ketols. — Aceto-phenone  Alcohol.       Amido-aceto- 

phenone  ........      371 

(4)  Phenyl- aldehyde  Ketones.     Phenyl-glyoxal        .          .          .      373 

(5)  Phenyl-paraffin    Diketones. — Benzoyl-acetone.      Tri-    and 

Tetraketones  .          .          .          .          .          .          .          .374 

(6)  Phenyl-paraffin    Alcohol    Acids. — Monoxy-alcohol    Acids. 

Mandelic  Acids.  Dioxindol.  Atro-lactonic  Acid. 
Tropic  Acid.  Phenyl-alanin.  Tyrosin.  Dioxy- 
alcohol  Acids.  Styceric  Acid.  Trioxy-alcohol  Acids.  376 

(7)  Phenyl-paraffin-aldehyde-carboxylic  Acids          .          .          .      386 

(8)  Phenyl  -  paraffin  -  ketone  -  carboxylic     A  cids. — Ketone  -  car- 

boxylic  Acids.  Phenyl  -  glyoxylic  Acid.  Isatin. 
Anthroxanic  Acid.  Cumarandione.  Thio-isatin. 
Homologous  Phenyl-glycol  Acids.  Phenyl-paraffin 
j3-ketone-carboxylic  Acids.  Benzoyl-acetic  Acid  .  387 

(9)  Phenyl-alcohol-ketone-carboxylic  Acids      ....      394 
(10)  Diketone-carboxylic   Acids. — Quinisatin.        Benzoyl-pyro- 

racemic  Acid  .          .          .  .          .          .          .  395 

(n)  Phenyl-paraffin-dicarboxylic  Acids. — Phenyl-malonic  Acid. 

Phenyl-  and  Benzyl-succinic  Acids     ....      396 

(12)  Phenyl-alcohol-dicarboxylic  Acids. — Phenyl-   and   Benzyl- 

malic  Acids     ........  397 

(13)  Phenyl-ketone-dicarboxylic  Acids. — Benzoyl-malonic  Ester  399 

(14)  Phenyl-oxy-ketone-dicarboxylic  Acids         ....  400 

(15)  Phenyl-paraffin-tricarboxylic  Acids  ....  400 

(16)  Phenyl- keto-tricarboxy lie  Acids        .....  400 

(17)  Polyketo-poly  carboxylic  Acids          .....  400 

(18)  Phenylene-oxy-dicarboxylic  Acids. — Carbo-mandelic   Acid 


(19 
20 

21 


Acetonyl-phthalide 
Phenylene-ketone-dicarboxylic  Acids 
Tri-  and  Tetracarboxylic  Acids 
Oxy-tri-,  -tetra-,  and  -penta-carboxylic  Acids 


(22)   Ketone-tricarboxylic  Acids 


401 
402 
402 
403 
403 


xiv  CONTENTS 

(g)    MONONUCLEAR      AROMATIC      SUBSTANCES      WITH       UNSATURATED 

SIDE  CHAINS  :  PAGE 

la.  Olefin-benzenes. — Styrol          ......      403 

16.  Acetylene  Benzenes. — Phenyl-acetylene    .  .407 

Ic.  Diolefin-benzols     .          .          .  .  .          »          .  .408 

Id.  Olefin-acetylene-benzols  ......      408 

Ila.  Ole fin-phenols. — (A)  Olefin-monoxy-benzols,  Vinyl-phenol, 
Chavicol,  Anethol.     (B)  Olefin-dioxy-benzols,  Eugenol, 
Safrol.     (C)   Olefin-trioxy-benzols,   Asarone,   Elemicin, 
Myristicin.     (D)  Olefin-tetraoxy-benzols,  Apiol   .          .      408 
116.  Acetyl-anisol  and  Phenetol      .          .          .  .          .  .      413 

Ilia.  Phenyl-olefin  Alcohols  and  their  Oxidation  Products. — (la) 
Phenyl-olefin  Alcohols,    Styrone.     (16)    Oxy-phenyl- 
olefin  Alcohols,  Coniferyl  Alcohol,     (ic)  Phenyl-acety- 
lene Alcohols.     (2 a)  Phenyl-olefin  Alcohols,  Cinnamic 
Aldehyde.      (26)  Oxy  -  phenyl  -  olefin    Aldehydes.      (3) 
Phenyl-diolefin  Aldehydes.    (4a)  Phenyl-olefin  Ketones. 
(5)  Phenyl-acetylene  Aldehydes.     (6)  Phenyl-acetylene 
Ketones.      (7)  Phenyl-diolefin    Ketones.     (8)   Phenyl  - 
olefin  -  carboxylic  Acids,  Cinnamic  Acid  and  its  Deri- 
vatives, Haloid  Cinnamic  Acids,  Nitro-cinnamic  Acids, 
Amido  -  cinnamic    Acids,    Hydrazin  -  cinnamic    Acids, 
Sulpho-cinnamic  Acids,  Homologous  Cinnamic  Acids, 
Atropic  Acid  ......  -413 

Illb.   Oxy-phenyl-olefin-carboxylic   Acids. — (A)   Monoxy-phenyl- 
olefin-carboxylic  Acids,   Cumarin,  Cumaroxime.       (B) 
Dioxy-phenyl-olefin-carboxylic    Acids,     Caffeic     Acid, 
Umbelliferone.     (C)  Trioxy-cinnamic  Acids.     (D)  Tetra- 
oxy-cinnamic  Acids,  Fraxetin.      (E)  Phenyl-acetylene- 
carboxylic  Acids.    (F)  Phenyl-diolefin-carboxylic  Acids, 
Piperic  Acid    .....  .     426 

IV.  Compounds  which  may  be  considered  as  Oxidation  Pro- 
ducts of  Mononuclear  Aromatic  Poly  alcohols  with  Un- 
saturated  Side  Chains. — (i)  Phenylene  -  oxy  -  olefin  - 
carboxylic  Acids,  Iso-cumarin,  Iso-carbo-styril,  Ber- 
gaptene.  (2)  Phenylene  -  aldehyde  -  carboxylic  Acids. 
(3)  Phenylene-dicarboxylic  Acids.  (4)  Phenyl-olefin- 
ketols.  (5)Phenyl-oxy-olefin-carboxylic  Acids.  (6) 
Phenyl-oxy-diolefin-carboxylic  Acids.  (7)  Phenyl- 
dioxy-olefin-carboxylic  Acids.  (8)  Phenyl-olefin-a- 
keto- carboxylic  Acids.  (9)  Phenyl-diolefin-a-keto-car- 
boxylic  Acids.  (10)  Phenyl-olefin- /?-ketone-carboxylic 
Acids.  (n)  Phenyl-olefin-  and  -diolefin-y-ketone-car- 
boxylic  Acids.  (12)  Phenyl-olefin-dicarboxylic  Acids. 

(13)  Phenyl-diolefin-dicarboxylic  Acids,  Benzal-malonic 
Acid,    Cyano-cinnamic   Acid,    Cinnamylidene  -  malonic 
Acid,   Phenyl-malei'c  Acid,  Cinnamenyl-glutaric  Acid. 

(14)  Phenyl-olefin-tricarboxylic    Acids.     (15)   Phenyl- 
oxy-olefin-dicarboxylic    Acids.       (16)     Phenylene-oxy- 
olefm-dicarboxylic  Acids.      (17)    Phenylene-oxy-olefin- 
tricarboxylic  Acids  .          .  .  .          .          .          .434 

B.    HYDRO-AROMATIC   SUBSTANCES   WITH    SINGLE 

NUCLEUS,    HYDRO-BENZOL   DERIVATIVES 
i.     Hydro-aromatic  Hydrocarbons   ........     443 

ia.  Cyclo-hexanes,   Hexahydro-benzols,   Naphthenes. — Halogen   Substitution 

Products  of  the  Hexahydro-benzols        ....  .      444 

i  b.  Cyclo-hexenes,  Tetrahydro-benzols,  Naphthylenes. — Methyl- and  Dimethyl- 

cyclo-hexene       .          .          .          .          .          .          .          ...  447 


ic.  Dihydro-benzols,  Cyclo-hexadienes       ...... 

2a.  Ring  Alcohols  of  the  Hydro-aromatic  Carbons. — Cyclo-hexanol.     Quinite 
Quercite.     Inosite.     Phenose         ...... 

26.  Ring  Alcohols  of  Tetrahydro -benzol       ...... 

2c.  Extra-cyclic  Hydro-aromatic  Alcohols  ..... 

2d.  Sulphur  Derivatives  of  Hydro-aromatic  Alcohols. 

$a.  Ring  Amines  of  Hydro-aromatic  Hydrocarbons. — Amido-cyclo-hexane 


449 


454 
454 
455 
455 


CONTENTS  xv 

PAGE 

36.  Extra-cyclic  Hydro-aromatic  Amines  .  ...     456 

4.  Ring-ketones  of   the    Hydro-aromatic    Hydrocarbons. — Ring-ketones    of 

Hexahydro-benzol.  Ring-ketols.  Dihydro-resorcin.  Tetrahydro- 
quinone.  Ring-ketones.  Tetrahydro-benzol.  Ring-ketones  of  the 
Dihydro-benzols  .........  456 

5.  Hydro-aromatic  Aldehydes. — Cyclo-citral     ......     466 

6.  Extra-cyclic  Hydro -aromatic  Ketones. — Irone.     lonone  .          .          .     467 

7.  Hydro-aromatic  Carboxylic  Acids. — (i)  Hydro-aromatic  monocarboxylic 

Acids,  Hexahydro-benzoic  Acids,  Tetrahydro-benzoic  Acids,  Di- 
hydro-benzoic  Acids,  Aliphatic  Acids,  Phenyl-fatty  Acids,  Hexa- 
hydro-oxy-benzoic  Acids,  Quinic  Acid,  Shikimic  Acid,  Keto-hydro- 
monocarboxylic  Acid.  (2)  Hydro-aromatic  Dicarboxylic  Acids. 
Hexahydro-dicarboxylic  Acids,  Hexahydro-terephthalic  Acids.  Tetra- 
hydro-dicarboxylic  Acids,  Dihydro-dicarboxylic  Acids,  Oxy-  and 
Keto-hydro-benzol-dicarboxylic  Acids,  Succino-succinic  Acid.  (3) 
Hydro-benzol-tricarboxylic  Acids.  (4)  Hydro-benzol-tetracarboxylic 
Acid  ...........  469 

TERPENES    ........  ...     484 

A.  Olefinic  Terpene  Group. — (i)  Olefinic  Terpenes,  Myrcene,  Ocimene, 

Isoprene.  (2)  Olefinic  Terpene  Alcohols,  Geraniol,  Nerol, 
Linalool.  (3)  Olefinic  Terpene  Aldehydes,  Citronellal,  Citral. 
(4)  Olefinic  Terpene  Acids,  Geranic  Acid  .  .  .  .487 

B.  Monocyclic     Terpene    or    Menthane    Group. — (i)  Limonene    and 

Dipentene  Group,  Terpinolene,  Terpinene,  Phellandrene.  (2) 
Alcohols  of  the  Monocyclic  Terpene  or  Menthane  Group,  Mon- 
acid  Menthane  Alcohols,  Secondary  Menthols,  Tertiary 
Menthols,  Diacid  Alcohols,  Terpin,  Cineol,  Terra-acid  Methane 
Alcohols,  Terpineol-menthadiene  Alcohols.  (3)  Bases  of  the 
Monocyclic  Terpene  or  Menthane  Group.  (4)  Ring-ketones 
of  the  Monocyclic  Terpene  or  Menthane  Group,  Menthone, 
Carvenone,  Pulegon,  Carvone  .  .  .  .  .  .491 

C.  Dicyclic  Terpene  Group  : 

I.  Sabinane  or  Tanacetane  Group. — Thujene.    Sabinane  .     510 

II.  Carane  Group. — Carone.     Eucarvone        .          .          .          -514 

III.  Pinane  Group. — Pinene.     Turpentine  Oil.     Terebinic  Acid. 

Myrtenol.     Pinol      .          .          .  .          .  -515 

IV.  Camphane    Group. — Camphene.      Bornylene.       Fenchene. 

Monacid  Alcohols.  Santene.  Borneol.  Iso-borneol. 
Amines.  Ketones.  Camphor.  Campholic  Acid. 
Azo-camphor.  Camphenone.  Camphanic  Acid. 
Lauronilic  Acid.  Apo-camphoric  Acid.  Fenchone  .  522 

D.  Sesqui-terpene  and  Poly-terpene  Group. — Cadinene.     Santalol        .      546 
Resins. — Caoutchouc       ........     548 

C.     AROMATIC   HYDROCARBONS   CONTAINING 
SEVERAL  NUCLEI 

A.    PHENYL-BENZOLS  AND  POLYPHENYL-FATTY  HYDROCARBONS        .          .     549 
I.  Phenyl-benzol  Group. — Diphenyl  Group.       Benzidin.       Benzidin 
Dyes.      Oxy-,  Monoxy-,  and  Dioxy-biphenyls.      Quinones  of 
the  Diphenyl  Series.    Ccerulignone.    Diphenic  Acid.   Diphenyl- 
benzol.     Tri-  and  Tetra-phenyl-benzol  ....     550 

II.  Benzyl-benzol    Group. — (i)     Hydrocarbons,     Diphenyl-methanes. 
(2)  Alcohols,  Benzo-hydrols.     (3)   Ketones,   Benzo-phenones, 
Halogen     Derivatives,     Phenyl-anthranile,     Diamido-benzo- 
phenones,  Oxy-benzo-phenones,  Cotoin.      (4)  Carboxylic  Acids 
of  the  Diphenyl-methane  Group,  Diphenyl-methane-carboxylic 
.Acids,    Benzo-hydrol-carboxylic    Acids,    Benzo-phenone-car- 
boxylic  Acids    .........      562 

III.  Triphenyl-methane  Group. — (i)  Hydrocarbons,  Triphenyl-methane, 
Nitro- substitution  Products.  (2)  Carbinols,  Fuchsine, 
Rosanilin,  Methyl-violet,  Phenylated  Rosanilins.  (3)  Phenol 
Derivatives,  Monoxy- triphenyl-methanes  .  .  .  -576 
IIlA.  Phenyl  Derivatives  of  Triphenyl-carbinol . — Triphenyl-carbinols, 
hydroxylated  in  a  Benzene  Nucleus.  Benzems.  Rosamines. 
Aurins  and  Rosolic  Acids.  Eupittonic  Acid.  Triphenyl- 


xvi  CONTENTS 

PAGE 

methane-carboxylic  Acid.    Carboxyl  Derivatives  of  Triphenyl- 
carbinol    Phthalides.       Carboxyl    Derivatives    of    the    Oxy- 
triphenyl-carbinols.     Phthaleins.  Fluorane.  Phloxin. 

Rhodamins        .........     590 

IIlB.  Phenyl-bis-diphenyl-methane    .......      602 

IIIc.  Tetraphenyl-methane        ........      602 

IV.  Homologous  Di-  and  Poly-phenyl-paraffins. — (a)  Gem-diphenyl- 
paraffins  and  their  Derivatives,  Diphenyl- ethane,  Diphenyl- 
ketene,  Benzilic  Acid,  Triphenyl- acetic  Acid.  (6)  Syrn. 
Diphenyl-ethane  Group,  Dibenzyl,  Stilbene,  Tolane,  Alcohol 
and  Ketone  Derivatives  of  Dibenzyl,  Benzoin,  Benzile,  Alcohol 
Derivatives  of  Stilbene,  Carboxylic  Acids  of  the  Dibenzyl 
Group,  Dibenzyl-carboxylic  Acid,  (c)  Tri-,  Tetra-,  Penta-,  and 
Hexaphenyl  Group,  Benzo-pinacone,  Hexaphenyl-ethane. 
(d)  Diphenyl-propane  Group,  Dibenzyl-ketone,  Dypnone. 
Dibenzol-methane-carboxylic  Acids.  (e)  Diphenyl-butane 
Group,  Diphenacyl,  Bidesyl,  Diphenyl-tetra-ketone,  Carboxylic 
Acids,  Vulpic  Acid.  (/)  Diphenyl-pentane  Group,  Di- 
benzylidene-acetone,  Benzamarone-carboxyl  Derivatives,  (g) 
Diphenyl-hexene  Group,  and  Higher  Homologues .  .  .  603 

B.    CONDENSED  NUCLEI        .........     640 

1.  Indene   and   Hydrindene   Group.  —  Indene    and   its   derivatives. 

Hydrindene.     Diketo-hydrindene.     Indacene         .  .  .      643 

2.  Naphthalene  Group. — Constitution.     Isomerisms.     Ring   Forma- 

tions.    Decompositions.     Homologues  ....     650 

(i)  Halogen  Naphthalenes.      (2)  Nitro-naphthalenes.     (3) 
Nitroso-naphthalenes.         (4)     Amido-naphthalenes, 
Naphthalamines,       Naphthylene  -  diamines.          (5) 
Diazo-  and  Azo-compounds.       (6)  Hydrazin  Com- 
pounds.     (7)  Sulphonic  Acids.       (8)  Naphthalene- 
sulphonic   Acids.     (9)    Naphthols,  Nitro-,  Amido-, 
and     Azo-naphthols,      Naphthol-sulphonic    Acids, 
Naphtho-sultone,  Thio-naphthols.       (10)  Naphtho- 
quinones,    Juglone,    Nitrogen    Derivatives    of    the 
Naphtho-quinones        .          .          .  .          .          .658 

(n)  Alcohols  of  the  Naphthalene  Series  and  their  Oxidation 
Products. — (A)  Alcohols.  (B)  Aldehydes  and 
Ketones.  (C)  Naphthalene-monocarboxylic  Acids. 
(D)  Naphthalene  Di-  and  Poly-carboxylic  Acids  .  676 

(12)  Di-  and  Trinaphthyl-methane  Derivatives  .          .          .      681 

(13)  Acenaphthene  .......      682 

(14)  Hydro-naphthalene     Derivatives.  —  (A)    Dihydro-deri- 

vatives.      (B)   Tetrahydro-derivatives.      (C)   Hexa-, 
Octo-,  Deca-,  and  Dodeca-hydro-naphthalenes          .      683 

3.  Phenanthrene   Group. — Halogen   Nitro-,  Oxy-,  and  Amido-Phen- 

anthrenes.  Carboxylic  Acids.  Hydro  -  phenanthrenes. 
Betene.  Chrysene.  Picene.  Pyrene.  Triphenylene  .  .  687 

4.  Fluorene    Group. — Fluorene.     Retene,     Chrysene,     and     Picene. 

Fluorene.  Phenyl-fluorene.  Diphenylene-ketone.  Fluor- 
enone.  Fluoranthene  .......  695 

5.  Anthracene    Group. — Anthracene.      Alkylic    Anthracenes.       Sub- 

stituted Anthracenes.  Oxy-anthracenes.  Anthranol. 
Anthrone.  Anthra-hydroquinone.  Oxanthrone.  Carboxylic 
Acids.  Hydro-anthracene.  Dihydro-anthranol.  Anthra- 
quinone.  Alizarin.  Purpurin.  Emodin.  Dianthraquinoyl. 
Pyran  throne.  Benzanthrone  .  .  .  .  .  .710 

6.  Glycosides    or    Glucosides    and    Pentosides. — Sinigrin.       Sinalbin. 

Arbutin.  Salicin.  Populin.  Gem.  Gaultherin.  Coni- 
ferin.  Syringin.  Phlorizin.  /Esculin.  Daphnin.  Fraxin. 
Indin.  Saponarin.  Digitalin.  Saponin.  Convolvulin. 
Jalapin.  Polygonin.  Amygdalin.  Naringin.  Hesperidin. 
Quercitrin.  Frangulin.  Aloin  .  .  .  .  .  .719 

7.  Bitter    Principles. — Cantharidin.          Anemonin.  Picro-toxin. 

Picrotin.     Santonin.     Artemisin  .....      724 

8.  Natural  Dyes. — Brasilin.    Haematoxylin.     Carthamin.     Curcumin. 

Lichen  Dyes.     Carminic  Acid.     Kermessic  Acid   .          .          .     725 


A  TEXT-BOOK 

OF 

ORGANIC    CHEMISTRY 


II.    CARBOCYCLIC    COMPOUNDS 


THE  methane  derivatives,  or  acyclic  carbon  compounds,  with  open 
carbon  chains,  dealt  with  in  the  first  volume  of  this  work,  are  here 
followed  by  organic  compounds  with  closed  carbon  chains,  or  carbon 
rings,  and  these  compounds  I  call  by  the  name  of  Carbocyclic  Com- 
pounds. In  contrast  with  these  we  have,  e.g.,  the  azocyclic  compounds 
with  a  ring  consisting  only  of  nitrogen  atoms,  such  as  nitrogen  hydride, 
and  its  derivatives.  The  carbocyclic  compounds  are  also  called  isocyclic 
compounds,  but  the  latter  expression  is  too  comprehensive,  since  it 
denotes  compounds  containing  a  ring  consisting  of  a  number  of  atoms, 
of  any  element.  In  contradistinction  to  isocyclic  compounds  we  have 
the  heterocyclic  compounds,  in  which  the  atoms  of  several  different 
elements  take  part  in  the  formation  of  the  ring. 

The  fundamental  carbocyclic  hydrocarbons  are  those  with  a  carbon 
ring  consisting  of  from  three  to  nine  methylene  groups.  They  are 
isomeric  with  the  olefins,  with  an  equal  number  of  carbon  atoms. 
They  are  designated  either  as  polymethylenes,  in  accordance  with  the 
number  of  methylene  groups  which  they  contain  ;  or  by  prefixing  an 
"  R  "  or  "  R-"  to  the  names  of  the  normal  olefins  with  which  they 
are  isomeric  ("  ring  olefins  ")  ;  or,  according  to  the  Geneva  resolu- 
tions, by  the  names  of  the  normal  paraffins  containing  an  equal  number 
of  carbon  atoms  with  the  word  "  cyclo-"  prefixed  (cyclo-paraffins). 
The  first  and  third  of  these  designations  are  to  be  preferred. 

/-TT     . 

Trimethylene  [Cyclopropane]  2  ;CH2 

Crl2/ 

/"*  TT  f"*TT 

Tetramethylene  [Cyclobutane] 

C±12  —  C.H2 

/-"TT     _  C~H     \. 

Pentamethylene  [Cyclopentane]    f  2  >CH2 

CH2  —  CH2/ 


Hexamethylene  [Cyclohexane]      cH—CUCll 
Heptamethylene  [Cycloheptane] 
Octomethylene  [Cyclooctane] 
Nonomethylene  [Cyclononane] 


VOL.  II. 


2  ORGANIC  CHEMISTRY 

Hexamethylene  is  also  called  hexahydrobenzol,  and  heptamethylene, 
suberane.  For  the  nomenclature  of  ring  substances  see  also  B.  29,  587. 

As  the  paraffins  are  followed  by  olefins  and  diolefins,  so  the  cyclo- 
paraffins  are  followed  by  cyclo-olefin,  cyclo-diolefin,  and  cyclo- 
triolefin. 

Among  the  carbocyclic  structures  a  special  significance  attaches  to 
benzol  (benzene),  the  fundamental  hydrocarbon  of  the  so-called 
aromatic  substances  or  benzol  derivatives,  the  most  numerous  class 
of  organic  compounds.  If,  in  accordance  with  A.  Kekule,  we  assume 
in  benzol  a  ring  of  six  carbon  atoms  linked  together  in  alternate  single 
and  double  linking  —  an  assumption  which  the  author  prefers  —  benzol 
is  a  cyclo»triolefin  : 


Benzol  [Cyclohexatri6n]  C 

\CH  =CH 

By  the  addition  of  hydrogen  it  is  possible  to  convert  benzol  into 
hexahydrobenzol,  hexamethylene,  and  cyclo-hexane.  A  constantly 
increasing  number  of  transformation  products  of  aromatic  compounds 
are  becoming  known,  which  can  be  referred  to  dihydro-  or  tetrahydro- 
benzol  (cyclo-hexadiene  and  cyclo-hexene),  and  which,  together  with 
the  hexamethylene  or  hexahydrobenzol  derivatives,  are  termed  "  hydro- 
aromatic  compounds."  To  these  belong  many  natural  products, 
especially  those  of  the  terpene  and  camphor  series.  If  this 
system  were  rigidly  followed,  every  cyclo-paraffin  system  would  be 
associated  with  the  corresponding  cyclo-olefin  system  having  the  same 
number  of  carbon  atoms.  But  the  treatment  of  the  hydro-aromatic 
substances  presupposes  a  knowledge  of  the  aromatic  substances,  to 
such  an  extent  that  it  is  better  to  deal  first  with  the  latter.  We  there- 
fore treat  first  of  the  tri-,  tetra-,  penta-,  hepta-,  octo-,  and  nono- 
carbocyclic  compounds,  and  afterwards  of  the  hexacarbocyclic 
compounds. 

In  many  ways  the  aromatic  substances  show  a  peculiar  behaviour, 
different  from  that  of  the  aliphatic  compounds.  But  the  hydro- 
aromatic  compounds,  as  well  as  the  other  known  polycarbocyclic 
compounds,  approach  in  their  chemical  properties  the  saturated 
aliphatic  substances,  or  the  unsaturated  ones,  if  there  are  any  double- 
linked  pairs  of  carbon  atoms  in  the  ring.  These  compounds  are  there- 
fore called  aliphatic  cyclic,  or  alicyclic  saturated,  and  unsaturated, 
compounds,  to  distinguish  them  from  the  aromatic  compounds 
(B.  22,  769). 

The  study  of  the  carbocyclic  compounds  has  shown  that  the  tri- 
and  tetramethylene  ring  is  more  easily  split  than  the  more  stable 
pentamethylene  or  hexamethylene  ring,  while  hepta-  and  octomethy- 
lene  rings  are  formed  with  greater  difficulty,  and  can  usually  be  easily 
transformed  into  rings  of  a  smaller  number  of  carbon  atoms. 

We  have  met  similar  phenomena  in  the  formation  of  some  hetero- 
cyclic  derivatives  of  aliphatic  substances,  e.g.  the  lactones,  lactames, 
and  dicarboxylic  anhydrides  (Vol.  I.).  In  the  case  of  the  oxy-acids  we 
indicated  a  scheme  of  the  space-configuration  of  carbon  chains, 
designed  to  explain  the  rare  formation  of  a-  and  j3-lactones,  in  com- 
parison with  the  ease  with  which  y-  and  8-lactones  are  produced.  An 
attempt  at  explaining  the  different  stabilities  of  the  tri-,  tetra-,  penta-, 


METHODS   OF   RING  FORMATION  3 

and  hexamethylene  rings  is  made  in  the  tension  theory  of  A.  v. 
Baeyer  (B.  18,  2278;  23,  1275).  This  theory  proceeds  from  the 
following  assumption  : — "  The  four  valencies  of  the  carbon  atom  act 
in  directions  joining  the  centre  of  a  sphere  with  the  corners  of  an 
inscribed  regular  tetrahedron,  and  therefore  form  angles  of  109°  28' 
with  each  other."  These  four  lines  are  called  axes. 

"The  direction  of  attraction  can  undergo  a  deflection,  but  this  is 
accompanied  by  a  tension,  increasing  with  the  amount  of  the  latter." 
The  assumption  of  valency  forces  acting  at  an  angle  is  excluded,  the 
amount  of  deflection  being  proportional  to  the  tension.  "  In  ethylene 
the  direction  of  attraction  is  equally  deflected,  for  both  valencies  of 
each  carbon  atom,  until  the  directions  have  become  parallel.  In 
ethylene  the  angle  of  deflection  is  £(109°  28') =54°  44'.  In  trimethy- 
lene,  which  may  be  figured  as  an  equilateral  triangle,  the  angle  between 
the  axes  must  be  60°,  and  the  deflection  of  each  must  be  4(109°  28'— 60°) 

=24°  44'." 

In  the  same  way  we  obtain  the  following  deflections  : 

Tetramethylene  1(109°  28'—  9°°)  =  9°  44' 
Pentamethylene  ((109°  28'— 108°)  =  o°  44' 
Hexamethylene  {(109°  28'— 120°)  =—5°  16' 
Heptamethylene  |(iO9°  28'— 128°  34')  =  —  9°  33' 
Octomethylene  £(109°  28'— 135°)  =—12°  51' 
Nonomethylene  £(109°  28'— 140°)  =—15°  16' 

This  supposes,  of  course,  that  the  carbon  atoms  all  lie  in  the  same 
plane,  viz.  the  plane  of  the  ring. 

In  dimethylene  or  ethylene  the  greatest  deflection  of  the  direction 
of  action  of  both  valencies  has  taken  place.  It  has  the  greatest  tension 
and  is  the  loosest  ring,  which  is  easily  split  up  by  chlorine,  bromine, 
hydrobromic  acid,  and  iodine.  Trimethylene  reacts  with  much  greater 
difficulty.  Tetra-,  penta-,  and  hexamethylene  rings  no  longer  behave 
like  unsaturated  compounds,  and  are  very  stable  in  the  presence  of 
halogens,  hydrohalogen  acids,  and  potassium  permanganate.  In 
harmony  with  these  views,  the  determination  of  the  heats  of  combustion 
of  the  simplest  cyclo-paraffins  showed  a  considerable  decrease  from 
tri-  to  hexamethylene  (B.  25,  496).  According  to  Baeyer's  tension 
theory,  the  pentamethylene  ring  should  form  even  more  easily  than  the 
hexamethylene  ring — a  conclusion  which  led  to  successful  attempts  to 
prepare  pentamethylene  derivatives  (B.  28,  655). 

METHODS  OF  RING  FORMATION  IN  CYCLO-PARAFFIN  BODIES. 

Special  importance  is  attached  to  the  methods  by  which  open 
carbon  chains  are  converted  into  closed  carbon  chains.  In  accordance 
with  the  definition  of  nuclear  syntheses  as  reactions  in  which  previously 
unlinked  carbon  atoms  are  linked  together  (Vol.  I.),  every  transforma- 
tion of  an  open  carbon  chain  into  a  closed  one  must  be  regarded  as  a 
nuclear  synthesis.  And  indeed  it  is  by  well-known  nuclear  synthesis 
methods  applied  to  suitable  aliphatic  substances  that  the  closing  of 
rings  with  formation  of  cyclo-paraffin  bodies  has  been  carried  out.  The 
facts  in  question,  already  mentioned  in  divers  places  in  Vol.  I.,  con- 
stitute the  transition  reactions  joining  the  class  of  paraffins  with  that 


4  ORGANIC  CHEMISTRY 

of  cyclo-paraffins.  The  most  important  items  may  be  briefly 
enumerated. 

1.  Cyelo-paraffins  themselves  are  produced  by  the  action  of  sodium 
or   zinc   upon   dibromo-substituted   paraffins,   the  hydrobromic   acid 
esters  of  the  glycols  : 

/CH2Br     CH2—  CHBr.CH3     CH  /CH2—  CHBrCH3     CH2—  CH2—  CH2Br 
2\CH2B     |  CH2—  CH2Br  '    2\CH2—  CH2Br         |  CH2—  CH2—  CH2Br 

I  rH'/CH2       I  CH2—  CHCH3         !  CH  /CH2—  CHCH3       I  CH2—  CH2—  CH2 
2\CH,          CH2—  CH2  2\CH2—  CH2  CH2—  CH2—  CH2 

a-Monobromine  derivatives  of  the  glutaric  acid  series  yield  tri- 
methylene-carboxylic  acids  even  when  treated  with  alcoholic  potash. 

2.  Intramolecular  pinacone  formation.  —  Besides  secondary  alcohols, 
the  reduction  of  the  ketones  yields  ditertiary  glycols,  the  pinacones. 
On  reducing  diacetyl-pentane  we  obtain  besides  an  aliphatic  disecondary 
glycol  a  ditertiary  glycol,  a  cyclic  pinacone  : 

CH  /CH2—  CH2—  CH(OH)CH3 

rH  /CH2—  CH2—  CO.CH3_  2\CH2—  CH2—  CH(OH)CH3 

2\CHa—  CH2—  CO.CH3          __  ^  CH  /CH2—  CH2—  C(OH)CH3 

2\CH2—  CH2—  C(OH)CH3 

3.  Cyclic  syntheses  with  the  aid  of  metallorganic  compounds.  —  By 

treating  the  di-magnesium  compound  of  the  i,  5-dibromo-pentane  with 
acetic  ester  we  obtain  methyl-cyclo-hexanol.  Carbonic  acid  reacts 
with  the  formation  of  cyclo-hexanone  : 

CH2\rn   co2         /CH2.CH2.MgBr  CH.COOCH,  /CH2—  CH2\r/OH 

'Ha\CH2.CH2.MgBr~  'H2\CH2_CH2/   '\CH3 


The  synthesis  of  a  tertiary  alcohol  from  a  magnesium  alkyl  iodide 
and  a  ketone  proceeds  intramolecularly  in  the  action  of  magnesium 
upon  8-aceto-butyl  iodide  : 

CH2.CH2I  Mg       CH2.CH2\c/OMgI 

CH2.CH2.COCH3  "*  CH2.CH2/  '\CH3 

4«.  Intramolecular  aceto-acetic  ester  condensation.  —  When  sodium 
acts  upon  adipinic  acid  ester  there  is  intramolecular  condensation  cor- 
responding to  the  formation  of  acetic  ester,  and  a  cyclic  /3-ketone- 
carboxylic  ester  is  formed  : 

CH2—  CH2—  COOC2H5  _       CH2—  CH—  --  COOC2H5 
CHa—  CH2—  COOC2H6     —  caH6OH~"  CH2—  CH2/CO 

The  same  behaviour  is  shown  by  the  esters  of  the  pimelinic  acids, 
which  yield  j8-ketone  acid  esters  with  six-membered  ring  chains. 

46.  Oxalo-acetic  ester  condensation.  —  The  action  of  oxalic  ester 
and  glutaric  acid  ester  upon  sodium  ethylate  produces  diketo-penta- 
methylene-carboxylic  ester  : 

CH  /CH2C02C2H5     COOC2H5  _  >  CH  /CH(COaC2H5)—  CO 
2  \CH2CO2C2H5     COOC2H6  2\CH(CO2C2H5)—  CO 

Similar  reactions  are  shown  by  /2-substituted  glutaric  acid  ester, 
acetone-dicarboxylic  acid  ester,  methyl-ethyl-ketone,  dibenzyl-ketone, 
etc.,  with  oxalic  ester  and  sodium  ethylate. 


METHODS   OF   RING  FORMATION  5 

40.  Intramolecular    formation    of     j9-diketones.  —  y-acetyl-butyric 
acid  ester  is  condensed  by  sodium  ethylate  to  diketo-hexamethylene  ; 

CH2—  CO—  CH3  __  >   CH2—  CO—  CH2 

CH2—  CH2—  COOC2H5  CH2—  CH2-CO 

With  the  same  treatment  the  €-  and  £-ketonic  acid  esters  yield  extra- 
cyclic  /2-diketones  of  the  pentamethylene  and  hexamethylene  series. 

5.  Cyclic  syntheses  with  malonic  acid  esters,  acetic  acid  esters,  etc. 
—Through  the  action  of  alkylene  bromides  upon  sodium  malonic  acid 
esters  we  obtain  cyclo-paraffin  acid  esters  (W.  H.  Perkin,  jun.). 

The  reaction  takes  place  in  three  phases  : 

CH^  +  NaHClCOAHJ.    _  CH2CH(C0!C,H6)2  +  NaBr 

CH2Br  CH2Br 

CH2.CH(CO2C2H5)2+NaHC(CO2C2H6)2    =  CH2.CNa(CO2C2H5)2 
CH2Br  —NaBr    CH*Br  +CH8(CO2C2H5)2 


CH,—  CH,Br     2NaHC(CO,C.H.), 
CH!-CH,Br  -  •* 

By  introducing  the  bromination  products  of  olefin-mono-  and  olefin- 
dicarboxylic  acid  esters  in  the  place  of  alkylene  bromides,  this  reaction 
has  been  used  for  preparing  numerous  trimethylene  derivatives. 
Cyano-acetic  ester  behaves  like  malonic  ester  (C.  1899,  II.  36,  824). 

If  sodium    aceto-acetic    ester  acts   upon    1,  4-dibromo-n-pentane, 
i,  2-methyl-acetyl-pentamethylene-carboxylic  acid  ester  is  produced: 


CHNa.CO2C2H5  _CH2.CH  \     /CO2C2HS     CH2CO2C2H5 
CH2.CH2.Br      "r2CO.CH3  =CH2.CH2/    \COCH3    +COCH3      +2NaBr 


From  i,  5-dibromo-pentane  we  correspondingly  obtain  a-acetyl-hexa- 
methylene-carboxylic  ester  (B.  21,  742  ;  40,  3943). 

6.  From  the  di-sodium  compounds  of  alkylene-dimalonic   esters 
iodine  or  bromine  extracts  the  sodium  with  the  formation  of  a  ring, 
just  as  iodine  converts  the  sodium  aceto-acetic  ester  into  diaceto- 
succinic  ester,  and  mono-sodium  malonic  ester  into  dimalonic  ester. 
From  the  cyclo-paraffin-tetracarboxyUc  acids  thus  produced  we  may 
obtain  cyclo-paramn-dicarboxylic  acids  by  splitting  off  2CO2  (W.  H. 
Perkin,  jun.). 

Tri,  tetra-,  penta-,  hepta-,  octo-,  and  nonocarbocyclic  compounds  : 

CH  /CNa(C02C2H5)2_                  H  /C(COaC2H5)2_  CR  /CHCO2H 

2\CNa(C02C2H6)2                         2\C(C02C2H5)a  2\CHCO2H 

CH2— CNa(C02C2H5)2_               CH2— C(CO2C2H5)2_  CH2— CHCO2H 

CH2— CNa(C02C2H5)2    '               CH2— C(CO2C2H5)2    '  CH2— CHCO2H 

CH  /CH1.CNa(C01C1HB)a__>CH  /CH2— C(CO2C2H5)2  /CH2— CHCO2H 

!\CH2.CNa(C02C2H5)2              !\CH2— C(CO2C2H6)2  !\CHa— CHCO2H 

7.  Cyclic  ketone  formation. — As  the  calcium  salts  of  the  paraffin- 
monocarboxylic  acids  during  distillation  yield  open  ketones,  so  the 


ORGANIC  CHEMISTRY 


CH2— CH2— C02\Ca 
CH2— CH2— C02/ 
iCH2— CH2\CQ 
CH2— CH2/ 

CH  /CH2— CH2— CH2— C02 
2\CH2— CH2— CH2— CO2 

I  CH2</CH2— CH2— CH2\CO 
\CH2— CH2— CH2/ 


c 


XV 

>.co 


>Ca 


calcium  salts  of  some  higher  normal  paraffin-dicarboxylic  acids  yield 
during  dry  distillation  cyclic  ketones  (J.  Wislicenus)  : 

/CH2— CH2— C02\c      CH2— CH2— CH2— C02\c 
Z\CH2— CH2— C02/     '  I  CH2— CH2— CH2— COa/ 
-»  1  CH2 — CH2 — CH2\ro 

*CH2— CH2— CH2/ 
CH2— CH2— CH2— CH2— CO2N 
j  CH2— CH2— CH2— CH2- 
j  CH2— CH2— CH2— CH2N 
V  CH2— CH2— CH2— CH2/ 

7«.  During  distillation  at  ordinary  pressures  the  anhydrides  of 
adipinic  and  pimelinic  acids  and  their  alkyl  substitution  products  split 
into  CO2  and  cyclic  ketones  (H.  G.  Blanc ;  see  Vol.  I.). 

8.  Aliphatic  diazo-compounds,  like  diazo-methane  (Vol.  I.)  and 
diazo-acetic  ester,  add  themselves  to  olefin-mono-  and  -dicarboxylic 
esters  with  the  formation  of  cyclic  azo-compounds  or  pyrazolin  com- 
pounds, which,  by  splitting  off  nitrogen,  pass  easily  into  trimethylene- 
carboxylic  acids  (E.  Buchner)  : 

N=N     CHCO2R  N=N— CHCO2R_N 

'+cL2 


C02RCH 


CO2RCH 


H2 


N=N— CHC02R      _NZ 


Cp. 


N=N     CHCO2R 

\/   +11                = 
CH2    CHC02R  CH2 CHC02R 

also  the  condensation  of  benzol  with 


CH2<| 


CHCO2R 

\CH2 
CHCO2R 


diazo-acetic   ester   to 


isophenyl-acetic  or  norcaradiene-carboxylic  ester. 


I.—TRI-,  TETRA-,   PENTA-,   HEPTA-,   OCTO-  AND  NONO- 
CARBOCYCLIC  COMPOUNDS 

A  number  of  natural  products  are  closely  related  to  these  groups 
of  carbocyclic  compounds  :  carone,  eucarvone,  pinene,  camphor, 
tropin,  ecgonin,  pseudo-pelletierin,  etc.  This  group  of  bodies,  there- 
fore, has  lately  grown  in  scientific  and  practical  interest. 

We  may  here  first  give  a  summary  of  the  physical  properties  of 
the  simplest  cyclo -paraffins  (B.  40,  3981)  : 


Refractive 

Name. 

Melting-point. 

Boiling-point. 

Sp.  G.  at  4°. 

Index 

for  D  Line. 

Cyclopropane 

Gaseous 

Approx.  -35° 

.. 

Cyclobutane 

Liquid 

0-7038 

•37520 

Cyclopentane 
Cyclohexane 

+  6-4° 

II49°2 
81° 

0-7635 
0-7934 

•40855 
•4266 

Cycloheptane 

-12° 

118° 

0-8275 

•44521 

Cyclooctane 

+  n  "5° 

i45-3°-i48° 

0-850 

•44777 

Cyclononane 

o-785(?) 

•4328 

The    molecular   refractions    determined    from    the    densities    and 
refractive  indices  indicated  agree  with  those  calculated  from  theory 


TRIMETHYLENE   GROUP  7 

(see  Vol.  I.,  Introduction).  It  follows  that  in  the  cycle  -paraffins  the 
formation  of  rings  has  no  influence  upon  the  molecular  refraction. 

A.  Trimethylene  Group. 

OH  \ 

Trimethylene  (cyclopropane)  ;™2;CH8  is  an  easily  condensible  gas. 

CH2/ 

It  is  obtained  from  trimethylene  bromide  with  the  aid  of  sodium 
(Freund,  1882),  or  of  alcohol  and  zinc  dust  (B.  20,  R.  706  ;  /.  pr.  Ch. 
2,  7,  512).  It  may  combine  with  bromine,  especially  in  the  presence 
of  HBr  acid,  whereby  chiefly  trimethylene  bromide  CH,Br.CH,CH.Br 
is  produced,  or  with  hydriodic  acid,  forming  n-propyl  iodide,  but 
it  does  so  with  greater  difficulty  than  propylene.  At  a  red  heat  it 
transforms  itself  into  propylene  (B.  29,  1297  ;  C.  1899,  I.  925,  II.  287). 
In  the  presence  of  finely  divided  nickel,  hydrogen  reduces  it  to  propane 
already  at  80°  (B.  40,  4459).  MnKO  solution  does  not  oxidise  tri- 
methylene in  the  cold  (B.  21,  1282). 

Concerning  the  difference  in  the  heats  of  formation  of  trimethylene 
and  propylene,  see  C.  1899,  II.  801. 

Methyl-trimethylene,  b.p.  4°  (B.  28,  22  ;  C.  1902,  I.  1277)  ; 
1,  1-Dimethyl-trimethylene  b.p.  21°  (C.  1899,  I.  254;  1900,  II.  1069)  ; 
1,  1,  2-  and  1,  2,  3-Trimethyl-trimeth^lene  (B.  34,  2856)  ;  Vinyl- 

CH2V 
trimethylene    I     ;>CHCH=CH,  b.p.  40°,  D  073,   are  produced  in  a 

CH2 

peculiar  reaction  by  the  action  of  alcohol  and  zinc  dust  on  the  tetra- 
bromate  of  penta-erythrite  (see  Vol.  I.)  ;  by  MnKO  it  is  oxidised  to 

CH2V  CHOH 

glycol      I      yen/  |  ,  which,    by   further   oxidation   with    dilute 

CHy  CH2OH 

HNO3,  yields  a-oxy-glutaric  acid  ;  with  Br  it  forms  a  dibromide, 
which,  on  treating  with  lead  oxide,  yields  keto-pentamethylene  (B.  29, 
R.  780  ;  C.  1897,  H-  696  ;  a150  c-  l898>  IL  475,  footnote)  ;  with  N2O3 
it  gives  a  pseudo-nitrosite,  m.p.  145°,  from  which  on  reduction,  besides 
diamine  C5H8(NH2)2,  b.p.  i8o°-i85°,  cyclo-butanone  is  formed  (B.  41, 
915).  Concerning  another  interpretation  of  vinyl-trimethylene,  see 
B.  40,  3884. 


Dimethyl-methylene-trimethylene  I     >C=C\      (?),  b.p.  70°-7i°, 

CH2  CH<j 

is  produced  from  dimethyl-  trimethylene-carbinol  on  boiling  with  acetic 
anhydride  (C.  1905,  II.  403  ;   1909,  I.  1859). 

Monochloro-trimethylene,  b.p.  43°  (B.  24,  R.  637). 

Dichloro-trimethylene,  b.p.  74°  (B.  25,  1954). 

Amino-trimethylene  (C3H5)NH2,  b.p.  49°,  from  trimethylene- 
carboxylic  amide  with  KOBr  (C.  1901,  II.  579).  Miscible  with  water 
in  all  proportions.  Smells  like  propylamine.  With  nitrous  acid  it 
yields  ally!  alcohol,  with  splitting  of  the  ring  (C.  1905,  I.  1704). 

Trimethylene-methylamine  (C3H5)CH2NH2,  b.p.  86°,  from  tri- 
methylene-carboxylic  nitrile  by  reduction.  Gives  with  nitrous  acid 
trimethylene-carbinol  and  cyclo-butanol,  with  expansion  of  the  ring 
(B.  40,  4393) 

Trimethyl-carbinol  (C3H5)CH2OH,  by  the  reduction  of  trimethylene- 
carboxylic  ester  with  Na  and  alcohol  (B.  40,  4397).  With  concentrated 
HBr  it  passes  into  1,3-dibromo-butane  (C.  1908^  I.  818), 


8  ORGANIC   CHEMISTRY 

Trimethylene-ethyl-earblnol,  b.p.  14°. 

Trimethylene-isopropyl-carbinol,  b.p.  151°. 

These  two  are  obtained  by  reduction  of  the  corresponding  ketones. 

Trimethylene  -  dimethyl  -  carbinol  (C3H5)C(CH3)2OH,  by  treating 
Mg(CH3)I  with  acetyl-trimethylene  or  trimethylene-carboxylic  ester  ; 
chloride,  b.p.  132°  ;  bromide,  b.p.  152°.  By  oxalic  acid  it  is  isomerised, 
with  splitting  of  the  ring,  to  dimethyl  -  tetramethylene  oxide 

Cnll^cH^0  (B>  34'  3887)' 

2Trimethylene-diethyl-carbinol  (C3H5)C(C2H5)2OH,  b.p.  158°. 

Trimethylene-methyl-ethyl-carbinol  (C3H5)C(CH3)(C2H5)OH,  b.p. 
141°  (C.  1909,  I.  1859). 

CH2 

Trimethylene-aldehyde    I     V:H.CHO,    b.p.    98°,   by   oxidation   of 

CH2 
trimethylene-carbinol  with  chromic  acid. 

Acetyl-trimethylene  £^>CH.cocH3,  b.p.  113°  : 

1.  From   aceto-propyl-bromide   with   ejection   of   HBr   by   KOH 
(C.  1898,  II.  474). 

2.  From  acetyl-trimethylene-carboxylic  acid  by  heating. 

3.  By  the  action  of  Hg(OH3)I  upon  trimethylene  cyanide.     The 
three-ring  is  split  up  by  mineral  acids.     For  homologous  ketones  see 
C.  1909,  I.  1859. 

Trimethylene-carboxylic  acids  (A.  284,  197)  are  obtained  by  the 
general  methods  of  ring  formation  5,  6,  and  by  method  8,  which  only 
leads  to  trimethylene-derivatives  (p.  6).  From  those  trimethylene- 
polycarboxylic  acids  which  contain  two  carboxyls  bound  with  one 
carbon  atom,  we  obtain  the  carboxylic  acids  poorer  in  carboxyl  by 
splitting  off  CO2.  Certain  peculiar  phenomena  of  isomerism  (cis-  and 
trans-forms)  are  attributed  to  the  position  of  the  carboxyls  on  the 
same  side,  or  on  different  sides,  of  the  trimethylene  plane,  as  in  the 
case  of  the  isomerisms  of  the  tri-thio-aldehydes  (Vol.  I.). 

Trimethylene-carboxylic  acid  C3H5CO2H,  m.p.  18°,  b.p.  183°,  is 
isomeric  with  crotonic  acid.  The  trimethylene  ring  is  split  by  bromine 
with  formation  of  a,  y-dibromo-butyric  acid  (C.  1909,  II.  1130).  Its 
nitrite,  b.p.  118°,  has  been  obtained  by  distilling  y-chloro-butyro-nitrile 
over  KOH  ;  ethyl  ester,  b.p.  134°;  chloride,  b.p.  121°;  amide,  m.p. 

124°  (C.  1901,  II.  579  »   I902»  I-  9I3)- 

CH—  COOH 
Trans  -  phenyl  -  trimethylene  -  carboxylic  acid  C6H5CH<^  j 

CH2 

m.p.  105°,  has  been  obtained  by  method  8,  by  addition  of  diazo-acetic 
ester  to  styrol  (q.v.).  It  was  successfully  disintegrated  to  cis-trans- 
trimethylene-i,  2-dicarboxylic  acid. 

2,  2  -  Dimethyl  -  trimethylene  -  carboxylic    acid    (CH3)2c/^COOH 

\CH2 

b.p.  100°,  smells  strongly  of  butyric  acid.  The  ester,  b.p.  90°,  is  formed 
by  separation  of  HBr  from  the  3,  3-dimethyl-y-bromo-butyric  acid 
ester  (C.  1907,  II.  897). 

Trimethylene-1,  1-dicarboxylic  acid   (vinaconic  acid] 


m.p.  140°  (see  method  5,  p.  5).     With  HBr  this  passes  into  brom- 
ethyl-malonic  acid  CH(CO2H)2BrCH2CH2.      It  also  takes  up  bromine 


TRIMETHYLENE   GROUP  9 

(B.  18,  3314),  but  is  not  affected  by  HNO3,  MnKO4,  or  nascent  hydrogen 
(B.  23,  704  ;  28,  8).  With  Na-malonic  ester  the  ester  of  vinaconic 
acid  condenses  to  butane-tetracarboxylic  ester,  and  thus  behaves  quite 
like  a,  p-olefin-carboxylic  ester  (see  Vol.  I.  and  B.  28,  R.  464).  Con- 
cerning the  constitution  of  vinaconic  acid  and  the  homologous  methyl- 
vinaconic  acid,  see  A.  294,  89. 

1,  1-Cyano-trimethylene-earboxylic  acid,  m.p.  149°,  from  sodium- 
cyan-acetic  ester  and  ethylene  bromide  (C.  1899,  H-  824). 


Acetyl-trimethylene-carboxylie    ester        2c<s^  •  b-P-   I95°> 

CH2/      \COOC2H5 
from  sodium-aceto-acetic  ester  and  ethylene  bromide  (B.  17,  1440). 

Trimethylene-1,  2-dicarboxylic  acid  is  known  in  two  isomeric  forms, 
distinguished  as  cis-  and  cis-trans-  or  trans-  forms  (A.  245,  128)  : 

C02H         C02H  C02H         H 

ft\CH2/CO2H 
T-cis-  form.  T-cis-trans-  form. 

Cis-trimethylene-1,  2-dicarboxylic  acid,  m.p.  139°;  anhydride, 
m.p.  59°,  is  obtained  from  tr-i,  2-tri-  and  -I,  2-tetracarboxylic  acid  by 
heating.  Cis-trans-trimethylene-i,  2-dicarboxylic  acid,  m.p.  175°, 
from  monobromo-glutaric  acid  ester  with  alcoholic  caustic  potash 
(C.  1900,  I.  284).  It  has  been  separated  into  two  optically  active  com- 
ponents by  means  of  its  quinine  salt,  like  the  cis-trans-trimethylene- 

1,  2,  3-tricarboxylic  acid  described  below  (B.  38,  3112).    Its  methyl  ester, 
b.p.  about  210°,  is  obtained  from  acryl-diazo-acetic  ester  by  method  8, 
besides  glutaconic  acid  ester  ;  and  from  fumaric  acid  ester  with  diazo- 
methane  (B.  27,  1888  ;  28,  R.  290). 

Cis-phenyl-trans-2,  3-  trimethylene  -  dicarboxylic  acid 
ceH5CH/™COOH  ?  m.p.  175°;  anhydride,  m.p.  134°;  from  a-bromo- 

benzylidene-bis-malonic  ester  with  alcoholic  ammonia,  or  by  adding 
diazo-acetic  ester  to  cinnamic-acid  ester  (B.   36,  3774  ;     /.  pr.    Ch., 

2,  75,  490). 

Trimethylene-1,  2-tricarboxylic  acid  CH*\^COH'  m'p'  l87°'  by 
disintegration.  Its  ethyl  ester,  b.p.  276°,  from  a,  p-dibromo-propionic- 
acid  ester  (B.  17,  1187),  and  from  a-brom-acrylic  ester  with  Na-malonic- 
acid  ester  by  method  5  (B.  20,  R.  140,  258). 

Sym.  trimethylene-1,  2,  3-tricarboxylic  acid  C°2HCH2'  cis" 


form,  m.p.  I5o°-i53°  ;  cis-  trans-form,  m.p.  220°  ;  anhydride,  m.p.  187°, 
b.p.  265°.  The  cis-acid  is  obtained  from  the  I,  2,  3-tetracarboxylic 
acid  (B.  17,  1652),  the  cis-trans-acid  from  fumaric-acid-diazo-acetic 
ester  (B.  23,  2583).  The  latter  acid  is  also  obtained  from  the  oxidation 
of  isophenyl-acetic  or  norcaradiene-carboxylic  acid  (B.  27,  868). 

Trimethylene-1,  2-tetracarboxylic  acid  CH  /^c°22!2  passes  at  200° 

\C(CO2H)2 

into  the  anhydride  of  the  cis-i,  2-dicarboxylic  acid.  Its  ethyl  ester, 
m.p.  43°,  b.p~12  187°,  is  obtained  from  method  6  (B.  23,  R.  241). 

Trimethylene-1,  2,  3-tetracarboxylic  acid  (CO2H)2C<^^:°2^  passes 
at    95°-ioo°    into    cis-i,  2,  3-tricarboxylic    acid.      Its    ethyl    ester, 


io  ORGANIC   CHEMISTRY 

b.p.  246°,  from  dibromo-succinic  ester  by  method  5.  The  cis-i,  2,- 
trans-i,  3  acid  decomposes  at  i^6°-ig8°  (B.  28,  R.  290). 

1,  l-i)imethyl-trimethylene-2,  3-diearboxylic     acid,     caronic     acid 

(CH3)2C/^  ^2S>  trans-form,  m.p.  213°,  passes  on  heating  with  acetic 
\CHCO2H 

anhydride  into  the  cis-form,  m.p.  176°.  The  anhydride  of  the  cis-form 
melts  at  55°.  The  caronic  acids  are  obtained  by  oxidation  with 
MnO4K  from  carone  (see  Terpene  ketones),  which  therefore  contains  a 
trimethylene  ring.  Synthetically,  the  caronic  acids  have  been  obtained 
from  a-bromo-  (3  (3-dimethyl-glutaric-acid  ester  with  alcoholic  potash 
(C.  1899,  I.  522).  By  heating  with  HBr  the  caronic  acids  are  easily 
transformed  into  terebinic  acid  (q.v.).  On  heating  cuii-dibromo-  (3  (3- 
dimethyl-glutaric  ester  with  alcoholic  potash  we  obtain  etho-oxy- 

caronic  acid  (CH3)2C<(^(?)^)CO2H,  m.p.  138°  (C.  1901,  II.  no). 

1,  2-Dimethyl-trimethylene-2,  3-dicarboxylic  acid,  m.p.  154°,  is 
identified  with  the  acid  the  ester  of  which  is  obtained  with  PC15  from 
oxy-trimethyl-succinic  ester  (C.  1908,  I.  627). 

The    1,  l-dialkyl-2,  3-dicyano-trimethylene-2,  3-dicarboxylic    acids 

have  been  obtained  in  considerable  numbers  in  the  form  of  imides  of 

the  general  formula  R  /C\^N)—  CO/NH  '  from  the  corresPonding 
dialkyl-dicyano-bromo-glutarimides  (C.  1899,  II.  439  ;  1901,  I.  57). 

Trimethylene-tricyano-tricarboxylic-acid  ester  Rpc?cicNi/c\cooR' 
m.p.  119°,  is  formed  by  the  action  of  bromine  or  iodine  upon  sodium- 
cyano-acetic  ester  in  ether  ;  on  saponification  it  yields  trimethylene- 
tetra-  and  then  -i,  2,  3-tricarboxylic  acid  (B.  33,  2979). 

Methyl-eyelo-propene-dicarboxylic  acid  CH3CH<^§|cQ2HJ>  m-P-  200°> 
see  B.  26,  750. 

B.  Tetramethylene  Group. 

For  obtaining  tetramethylene  compounds  the  ring  formation 
methods  i,  5,  and  6  are  used. 

PTT  _  PT-T 

Tetramethylene-cyclo-butane  cj-f—  CH'  b'p'  Il0-I2°>  D4°  °7°38> 
is  obtained  by  reducing  cyclo-butene  with  Ni  and  H  at  100°  ;  at  higher 
temperatures  butane  is  also  produced,  with  splitting  of  the  ring.  It 
possesses  a  very  feeble  odour,  and  burns  with  a  luminous  flame.  In 
the  cold  it  is  stable  in  the  presence  of  bromine  and  concentrated  HI. 

Methyl-tetramethylene       -01*3'  b-P-  39°-42°,  method  i,  p.  4. 


Cyclo-butene  ^2—  CH'  easilv  condensible  gas  of  b.p.  i'5°-2°, 
D4°  0-733,  generated  together  with  A1>3-butadiene  during  dry  distilla- 
tion of  cyclo-butyl-trimethyl-ammonium  hydroxide.  Adds  bromine, 
forming  i,  2-dibromo-cyclo-butane,  b.p.24  69°,  m.p.  —2°,  which,  with 
KOH,  splits  off  HBr  and  passes  into  bromo-cydo-butene.  This  is  an 
oil  of  penetrating  odour,  b.p.  92°,  which  oxidises  to  succinic  acid.  With 
bromo-cyclo-butene  as  a  starting-point,  a  number  of  bromo-substitution 
products  of  cyclo-butane  have  been  prepared.  Thus  it  combines  with 
HBr  to  1,  1-dibromo-cyelo-butane  (I.),  b.p.  158°,  and  with  Br  to  1,  1,  2- 
tribromo-cyclo-butane  (!!.)>  b.p.19  109°.  This  gives»  with  alcoholic 


TETRAMETHYLENE   GROUP  u 

KOH,  1,  2-dibromo-eyclo-butene  (III.),  b.p.  155°,  distinguished  by  a 
great  faculty  for  polymerisation.  With  KMnO4  it  oxidises  to  succinic 
acid,  and  combines  with  Br  to  form  1,  2-tetra-bromo-eyclo-butane  (IV.), 
m.p.  126°,  which,  on  further  bromination,  yields  pentabromo-cyelo- 
butane  C4H3Br5,  b.p.19  i75°-i85°,  and  hexabromo-cyclo-butane 
C6H2Br6,  m.p.  186-5°,  which  is  remarkable  for  its  ease  of  crystallisation 
(B.  40,  3979)- 

(I.)  (II.)  (HI.)  (IV.) 

CH2— CBr_         CH2— CBr2         CH2— CBr2    CHa— CBr_         CH2— CBr2 

CH2— CH          "^CHa— CH2          CH2— CHBr         ~^CH2— CBr         ~*  CH2— CBr2 

The   name   dimethyl-methylene-tetramethylene  (       _c^   J          ,  b.p. 

ioo°-iO2°,  is  given  to  the  hydrocarbon  generated  from  the  bromide  of 
dimethyl-tetramethylene-carbinol  by  splitting  off  HBr.  On  reduction 
with  HI  it  passes  into  i,  3-dimethyl-pentamethylene. 

Oxy-tetramethylene,  cyclo  -  butanol  C4H7OH,  b.p.  123°,  from 
amido-tetramethylene  by  the  action  of  HNO2,  and  by  electrolysis  of 
potassium  tetramethylene-carboxylate  (B.  40,  2594,  4962). 

Amido-tetramethylene  C4H7.NH2,  b.p.  81°,  arises  from  the  amide  of 
tetramethylene-carboxylic  acid  with  bromine  and  an  alkali  (B.  40, 4745). 

Tetramethylene-methylamine      ^2rS'CH2NH2>     b.p.     110°,    by 

L/rl2.UJrl2 

reduction  of  tetramethylene-cyanide,  gives,  with  HNO2,  a  mixture  of 
tetramethylene-earbinol  C4H7.CH2OH,  and  cyclo-pentanol  C5H9.OH. 

Tetramethylene-carbinol  C4H7.CH2OH,  b.p.  142°,  by  reduction  of 
tetramethylene-carboxylic  ester  with  Na  and  alcohol  ;  bromide,  b.p. 
i37°-i39°(B.  40,4959). 

Tetramethylene-methyl-carbinol  C4H7.CH(OH)CH3,  b.p.  144°,  by 
reduction  of  tetramethylene-methyl-ketone. 

Tetramethylene-dimethyl-  and  diethyl-earbinol,  b.p.  147°  and  188° 
respectively,  by  the  action  of  Mg(CH3)I  and  Mg(C2H5)I  on  tetramethy- 
lene-carboxylic ester  (C.  1905,  II.  761  ;  1908,  II.  1342). 

Tetramethylene-diethyl-glyeol  [C4H7C(OH)C2H5]2,  m.p.  95°,  by 
reduction  of  tetramethylene-ethyl-ketone. 

Keto-tetramethylene-cyclo-butanone      ;^2~^  b.p.     09°,     D0° 

L/Jtl2 ^rl2 

0-9548,  generated  (i)  by  action  of  bromine  and  alkali  on  a-bromo- 
tetramethylene-carboxylic  amyl ;  (2)  during  boiling  of  i,  i-dibromo- 
butane  with  lead  oxide  and  water.  Nitric  acid  oxidises  it  to  succinic 
acid  (C.  1908,  I.  123). 

Tetramethylene-methyl-  and  ethyl-ketone,  b.p.  135°  and  145°,  from 
the  carboxyl  chloride  with  zinc  alkylene  (B.  25,  R.  371),  or  from  the 
amide  with  Mg(CH3)I  (B.  41,  2431). 

Di-tetramethylene-ketone  (C4H7)2CO,  b.p.  205°,  from  the  calcium 
salt  of  carboxylic  acid. 

Dimethyl-     and    diethyl-tetramethylene-ketone    CzU^l 

L-rl2 — UrlU2rl5 

m.p.    45°-i20°    and    i6o°-i65°.      This    constitution    is    ascribed    to 
substances  obtained  during  distillation  of  Ba  salts  of 
and  diethyl-glutaric  acid  (C.  1897,  II.  342). 

1,  3-Dimethyl-2,  4-diketo-tetramethylene  C 


12  ORGANIC   CHEMISTRY 

by   saponification   and  rejection  of  CO2  from  the  corresponding  car- 
boxylic-acid  ester,  on  boiling  with  bartya  water. 


1,  1,  3,  3-Tetramethyl-2,  4-diketo-tetramethylene 

m.p.  116°,  obtained  by  rejection  of  HC1  from  iso-butyryl  chloride.  Also 
by  action  of  molecular  silver  on  bromo-iso-butyryl  bromide.  In  both 
cases  we  must  assume  the  formation  of  dimethyl-ketene  (see  Vol.  I.), 
which  easily  polymerises  to  tetramethyl-2,  4-diketo-tetramethylene. 
Its  odour  recalls  both  menthol  and  camphor,  and  it  has  the  great 
volatility  of  these  compounds. 

Dioxime,  m.p.  281°  (B.  39,  970). 

Tetramethylene-carboxylie  acid  C4H7CO2H,  b.p.  194°,  smells  like 
the  fatty  acids,  and  is  generated  from  I,  i-dicarboxylic  acid  ;  on 
reduction  by  HI  it  yields  n-valerianic  acid,  with  splitting  of  the  ring 
(C.  1908,  II.  1342).  Ethyl  ester,  b.p.  160°  ;  chloride,  b.p.  142°  ; 
anhydride,  b.p.  160°  ;  amide,  m.p.  130°  ;  nitrite,  b.p.  150°  (B.  21,  2692  ; 
C.  1899,  II.  824). 

Tetramethylene-1,  1-dicarboxylie  acid  melts  at  155°,  passing  into 
monocarboxylic  acid.  Its  ethyl  ester,  b.p.  224°,  by  method  5,  p.  5  ; 
nitrile  ester,  b.p.  214°,  from  trimethylene  bromide,  and  sodium  cyan- 
acetic  ester  (C.  1899,  II.  824  ;  1905,  II.  761). 

Cis-tetramethylene-1,  2-dicarboxylie  acid,  m.p.  137°,  from  tetra- 
carboxylic  acid.  Anhydride,  m.p.  77°,  b.p.  271°  (B.  26,  2243).  Heating 
with  HC1  to  190°  produces  the  trans-acid,  m.p.  131°  (B.  27,  R.  734).  By 
bromination  with  Br  and  P,  i,  2-dibromo-tetramethylene-dicarboxylic 
acid  is  produced  ;  and  its  ester,  on  treating  with  alcohol  and  KI,  passes 

f^TT          C^f^C}   TT 

into  the  ester  of  cyclo-butene-dicarboxylic  acid  £H2~ccQ2H'  m'^'  I7^°- 
The  latter  easily  yields  an  anhydride  (/.  Ch.  Soc.  65,  950). 

Tetramethylene-1,  3-dicarboxylie  acid,  cis-form,  m.p.  136°  ;  anhy- 
dride, m.p.  51°;  trans-form,  m.p.  171°,  have  been  obtained  from  the 
products  of  the  action  of  formaldehyde  upon  malonic  ester,  and  from 
a-chloro-propionic-acid  ester,  with  the  aid  of  Na  alcoholate  (C.  1898, 
II.  29).  Also  produced  by  boiling  p-methoxy-methyl-malonic  ester 
with  concentrated  HC1  with  the  loss  of  two  molecules  of  methyl 
alcohol,  by  saponification,  and  CO2-rejection,  from  the  tetra-carbo- 
ester  first  formed  (C.  1909,  I.  152)  : 

CH30—  CH2—  CH  (COOR)  2  CH2—  C  (COOR)  2 

+  ----  > 

(ROCO)2CH—  CH2—  OCH3  (ROCO)2C  --  CH2 

Tetramethylene-1,  2-tetracarboxylie  acid,  m.p.  i45°-i5o°,  by  trans- 
formation into  cis-i,  2-dicarboxylic  acid.  Its  ester  is  formed  by 
method  6,  p.  . 

Diaeetyl-tetramethylene-dicarboxylic  ester  by  method  6,  p.  5 
(B.  19,  2048). 

Keto-tetramethylene-tricarbo-esters,  such  as  : 


CO-CHCOOR  CO-CQ-R  CO-C<C*R 

I   /CH«  I         I      r-u  I   /rw 

ROCOCH-C<COOR         ROCOCK-C<,COOR         ROC°CH    C<COOR 

are  formed  by  condensation  of  Na-malonic  esters,  or  methyl  and  ethyl 


TETRAMETHYLENE   GROUP  13 

malonic  esters,  with  citraconic  ester  in  alcoholic  solution,  in  which 
process  probably  the  tetracarboxylic  esters  first  formed  with  open 
chains  undergo  "  cyclic  aceto-acetic  ester  condensation.  By  saponi- 
fication  with  HCf  two  carbox-ethyl  groups  are  split  off  the  above 
substances,  and  the  following  i-keto-tetramethylene-3-car  boxy  lie  acids 
are  formed  (B.  33,  3751)  : 

CO  -  CH2  CO  --  CHCH3  CO  -  CHC,H6 

CH'-<COOH 


1,    3  -  Dimethyl  -2,    4  -  diketo  -  tetramethylene  -  earboxylic    ester 

CH3 

CO  _  C  _  COOC2H5,  m.p.  I33°-I35°,  has  been  obtained  by  the  action 
CH3CH—  CO 

of  concentrated  sulphuric  acid  upon  sym.  dimethyl-acetone-dicar- 
boxylic  ester.  By  alkalies  the  ring  is  easily  split  again  (B.  40,  1604). 

Diethyl  -  diketo  -  tetramethylene  -  dicarboxylic  ester, 

C2H5 

c°—  °—  COOC2H5    b         ca    II3°_n6°    is  identified  with  the 
C2H5OCOC  —  CO 

C2H5 

dimeric  ethyi-ketene-carboxylic  ester.  During  distillation  at  ordinary 
pressures  it  is  depolymerised.  Anilin  also  splits  the  molecule,  forming 
ethyl-malonic-ester  anilide  (B.  42,  4908). 

Tetramethylene-l,3-diglyoxylic  acid  '  ^^H^CO.CO.H*  m'p' 
240°,  produced  by  condensation  of  tartaric  acid  and  paraformaldehyde 
with  concentrated  H2SO4.  Decomposes  into  ethylene  and  oxalic  acid 
by  heating  with  alkalies,  and,  on  further  heating  with  H2SO4,  it  passes 
into  a  dilactone  (B.  29,  2273). 

By  polymerisation  of  olefin  and  acetylene  carboxylic  acids,  we 
sometimes  obtain  substances  with  a  four-membered  carbon  ring  : 

Diphenyl  -  tetramethylene  -  dicarboxylic     acid,      a-truxillic      acid, 

QH!CHICHCOOS'  m'P-  275°'  f°rmS  fr°m  Cmnamic  add  (?•"•)  by 
illumination  (B.  35,  2908,  4128),  and  is  found  among  the  subsidiary7 
alkaloids  of  coca'in  (q.v.).  By  distillation  it  again  decomposes  into 
two  molecules  of  cinnamic  acid. 

Diphenyl  -tetrene-  dicarboxylic    acid    ^BS=^1    ™,    m.p.    259°, 

Ucrl5U  =vAAJUrl 

formed  by  polymerisation  of  phenyl-propiolic  acid,   on  heating,   or 
with  POC13  ;   easily  forms  an  anhydride  or  imide  (B.  35,  1407). 
Pinic  acid  C°'"™         and  norpinic  acid  CO^H 


are  disintegration  products  ol  pinene  (see  Terpenes),  in  which  a  tetra- 
methylene ring,  the  so-called  piceane  ring,  is  assumed. 

C.  Pentacarbocyclic  Compounds. 

The  number  of  known  pentacarbocyclic  compounds  is  much 
greater  than  that  of  the  tri-  and  tetracarbocyclic  compounds.  They 
are  derived  partly  from  cyclo-pentane  or  pentamethylene,  partly  from 
cyclo-pentene.  Cyclo-pentadiene  is  found  in  the  inital  products  of  raw 
benzene,  as  obtained  from  coal-tar.  Pentamethylenes,  and  hexa- 


14  ORGANIC  CHEMISTRY 

methylenes,  have  also  been  obtained  from  the  naphthenes  of  Caucasian 
petroleum;  and  hexamethylenes  are  partially  transformed  into  the 
isomeric  pentamethylene  derivatives  by  heating  alone,  or  with  HI 
under  pressure  (cp.  A.  324,  I,  etc.).  Cyclo-pentane  and  its  progeny 
have  been  obtained,  not  only  by  the  methods  of  ring  synthesis 
specified  on  pp.  4,  5,  and  6,  but  also  from  hexacarbocyclic  ring  ortho- 
diketones  by  intramolecular  atomic  displacement  (see  Chloro-diketo- 
pentamethylene)  .  This  last  reaction  will  be  met  with  again  in  dealing 
with  the  disintegration  of  aromatic  substances.  In  the  same  manner 
some  remarkable  pentamethylene  derivatives  have  been  obtained  from 
hexa-oxy-benzol  :  croconic  acid  and  leuconic  acid,  which  are  dealt  with 
below  under  hexa-oxy-benzol. 

Camphor,  which  is  easily  converted  into  aromatic  substances,  and 
which  contains  a  five-membered  carbon  ring,  the  so-called  "  campho- 
ceanic  ring,"  gives  in  different  reactions  pentamethylene  derivatives, 
e.g.  camphorphorone,  camphoric  acid,  campholenic  acid,  campholytic 
acid,  etc.  Camphor  and  its  cyclic  transformation  products  are  dealt 
with  in  connection  with  the  terpenes  among  the  hydro-aromatic 
compounds,  after  the  benzol  derivatives. 

i.  HYDROCARBONS.  —  Pentamethylene,     R-pentene,     cyclopentane 


_ 

2         2,  b.p.  50°,  from  pentamethylene  iodide  by  reduction. 

V^Jrio  —  ^-'•^"2 

Methyl-pentamethylene,  b.p.  70°,  contained  in  the  so-called  hexa- 
naphthene  from  Caucasian  petroleum  (C.  1898,  II.  412,  576)  ;  formed 
synthetically  from  I,  5-dibromhexane,  also  from  methyl-cyclopenta- 
none,  as  well  as  tert.-methyl-cyclopentanol  (C.  1899,  I-  I211  '•  B.  35, 
2686).  1,2-Methyl-ethyl-eyelopentane,  b.p.  124°.  1,  3-Dimethyl- 
pentamethylene,  b.p.  93°,  from  the  corresponding  ketone,  is  optically 
inactive  ;  but  from  the  iodide  of  the  i,  3-dimethyl-tert.  -cyclopentanol 
by  reduction  an  optically  active  i,  3-dimethyl-cyclopentane,  b.p. 
91°,  [a]D  1-78°,  and  also  from  i,  3  -ethyl  -methyl  -cyclopentanol 
1,  3-Methyl-ethyl-cyelopentane,  b.p.  121°,  [a]D  4-34°,  is  obtained 
(B.  35,  2678).  1,  2-Diphenyl-pentamethylene,  m.p.  47°,  and  1,  2,  3,  4- 
Tetraphenyl-pentamethylene  from  anhydro-aceton-  and  anhydrodi- 
benzyl-ketone-benzile  (C.  1901,  II.  407,  1310).  Triphenyl-methyl-  and 
Triphenyl-dimethyl-pentamethylene  from  the  corresponding  cyclic  pina- 
cones  (C.  1903,  I.  568). 

Dipentamethenyl,  dicyclopentyl  C5H9-C5H9,  b.p.  190°,  from  penta- 
methenyl  bromide  with  Na  (C.  1899,  II.  367). 

Cyclopentene  CH\^  ICH*'  b'p<  ^°'  from  Pentametnylene  iodide 
or  bromide  with  potash,  or  from  cyclopentanol  with  P2O5  (C.  1899,  II. 
367),  yields  with  ozone  an  ozonide  C5H8O3,  which  in  water  decom- 
poses, forming  glutardialdehyde  (B.  41,  1701).  Perchloro-cyelopentene 
C5C18,  m.p.  41°,  b.p.  283°,  from  hexachloro-cyclopentenone  with  PC15 

(B.  23,  2214).  Methyl-eyclopentene  CH<cS2-CH^H3'  b-P-  7°°>  M" 
59-07°,  from  3-methyl-cyclopentanol  by  means  of  zinc  chloride  or 
oxalic  acid,  also  from  the  iodide  with  KOH.  By  oxidation  it  is  split 
into  a-methyl-glutaric  acid,  which,  together  with  the  optical  activity, 
proves  the  formula  assumed  (B.  26,  775  ;  35,  2491).  Isomeric  with 

the  methyl-cyclopentene  istheMethylene-cyelopentane  522'^S2^>C  =CH2, 


PENTACARBOCYCLIC   COMPOUNDS  15 

b.p.  78°-8i°,  a  liquid  of  penetrating  odour,  produced  from  cyclopentene- 
acetic  acid  by  rejection  of  CO2;  nitro  so-chloride,  m.p.  81°.  Gives  a 
glycol,  m.p.  40°,  by  oxidation  with  MnO4K,  and  also  cyclopentanone 
(A.  347,  325).  Similarly,  1  -  Methyl  -  3  -  methylene  -  cyelopentane 
CH2=  ;**2)>CH.CH3  has  been  obtained  from  methyl-cyclopentene- 

Orij.L/jlg/ 

acetic  acid.  By  oxidation  it  is  split  into  i,  3-methyl-cyclopentanone 
••(B.  34,  3950  ;  C.  1902,  I.  1222).  Like  methyl-cyclopentene,  it  is 
optically  active.  In  comparison  with  the  corresponding  saturated 
hydrocarbons,  the  strong  optical  activity  of  the  unsaturated  hydro- 
carbons with  five-membered  rings  is  very  remarkable. 

Ethylidene-eyelopentane  ™*—™*\C:CHCH3,  b.p.  114°,  Isopropyl- 


idene-eyclopentane        *~  :8cc<o«3}  b-P-  136°,  from  cyclopentene- 

CH2  —  CHj  /         XCHj 

isobutyric  acid,  with  displacement  of  the  double  linking.  By  alcoholic 
sulphuric  acid  it  is  isomerised  to  AMsopropyl-cyclopentene  (A.  353, 
307)- 

Cyclopentadiene,  pentol  (cp.  B.  22,  916)  CH*<£H=CH'  b'p'  4I°' 
an  initial  product  in  obtaining  raw  benzene  from  coal-tar,  is  a  colour- 
less liquid,  violently  attacked  by  both  acids  and  alkalies.  It  reduces 
ammoniacal  silver  solution.  It  soon  polymerises,  at  ordinary  tem- 
peratures, to  a  bimolecular  compound,  Dicyclopentadiene  (C5H6)2, 
b.p.  35  88°,  which  at  170°  boils  with  partial  re-formation  of  cyclopenta- 
diene.  It  is  much  more  stable  than  the  monomolecular  compound, 
and  resembles  the  terpenes  in  its  behaviour  (B.  39,  1492  ;  C.  1906, 
II.  1403).  On  heating  under  pressure,  both  the  simple  and  the  dimeric 
cyclopentadiene  are  transformed  into  a  higher-molecular  polymer, 
which  again  can  be  split  to  simple  cyclopentadiene  (B.  35,  4151)." 

The  H  atoms  of  the  CH2  group  of  cyclopentadiene  have  reaction 
capacities  similar  to  those  contained  in  the  group  .CO.CH2.CO 
(see  Vol.  I.).  With  K  in  benzene  solution  it  yields  the  highly  reactive 
potassium-cyclopentadiene,  which  absorbs  CO2  with  formation  of  a 
potassium  salt  of  the  bi-cyclopentadiene-carboxylic  acid  (C5H5. 
COOH)2,  m.p.  210°,  and  dimethyl  ester,  m.p.  85°.  With  oxalic  ester 
cyclopentadiene  in  the  presence  of  sodium  ethylate  it  condenses  to  cyclo- 
pentadiene-oxalic  ester  C5H5.COCOOC2H5  ;  with  N2O3  an  isonitro-deri- 
vative  is  formed.  With  aldehydes  and  ketones,  under  the  influence  of 
Na  alcoholate,  coloured  hydrocarbons  are  formed,  which,  referred  to  the 
hypothetical  simplest  representation  j  f\C=CH2,  are  termed 

OH.  =d~i/ 

fulvenes:  Dimethyl-fulvene  C5H4  :  C(CH3)2,  b.p.  46°;  Methyl-ethyl- 
fulvene  C5H4  :  C(CH3)C2H5,  b.p.  185°,  orange-coloured  oils  ;  Diphenyl- 
fulvene  C5H4  :  C(C6H5)2,  deep-red  prisms,  m.p.  82°.  Further  fulvenes, 
see  A.  348,  I.  Like  cyclopentadiene  itself,  the  fulvenes  absorb  the 
oxygen  of  the  air,  and  form  peroxides,  e.g.  [C5H4  :  C(CH3)2]O4  (B.  33, 
666  ;  34,  68,  2933). 

Cyclopentadiene  unites  with  the  quinones  in  molecular  proportions 
to  form  stable  compounds,  like  cyclopentadiene-quinone  C1]LH10O2, 
greenish-yellow  flakes  of  m.p.  78°  (A.  348,  31).  With  I  or  2  molecules  of 
the  halogen  hydrides  and  the  halogens  cyclopentadiene  yields  addition 
products  like  :  monochloro-cyclopentene  C5H7C1,  b.p.40  50°  ;  trichloro- 


16  ORGANIC  CHEMISTRY 

cyclopentane  C5H7C13,  b.p.  196°;  tetrachloro-cyclopentane  C5H6C14, 
b.p.1594°.  Monochloro-cyclopentene  gives  with  anilin  anilino-cyclo- 
pentene  QH7.NC5H10,  b.p.23  94°-96°  (B.  33,  3348).  By  adding  2Br 
to  the  conjugate  double  links  of  cyclopentadiene  (Thiele),  two  stereo- 

isomeric  i  vf-dibromides  are  generated  „  ZcHB^01^2'  a  so^  one 
and  a  liquid  one,  which,  on  oxidation,  yield  two  stereo-isomeric  aar 
dibromo-glutaric  acids  (A.  314,  296).  Methyl-ethyl-cyclopentadiene, 
see  below. 

1,  2,  4-Triphenyl-  and  1,  2,  3,  4-Tetraphenyl-cyclopentadiene,  m.p. 
149°  and  177°,  as  well  as  triphenyl-methyl-  and  triphenyl-dimethyl- 
cyclopentadiene,  m.p.  163°  and  128°,   are  obtained  from  the  corre- 
sponding cyclic  pinacones  by  splitting  off  2H2O  (C.   1898,    II.  924  ; 
1903,  I.  568  ;  B.  36,  933). 

2.  ALCOHOLS.  —  Cyclopentanol  C5H9OH,  b.p.  139°;    chloride,  b.p. 
115°  ;  bromide,  b.p.  137°  ;  iodide,  b.p.  164°  ;  amine,  b.p.  107°  (A.  275, 
322).     3-Methyl-cyclopentanol  HOCH/£^2~^CH3,  b.p.1249°;  amine, 

b.p.12  42°  (B.  25,  3519  ;  26,  775).  Both  alcohols  are  obtained  by  the 
reduction  of  the  corresponding  ketones. 

2-Methyl-cyclopentanol,  b.p.  148°,  from  methyl-cyclopentenone. 
I-  or  tert.-methyl-cyclopentanol,  m.p.  30°,  b.p.  136°,  from  the  corre- 
sponding amine,  b.p.  144°,  obtained  by  reduction  from  the  nitrification 
product  of  methyl-pentamethylene  ;  also  from  cyclopentanone  with 
CH3MgI,  as  well  as  by  direct  synthesis  from  S-aceto-butyl-iodide  with 
Mg  (p.  4,  and  B.  35,  2684  ;  C.  1899,  I.  1212). 

1,  3-Dimethyl-tert.-cyclopentanol,  b.p.94  89°,  from  i-methyl-3- 
cyclopentanone  with  CH3MgI  (B.  34,  3950). 

Pentamethylene-glycol  C5H8(OH)2,  m.p.  49°,  b.p.12  127°,  from  the 
dibromide  of  the  cyclopentene  (C.  1899,  II.  367).  A  further  number 
of  glycols  of  the  pentamethylene  series  have  been  obtained  by  intra- 
molecular pinacone  formation  (p.  4)  by  reduction  from  the  I,  5-di- 
ketones  (see  C.  1901,  II.  406  ;  1903,  I.  588). 

Pentamethylene-earbinol  C5H?CH2OH,  b.p.  162°,  from  cyclo- 
pentyl-magnesium  chloride  and  trioxy-methylene.  Also  by  the  action 
of  HNO2  on  pentamethylene-methylamine  C5H9CH2NH2,  b.p.  139°- 
145°,  besides  the  cyclohexanol  (q.v.)  produced  by  a  peculiar  ring 
expansion  (A.  353,  325  ;  B.  41,  2629). 

1-Isopropyl-cyclopentane-l,  6-diol  CH'-CH22/C(OH)~C(OH)\CH3' 
m.p.  62°,  b.p.u  108°,  produced  by  action  of  CH3MgI  upon  a-oxy-cyclo- 
pentane-carboxylic  ester.  On  heating  with  dilute  SO4H2  or  oxalic 
acid,  the  pinacone  undergoes  the  pinacolin  transformation  with 
extraordinary  facility,  2,  2-dimethyl-cyclohexanone  being  formed 
with  displacement  of  a  methylene  group  and  expansion  of  the  ring 
(A.  376,  152). 


C(OH)<CH3 


3.  RING-KETONES.^  —  The  cyclic  ketones  obtained  from  calcium  salts 
and  the  anhydrides  of  adipinic  acid  and  the  alkyl-adipinic  acids  by 
methods  7  and  70,  p.  6,  formed  the  starting  material  for  the  prepara- 


PENTACARBOCYCLIC  COMPOUNDS  17 

tion  of  the  corresponding  alcohols,  from  which  later  the  saturated, 
and  unsaturated,  pentacarbocyclic  hydrocarbons  were  obtained. 
The  oximes  of  these  ketones  yield  on  treatment  with  concentrated 
SO4H2,  S-lactames  by  Beckmann's  transformation  (see  Vol.  I.). 

Adipin-ketone  [cyclopentanone],  keto-pentamethylene  CO\CH2    />H2, 

b.p.  130°,  is  found  in  the  wood  acids  (B.  31,  1885),  and  is  also  generated 
from  2-keto-pentamethylene-carboxylic  ester  by  ketone  splitting. 
It  smells  like  peppermint,  and  yields  n-glutaric  acid  on  oxidation. 
Oxime,  m.p.  120°  (A.  275,  312).  Heating  with  acetic  anhydride  to  180° 
gives,  with  partial  enolisation,  cyclopentenol  acetate,  b.p.  I56°-I58°. 
With  benzaldehyde,  adipin-ketone  condenses  easily  to  a  mono-  or 
dibenzal  compound  C6H5CH  :  (C5H6O)  and  C6H5CH  :  (C5H4O)  :  CHC6H5 
(B.  29,  1601,  1836;  36,  1499;  c-  1908,  I.  637).  With  HNO2  we 
get  di-iso-nitroso-cyclopentanone  HON  :  (C5H4O)  :  NOH,  m.p.  215° 
(C.  1909,  II.  1549).  By  sodium  ethylate  two  and  three  molecules  of 
the  cyclopentanone  are  condensed,  forming  cyclopentane-pentanone 
(C5H6O)  :  (C5H8),  b.p.12  118°,  and  cyclodipentane-pentanone  (C5H8)  : 
(C5H4O)  :  (C6H8),  m.p.  77°,  b.p.12  190°  (B.  29,  2962).  3-Methyl-cyclo- 

pentanone  COCU^  b-P-  T420,  is  optically  active,  [a]  135-9° 


(B.  35,  2489),  and  smells  like  camphorphorone  (q.v.),  which  belongs 
to  the  cyclopentenones,  but  is  only  dealt  with  in  connection  with 
camphor.  The  oxime  of  methyl-cyclopentanone  is  split  up  by  P2O5 
to  the  nitrile  of  hexylenic  acid  C5H9CN,  with  p-methyl-pyridine  as  a 
by-product  (C.  1899,  II.  947).  Cp.  the  similar  behaviour  of  other 
cyclic  ketones. 

A  2-Methyl-eyelopentanone,  which  also  boils  at  i42°-i44°,  has  been 
obtained  from  a-methyl-adipinic  acid  (B.  29,  R.  1115).  2,  5-Dimethyl- 
cyclopentanone,  b.p.  146°,  from  ac^-dimethyl-adipinic  acid  (B.  29,403). 
2,  3,  3-Trimethyl-cyclopentanone  from  a,  J8,  p-trimethyl-adipinic  acid 
is  related  to  camphoric  acid  (B.  33,  54).  A  large  number  of  other 
homologues  of  cyclopentanone  have  been  prepared  by  method  70,  p.  6, 
from  the  anhydrides  of  the  alkylated  adipinic  acids  (C.  1908,  II.  776). 

l,3-Dimethyl-4,  5-diphenyl-eyelopentanone  clH^CH^CHiCH^00' 
m.p.  122°,  by  reduction  of  dimethyl-anhydro-acetone-benzile  with 
HI  and  P.  As  an  intermediate  product  we  obtain  1,  3-Dimethyl- 
4,  5-diphenyI-A4-cyelopentenone,  m.p.  122°  (C.  1905,  1.  172). 

Methyl-cyelopentenone  CH3-c^cH—  CH''  b'p'  I57°'  in  wood  oiL 
Oxime,  m.p.  128°  (B.  27,  1538). 

Phenyl-eyclopentenone  c6H6c/£^2~  |P*2,  m.p.  84°,  from  phenacyl- 
acetone  (q.v.)  with  dilute  NaOH.  Oxime,  m.p.  147°  (B.  41,  194). 

P  TJ  /-»  PTT  \ 

Diphenyl-cyclopentenolone,a^y^o-ac^owe6^n^7^^6^:^T^^>CO, 

m.p.  149°,  from  benzile  (q.v.)  and  acetone.  By  condensation  with 
other  ketones,  such  as  methyl-ethyl-ketone  and  dibenzyl-ketone, 
several  more  such  ketone  alcohols,  of  the  cyclopentene  series,  have 
been  formed;  from  benzile  and  laevulinic  acid  (Vol.  I.)  we  obtain  similarly 
a  Diphenyl-eyelopentenolone-acetic  acid  or  anhydro-benzile-laevulinic 
acid  (C.  1899,  II-  I05I  '>  I9OI>  II.  I3I°  J  I9°3>  I-  5^9).  An  isomeric 
VOL.  II.  C 


ORGANIC   CHEMISTRY 


diphenyl-cyclopentenolone       657^>CO'     m-P-     J76°'     is     ob~ 

v-'giricL-'  —  \_/(  vJJbjLj  / 

tained  by  the  action  of  concentrated  SO4H2  upon  dibenzal-acetone, 
which  is  oxidised  by  potassium  permanganate  to  benzile,  and  desyl- 
acetic  acid  (q.v.).  With  HI  both  isomeric  compounds  are  reduced  to 
1,  2-Diphenyl-cyelopentane  (B.  37,  1133). 

Hexachloro-cyclopentenones  00'  m'p>  28°'  b'p'80  I56°'  and 


^•^J'Nco,  m.p.  92°,  b.p.75  148°,  by  oxidation  with  Cr03,  from  the 
CCl  CCi2' 

corresponding  a-oxy-acids,  obtained  from  benzene  derivatives,  like 
o-amido-phenol  and  pyro-catechin  (B.  24,  926  ;  25,  2697).  For  the 
action  of  NH3  upon  these  ketones,  see  C.  1898,  I.  607. 

1,2-Diketo-pentamethylene  co'Ir^2/^2'  m>P-  56°'  Produced  by 
ketone  splitting  of  the  i,2-diketo-pentamethylene-3,  5-dicarboxylic 
ester.  The  diketone  has  acid  qualities.  In  accordance  with  the 

desmotropic  formula  of  a  Cyclopentenolone  c^^cH2/*01*2'  ^  forms 
salts  and  reacts  with  acetyl  chloride,  benzoyl  chloride,  and  phenyl 
cyanate  (B.  35,  3201). 

Chlorine  easily  acts  upon  diketo-pentamethylene,  with  formation 
of  3-Chloro-l,  2-diketo-pentamethylene,  m.p.  139°.  Chlorinated  1,2- 
diketo-pentamethylenes  are  also  formed  in  a  manner  analogous  to  the 
chlorinated  cyclopentenones,  from  benzoyl  derivatives,  like  phenol,  and 
chloranilic  acid.  From  potassium  chloranilate  with  chlorine  and  water 

we   obtain:    ^'^'"/CO,   m.p.    125°    (B.    25,848).     Starting   from 

CO.CH.C1/ 


resorcin,  Tetraehloro-diketo-R-pentene    QZco/>CCl2'  m<p'  ^°'  b-p<27 
148°,  was  obtained  (B.  24,  916  ;    25,  2225). 

The  primary  disintegration  products  of  the  benzene  derivatives 
serving  as  basic  products  in  these  reactions  are  often  chlorinated  ketonic 
acids.  Thus,in  the  last  case,  from  resorcin  the  acid  CC13.CO.CC1  :  CC1CC12 
COOH,  perchlor-acetyl-crotonic  acid,  in  which  the  ring  completion  to 
the  keto-pentamethylenes  is  then  carried  out  by  heating  with  con- 
centrated sulphuric  acid  (B.  26,  513).  In  a  similar  manner  it  has 
been  found  possible  to  convert  the  j8,  8-dibromo-laevulinic  acid 
CH2Br.COCHBr.CH2.COOH  by  means  of  fuming  sulphuric  acid 

CBr—  COX 
into  two  :   Dibromo-diketo-R-pentene   ||  >CHBr,  m.p.  99°,  and 

CH—  CO  /'*. 

CH—  CO. 

*  m.p.  137°  (A.  294,  183). 


Methyl-triketo-pentamethylene  co/™(CHa)~SS»  m-P-   Il8°>  from 

\CH2  -  CO 

oxalic  ester,  and  methyl-ethyl-ketone,  by  method  46  (p.  4)  (B.  39, 
1336). 

By  analogy,  we  have  from  dibenzyl-ketone  : 

Diphenyl-triketo-pentamethylene,  oxalyl-dibenzy  I-  ketone 

C°\CH(C6H5)—  Co'  m'P>  I39°'  On  heatinS>  U  transposes  itself  into 
isoxalyl-dibenzyl-ketone,  the  lactone  of  an  acyclic  acid  (B.  27,  1353  ; 
A.  284,  245). 


PENTACARBOCYCLIC   COMPOUNDS  19 

Pentaketo-pentamethylene  is  the  leuconic  acid  (q.v.)  produced  by 
oxidation  of  croconic  acid  (q.v.).  Both  compounds  are  dealt  with 
among  the  oxy-benzo-quinones  in  connection  with  rhodizonic  acid. 

4.  ALDEHYDES  AND  EXTRA-CYCLIC  KETONES.  —  Cyelopentane-alde- 
hyde  C5H9CHO,  an  oil  with  a  penetrating  odour,  resembling  valeralde- 
hyde,  has  been  obtained  by  the  action  of  dilute  SO4H2  on  methylene- 
cyclopentane-glycol  (q.v.).  Semicarbazone,  m.p.  123°. 

A'-Cyclopentenaldehyde  ™2~     :  V.CHO,  an  unstable  liquid,  smell- 

Cri3  —  Crl2/  - 

ing  like  benzaldehyde,  formed  easily  by  condensation  of  the  dialdehyde 
of  adipinic  acid  (Vol.  I.).  Also  from  the  nitroso-chloride  of  methylene- 
cydopentane  by  rejection  of  HC1  and  splitting  of  the  initially  formed 
oxime  with  dilute  acids. 

l-Methyl-2-aeetyl-pentamethylene  C5H8(CH3)(COCH3),  b.p.  170°, 
from  its  carboxylic  acid. 


Acetyl-A  '-cyclopentene       'Hcn  /CCOCH3'  b-P-  I73-i74 
distinctly  of  benzaldehyde.     Its  oxi'me,  m.p.  91°,  is  generated  by  HC1 
rejection  from  the  nitroso-chloride  of  ethylidene-cyclopentane. 


l-Methyl-2-acetyl-A1-cyclopentene  ^2"~        3v)c.cocH3,  b.p.  191°. 

CH2  —  -Crla  -  f 

Oxime,  m.p.  85°,  generated  from  the  e-diketonane  by  Na  ethylate. 
Oxidised  with  MnO4K  it  yields  y-acetyl-butyric  acid.  The  inter- 
mediate formation  of  a  i,6-diketone  is  also,  probably,  a  step  in  the 
formation  of  : 


Pentamethyl  -  acetyl  -  cyclopentene 

2io°-230°,  by  reduction  of  the  mesityl  oxide  (Vol.  I.  ;  C.  1897,  II.  579). 
Concerning  similar  ring  completions  of  i,6-diketones  to  cyclopentene 
derivatives,  see  C.  1899,  I.  21  ;  1909,  I.  119). 

1-Acetyl-eyelopentanone  ^T^°VHCOCH3>  b-P-s  75°,  by  method 

L/rl2—  CJbi^/ 

4c,  p.  5,  from  e-keto-oenanthylic  acid.  By  heating  with  alcoholic  Na 
ethylate  the  ring  is  easily  split  again  (C.  1909,  II.  119). 

By  attaching  cyclopentanone  to  benzal  -  aceto  -  phenone,  by 
means  of  alcoholic  caustic  soda  we  obtain  the  diketone 

CH:lco!>CH-CH<cgcOC,H5  (B-  35'  '445). 

5.  CARBOXYLIC  ACIDS.  —  Cyclopentane-carboxylie  acid,  b.p.  214°, 
smells  of  sweat  ;  2-Methyl-eyclopentane-earboxylie  acid,  b.p.  219°;  2,  5- 
Dimethyl-eyclopentane-carboxylic  acid,  three  stereo-isomeric  forms: 
m-P-  75°-77°>  m.p.  26°-3o°,  and  m.p.  49°-5o°  : 

:H2.CH2\C  CH2.CH(CH3)\CHCOOH        CH2.CH(CH3)\CHCOOH 

CH2.CH2/  CH2.CH2  _  _/  CH2.CH(CH3)/ 

These  acids  have  been  obtained  from  the  cyclic  malonic  esters  : 


obtained  from  the  corresponding  alkylene  dibromides  by  method  5  (p.  5) 
(B.  26,  2246  ;   27,  1228  ;   34,  2565). 

Cyclopentane-carboxylie  acid  has  been  prepared  from  the  chloro- 


20  ORGANIC  CHEMISTRY 

cyclopentane  with  Mg  and  CO2,  and  from  the  corresponding  a-oxy-acid. 
The  2-methyl-cyclopentane-carboxylic  acid  has  been  obtained  from  the 
corresponding  a-acetyl-carboxylic  acid. 

3-Methyl-cyclopentane-carboxylic  acid,  b.p.15  116°,  [a]D  --5*89°, 
from  the  iodide  of  3-methyl-cyclopentanol  with  Mg  and  CO2  (B.  35, 
2690).  Isomeric  with  this  is  cyclopentane-acetic  acid  C5H9.CH2COOH, 
by  disintegration  of  the  condensation  product  of  iodo-cyclopentane 
with  Na-malonic  ester  (B.  29,  1907). 

Cyclopentane-1, 2-diearboxylic  acid  is  known  in  two  modifications. 
The  cis-form  forms  an  anhydride,  and  is  generated  by  heating  the 
cyclopentane-i,2-tetracarboxylic  acid  obtained  by  method  6  (p.  5),  or 
from  trimethylene  bromide  with  sodium-malonic  ester  (B.  18,  3246  ; 
C.  1901,  II.  1264). 

1, 3  -  Cyclopentane  -  tetracarboxylic  acid,  produced  in  a  similar 
manner,  yields,  on  heating,  Cis-eyelopentane-1,  3-dicarboxylie  acid,  m.p. 
121°  (anhydride,  m.p.  161°),  which  on  heating  with  HC1  is  partly  trans- 
posed into  the  trans-acid,  m.p.  88°  (C.  1898,  II.  770). 

Cyclopentane-1,  2,  4-tricarboxylic  acid  C5H7(COOH)3  is  obtained  by 
the  splitting  of  I,  2, 4-cyclopentane-hexacarboxylic  ester,  which  is 
formed  by  method  6  (p.  5),  by  the  action  of  Br  upon  pentane-i,  3,  5- 
hexacarboxylic  ester  (C.  1900,  I.  802). 

Cyelopentene-earboxylie  acid  C5H7.COOH,  m.p.  120°,  from  the 
corresponding  aldehyde  with  Ag2O  (C.  1898,  II.  761). 

Cyclopentene-1, 2-dicarboxylic  acid  CH^cH2-CcooH'  m>p'  I78°' 
from  aa1-dibromo-pimelinic  acid  by  the  action  of  Na  alcoholate  (see  also 
p.  5).  Also  from  1, 2-dibromo-cyclopentane-i,  2-dicarboxylic  acid, 
obtained  by  bromination  of  cyclopentane-dicarboxylic  acid,  by  treat- 
ment with  alcohol,  and  KI.  The  acid  easily  adds  2Br  ;  by  melting 
with  potash  it  is  disintegrated  to  adipinic  acid  (B.  28,  655). 

Bis-cyclopentadiene-earboxylie  acid  was  mentioned  above  in  connec- 
tion with  cyclopentadiene. 

Cyclopentane-acetic  acid  C5H9CH2COOH,  b.p.  226°-23O°,  has 
been  obtained  by  transposition  of  cyclopentanol-acetic  ester  with 
HBr  and  reduction  of  the  compound  produced.  Amide,  m.p.  145° 
(A.  353,  304). 

Several  a,  j8-unsaturated  acids  are  obtained  by  rejection  of  water 
from  the  oxy-acids  dealt  with  below. 

Cyelopentsne-acetie  acid  (C5H8) :  CHCOOH,  m.p.  52°,  b.p.13  128°- 
130°;  Methyl-cyclopentene-acetic  acid  (CH3C5H7) :  CHCOOH,  b.p.n 

128° ;    Cyclopentene-propionic  acid  (C5H8) :  cS™**      m.p.  108°. 

\UUUJtl 

On  dry  distillation  these  acids  expel  CO2  and  pass  into  cyclopentene- 
hydrocarbons  with  semicyclic  double  linking ;  see  Methylene-cyclo- 
pentane  (A.  365,  273  ;  C.  1902,  I.  1222).  By  nuclear  synthesis  from 
laevulinic  ester  with  Na  alcoholate  a  Methyl-eyclopentadiene-carboxyl- 
propionic  acid  CH^H^CH^^)  has  been  obtained_  which 

at  218°  gives  off  CO2,  and  melts,  forming  at  first  methyl-cyclo- 
pentadiene-propionic  acid  C5H4(CH3)(CH2CH2COOH),  m.p.  65°,  and 
then  methyl-ethyl-cyclopentadiene  C5H4(CH3)(CH2CH3),  b.p.  135°. 
These  substances  resemble  cyclopentadiene  in  their  behaviour 
(B.  36,  944). 


PENTACARBOCYCLIC   COMPOUNDS  21 

Camphoric  acid,  i-methyl-2-dimethyl-cyclopentane-i,  3-dicarbo- 
xylic  acid,  is  dealt  with  under  camphor  (q.v.). 

6.  ALCOHOL  -  CARBOXYLIC  ACIDS.  —  a-Oxy-eyclopentane-earboxylie 
acid  ^Ha~~  ;H2\c/c°aH,  m  p  ^^  from  cyclopentanone  CyH  and  HC1 

CHg  —  CH2/     \OH 

(A.  275,  333),'  yields  by  reduction  pentamethylene-carboxylic  acid. 

1-Methyl-a-amido-cyclopentane-carboxylie  acid  CH3.C5HS(NH2) 
COOH,  m.p.  299°  (B.  39,  1728).  Hexaehloro-a-oxy-eyclopentene- 

carboxylic  acid        2~aCH'  Senerated  from  chlorinated  cyclo- 


hexene-i,  2-diketone  with  NaCO3  or  sodium  acetate.  On  heating 
it  passes  into  an  isomeric  acid  (B.  23,  824).  Both  acids,  boiled  with 
water,  yield  perchloro-indone  (q.v.)  (A.  272,  243).  Triehloro-eyclo- 
pentene-dioxy-carboxylie  acid  %&*  ]^2)>c<(£°2H,  by  the  action  of 
chlorine  on  alkaline  phenol  solution  (B.  22,  2827). 

1,1-Cyclopentanol  acid  ester  ^SX^cooc^'  b'P'»  I05°- 
107°,  by  condensation  of  cyclopentanone  and  bromacetic  ester  by 
means  of  zinc.  In  the  same  manner  we  obtain  3-Methyl-l,  1-cyclo- 
pentanol-acetic  ester  C5H7(OH)(CH2COOC2H5),  b.p.n  9o°-92°  ;  1,1- 
Cyclopentanol-propionic  ester  C5H8(OH)CH(CH3)COOC2H5  ;  1,  1- 
Cyclopentanol-isobutyric  ester  C5H8(OH)C(CH3)2COOC2H5,  b.p.n  108°- 

ii3°- 

7.  KETONE-CARBOXYLIC  ACIDS.  —  2-Keto-pentamethylene-earboxylic 
ester  CH2.CH(CO2R)\  CO)  from  a^pinic  ester  by  method  40,  p.  4  ;  this 

CH2.CH2  -  / 

ester  may  be  regarded  as  a  carbocyclic  derivative  of.  aceto-acetic 
ester,  and  shows  its  typical  reactions  (Vol.  I.).  With  Na  alcoholate 
and  methyl  iodide  it  yields  l-Methyl-2-keto-pentamethylene-carboxylic 
ester,  b.p.22  108°,  and  by  ketone  splitting,  keto-pentamethylene.  By 
acid  splitting,  adipinic  acid  is  regenerated.  With  amyl  nitrite  and 
Na  ethylate,  a-oximido-adipinic  ester  is  produced. 

4-Methyl-2-keto-pentamethylene-carboxylic  ester  from  j5-methyl- 
adipinic  ester  (A.  317,  27,  etc.  ;  C.  1908,  I.  1169). 

Keto-pentamethylene-3,4-dicarboxylic  acid  CO\CH2CHCO2H'  b>p' 
189°,  by  condensation  of  aconitic  ester  and  Na-malonic  ester,  and 
subsequent  disintegration  (B.  26,  373). 

Keto-pentamethylene-2,  3-dicarboxylic  ester  C 


b.p.18  166°,  obtained  from  butane-i,  2,  4-tricarboxylic  ester  by  method 
4«  (p.  4).     On  saponification  it  expels  CO2,  and  passes  into  : 

Keto-pentamethylene-3-carboxylic  acid,  CH2/^    ~5^V  r       »  m-P- 

\Crla  —  Crl.COOH 

65°  (C.  1908,  II.  1781). 

A  Phenyl-keto-pentamethylene-dicarboxylie  acid  has  been  prepared 
by  condensation  of  2  -  phenyl  -  1,  3,  4  -  butane  -  tricarboxylic  ester 
(A.  315,  219). 

A  Trimethyl-keto-pentamethylene-dicarboxylic  ester,  obtained  from 
dimethyl-butane-tricarboxylic  ester  by  condensation  with  Na  and 
methyl  iodide,  possibly  contains  an  atomic  group  similar  to  that  of 
camphoric  acid  (C.  1900,  II.  332). 


22  ORGANIC  CHEMISTRY 


l-Imino-2-eyano-eyelopentane      2~  =NH>  m-P-  X47°>  Pr°- 

C±i2  —  ^t±z  -  ' 

duced  by  intramolecular  condensation  of  adipinic  dinitrile  with  Na 
ethylate.  Similarly,  2-Imino-3-cyano-cyclopentane-l-carboxylic  ester 

CH2—  CH!CO)R)/>C=NH>  m'p*  I:r9'50'  is  obtained  by  the  action  of 
sodium  cyanacetic  ester  upon  I,  i-cyano-trimethylene-carboxylic  ester 
where  an  intermediate  production  of  ac^-di-cyanadipinic  ester  must 
be  assumed.  On  treatment  with  acids  we  obtain  in  succession  : 
3-Cyano-2-keto-pentamethylene-carboxylicester,b.p.18i72°-i74°,Cyano- 

cyclopentanone      2         ^         CO'  b-P-  229°»  an(i'  nna%>  cyclopentanone 


(C.  1909,  II.  14). 

Several  1,  2-diketo-pentamethylene-carboxylic  acids  have  been 
obtained  by  method  46  (p.  4),  by  condensation  of  oxalic  ester  with 
esters  of  the  glutaric  acid  series,  and  similar  acids,  e.g.  1,  2-Diketo- 

pentamethyIene-3,5-dicarboxylie  ester  cocH(COJR))CH2  (B'  35' 
3206),  and  the  corresponding  methylated  and  phenylated  ester  in  the 
4-position.  Some  interest  attaches  to  the  ester  of  4,  4-Dimethyl- 

1,  2-diketo-pentamethylene-3,  5-dicarboxylic  acid  §o  CH(CO2H)^C(CH3)2' 
which  has  been  made  to  pass  in  succession  into  apocamphoric  acid, 
and  dimethyl-pentamethylene-dicarboxylic  acid,  by  replacement  of 
the  keto-oxygen  atoms  by  hydrogen  (A.  368,  126). 

By  similar  syntheses  we  obtain  from  oxalic  and  tricarbullylic 
ester  :  1,2-  Diketo  -  pentamethylene  -  3,  4,  5  -  tricarboxylic  ester  ;  from 
oxalic  acid  acetone-dicarboxylic  ester  :  1,  2,  4-Triketo-pentamethy- 
lene-3,  5-diearboxylie  ester  (C.  1897,  II.  892  ;  B.  29,  R.  1117). 

2  -  Methyl  -  1  -  acetyl  -  pentamethylene  -  carboxylic    acid 

CH^CH^>KcoOR3'  obtained  by  method  5  (P.  5),  is  an  extracylic 
ketone-carboxylic  ester  (B.  21,  742). 

A  special  group  is  formed  by  some  substances,  in  which  a  five- 
membered  ring  includes  a  three-membered  ring,  the  so-called  bicyclo- 
pentanes.  By  condensation  of  aardibromo-p-dimethyl-glutaric  ester 
with  Na-malonic  ester  a  dimethyl-keto-bicyclopentane-tricarboxylic  ester 
is  formed,  through  the  intermediary  of  a  Dimethyl-trimethylene- 
dicarbo-malonic  ester  : 

COOR          COOR  COOR 

/CHBr  _,rH  s  r/C  -  CH(COOR)2  _  ,rH  .  r/C  -  CH.COOR 
- 


COOR  COOR  COOR 

The  tricarboxylic  ester  is  changed  by  successive  rejection  of 
2COOR  into  Dimethyl-keto-bicyclopentane-di-and-monocarboxylic  acid 
(CH3)2C<^«H(COOH,  and  (CH3)2C/C(COOH).CH2  In  ^  ^^ 

acid  the  trimethylene  ring  is  broken  up  with  formation  of  2-Dimethyl- 
4-keto-pentamethylene-carboxylic  acid  (B.  35,  2126  ;  B.  42,  2770). 

D.  Heptacarbocyclic  Compounds. 

These  substances  have  lately  acquired  additional  importance 
through  their  relations  with  alkaloids  and  terpenes,  as  well  as  the 


HEPTACARBOCYCLIC   COMPOUNDS  23 

so-called  isophenyl-acetic  acid.  The  frequently  easy  transformation 
of  heptacarbocyclic  compounds  into  benzene  derivatives  is  worthy  of 
note.  Synthetically,  most  of  the  suberane  derivatives  have  been 
obtained  by  starting  from  suberone  (cp.  A.  275,  356). 

Suberane,  heptamethylene,  cycloheptane  ™2'^52'^52^CH2>  b.p.  117°, 

Orl2.OjT-2.Lx  rig/ 

generated  by  reduction  of  suberyl  bromide  or  iodide.  By  bromine 
and  Al  bromide  suberane  is  converted  into  penta-bromo-toluol  (q.v.) ; 
by  heating  with  HI,  into  methyl-cyclohexane  and  hexa-hydro-toluol 
(B.  27,  R.  47). 

Ethyl-suberane  C7H13.C2H5,  b.p.  163°,  from  zinc  ethyl  and  suberyl 
bromide.  Two  molecules  of  suberyl  bromide  and  sodium  yield  di- 
suberyl  C7H13.C7H13,  b.p.  291°  (A.  327,  70). 

Suberene,  cycloheptene  ^'^S2'^22^>CH2»  b.p.  114°,  obtained  from 

L-.rl.v_<.H.2.v_/.rl2/ 

suberyl  iodide  with  alcoholic  potash.  Also  from  suberylamine 
by  treatment  with  suberyl-trimethyl-ammonium  hydroxide,  and 
distillation  of  the  latter  (A.  317,  218).  Combines  with  Br  to  form 
a  dibromide. 

AMttethyl-suberene  2!1™1™  ^CCH3»   b-P-   I3^°>  from    methyl- 

U.H.g.L/.H^'L'.H^' 

suberol  on  heating  with  potassium  bisulphate.  On  oxidation  with 
MnO4K  it  yields  c-acetyl-capronic  acid.  Nitroso-chloride,  m.p.  106° 
(A.  345,  139).  Isomeric  with  this  hydrocarbon  is : 

Methylene-cycloheptane  ™2'^52  ™2 /c  =CH"  b-P-  W,  obtained  bv 

L/rl2.L/rl2.Ori2/ 

distillation  of  suberene-acetic  acid.  Nitroso-chloride,  m.p.  81°; 
MnO4K  oxidises  to  glycol  (C6H12)  :  C(OH)CH2OH,  m.p.  50°,  which, 
on  further  action,  passes  into  oxy-suberane-carboxylic  acid  and  into 
suberone  (A.  345,  146). 

Cycloheptadiene,     heptamethylene  -  terpene,     hydro-tropilidene 

;**2\CH2,  b.p.  121°,  by  distillation  of  the  quaternary  ammonium 

Crl  :  Cri.Crl2/ 

bases  generated  by  the  complete  methylation  of  the  various  amino- 
cycloheptenes  (see  below),  produced  partly  by  synthesis  and  partly  by 
disintegration  of  tropin.  Combines  with  Br  to  a  i,  4-dibromide,  which, 
on  heating  with  quinolin,  rejects  2HB  and  becomes : 

Cycloheptatriene,  tropilidene  £^'™  |  en/01*2'  b'p'  Il6°  'A' 317j  2Q^ '' 
the  dibromide  of  the  latter  passes  into  benzyl  bromide  on  heating  to 
100°  with  HBr  (B.  31,  1544). 

Suberyl-aleohol,  cycloheptanol,  C7H13.OH,  b.p.  184°,  is  formed 
besides  suberyl-pinacone  by  reduction  of  suberone  with  Na  and 
alcohol ;  by  strong  reduction  with  HI,  suberyl-alcohol  is  converted 
into  hexahydro-toluol  (B.  30,  1216).  Chloride,  b.p.  174°  ;  bromide, 
b.p.40  101°";  iodide,  D15  1-572.  Suberylamine,  C7H13.NH2,  b.p.  169°, 
by  reduction  of  suberone  oxime,  or  from  suberane-carboxyl  amide 
with  KOBr  (B.  26,  R.  813  ;  A.  317,  219). 

Methyl-suberol  (C6H12)  :  C(OH)CH3,  b.p.  i83°-i85°,  from  suberone 
withMg(CH3)I. 

Cycloheptenol-ethyl  ether,  C7Hn.OC2H5,  b.p.  174°,  from  suberene 
dibromide  with  alcoholic  potash. 

Suberyl-methylamine   (C7H13).CH2NH2,  b.p.   i93°-i95°,  from  the 


24  ORGANIC   CHEMISTRY 

amide  of  suberane-acetic  acid  with  Br  and  alkali.  Nitrous  acid  gives 
suberyl-carbinol,  and  azealol  (A.  353,  327). 

A2-Amino-eyeloheptene  ™2'™2'^525CH-NH1S>  b.p.  166°,  from  A2- 

Crl2.Crl :  Crl  / 

cycloheptene-carboxylic  amide  with  KOBr,  yields  on  methylation 
A2-dimethyl-amino-cycloheptene  C7Hn.N(CH3)2,  b.p.  188°.  this  is 
also  produced  from  suberene  dibromide  with  dimethylamine,  and 
shows  positive  isomerism  with  the  two  methyl-tropanes  interpreted 
as  A3-  and  A4-dimethyl-amino-cycloheptene,  produced  by  disin- 
tegration of  the  alkaloid  tropin  (A.  317,  204  seq.). 

Suberone  [cycloheptanone]  ^S2~~^S2~  S2V°>  b-P-  l8o°>  smells  of 

C112 — Crl2 — L/.hi2/ 

peppermint.  From  distillation  of  Ca  suberinate.  Passes  on  oxidation 
into  pimelinic  acid.  Condenses  like  adipin-ketone  with  benzaldehyde 
into  a  dibenzal  form,  m.p.  108°  (B.  29,  1600).  Suberone  oxime 
C7H12(NOH),  m.p.  23°,  b.p.  230°,  is  transposed  by  concentrated 
H2SO4  into  £-heptolactame  (see  Vol.  I.)  Semicarbazone,  m.p.  164°. 

AVMethyl-suberenone  ™2-^2'£2^c.CH3,  b.p.  2oo°-205°.    Its  oxime 

C-rl  2 .  C/H  2  .GH.'X 

has  been  obtained  from  the  nitroso-chloride  of  A1-methyl-suberene  by 
rejection  of  HC1  (A.  345,  145). 

Suberane-aldehyde  ™2'^2^H2\CH— CHO,  an  oil  smelling  strongly 

CH2.CH2.CH2/ 

of  benzaldehyde,  from  the  glycol  of  methylene-cycloheptane  by  the 
action  of  dilute  H2SO4  (A.  345,  149). 

A^Suberene-aldehyde  $22'^S2'^T :  ^C.CHO  also  smells  strongly  of 

O-H.2.OH2.C/H2/ 

benzaldehyde.  It  has  been  obtained  from  the  nitroso-chloride  of 
methylene-suberane  by  withdrawal  of  HC1,  and  splitting  of  the  oxime 
thus  generated  with  acids.  Silver  oxide  oxidises  it  to  suberane- 
carboxylic  acid. 

Suberane-carboxylic  acid,  cycloheptane-carboxylic  acid,  C7H]3CO2H, 
b.p.15  139°.  Amide,  m.p.  195°,  has  been  obtained  synthetically  from 
Suberane-1, 1-diearboxylic  acid,  the  ester  of  which  is  formed  to  a  slight 
extent  from  hexamethylene  bromide  and  Na-malonic  ester  (B.  27, 
R-  735).  Suberane-carboxylic  acid  is  also  obtained  from  suberyl 
bromide  with  Mg  and  CO2  in  ether,  and  by  reduction  from  the  various 
cycloheptene,  heptadiene,  and  heptatriene  carboxylic  acids.  With 
Br  and  P  it  yields  a-Bromo-suberane-carboxylic  acid,  m.p.  93°,  which, 
by  rejection  of  HBr,  gives  : 

A^Cycloheptene-earboxylie  acid  C7HnCOOH,  m.p.  52°.  Amide, 
m.p.  126°.  This  acid  is  also  obtained,  by  heating  with  caustic  alkali, 
from  the  isomeric  A2-Cyeloheptene-earboxylic  acid,  m.p.  19° ;  amide, 
m.p.  158°.  Both  acids  have  also  been  obtained,  together  with  some 
other  isomers,  by  the  reduction  of  cycloheptatriene-carboxylic  acids 
or  their  dihydrobromides  (A.  317,  234). 

Cycloheptadiene-carboxylie  acid  C7H9.COOH,  m.p.  78°,  identical 
with  hydro-tropilidene-carboxylic  acid,  a  disintegration  product  of 
hydro-ecgonidin  (q.v.). 

Cycloheptatriene  -  carboxylic  acids,  tropilidene  -  carboxylic  acids, 
isophenyl-acetic  acids,  C7H7.COOH :  a,  m.p.  71°  (amide  129°);  ]8,  m.p. 
56°  (amide  98°) ;  y,  liquid  (amide  90°) ;  8,  m.p.  32°  (amide  125°).  The 
isomerism  of  these  acids  is  governed  by  the  various  positions  of  the 


HEPTACARBOCYCLIC   COMPOUNDS  25 

three  double  linkages.  With  HBr  they  form  mono-,  di-,  and  even 
trihydrobromides,  but  on  energetic  treatment  with  HBr  they  are 
transposed  into  the  dihydrobromide  of  p-toluylic  acid.  They  have 
been  obtained  :  (i)  by  disintegration  of  the  alkaloid  ecgonin,  which 
therefore,  like  the  related  tropin,  contains  a  seven-member  carbon 
ring  (B.  31,  2498)  ;  (2)  by  transposition  of  the  pseudo-phenyl-acetic 
acid  or  norcaradiene-carboxylic  acid  (C.  1900,  I.  811).  The  latter, 
generated  from  benzene  and  diazo-acetic  ester  (Vol.  I.)  by  rejection 

of  N,  has  the  formula  ^H=CH^CH/CHC°°H'  and  rePresents  the 
combination  of  a  six-member  ring  with  a  trimethylene  ring,  and 
therefore  a  condensed  nucleus  such  as  is  dealt  with  below.  Similar 
combinations  are  probably  also  contained  in  the  terpene-ketones 
carvone  (q.v.)  and  eucarvone  (q.v.),  of  which  the  latter  passes  by  reduction 
into  dihydro-eucarvone,  which  should  be  regarded  as  methyl-gem- 

dimethyl-cycloheptenone  ^ca\^^^^t  (B.  31,  2068). 

1  -  Oxy  -  suberane  -  earboxylie  acid,  suberyl-glycolic  acid,  C7H12 
(OH)CO2H-f-JH2O,  melts  anhydrously  at  79°.  From  suberone 
with  HCy  and  HC1  ;  also  from  a-bromo-suberane-carboxylic  acid 
with  baryta  water  (B.  31,  2505).  With  PbO2  it  may  be  oxidised 
again  completely  to  suberone  (B.  31,  2507).  With  concentrated  HC1 
or  PC15  it  passes  into  chloro-suberanic  acid,  m.p.  43°  (A.  211,  117  ; 
B.  31,  2004). 

a-Amido-suberane-carboxylie  acid  C7H12(NH2)COOH,  m.p.  (an- 
hydrous) 3o6°-307°  (B.  39,  1730). 

1-Oxy-suberane-acetic    acid,    cydoheptanol  -  acetic    acid 

C.H12>C<^COOH;  the  esters  of  this  acid  (methyl,  b.p.12  1410-145°; 

ethyl,  b.p.n  134°)  are  obtained  from  suberone  and  brom-acetic  esters 
with  Zn  or  Mg.  On  heating  with  potassium  bisulphate,  the  esters 
split  off  H2O  and  pass  into  esters  of  Suberylene-  acetic  acid 
C6H12>  C=CHCOOH,  b.p.17  159°,  which,  on  distillation  at  atmo- 
spheric pressure,  decomposes  into  CO2  and  methylene-cycloheptane 
C6H12>C=CH2  (H.  314,  156;  B.  35,  2143).  By  transposition  with 
halogen  hydrides,  oxy-suberane-acetic  acid  yields  bromo-  and  iodo- 
suberane-acetic  acid,  m.p.  69°  and  81°,  which  by  reduction  pass  into 
Suberane-acetic  acid  (C7H13)CH2COOH,  b.p.19  165°.  Amide,  m.p.  148° 
(A.  353,  301). 

E.  Octocarbocyclic  Compounds. 

The  doubly  unsaturated  hydrocarbons  of  cyclo-octane  have  lately 
attracted  particular  interest  on  account  of  their  relations  to  rubber. 
Pseudo-pelletierin,  the  alkaloid  closely  related  to  tropin  and  tropinone, 
also  contains  the  eight-member  carbon  ring.  It  forms  the  basis  for 
the  majority  of  the  compounds  here  to  be  described. 

Cyelo-octane 


D4  0-849,  nas  been  obtained  by  reduction  of  jS-cyclo-octadiene  with 
Ni  and  H. 


A-'-Cyclo-octadiene  ,    b'P'16    39°'    °4 

generated   together   with    small   quantities   of   an   isomeric,    bicyclic 


26  ORGANIC   CHEMISTRY 

hydrocarbon  during  distillation  of  the  quaternary  ammonium  base 
obtained  by  thorough  methylation  of  N-methyl-granatanin,  a  reduction 
product  of  pseudo-pelletierin  (q.v.)  (cp.  the  analogous  preparation  of 
cycloheptadiene  from  tropane).  The  cyclo-octadiene  is  a  mobile  oil 
of  penetrating  odour,  the  vapour  of  which  is  poisonous.  It  polymerises 
with  extraordinary  facility  even  in  the  cold,  and  explosively  on  heating. 
This  produces  a  dicyclo-octadiene  (C8H12)2,  m.p.  114°,  and  a  polycyclo- 
octadiene  (CsH12)a.,  an  amorphous  mass  with  a  m.p.  above  300°.  Ozone 
transforms  the  cyclo-octadiene  into  a  di-ozonide  C8H12O6,  which,  with 
water,  decomposes  with  formation  of  succinic  dialdehyde.  With 
HBr  it  combines  to  form  a  dihydrobromide  C8H14Br2,  b.p.12  150°, 
from  which,  by  the  action  of  caustic  potash  or  quinolin,  a  /?- Cyclo- 
octadiene,  b.p.  143°,  is  obtained,  which  is  isomeric  with  the  original 
compound.  It  has  an  agreeable  odour  and  shows  no  tendency  to 
polymerisation  (B.  40,  957). 

According  to  Harries,  Para  rubber  is  a  polymerisation  product  of 

[CH3.C CH2 — CHo — CH     ~| 
II  .It 

CH— CH2— CH2— C.CHgJ-r 

is  probably,  therefore,  also  the  intermediate  product  in  the  poly- 
merisation of  isoprene  (Vol.  I.),  which  has  lately  acquired  technical 
importance  (B.  38,  3985). 

As  from  suberinic  acid  we  obtain  suberone,  so  by  distillation  of  cal- 

/->TT  PfT  PW  f*O 

cium  azelainate  we  obtain  Azelaone,  cydo-octanone  *    2 !  ~ ,     , 

but  only  in  small  quantities.  It  is  an  oil  with  an  odour  closely 
resembling  suberane,  b.p.  I95°-I97°,  m.p.  25°-26°.  Semicarbazone, 
m.p.  85°.  On  oxidation  with  MnO4K  the  ketone  yields  cork  acid. 
By  reduction  with  Na  and  alcohol  it  passes  into  the  corresponding 

alcohol  called  Azelaol  CH2-CH2— CH2— CH°H'  b'p'  l88°'  This  is  also 
obtained  by  the  action  of  nitrous  acid  upon  suberyl-methylamine 
(B.  31,  1957  ;  C.  1899,  II.  182  ;  A.  353,  328). 

Tricyclo-octane-,  dimethyl-,  and  diphenyl-trieyclo-oetane  are  sup- 
posed to  be  represented  by  the  hydrocarbons  derived  from  the  diolefin- 
carboxylic  acids  (vinyl-acrylic  acid,  sorbinic  acid,  and  cinnamenyl- 
acrylic  acid)  on  heating  with  baryta  water,  polymerisation,  and 
rejection  of  CO2  (B.  40,  146).  These  formulae  are,  however,  not  yet 
sufficiently  well  established. 

F.  Nonocarbocyclic  Compounds. 

Compounds  with  a  ring  of  nine  carbon  atoms  have  only  been 
obtained  quite  recently.  But  the  physical  data  indicate  that  these 
substances  are  not  yet  obtainable  in  a  state  of  purity. 

Cyclononanone  ^H'— CH"— CH'— CH' /CO'  b'p'17  95°~97°'  D422'5 
0-8665,  is  obtained  in  minute  quantities  on  distilling  sebazinic  acid 
with  slaked  lime.  Semicarbazone,  m.p.  105°.  Na  reduces  it  to : 

Cyclononanol  ^'Zcn2— CH'— CH2/CHOH>  b'p'13  97°~I05°>  which> 
through  the  corresponding  iodide,  can  be  transformed  into : 

the  fundamental  hydrocarbon  of  this  series  (B.  40,  3277,  3876). 


BENZENE  DERIVATIVES  27 

II. -HEXACARBOCYCLIC  COMPOUNDS 

THE  chemistry  of  hexacarbocyclic  compounds  is  incomparably 
greater  and  more  richly  developed  than  the  chemistry  of  the  ring 
systems  dealt  with  in  the  preceding  chapter.  Hexacarbocyclic 
compounds  may  be  divided  into  three  classes  : 

A.  Mononuclear  aromatic  substances,  or  benzene  derivatives. 

B.  Mononuclear  hydro-aromatic  substances.    This  class  contains 
the  terpene  group  and  the  camphor  group. 

C.  Polynuclear   aromatic    substances.     The   fundamental   hydro- 
carbons of   this  group  contain  (a)  several  benzene   nuclei   connected 
direct  or  by  aliphatic  hydrocarbon  residues  ;  or  (b)  two  or  more  nuclei 
are  so  combined  with  one  another  that  two  carbon  atoms  are  common 
to  each  (twin  nuclei,  condensed  nuclei). 

CTT  /"^     TT    V  /"*     "1 

6^5  ^e^sXpTj  W 

C6H5  C.H5/       2  C.1 

Diphenyl     Diphenyl-methane    Triphenyl-methane     Tetraphenyl-methane 

C6H5CH2         C6H5CH  CaH6C 

II  III 

C6H5CH2         C6H5CH  C6H5C 

Dibenzyl         Stilbene  Tolane 

/CH%  C.H4X 

Indene  Fluorene          Naphthalin   Anthracene,  etc. 

With  each  of  these  hydrocarbons  numerous  derivatives  of  all 
kinds  may  be  associated,  thus  forming  an  unlimited  field.  Many  of 
these  bodies,  especially  naphthalin  and  its  derivatives,  give  rise  to 
hydro-compounds.  These  are,  however,  not  dealt  with  as  a  separate 
fourth  class,  but  always  in  connection  with  the  unhydrogenated 
derivatives  of  the  hydrocarbons  in  question. 

A.  Mononuclear  Aromatic  Substances  or  Benzene  Derivatives. 

By  the  name  "  aromatic  "  compounds  we  designate  substances 
which  are  mostly  obtained  from  aromatic  oils  and  resins,  and  which 
differ  in  general  from  the  fatty  bodies  or  methane  derivatives  by 
various  peculiarities,  especially  a  greater  content  of  carbon  and  a 
well-marked  "  aromatic  "  odour.  Our  theoretical  conceptions  con- 
cerning the  constitution  of  these  compounds  are  mainly  derived  from 
the  benzene  theory  formulated  in  1865  by  Kekule.  It  may  be 
summarised  in  the  following  theses  (cp.  Kekule,  Lehrbuch  der  org. 
Chemie,  ii.  493 ;  A.  137,  129)  : 

1.  "  All  aromatic  compounds  are  derived  from  a  nucleus  consisting 
of  six  carbon  atoms,  the  simplest  combination  of  which  is  benzene 
C6H6.     They  are  produced  by  the  replacement  of  the  H  atoms  by 
other  atoms  or  groups  of  atoms  (side  groups).     They  all  show  the 
specific     benzene    characteristics,    contrasting     with     the    methane 
derivatives,  and  should  be  called  '  benzene  derivatives.'  ' 

2.  "  Benzene  has  a  symmetrical  constitution.     Each  carbon  atom 
is  joined  to  an  H  atom  to  a  carbin  group  CH.     As  in  the  case  of  the 
polymethylene  derivatives,  no  differences  can  be  traced  between  the 


28  ORGANIC   CHEMISTRY 

several  C  or  H  atoms,  and  isomerisms  of  derivatives  are  therefore 
only  found  in  the  case  of  two  or  more  side  groups." 

3.  "  The  structure  of  the  benzene  nucleus  resembles  the  methane 
derivatives  in  that  the  six  atoms,  or  CH  group,  are  alternately  bound 
by  single  and  double  links,  thus  making  a  closed  ring-formed  chain  of 
six  carbon  atoms,  according  to  the  scheme  : 

C=C 
C=C— C=C— C=C     or  — C  C— 

1 '        V/ 

/      \ 

which  can  also  be  expressed  by  a  regular  hexagon.  The  fourth  valence 
of  the  carbon  atoms  is  attached  in  benzene  to  an  H  atom,  and  in  its 
derivatives  to  other  atomic  groups." 

Historical. — The  first  to  invent  a  structural  formula  for  an  aromatic 
compound  was  Archibald  Scott  Couper,  who  in  1858,  in  his  work  on 
salicylic  acid  (C.R.  46,  1107),  represented  it  by  the  formula: 

C        H2 
C         H 


fC         H 
1C        o 


OH  <°=8> 


c|02 
1  O 


OH 


In  1861  J.  Loschmidt  published  a  pamphlet  called  Chemisette 
Studien  (Wien,  Gerold),  with  new  graphic  formulae  for  360  substances, 
among  them  being  180  aromatic  compounds.  Loschmidt  charac- 
terises the  aromatic  acids  as  substances  with  incomplete  nuclei,  having 
incompletenesses  in  eight  places.  The  simplest  of  these  nuclei  is 
C6VI,  for  which  he  brings  the  six  carbon  atoms  close  together : 

(Scheme  181  of  Loschmidt) 

thus  obtaining  a  formula  as  contained  in  Couper's  salicylic  acid 
formula.  He  figures  the  C  atoms  by  means  of  circles  touching  where 
there  is  single  binding,  and  intersecting  where  there  is  plural  binding. 
He  prefers,  however,  a  "  stratification  "  of  the  six  C  atoms  to  their 


Allyl  JL_  ^^^J^J  "    Benzo1  nucleus 

(Scheme  68).  ^~~Y]fll  (Scheme  182). 


"  condensation,"  and  imagines  the  nucleus  as  a  double  allyl  nucleus 
(scheme  182).  For  allyl,  Loschmidt  had  considered  the  trimethylene 
formula  (scheme  68).  Loschmidt,  however,  left  the  question  of 
nuclear  constitution  in  suspense,  his  constructions  being  independent 


BENZENE   DERIVATIVES 


29 


of  it.     He  says  :  "  We  assume  for  the  nucleus  C6VI  the  symbol  184  " 
— a  larger  circle — "  and  treat  it  as  if  it  were  a  hexavalent  element." 

Loschmidt  then  gives  graphic  formulae  for  many  benzene  deriva- 
tives, some  of  which  are  given  here  : 


o 

C,VI  (184). 


C6H6  (i  86). 


CeH6CH3  (197). 


Of  these,  185  represents  phenol,  and  197  toluol. 

Loschmidt  had  therefore  already  formed  the  first  thesis  of  Kekule's 
benzene  theory.  He  says  nothing  about  the  equivalence  of  the  six 
benzene  H  atoms.  It  was,  in  fact,  excluded  on  the  assumption  that  the 
benzene  molecule  consisted  of  two  stratified  allyl  rings,  since  in  scheme 
182  the  free  valencies  are  unequally  distributed,  as  shown  by  the 
points  of  scheme  181.  Kekule,  on  the  other  hand,  places  the  structure 
of  the  nucleus  into  the  foreground,  and  derives  from  it  the  equivalence 
of  the  six  H  atoms  and  the  explanation  of  the  isomerism  of  the  substi- 
tution products. 

GENERAL  SURVEY  OF  THE  BENZENE  DERIVATIVES. 

The  benzene  derivatives  can  be  derived  from  the  replacement  of 
the  H  atoms  of  benzene  in  the  same  manner  as  the  aliphatic  substances 
are  derived  from  methane.  Benzene  derivatives  with  side  chains 
containing  carbon  may  be  built  up  from  benzene  and  brought  back 
to  benzene  by  eliminating  the  side  chains.  Benzene  derivatives  differ 
from  methane  derivatives  in  the  stability  of  the  benzene  nucleus. 
Thus  oxidation  usually  stops  short  at  the  benzene  nucleus,  and  so 
does  reduction  in  general,  leading  finally,  as  a  rule,  to  cyclohexane 
derivatives  or  hexahydro-benzene  derivatives,  without  any  splitting 
of  the  benzene  ring.  Reduction  therefore  connects  benzene  deriva- 
tives with  cyclohexane  derivatives  (p.  2). 

Those  benzene  derivatives  which  are  solid  at  ordinary  temperatures 
are  often  distinguished  for  their  ease  of  crystallisation,  and  this  is  a 
great  aid  to  their  experimental  investigation. 

The  H  of  benzene  is  easily  replaced  by  the  halogens  and  the 
groups  nitro  NO2  and  snip  ho  SO3H  : 


Chloro-benzene     . 

Nitrobenzene 

Benzol-sulpho-acid 


CaH5Cl 

C6H5N02 

C6H5S03H 


C6H4C12 

C6H4(N02)2 

C6H4(S03H)2 


C6H3C13 C6C16 

C6H3(N02)3 
C6H3(S03H)3 


According  as  to  whether  one,  two,  three,  or  more  H  atoms  of  benzene 
are  replaced,  we  distinguish  mono-,  di-,  tri-,  tetra-,  penta-,  or  hexa- 
derivatives  of  benzene. 

Specially  characteristic  for  the  benzene  derivatives  is  the  formation 
of  nitro-bodies  through  the  direct  action  of  HNOg,  whereas  the  aliphatic 
bodies  are  generally  oxidised  or  decomposed  by  it. 

Reduction  of  the  nitro-bodies  produces  the  amido-compounds  : 

Amido-benzene  (aniline)     C6H5NH2     C6H4(NH2)2     C6H3(NH2)3. 


3o  ORGANIC   CHEMISTRY 

As  intermediate  products  of  reduction,  we  have  the  so-called  azo- 
compounds,  while  the  action  of  nitrous  acid  upon  amido-compounds 
produces  the  diazo-compounds  ;  both  classes  of  bodies  are  only  excep- 
tionally present  in  the  aliphatic  series  (Vol.  I.). 

On  replacing  the  H  in  benzene  by  hydroxyl  we  obtain  the  phenols, 
comparable  to  the  alcohols  : 

C6H6OH  C6H4(OH)2  C6H3(OH)3 

Phenol  (carbolic  acid)  Dioxy-benzol  Trioxy-benzol. 

Like  the  tertiary  alcohols,  the  phenols  contain  the  group  C.OH 
linked  to  three  C  valences,  and  they  cannot  therefore  form  any  corre- 
sponding aldehydes,  ketones,  or  acids  by  oxidation. 

The  benzene  nucleus  weakens  the  basic  properties  of  the  amido- 
group  and  imparts  acid  properties  to  phenyl-hydroxyl.  It  possesses 
a  more  negative  character  than  the  residues  of  aliphatic  hydrocarbons. 

By  the  entry  of  monovalent  paraffin,  olefin,  and  acetylene  residues, 
the  so-called  homologous  benzene  hydrocarbons  are  derived,  both 
saturated  and  unsaturated  : 


C6H6  C6H5CH3  C6H4(CH3)2         C6H5CH2.CH3         CeH^H,,  etc. 

Benzolene     Methyl-benzol      Dimethyl-benzol    Ethyl-benzol         Propyl-benzol 
(toluol)  (xylol) 

C6H5CH=CH2  C6H5C=CH,  etc. 

Vinyl-benzol  (styrol)  Acetylene-benzol. 

In  these  hydrocarbons  the  benzene  nucleus  preserves  the  specific 
properties  of  benzene.  Its  hydrogen  is  easily  replaced  by  halogens 
and  by  the  groups  NO2  and  SO3H.  But  the  side  chains  behave  just 
like  the  hydrocarbons  of  the  fatty  series  ;  its  hydrogen  can  be  replaced 
by  halogens,  but  not  (through  action  of  concentrated  HNO3  or  H2SO4) 
by  the  groups  NO2  or  SO3H.  According  as  to  whether  the  halogens 
(or  other  groups)  enter  into  the  benzene  residue  or  into  the  side  chains, 
we  obtain  different  isomers  : 

Chloro-toluol     C6H4C1.CH3  Benzyl  chloride  C6H5.CH2C1 

Dichloro-toluol  C6H3C12.CH3  Chloro-benzyl  chloride  C6H4C1.CH2C1 

Benzal  chloride  C6H5CHC12. 

The  halogen  atoms  in  the  benzene  residue  are  firmly  held,  and  usually 
incapable  of  a  double  substitution,  while  the  halogen  atoms  in  the 
side  chains  act  just  as  in  the  methane  derivatives. 

If  in  the  side  chains  H  is  replaced  by  hydroxyl,  we  get  the  true 
alcohols  of  the  benzene  series  : 


C6H5.CH2OH  C6H5.CH2.CH2OH  C' 

Benzyl-alcohol  Phenyl-ethyl-alcohol  Tolyl-alcohol 

the  primary  ones  of  which  form  aldehydes  and  acids  by  oxidation  : 


CHO 
Benzaldehyde  Phenyl-acetaldehyde  Tolyl-aldehyde. 

The  acids  in  which  COOH  is  joined  to  the  benzene  nucleus  may 
also  be  produced  by  direct  introduction  of  carboxyl  into  the  benzene, 
or  by  oxidation  of  the  homologues  of  benzene  : 


1SOMERISM   OF  THE   BENZENE   DERIVATIVES          31 

C6H5.C02H  C6H4(C02H)a  C6H3(CO2H)3 

Benzol-carboxylic  acid   Benzol-dicarboxylic  acid    Benzol-tricarboxylic  acid 


/->  TU  3  r  TJ    /TJ    m  TJ  r  W  ••'•"•32 

C6H*\CO?H  C6H5.CH2.C02H  C«H3\CO2H 

Toluylic  acid  Phenyl-acetic  acid  Mesitylenic  acid. 

In  these  acids,  as  well  as  the  alcohols  and  aldehydes,  the  H  of  the 
benzene  residue  is  also  replaceable  by  halogens  and  by  the  groups 
NO  2,  SO3H,  OH,  etc. 

In  the  above  discussion  benzene  was  regarded  as  the  foundation. 
The  various  benzene  derivatives  with  aliphatic  side  chains  were  all 
regarded  as  benzene  substitution  products.  It  is  obvious  that  this 
view  may  be  reversed.  Then  the  benzene  derivatives  with  a  single 
side  chain  appear,  e.g.  as  phenyl  substitution  products  of  the  aliphatic 
substances,  as  exemplified  by  the  following  terminology  : 
C6H5CH3  Phenyl-methane  C6H5CH2CH2OH  Phenyl-ethyl-alcohol 

CSH5CC13        Phenyl-chloroform  C6H5CH2CHO  Phenyl-acetaldchyde 

C6H5CH2OH  Phenyl-methyl-alcohol     C6H5CH2COOH         Phenyl-acetic  acid 
C6H5COOH    Phenyl-formic  acid  C6H6CH2CH2CO2H  Phenyl-propionic  acid. 

ISOMERISM   OF  THE   BENZENE   DERIVATIVES. 

Proof  of  the  equivalence  of  the  six  H  atoms  of  Benzene.  —  If  in  benzene 
one  H  atom  is  replaced  by  another  atom  or  atomic  group,  any  compound 
so  obtained  is  only  found  in  one  modification  ;  there  is  but  one  chloro- 
benzene,  one  nitro-benzene,  one  amido-benzene,  one  toluol,  one  benzoic 
acid  ;  so  the  compounds 

C6H5C1    C6H5.N02    C6H5.NH2    C6H5CH3     C6H5.CO2H2  etc. 

are  only  known  in  one  modification.  The  six  H  atoms  of  benzene 
are  equivalent,  like  the  four  H  atoms  of  methane  (Vol.  I.).  Benzene 
has  a  symmetrical  structure. 

Historical.  —  The  proof  of  the  equivalence  of  the  six  hydrogen  atoms 
of  benzene  was  given  in  1869  simultaneously  and  independently  by 
W.  Korner  and  A.  Ladenburg  (B.  2,  274,  1869  ;  7,  1684  ;  8,  1666). 

i.  Both  investigators  used  the  transformation  of  the  three  monoxy- 
benzoic  acids  into  the  same  phenol,  in  order  to  prove  the  equivalence 
of  the  three  positions  taken  by  the  carboxyl  in  benzene. 

According  to  Korner,  it  follows  from  the  reduction  of  the  three 
monochloro-benzoic  acids  with  Na  amalgam  to  the  same  benzoic  acid. 

The  equivalence  of  a  fourth  H  atom  follows,  according  to  Laden- 
burg,  from  the  transformation  of  phenol  into  bromo-benzol,  and  from 
this  into  benzoic  acid.     Ladenburg's  proof  of  the  equivalence  of  four 
H  atoms  of  benzene  may  therefore  be  represented  as  follows  : 
a  b        c        d       e         f 


C6  (OH)  H  H  H  H  H 

C6  Br  H  H  H  H  H 

C6  (C02H)  H  H  H  H  H 

C6  (C02H)  OH  H  H  H  H 

C6  (CO2H)  H  OH  H  H  H 

C6  (CO2H)  H  H  OH  H  H 


Phenol 

|    Bromo-benzol 

.!.    Benzoic  acid  t 


I    Ortho-oxy-benzoic  acid 


Meta-oxy-benzoic  acid 
Para-oxy-benzoic  acid 


Korner  deduced  the  equivalence  of   the  fourth  H  atom  with  the 
three  H  atoms  replaced  by  carboxyl  in  the  three  monoxy-  and  the 


32  ORGANIC  CHEMISTRY 

three  monochloro-benzoic  acids  from  the  following  facts  : — Para-oxy- 
benzoic  acid  corresponds  to  para-nitraniline  (Arppe),  which  is  con- 
vertible into  either  paranitro-chloro-  or  paranitro-bromo-benzene. 

Paranitro-chloro-benzene,  by  replacement  of  the  nitro-group  by 
Br,  gives  the  same  parabromo-chloro-benzene  as  is  obtained  on  sub- 
stituting Cl  for  the  nitro-group  in  paranitro-bromo-benzene.  Hence 
the  two  H  atoms  which  are  replaced  in  para-nitraniline  by  the  nitro- 
and  amido-group  respectively,  are  equivalent,  as  are  also  the  H  atoms  re- 
placed by  hydroxyl  and  carboxyl  respectively  in  para-oxy-benzoic  acid. 

a          bed  e        f 

C6      OH       H      H      CO2H     H      H      Para-oxy-benzoic  acid 
C6      NO2      H      H      NH2       H      H      Para-nitraniline 

^C6      N02      H      H      Cl  H      H  >  C6      Br      H      H      Cl      H      H 

C6      N02      H      H      Br          H      H  >  C6      Cl       H      H      Br      H      H 

This  proves  the  equivalence  of  four  H  atoms  of  benzene. 

2.  Each  hydrogen  atom  of  benzene  has  two  pairs  of  H  atoms 
arranged  symmetrically  with  respect  to  it,  i.e.  so  that  the  replacement 
of  either  of  the  two  H  atoms  of  a  pair  by  the  same  atom  or  the  same 
atomic  group  leads  to  the  same  compound. 

Korner  proves  this  symmetry  as  follows  for  two  H  atoms.  The 
volatile  nitro-phenol  which  is  convertible  into  pyrocatechin,  and  there- 
fore belongs  to  the  same  series  as  salicylic  acid,  may,  by  replacing  two 
H  atoms  by  one  Br  atom  and  one  nitro-group  respectively,  be  converted 
into  the  same  bromo-nitro-ortho-nitro-phenol  as  is  obtained  by  intro- 
ducing two  nitro-groups  into  ortho-bromo-phenol : 

abcdef  abcdef 

Cl      OH      Br°2      H      H      H      H^  °«       °H      N°>      H      N°«      H      * 

b=f. 

It  is  therefore  clear  that  in  phenol  there  are  two  H  atoms  sym- 
metrical to  hydroxyl,  and  that  it  is  immaterial  which  of  them  is  repre- 
sented by  bromine,  and  which  by  a  nitro-group.  But  if  this  symmetry 
is  established  for  one  pair  of  H  atoms,  it  is  also  established  for  the 
second  pair,  since  the  symmetry  of  the  first  pair  is  unthinkable  without 
the  symmetry  of  the  second  pair.  Hence  follows  the  equivalence  of 
all  the  H  atoms  of  benzene. 

The  symmetrical  arrangement  of  two  H-atom  pairs  in  benzene  can 
also  be  proved  as  follows.  For  one  pair,  b  and  /,  this  thesis  follows 
from  the  formation  of  the  same  ortho-amido-benzoic  acid  out  of  two 
different  nitro-bromo-benzoic  acids,  obtained  by  the  nitration  of  meta- 
bromo-benzoic  acid  (Hiibner  and  Petermann,  A.  149,  129  ;  222,  in  ; 
Ladenburg,  B.  2,  140) : 

a          b         c       d      e       f 
C      COjjH     H       Br     H     H     H      Meta-bromo-benzoic  acid 


C,     C02H     N02  Br     H     H     H 
C6     CO2H     H       Br     H     H     NO2 
C6     C02H     NH2  H      H     H     H 


v-Meta-bromo-ortho-nitro-benzoic  acid* 
as-Meta-brorao-ortho-nitro-benzoic  acid  * 
Ortho-amido-benzoic  acid 


C      CO2H     H       H      H     H     NH2          Ortho-amido-benzoic  acid  < ' 

Hence  ab  =af. 

*  The   designations  v  and  as  are  dealt  with  below  in   connection   with   the 
tri-derivatives. 


ISOMERISM   OF  THE   BENZENE   DERIVATIVES         33 

For  the  second  pair  the  proof  is  furnished  by  the  formation  of 
the  same  meta-bromo-toluol  from  two  bromine  compounds  (Wro- 
blewsky,  A.  192,  213  ;  234,  154),  in  which  bromine  replaces  two 
different  H  atoms,  which  therefore  are  symmetrical  with  the  H  atom 
replaced  by  the  methyl  group  of  toluol  :  ac=ae. 


a         b     c  d  e    f 

C,  CH3      H  H    NH(COCH3)  H  H 
C6  CH3      H  Br  NH(COCH3)  H  H 


C,  C02H  H  Br  H  H  H 


a      b    c  d  e      f 

C6  CH3  H  Br  NH(COCH3)    NO2  H 


C,  CH3      H  Br          NH2          H  H  v  C6  CH3  H  Br  H  NO,  H 

C6  CH3      H  Br  H  H  H  |  C,  CH3  H  H  H  NH,  H 


C8  CH3  H  H  H  Br     H 


By  oxidation  this  bromo-toluol  passes  into  the  same  meta-bromo- 
benzoic  acid  which  above  served  as  a  basis  for  the  proportion  of  v- 
and  rts-meta-brom-ortho-nitro-benzoic  acid.  Hence  it  follows  that 
bromine  in  the  last  proof  replaces  two  H  atoms  other  than  those  re- 
placed by  the  amido-group  in  ortho-amido-benzoic  acid,  and  that  in 
benzene  there  are  not  one  but  two  pairs  of  H  atoms  in  symmetrical 
position  with  respect  to  an  H  atom.  This  establishes  the  equivalence 
of  the  six  pairs  of  H  atoms.  (See  also  Ladenburg,  B.  10, 1218.) 

For  the  second  pair  of  H  atoms  the  proof  of  symmetry  may  be  given 
as  follows.  The  ortho-amido-benzoic  acid  obtained  in  two  ways  (see 
above)  may  be  converted  into  the  same  oxy-benzoic  acid,  viz.  salicylic 
acid,  which  on  nitrogenation  gives  two  different  mononitro-salicylic 
acids.  By  heating  the  ethyl  ethers  of  these  two  nitre-salicylic  acids 
with  ammonia  the  ethoxyl  groups  can  be  replaced  by  the  amido- 
groups,  and,  from  the  nitro-amido-benzoic  amides,  the  free  nitro- 
amido-benzoic  acids  may  be  obtained,  which  with  nitrous  acid  and 
alcohol  are  converted  into  the  same  nitro-benzoic  acid.  Since  this 
nitro-benzoic  acid,  obtained  from  two  different  nitro-salicylic  acids, 
yields  a  (meta)  amido-benzoic  acid  different  from  the  amido-benzoic 
acid  from  which  the  salicylic  acid  was  obtained,  and  since  it  yields  a 
(meta)  oxy-benzoic  acid  different  from  salicylic  acid,  it  follows  that 
there  are  two  further  H  atoms  symmetrically  placed  with  respect  to 
the  H  atom  replaced  by  the  COOH  group : 

a  bcdef  a  bcde           f 

!  Ca  CO2H  NH2    H  H  H  H  =  C6  CO2H  H  H     H  H  NH2  , 

|C6  CO2H  OH      H  H  H  H  =  C6  CO2H  H  H     H  H  OH  4- 

|C6  CO2H  OH      NO2  H  H  H~~   ~-^C6CO2H  H  H     H  NO2  OH 

TC6  CO2H  NH2    NO2  H  H  H  I  C6  CO2H  H  H     H  NO2  NH2 

tie,  C02H  H        N02  H  H  H  =  |  C.  CO2H  H  H     H  NO2  H 

JC6  CO2H  H        NH2  H  H  H  =  j  C6  CO2H  H  H     H  NH2  H 

1C,  C02H  H        OH  H  H  H  =  I  C«  CO2H  H  H     H  OH  H 

For  the  third  oxy-benzoic  acid,  para-oxy-benzoic  acid,  only  one 
position  therefore  remains,  viz.  the  para  position,  which  in  benzene 
is  only  possible  once. 

The  equivalence  of  the  six  H  atoms  has  lately  been  proved  by 
Noelting  in  a  very  simple  manner  (B.  37,  1027). 

In  amido-benzol  or  aniline  the  amido-group  is  easily  replaced  by 
bromine,  and  the  latter  by  the  CH3  group  with  the  aid  of  methyl  iodide 
VOL.  II.  D 


34 


ORGANIC   CHEMISTRY 


and  sodium.  In  the  toluol  thus  produced  the  methyl  group  therefore 
takes  up  the  same  position  as  the  amido-group  does  in  aniline.  From 
the  toluol  we  obtain  by  nitrogenation  three  isomeric  nitro-toluols, 
and  from  these  by  reduction  three  toluidins,  which  by  acetylation, 
oxidation,  and  the  elimination  of  the  acetyl  group  can  be  transformed 
into  three  different  amido-benzoic  acids.  These  all  yield,  by  rejection 
of  CO 2,  an  amido-benzol  identical  with  the  initial  product,  which 
proves  the  equivalence  of  four  H  atoms : 


a 

b 

c 

d 

e 

f 

|C6 

NH2 

H 

H 

H 

H 

H 

r* 

^6 

CH3 

H 

H 

H 

H 

H 

V.P 

-^•v^8 

CH3 

NH2 

H 

H 

H 

H 

-^C6 

CH3 

H 

NH2 

H 

H 

H 

—*c. 

CH3 

H 

H 

NH5 

H 

H 

f 

H<  

H 

a 

b 

c 

H  > 

-c6 

C02H 

NH2 

H 

H  — 

-ce 

C02H 

H 

H 

H  >—  C6 

CO2H 

H 

H 

a=b=c=d. 

d  e 
H  II 
NH2H 
NH,  H 


The  proof  of  the  second  thesis  (that  one  H  atom  has  two  other  H 
atoms  placed  symmetrically  to  it)  is  based  upon  one  of  the  nitro- 
toluols  just  referred  to,  in  which  the  CH3  group  takes  up  position  a. 
This,  on  reduction,  yields  a  toluidin  from  which,  by  nitrogenation  of 
its  acetyl  compound  and  saponification,  four  isomeric  nitro-toluidins 
are  obtained.  By  elimination  of  the  amido-group  these  yield  four 
nitro-toluols.  Now,  it  is  found  that  of  these  two  are  identical  with 
each  other  and  two  with  the  initial  nitro-toluol,  which  proves  the 
symmetrical  position  of  two  pairs  of  H  atoms  : 


!  C6  CH3  N02  H 

i  C6  CH3  NH2  H 

— >C6  CH3  NH2  H 

-^C6  CH3  NH2  H 

— >C6  CH3  NH2  NO2  H 

— >C«  CHo  NH,  H 


d 
H 
H 

e 
H 
H 

f 
H 

H 

H 

N02- 

H 

N02 

H—                  a 

b 

c 

d 

e 

f 

H 

H 

H  ^C6  CH3 

H 

N02 

H 

H 

H 

N02 

H 

H  >  Cg  CH3 

H 

H 

N02 

H 

H 

ab  =  af     ac=ae. 


The  six  H  atoms  of  benzene  are  therefore  equivalent,  and,  since  there 
are  two  pairs  of  symmetrically  placed  H  atoms  to  each  single  H  atom, 
a  di-substitution  product  of  benzene  can  only  occur  in  three  isomeric 
modifications. 

PRINCIPLES  OF  LOCATION  FOR  BENZENE  SUBSTITUTION  PRODUCTS. 
The  equivalence  of  the  six  H  atoms  in  benzene  is  expressed  by  the 


hexagon  diagram,  in  which  the  mutual  linking  of  the  C  atoms  may  for 
the  present  be  disregarded.     It  is  obvious  that  of  each  bi-derivative 


BENZENE   SUBSTITUTION   PRODUCTS  35 

CGH4X2  obtained  by  replacement  of  two  H  atoms  three  modifications 
are  possible  and  that  their  isomerism  depends  upon  the  relative 
position  of  the  two  new  groups  entering  the  benzene  scherrte.  This 
is  called  isomerism  of  position  or  geometrical  isomerism  (Vol.  I.  p.  32). 
And  in  fact  three  modifications  are  known  of  most  di-derivatives,  but 
not  more  than  three.  Thus  there  are  three 

r  w  / 
C'H< 


OH  r  „  /Br  r  „  /NH2  r  „  /OH 

OH  C'H*\N02  C'H<NH2  C'H<N02 

Dioxy-benzols    Bromo-nitro-benzols    Dianiido-benzols         Nitro-phenols 


T/ 
C'H< 


C02H  rw/CH3  PTT/C02H 

OH  C'H4\CH3  C«H*\CH3  'C02H 


Oxy-benzoic  acids    Dimethyl-benzols         Toluylic  acids        Phthalic  acids,  etc. 

The  three  modifications  of  each  of  these  compounds  can  be  con- 
verted into  the  corresponding  modifications  of  the  others.  If,  therefore, 
we  have  determined  the  relative  positions  of  the  replacing  atoms  or 
atomic  groups  in  the  three  modifications  of  one  of  these  bodies,  it  is 
known  for  all  the  others,  and  they  can  be  converted  into  the  three 
modifications  of  the  first  body  by  straightforward  reactions  free  from 
intramolecular  atomic  displacements.  The  relative  positions  of  re- 
placing groups  have  been  determined  in  the  case  of  several  di- 
substitution  products,  e.g.  the  three  dibromo-benzols,  the  three 
diamido-benzols,  and  the  three  phthalic  acids.  In  this  way  a 
basis  has  been  obtained  for  arranging  the  other  di-substitution 
products  in  three  series,  designated  as  ortho-,  meta-,  and  para-series 
respectively. 

In  the  ortho-compounds  two  adjoining  H  atoms  are  replaced.  If 
the  six  H  atoms  of  benzene  are  indicated  by  numbers  or  letters,  and 
any  one  of  them  by  i  or  a,  we  see  that  there  are  two  ortho-positions  : 
a,  b=a,  f,  or  i,  2=1,  6  ;  b  or  2  and/  or  6  are  symmetrical  to  a  or  i. 
The  meta-compounds  are  produced  by  replacement  of  the  atoms  a,  c 
=a,  e,  or  i,  3=1,  5,  the  positions  c  (3)  and  e  (5)  being  symmetrical 
to  a  (i).  The  ^am-compounds  are  produced  by  replacing  the  H  atoms 
a,  d  or  i,  4.  While,  therefore,  there  are  two  equivalent  places  for  the 
ortho-  and  meta-positions,  viz.  2  and  6,  3  and  5  respectively,  the  para- 
position  has  only  one  location  corresponding  to  i,  viz.  4. 

The  location  of  the  replacing  groups  in  the  di-derivatives  is  indi- 
cated by  prefixing  ortho-,  meta-,  and  para-  to  the  compounds,  abbreviated 
into  o,  m,  and  p,  or  by  prefixing  the  numbers  [i,  2]-,  [i,  3]-,  [i,  4]- 
enclosed  in  square  brackets.  The  formulas  are  often  represented  by 
writing  the  benzene  ring  as  a  hexagon  and  attaching  the  atoms  or 
atomic  groups  to  its  corners.  Or,  again,  by  introducing  the  location 
figures  between  the  benzene  residue  and  the  substitution  groups  : 

OH  OH  OH 

^"  -  10H 


H  H  OH 

Pyro-catechin                          Resorcin  Hydroquinone 

o-Dioxy-benzol                       m-Dioxy-benzol  p-Dioxy-benzol 

[i ,  2]-Dioxy-benzol  [i ,  3]-Dioxy-benzol  [i ,  4J-Dioxy-benzol. 


36  ORGANIC  CHEMISTRY 

Among  the  principal  representatives  of  the  three  isomeric  series  we 
may  put  the  following  : 

Ortho,  [1,2]  Meta,  [1,3]  Para,  [1,4] 

C6H4\  Salicylic  acid     Meta-oxy-benzoic  acid       Para-oxy-benzoic  acid. 

\CO2H 


\CH 

Phthalic  acid  Isophthalic  acid  Terephthalic  acid. 


C6H4/CH3  Ortho-xylol  Iso-xylol  Para-xylol. 

CH3 

^°2** 
CO2Jtl 

LOCATION  OF  THE  DI-DERIVATIVES. 

The  benzene  hexagon  indicates  two  chemically  identical  ortho- 
derivatives,  two  chemically  identical  meta-derivatives,  and  a  single 
para-derivative,  if  we  neglect  the  mutual  linking  of  the  six  C  atoms. 

The  first  to  indicate  a  way  of  experimentally  determining  the 
location  of  the  substituents  in  benzene  multiple-substitution  products 
was  W.  Korner.  In  1867  he  propounded  the  opinion  that  a  trioxy- 
benzol,  obtained  from  any  of  the  three  isomeric  dioxy-benzols,  must 
necessarily  be  a  I,  3,  4-trioxy-benzol  (Bull.  Acad.  Roy.  Belg.  2,  24, 
166)  .  As  the  transformation  of  dioxy-  into  trioxy-benzols  was  attended 
with  difficulties,  Korner  replaced  the  dioxy-benzols  by  dibromo- 
benzols,  and  for  these  he  determined  the  absolute  constitution,  in  1874, 
by  conversion  into  tribromo-benzols  (Gazz.  Chim.  Ital.  4,  305).  Korner 
nitrogenated  the  three  dibromo-benzols.  One  of  them  gave  two 
mononitro-dibromo-benzols  ;  the  second,  three  more  ;  and  the  last,  one, 
all  different.  These  six  mononitro-dibromo-benzols  were  then  reduced 
to  the  corresponding  mono-amido-dibromo-benzols,  and  afterwards 
transformed  into  the  three  tribromo-benzols.  Korner  showed  that  in 
this  last  transformation  the  first  dibromo-benzol  yielded  two  different 
tribromo-benzols  ;  the  second,  three  different  ones  ;  and  the  third,  only 
one  tribromo-benzol.  Korner  concluded  that  the  first  dibromo-benzol 
had  the  two  Br  in  the  ortho-positiou,  the  second  in  the  meta-position, 
and  the  third  one  in  the  ^wa-position.  Thus  the  absolute  position  of 
the  bromine  atoms  in  the  three  tribromo-benzols  was  determined  and 
the  constitution  of  the  six  mononitro-benzols  was  cleared  up.  The 
following  diagrams  illustrate  this  argument.  For  the  sake  of  clearness, 
the  H  atoms  have  been  omitted. 

Br 


V 

Br 
Br 

ft 

YN°° 

Br 


Br 


Br  Br 


BENZENE   DI-DERIVATIVES  37 

What  may  be  called  a  reversal  of  this  argument  is  found  in 
the  process  experimentally  realised  by  P.  Griers  (B.  5,  192 ; 
7,  1223). 

There  are  six  isomeric  diamido-benzoic  acids,  and  the  diamido- 
benzol  generated  by  the  rejection  of  CO2  from  two  of  these  acids  is  the 
0-compound,  that  which  is  generated  from  three  of  the  six  acids  is  the 
/^-compound,  and  that  which  is  generated  from  the  sixth  acid  is  the 
^-compound. 

NH2  NH2  NH2 

i  li        f    i 


VNH2      '^C 
C02H  NH2 


NH2  NH2 


NH2 

The  constitution  of  benzene  derivatives  containing  side  chains  is 
produced  by  transformation  into  benzol-carboxylic  acids.  For  the 
three  phthalic  acids  or  benzol-dicarboxylic  acids  the  constitution  is 
determined  by  the  following  facts  (B.  4,  101)  : 

The  phthalic  acid  obtained  by  oxidation  of  naphthalin  is  the  [i,  2]- 
or  ortho-benzol-dicarboxylic  acid.  Naphthalin  consists  of  two 
benzene  nuclei  having  two  C  atoms  in  common  in  the  ortho- 
positions. 

By  oxidation  of  nitro-naphthalin  we  obtain  nitro-c-phthalic  acid, 
which  can  be  converted  into  phthalic  acid  ;  on  oxidising  the  amido- 
naphthalin  obtained  by  reduction  of  nitro-naphthalin,  we  obtain 
o-phthalic  acid,  the  oxidation  destroying,  first  the  one,  and  then  the 
other,  side  of  the  naphthalin  molecule.  This  determines  the  constitu- 
tion of  both  the  naphthalin  and  of  phthalic  acid  as  an  o-dicarboxylic 
acid  of  benzene  : 

N02  H 

H/VNn 


a-Amido-naphthalin  Benzol-o-dicarboxylic  acid 
Phthalic  acid. 

The  so-called  isophthalic  acid  is  benzol  -  m  -  dicarboxylic  acid, 
since  it  can  be  obtained  by  oxidation  from  isoxylol.  Isoxylol 
is  m-dimethyl-benzol,  as  shown  by  its  formation  from  mesitylenic 


38 


ORGANIC  CHEMISTRY 


acid,    the   first    oxidation    product    of    mesitylene,    or    [i,  3,  5]-tri- 
methyl-benzol  : 

CH3  COH 


CH3 


CH3 


H 

Mesitylene 
[x,  3,  53-Tnmetiiyi- 

benzol 


H 
Mesitylenic  acid 


H 

Isoxylol 

[i,3]-Dimethy- 

benzol 


H 

Isophthalic  acid 
Benzol-[i,  3]-di- 
carboxylic  acid. 


The  proof  that  mesitylene  is  really  [i,  3,  5]-trimethyl-benzol  is  due 
to  Ladenburg,  who  showed  that  the  three  unreplaced  H  atoms  of 
mesitylene  are  equivalent  (A.  179,  174)  : 


a 

b 

c 

i   C,(CH,), 

H 

H 

H 

4,  C,(CH3), 

N02 

NO, 

H 

a 

b 

c 

4,  C.(CH,), 

N02 

NH2 

H-i 

>  C6(CH3), 

NO, 

H 

H 

4,  Q(CH3)3 

N0a 

NHCOCHa 

H 

^  C6(CH3)S 

NH2 

H 

H 

4,  C4(CH3)a 

NO, 

NHCOCHa 

N02 

if  C6(CH,)3 

NHCOCH3 

H 

H 

a 

b 

c 

4,  C9(CH3)3 

NO, 

NH2 

NO2 

^  C6(CH3)3 

NHCOCHj, 

NO2 

H  or      C,(CHS)3 

NHCOCH3 

H 

NO2 

4,  C,(CH3)3 

N02 

H 

N02^C6(CH3)3 

NH, 

NO2 

H  or  1  C6(CH3)3 

NH2 

H 

NO2 

b=c 


The  above  scheme  clearly  illustrates  the  argument.  Mesitylene  gives 
dinitro-mesitylene,  of  which  the  NO2  groups  may  replace  the  H  atoms 
a  and  b,  and  then  in  succession  nitro-amido-,  nitro-acetamido-,  dinitro- 
acetamido-,  dinitro-amido-,  and  dinitro-mesitylene,  identical  with  the 
origin.  Hence  b  and  c  are  equivalent.  The  nitro-amido-mesitylene,  in 
which  we  assume  the  NH2  group  at  b,  yields  mono-nitro-,  mono-amido-, 
mono-acetamido-,  mono-acetamido-nitro-,  and  mono-amido-nitro- 
mesitylene,  identical  with  the  first  nitro-amido-mesitylene  obtained  by 
reduction  of  dinitro-mesitylene.  Hence  a  and  b  or  a  and  c  are  equi- 
valent ;  but,  since  b  and  c  are  already  proved  to  be  equivalent,  the 
equivalence  of  the  three  unreplaced  H  atoms  of  mesitylene  is  proved. 
Mesitylene  is  symmetrical;  therefore  its  three  methyl  groups  must 
occupy  the  positions  [i,  3,  5]. 

For  the  third  benzol-dicarboxylic  acid,  terephthalic  acid,  only  the 
i,  4-position  remains,  as  may  be  proved  as  follows  : — Terephthalic  acid 
is  derived  from  p-dimethyl-benzol,  and  this  again  from  p-bromo- 
toluol  (through  methyl  iodide  and  Na).  Now,  p-bromo-toluol  yields, 
by  oxidation,  p-bromo-benzoic  acid ;  p-bromo-benzoic  acid  and 
p-oxy-benzoic  acid  belong  to  the  same  series,  for  p-oxy-benzoic  acid 
originates  in  the  same  p-amido-benzoic  acid  through  the  diazo-com- 
pound,  through  which  p-bromo-benzoic  acid  may  also  be  obtained. 
But  of  p-oxy-benzoic  acid  we  have  already  proved  that  its  hydroxyl 
group  represents  an  H  atom  symmetrical  to  no  other  H  atom  of 
benzene. 

With  the  di-derivatives  of  benzene  containing  no  carbon-bearing 
radicles  as  substituents,  the  three  phthalic  acids  have  a  genetic  relation. 
The  three  dinitro-benzols  may  be  converted  into  nitro-amido-,  bromo- 
nitro-,  brom-amido-,  and  dibromo-benzols  on  the  one  hand,  and  into 
nitre-cyanic,  nitro-carboxylic,  amido-carboxylic,  cyano-carboxylic, 


BENZENE   DI-DERIVATIVES  39 

and  phthalic  acids  on  the  other  hand,  by  reactions  in  which  no  intra- 
molecular atomic  displacements  are  observed  (B.  18,  1492,  1496). 

NO2        _~  TT  /NO2        _^r  TT  /NH2  r  „  /Br 

- 


r  TT  /N02         ~  TT  /N02  ~  TT  /NH2  r  TT  /CN  -  TT  /C02H 

C«H<CN         >C'H<C02H-  >C«H4\C02H-  >C<H<\C02H-  ^'Vo.H 

A  further  proof  is  furnished  by  the  derivatives  of  the  three  isomeric 
xylols.  We  have 

from  Metaxylol,  3  nitroxylols,  xylidins,  and  xylenols 
from  Orthoxylol,  2  nitroxylols,  xylidins,  and  xylenols 
from  Paraxylol,  I  nitroxylol. 

from  which  the  following  positions  may  be  ascertained  : 

[i,  3]  meta-  or  isoxylol  and  isophthalic  acid 
[1,2]  orthoxylol  and  phthalic  acid 
[1,4]  paraxylol  and  terephthalic  acid. 

(B.  18,  2687.) 

That  in  the  ortho-compounds  two  neighbouring  C  atoms  of  the 
benzene  nucleus  hold  the  side  groups,  is  shown  by  their  capacity  for 
simple  reactions,  in  which  a  union  of  the  side  chains  gives  rise  to 
carbo-  and,  especially,  hetero-cyclic  condensation  products  (o-pheny- 
lene-diamine,  o-amido-phenol,  o-amido-thiophenol,  o-amido-benzalde- 
hyde,  o-phthalic  acid,  o-oxy-cinnamic  acid,  etc.).  There  are  also 
crystallographic  reasons  for  supposing  that  the  meta-compounds  stand 
between  ortho-  and  /wra-compounds  (Zeitschr.  f.  Kryst.,  1879,  171  ; 
B.  18,  R.  148). 

The  hexagon  scheme  of  benzene,  therefore,  not  only  represents 
all  the  isomeric  relations  of  benzene  derivatives,  but  sheds  light  on 
their  chemical  and  physical  behaviour. 

ISOMERISM   OF  THE   BENZENE   POLY-SUBSTITUTION   PRODUCTS. 

When  three  or  more  H  atoms  are  replaced  in  benzene,  three  cases 
must  be  distinguished  :  —  The  substituents  are  equal  or  different.  In 
the  first  case  there  are  three  possible  isomers  of  the  tri-derivatives, 
such  as  C6H3(CH3)3,  with  the  positions 

[i,  2,  3]     [i,  2,  4]     or     [i,  3,  5]. 
They  are  termed 

adjoining          [i,  2,  3]  or  v  =  vicinal 

unsymmetrical  [i,  2,  4]  or  as  =  asymmetric 

symmetrical      [i,  3,  5]  or  s  =symmetric  tri-derivatives. 

For  the  tetra-derivatives  with  four  equal  groups  C6H2X4  there  are 
also  three  possible  isomeric  structures  : 

[i,  2,  3,  4]     [i,  2,  4,  5]     [i,  2,  3,  5]. 
v  s  as 


40  ORGANIC   CHEMISTRY 

With  five  or  six  equal  groups  only  one  modification  is  possible  ;  there 
is  but  one  pentachloro-benzol  C6HC15,  and  only  one  hexachloro- 
benzol  C6C1G. 

If  the  substituent  groups  are  unequal,  the  number  of  possible 
isomers  is  much  greater  ;  it  is  easily  derived  from  the  hexagon  scheme. 
Thus  we  have  for  the  formula  of  dinitro-benzoic  acid  C6H3(NO2)2COOH 
six  isomers  : 

[i,  2,  3]     [i,  2,  4]     [i,  2,  5]     [i,  2,  6]     [i,  3,  4]     [i,  3,  5], 

assigning  position  i  to  the  carboxyl  group. 

The  constitution  of  the  poly-substitution  products  of  benzene  is 
determined  by  their  genetic  relations  to  the  di-substitution  products 
of  known  structure. 

CONSTITUTION  OF  THE  BENZENE  NUCLEUS. 

According  to  the  benzene  formula  established  by  Kekule  in  1865, 
six  C  atoms  are  alternately  simply  and  doubly  linked  into  a  closed 
chain.  This  assumption  gives  a  comprehensive  picture  of  the  whole 
behaviour  of  the  benzene  derivatives  : 

1.  It  illustrates  the  synthetic  formation  of  the  benzene  derivatives, 
the  condensed  benzols,  naphthalin,  phenanthrene,  etc.  ;  and  is  corro- 
borated by  all  recent  syntheses,   such  as  that  of   a-naphthol  from 
phenyl-isocrotonic  acid,  etc.  (see  also  B.  24,  3117). 

2.  It  agrees  with  the  splitting  reactions  of  the  benzene  nucleus. 

3.  It  explains,  in  a  simple  manner,  how  the  ortho-derivatives — on 
account  of  the  neighbouring  position  of  two  side  groups — are  capable 
of  forming  anhydrides   and  numerous   derivatives  founded  upon  an 
ortho-condensation.     The  benzene  formula  also  results  clearly  from 
the  ring  formation  of  quinolin  (A.  280,  i). 

4.  The  existence  of  three  bivalent  linkings  explains  in  a  simple 
manner,  without  new  hypotheses,   the  faculty  for  forming  addition 
products  possessed  by  the  benzene  derivatives  (p.  45).     Such  additions 
do  not,  indeed,  take  place  with  the  same  ease  as  in  the  case  of  ethylene 
linkings,  in  the  methane  bodies  ;  but  aliphatic  olefin  compounds  also 
show  gradual  differences   in   powers   of   addition   (see  Allyl  alcohol, 
Vol.  I.). 

5.  Several  physical  properties  also  indicate  the  existence,  in  benzene 
bodies,  of  double  linkings  similar  to  those  found  in  ethylene  derivatives. 
Thus,  according  to  Briihl  (B.  27,  1065),  the  refractivities  show  that  in 
benzene  derivatives  there  are  three  ethylene  linkings  CH=CH  (Vol.  I.), 
but  in  naphthalin  five.     The  specific  volumes  of  the  benzene  bodies 
also  seem  to  speak  for  the  existence  of  three  double  linkings  (Vol.  I.). 

Kekule's  benzene  formula  does  not,  however,  completely  express 
the  symmetry  of  the  benzene  nucleus  ;  for  it  would  indicate  a  differ- 
ence in  the  ortho-derivatives  [i,  2]  and  [i,  6],  and  they  would  have 
to  give  rise  to  four  di-derivatives  each — unless  we  follow  Kekule"  in 
assuming  oscillations  of  neighbouring  carbon  atoms  (A.  162,  86  ;  B.  5, 
463  ;  A.  279,  195). 

Perhaps,  during  the  formation  of  an  ortho-derivative,  a  displace- 
ment of  the  double  linkings  occurs  when  the  substituting  groups 
approach  two  single-linked  C  atoms,  so  that  what  is  formed  is  always 


CONSTITUTION  OF  THE  BENZENE  NUCLEUS 


the  di-derivative  in  which  the  substituent  groups  are  attached  to  two 
doubly  linked  C  atoms.  This  would  explain  the  easier  complete  oxi- 
dation of  the  o-derivatives,  in  comparison  with  the  corresponding  m- 
and  p-derivatives. 

It  cannot  be  denied  that  the  prediction  of  the  existence  of  two 
modifications  of  an  ortho-substitution  product  instead  of  one  con- 
stitutes a  weakness  of  Kekule's  benzene  formula.  It  must  also  be 
remarked  that  the  many  analogies  between  the  ortho-  and  para- 
derivatives,  in  comparison  with  the  meta-derivatives  (see  Quinone 
and  Quinone  derivatives) ,  are  not  sufficiently  expressed  by  this  formula. 
Still,  we  give  it  preference,  in  comparison  with  other  benzene  formulae, 
because  it  gives  a  consistent  view  of  the  connection  between  aromatic 
and  aliphatic  compounds. 

Among  other  benzene  schemes  we  may  figure  the  diagonal  scheme 
of  Claus  (A),  the  prismatic  scheme  of  Ladenburg  (Bt,  B2,  B3),  and  the 
centric  scheme  of  Armstrong  and  von  Baeyer  (C). 

A  B,  B2  B, 


V 


Claus: 
Diagonal  scheme 


Ladenburg : 
Prismatic  scheme 


Annstrong-Baeyer : 
Centric  scheme. 


According  to  formulae  A  and  B  there  are  no  double  linkings  in  the 
benzene  nucleus.  The  existence  of  nine  univalent  links  was  supposed 
to  be  proved  by  the  specific  volume  of  the  benzene  compounds, 
and  especially  by  their  heats  of  combustion  ("Theory  of  Heats  of 
Formation,"  by  J.  Thomson,  B.  13,  1808  ;  19,  2944).  But,  according 
to  more  recent  investigations,  the  specific  volumes  rather  indicate  the 
existence  of  three  double  links  in  the  benzene  nucleus,  and  the 
conclusions  derived  from  the  heats  of  combustion  do  not  appear  to 
be  irrefutable  (Briihi,  /.  pr.  Ch.  2,  49,  201). 

The  prismatic  formula  of  Ladenburg  "  accounts  for  all  the  static 
conditions  of  benzene,"  and  illustrates  the  isomerisms  of  the  benzene 
derivatives.  But  it  denies  all  double  linkages  such  as  are  proved  to 
exist  in  the  partly  reduced  nuclei  of  the  di-  and  tetrahydro-addition 
products ;  it  gives  a  spatial  arrangement,  of  the  four  affinities  of  the 
carbon  atoms,  having  no  analogy  among  the  methane  bodies;  and, 
according  to  its  author,  "it  yields  priority  to  Kekule's  scheme  for 
all  processes  of  formation  and  decomposition  of  benzene  bodies" 
(B.  23,  1010). 

Although  Claus's  diagonal  formula  is  consistent  with  isomeric 
relations,  and  allows  of  any  para-  and  ortho-additions  (B.  20,  1422  ; 
/.  pr.  Ch.  2,  49,  505),  it  arranges  the  four  C  affinities  without  analogy, 
and  assumes  a  peculiar  central  valency  of  a  new  kind. 

Baeyer's  new  centric  formula  leaves  the  condition  of  the  fourth  C 
valency  indefinite,  simply  assuming  that  it  exerts  a  centrally  directed 
pressure.  In  this  way  it  returns  to  Kekule's  scheme,  which  does  not 
profess  to  explain  the  linking  of  the  fourth  valency  (B.  23,  1272  ; 
24,  2689 ;  A.  269,  145  ;  B.  24,  R.  728). 


42  ORGANIC   CHEMISTRY 

Thiele  has  lately  made  a  different  attempt  to  explain  the  required 
symmetry  of  the  benzene  nucleus.  He  assumes  that,  in  ordinary 
double  linkings,  certain  "residual  valencies"  remain,  two  of  which 
mutually  saturate  each  other  when  the  double  linkings  adjoin.  On 
assuming  such  a  saturation  of  all  the  residual  valencies  of  the  three 
ethylene  links,  the  six  C  atoms  are  seen  to  be  linked  by  six  "  inactive  " 
double  links  (A.  308,  213  ;  311,  194). 

Some  constitutional  formulae  for  benzene  are  based  upon  stereo- 
chemical  considerations,  such  as  Thomson's  octahedral  formula  (B.  19, 
2944),  and  especially  the  benzene  model  of  Sachse  (B.  21,  2530  ;  Z.f. 
physik.  Ch.  11,  214;  23,  2062),  as  well  as  that  of  J.  Loschmidt  (Wien. 
Akad.  Ber.  1890,  vol.  99,  ii.  p.  20).  For  later  discussions  of  the 
various  stereo-chemical  formulse,  see  B.  35,  526,  703 ;  and  C.  1902, 
II.  350. 

BENZENE  RING  FORMATIONS. 

The  nuclear  synthesis  reactions  of  aliphatic  substances,  in  which 
benzene  rings  are  formed,  are  important  mainly  as  joining  aliphatic 
and  aromatic  substances  genetically.  They  will  therefore  be  passed  in 
review,  before  dealing  with  the  various  classes  of  bodies,  in  the  same 
succession  as  that  in  which  the  initial  bodies  were  dealt  with  in  the 
aliphatic  series  (Vol.  I.). 

1.  CH4,  methane,  conducted  through  an  incandescent  tube,  gives 
benzene  and  other  products. 

2.  3CH  =  CH,  acetylene,  polymerises  at  a  red  heat  to  benzene. 

3«.  3CH  =  C.CH3,  allylene,  polymerises  in  SO4H2  to  [i,  3,  5]-/n- 
methyl-benzol  or  mesitylene. 

36.  3CH3.C=C.CH3,  crotonylene,  polymerises  to  hexamethyl- 
benzol. 

4.  CC14,  perchloro-methane,  and  CC12=CC12,  perchloro-ethylene,  on 
passing  through  an  incandescent  tube,  give  perchloro-benzol ;    see  also 
perbromo-benzol. 

5.  3CH^CBr,   monobromo-acetylene,  polymerises  to    [i,  3,  $]-tri- 
bromo-benzol. 

6.  C6H13I,  hexyl  iodide,  gives  with  Cl  iodide  hexachloro-benzol ;  with 
bromine,  hexabromo-benzol. 

ya.  (CH3)2C  :  CH.CH2.CH2C(CH3)  :CH.CHO,  geraniol  or  citral,  gives 
with  potassium  bisulphate  [i,  ^\-isopropyl-tohwl  or  cymol. 

jb.  CH3.CH2CH  :C(CH3)CH  :CH.COCH3,  from  methyl-ethyl-acrolein 
and  acetone,  yields  pseudo-cumol. 

yc.  (C3H7).CH2CH  :  C(C3H7).CH  :  CH.CO.CH3,  from  2  mol.  isovaler- 
aldehyde  and  i  mol.  acetone,  gives  di-isopropyl-toluol  (B.  28,  R.  608). 

8a.  3CH3COCH3,  acetone,  gives  with  SO4H2  [i,  3,  $}-trimethyl-benzol 
or  mesitylene. 

8b.  3CH3CO.CH2CH3,  methyl-ethyl-ketone,  gives  [i,  3, 5\-triethyl- 
benzol. 

8c.  3CH3CO.CH2CH2CH3,  methyl-n-propyl-ketone,  gives  [i,  3, $}-tri- 
n-propyl-benzol. 

9.  6CO,  carbon  monoxide,  combines  with  K  on  heating  to  potassium- 
he  xaoxy -benzol. 

10.  3CH3CH2CH2COC1,  butyryl   chloride,  is  condensed  by  A12C16 
into  triethyl-phoroglucin. 


BENZENE   RING   FORMATIONS  43 

11.  3CH  =  C.CO2H,    propiolic    acid,    polymerises    in    sunlight   to 
[i,  3,  5]-benzol-tricarboxylic  acid  or  trimesinic  acid. 

12.  3NO2CH(CHO)2,  nitro-malonic  aldehyde,  gives,  on  decomposi- 
tion of  its  Na  salt,  sym.  trinitro-benzol. 

13.  NO2.CH(CHO)2,    nitro-malonic     aldehyde,    and    CH3COCH3, 
acetone,  give  p-nitro-phenol  (B.  28,  2597  ;  C.  1899,  II.  609). 

14.  3CH3.CO.CH==CHOH,  oxymethylene-acetone  or  formyl-acetone, 
condenses  easily  to  [i,  3,  S\-triacetyl-benzol  C6H3(COCH3)3. 

150.  2CH3CO.CO.CH3,  diacetyl,  condenses  with  alkalies  to  p- 
xylo-qninone  or  [2,  $}-dimethyl-quinone. 

156.  2CH3.CO.CO.CH2CH3,  acetyl-propionyl,  gives  duro-quinone  or 
tetramethyl-quinone. 

16.  3CH(OH)=CH.CO2C2H5,  oxymethylene-acetic  ester  or  formyl- 
acetic   ester,  and   their  dimolecular  condensation  product,  cumalinic 
acid,  condense  easily  to  esters  of  the  [i,  3,  5]-benzol-tricarboxylic  acid 
or  trimesinic  acid  ;    this  is  also  obtained  from  a  mixture  of  formic 
and  chloracetic  acids  with  zinc  (C.  1898,  II.  472). 

17.  4CH3COCO2H,  pyro-traubenic  acid,  condenses  on  heating  with 
NaHO  with  rejection  of  oxalic  acid  and  water  to  methyl-dihydro- 
trimesinic  acid,  which  passes  easily  into  uvitinic  acid  with  rejection 
of  CO2. 

18.  2CHOCH2CH2COOH,  j3-formyl-propionic  acid,  gives  terephthalic 
acid  or  p-benzol-dicarboxylic  acid. 

19.  2CH3CO.CHNa.CO2C2H5,    sodium-acetic    ester,    and    CHC13, 
chloroform,  combine  to  oxy uvitinic  ester  or  oxymethyl-isofrhthalic  ester, 

also  obtained  direct  from  methenyl-bisacetic  ester  cH/CH(c°2C2H5)COCH3 

^  C(CO2C2H5)COCH3 

with  Na  alcoholate. 

20.  2ROCOCH  :  CH.CH2COOR,  glutaconic  acid  ester,  unites  under 
the  action  of  sodium  ethylate,  with  rejection  of  one  molecule  of  alcohol, 
and  acetic  ester  to  form  ^-oxy-iso-phthalic  acid  ester  (B.  37,  2117). 

21.  CH3C:CH.CO.CH.COCH3  dehydracetic  addj  ^^  orcin  or  ^  5_ 

vJ   \-^\_J 

dioxy-toluol. 

22.  2CH3.CO.CH2.CO.CO2C2H5,  acetone-oxalic  ester,  is  condensed 
to  oxy-toluylic  acid  ester. 

2$a.  CH3.CH2CH  :  C(CH3).CH  :  C(COOR)2,  from  methyl  -  ethyl  - 
acrolei'n  and  malonic  ester,  yields  with  Na  alcoholate  oxy-mesitylenic  acid. 

236.  (CH3)2  :  CH.CH2.CH2.C(CH3)  :  CH.CH  :  C(COOR)2,  citralidene- 
malonic  ester,  yields  ^-isoamenyl-^-methyl-salicylic  acid. 

It  is  doubtful  whether  in  the  formation  of  mellithic  acid  or  benzol- 
hexacarboxylic  acid  C6(CO2H)6  by  the  oxidation  of  charcoal  or  graphite 
a  synthesis  occurs  ;  perhaps  this  reaction  must  be  regarded  as  the 
transformation  of  a  molecule  consisting  of  twelve  C  atoms. 

On  again  surveying  the  reactions  by  which  aliphatic  bodies  are 
converted  into  benzene  bodies  by  nuclear  synthesis,  we  find  that : 

(1)  Some    saturated    compounds,   like  methane  and  tetrachloro- 
methane,  yield  the  benzene  ring  by  the  action   of  heat  (pyro-con- 
densation).     Many  benzene  derivatives,  like  benzene  and  the  methyl- 
benzols,  simple   amido-  and   oxy-benzols,  are  distinguished  for  their 
constancy  at  high  temperatures  (see  Coal-tar). 

(2)  During  perchloration  of  many  aliphatic  compounds  the  occur- 


44  ORGANIC  CHEMISTRY 

rence  of  perchloro-benzol  was  observed.     Hexyl  iodide  is  transformed 
particularly  easily  into  perchloro-  and  perbromo-benzol. 

(3)  A  large  number  of  aliphatic  acetylene  compounds  containing 
a  triply  linked  pair  of  C  atoms,  yield  benzene  derivatives  by  polymerisa- 
tion of  three  similar  molecules.      A  difficult  polymerisation  is  that  of 
acetylene  to   benzene.     Brom-acetylene   is   much   more   easily  poly- 
merised.    Allylene  and  crotonylene  require  sulphuric  acid,  propiolic 
acid,  and  sunlight  for  aromatic  polymerisation. 

The  other  aliphatic  compounds  above  referred  to,  which  may 
condense  themselves  to  aromatic  substances  (aromatic  condensation), 
contain  carbon  and  oxygen  in  double  linking.  Many  are  ketones, 
or  they  contain  the  oxy-methylene  group. 

(4)  A  direct  addition  reaction  is  exemplified  by  the  manner  in  which 
potassium  hexa-oxy-benzol  is  formed  from  CO  and  K. 

(5)  Hydrolytic    condensation    is    exemplified   by   the   simple   ring 
formation  in  the  transition  of  citral  or  geranial  and  other  high-mole- 
cular keto-olefins  into  cymol,  pseudo-cumol,  and  di-isopropyl-toluol, 
as  well  as  the  condensation  of  di-hydro-acetic  acid  to  orcin,  with 
liberation  of  CO2. 

(6)  The   condensation   of    acetone,   methyl-ethyl-   and   methyl-n- 
propyl-ketone  to  [i,  3,  5]-tri-alkyl-benzols  is  paralleled  by  condensation 
of  butyryl  chloride  to  tri-ethyl-phloroglucin,  with  a  triple  rejection  of 
HC1 ;    also  by  the  condensation  of  two  molecules  j8-formyl-propionic 
acid  to  terephthalic  acid,  with  rejection  of  water  and  hydrogen. 

(7)  These  condensations  are  related  to  the  condensations  of  nitro- 
malonic-acid  aldehyde,  and  the  oxy-methylene  compounds  (12  to  16). 
Also  to 

(8)  The  condensation  of  the  a-diketones  to  quinones  ; 

(9)  Of  acetone-oxalic  acid  to  oxy-toluylic  acid  ;  and 

(10)  The   condensation  of   chloroform  and  sodium-acetic  ester  to 
oxy-uvitinic-acid    ester,   in   which    methenyl-bis-acetic   ester   can   be 
assumed  as  an  intermediate  product. 

(n)  The  formation  of  homologous  salicylic  acids  from  alkengli- 
dene-malonic  esters  with  Na  alcoholate  is  based  upon  an  intramolecular 
aceto-acetic  ester  condensation. 

There  is  also  a  peculiar  condensation  of  pyro-traubenic  acid  to 
methyl-dihydro-trimesinic  or  uvitinic  acid,  in  which  oxalic  acid  is  first 
split  off. 

These  benzene  formations  are  associated  with  several  reactions 
leading  to  hydro-aromatic  compounds  having  a  close  relation  to 
benzene  derivatives.  We  may  mention  the  following  : 

i.  Sodium-malonic  ester  condenses  to  phloroglucin-dicarboxylic 
ester,  formed  from  acetone-dicarboxylic  ester  and  malonic  ester 
(B.  29,  R.  1117).  Sodium-acetonic-dicarboxylic  ester  condenses  to 
dioxy-phenyl-dicarboxylic  ester  (B.  31,  2014  ;  C.  1897,  II.  741). 
All  these  condensation  products  are  probably  derivatives  of  hexa- 
hydro-benzol. 

Cp.  also  the  condensations  of  sodium-acetone-dicarboxylic  ester 
with  iodine  to  hydroquinone-tetracarboxylic  ester  (B.  30,  2569),  with 
eth-oxy-methylene,  aceto-acetic,  and  eth-oxy-methylene-malonic  ester 
to  oxy-trimesinic  ester,  and  resorcin-tricarboxylic  ester,  respectively 
(C.  1899,  II.  1018,  1020). 


BENZENE   RING  SPLITTINGS  45 

2.  Succinic  acid  ester  condenses  with  sodium  to  succinylo-succinic 
acid  ester. 

3.  i,  5-diketo-compounds,  which   contain,  in   the  terminal  place, 
besides  a  CO  group,  a  CH3  or  CH2R  group,  condense  to  cyclic  aldols, 
of  the  hexamethylene  series,  which  easily  pass  into  keto-tetra-hydro- 
benzene   derivatives.     Methylene-bis-aceto-acetic   ester,   a,  y-diacetyl- 
glutaric    ester,    thus    gives    methyl-keto-tetramethylene-dicarboxylic 
ester.     Similarly,   with   sodium   ethylate,   the  y-acetyl-butyric   ester 
CH3CO.CH2.CH2.CH2.COOC2H5   yields   dihydro-resorcin,   which    can, 
by  a  reversed  process,  pass  into  y-acetyl-butyric  acid  by  splitting 
(cp.  benzol  ring  splitting). 

Some  other  methods  of  synthesising  hydro-aromatic  compounds 
were  mentioned  on  pp.  4  and  5. 

BENZENE  RING  SPLITTINGS. 

As  already  mentioned,  the  benzene  derivatives  are  in  general 
distinguished  by  the  tenacity  of  the  benzene  ring.  In  order  to  split 
the  benzene  ring,  suitable  benzene  derivatives  are  treated  with  reagents 
which,  partly  or  wholly,  dissolve  the  double  links  of  the  nucleus. 
The  splitting  is  therefore  always  preceded  by  the  formation  of  hydro- 
aromatic  intermediate  products,  which,  as  a  rule,  could  not  be  retained. 
Sometimes  we  obtain  split  products  containing  the  six  nuclear  C 
atoms  in  the  molecule  as  an  open  chain,  in  some  cases  pentacarbocyclic 
compounds  from  hexacarbocyclic  a-diketones. 

Ring  splittings  were  found  most  easily  practicable  in  the  case  of 
phenols,  amido-phenols,  quinones,  oxy-quinones,  and  phenol-carboxylic 
acids. 

i.  Splitting  by  feeble  oxidation. — While  strong  oxidisers  convert 
the  benzene  nucleus  into  CO2,  formic  acid,  and  oxalic  acid,  ozone 
is  capable  of  producing  a  straightforward,  and  extremely  clear, 
splitting  of  benzene.  By  addition  of  three  molecules  of  ozone  to  the 
three  double  links  of  the  benzene  nucleus,  we  get,  first,  ozobenzol,  or 
benzol-triozonide  C6H6O9,  which  is  decomposed  by  water  into  three 
molecules  of  glyoxal  (Harries)  : 

0-0 
CH     O  OCH 


H  CH  OCH      CHO 

CHO 


H  AH  +  3H°°  -  oin  + 


H     O  OCH 

J 


Vc 


This  splitting  furnishes  one  of  the  strongest  supports  for  Kekule's 
benzene  formula.  The  homologous  benzene  hydrocarbons  behave 
similarly. 

Pyro-catechin  or  [i,  2]-dioxy-benzol  C6H4[i,2](OH)2  and  proro- 
catechuic  acid  or  [3, 4>dioxy-benzoic  acid  CO2Ii[i]C6H3[3,4J(OH)2 
are  oxidised  to  dioxy-tartaric  acid  (Kekule). 


46  ORGANIC  CHEMISTRY 

Hydroquinone  or  [i,  4]-dioxy-benzol,  and  the  quinone  easily 
generated  from  this,  are  split  up  by  silver  peroxide  into  malemic 
acid  and  CO2  (R.  Kempf)  : 

COH  CO  COOH 

HC     CH  HC     CH  HC 

II       |   >     II      II    >     II  +2C02 

HC     HC  HC     CH  HC 

\/  V  \ 

COH  CO  COOH 

Phenol  C6H5OH  has  been  transformed  by  potassium  permanganate 
solution  into  meso-tartaric  acid  (Dobner).  Probably  in  this  case  also 
quinone  is  formed  in  the  first  instance,  and  then  maleinic  acid,  which 
with  MnO^K  passes  into  meso-tartaric  acid  (see  Vol.  I.). 

By  oxidation  of  o-nitro-p-cresol  with  fuming  sulphuric  acid  we 
obtain  jS-acetyl-acrylic  acid  (Schultz  and  Low) : 

C— CH3  COCH3 

HC     CH  HC 

II      I          >      II 

HC     CN02  HC 

C— OH  COOH 

2.  Splitting  by  simultaneous  chlorination  and  oxidation. — Benzene 
treated  with  potassium  chlorate  and  sulphuric  acid  passes  first  into 
chlorinated  quinone  and  then  into  trichloro-pheno-malic  acid  and 
j8-trichlor-acetyl-acrylic  acid  (see  Vol.  I.),  which  with  baryta  water 
decomposes  into  chloroform  and  maleiic  acid  (Kekule  and  Strecker)  : 

CH  CO  C02H  C02H 

HC     CH  HC     CH  HC  HC 

II       I     >     \\       II     ->     II  ->     II  +HCC13 

HC     CH  HC     CC1  HC     CC13  HC 

CH  CO  CO  C02H 

Benzene         Monochloro-  Trichloro-pheno-malic  acid  Maleic  acid, 
quinone        £-Trichlor-acetyl-acrylic 
acid 

From  phenol,  salicylic  acid,  or  ortho-oxy-benzoic  acid  COOH[i]C6H6 
[2]OH,  and  from  gallic  acid  COOH[i]C6H2[2,  3,  4](OH)3,  we  obtain, 
by  treatment  with  potassium  chromate  and  HC1,  iso-trichloro-glycerinic 
acid  CC13C(OH)2COOH  (see  Vol.  I.). 

Picric  acid  or  [i,  OH,  2,  4,  6]-trinitro-phenol,  treated  with  bleaching 
powder,  yields  chloro-picrin  (Vol.  I.) ;  with  bromine,  and  lime  water, 
bromo-picrin. 

Specially  illuminating  are  the  methods  of  benzene  splitting  worked 
out  by  Zincke.  They  consist  in  the  formation  of  chlorinated  R- 
hexene  and  R-hexylene-ketones,  from  suitable  aromatic  compounds, 
and  the  splitting  of  the  former. 

We  shall  give,  in  what  follows,  four  examples,  the  first  three  of 
which  start  from  the  three  dioxy-benzols,  and  the  fourth  from  [i,  3,  5]- 
trioxy-benzol,  or  phloroglucin. 


BENZENE   RING   SPLITTINGS  47 

(i)  Pyro-catechin  or  o-dioxy-benzol,  treated  with  chlorine,  passes 
into  tetrachlor-ortho-quinone,  and  then  into  hexachlor-o-diketo-R- 
hexene.  By  merely  heating  in  water  the  latter  is  converted  into 
hexachloro-R-pentene-oxy-carboxylic  acid,  which  may  be  oxidised  by 
means  of  chromic  acid  to  hexachloro-keto-R-pentene.  With  caustic 
soda  the  hexachloro-R-pentene-ketone  splits  to  form  perchloro-vinyl- 
acrylic  acid,  which,  on  reduction,  yields  ethylidene-propionic  acid 
(B.  27,  3364)  : 


CCI 

CCI 

CCI 

CCI 

CCI 

CH2 

CCI     CO 

CCI      CO 

^    \ 
CCI      \   /rnw 

t   cci    \ 

CCI     CO2H 

CH     C02H 

CCI     CO 

H        1    H 

CC12    CO 

H              C/C02K 
CC12     /  \OH 

CC12    / 

-H 
CCI 

~tH 

CCI 

cci2 

CC12 

CC12 

CCI, 

CH3 

Tetra- 

Hexachlor- 

Hexachloro-R- 

Hexachloro- 

Perchloro- 

Ethylidene- 

chloro- 

o-diketo- 

pentene-oxy- 

keto- 

vinyl- 

propionic 

quinone 

R-hexene 

carboxylic  acid 

R-pentene 

acrylic  acid 

acid. 

(2)  The  splitting  up  of  hydroquinone  is  simpler.  By  the  action  of 
chlorine  upon  hydroquinone,  or  quinone,  as  well  as  of  potassium  chlorate 
and  HC1  upon  phenol,  we  can  easily  obtain  tetrachloro-para-quinone 
(chloranile),  and  from  this,  by  chlorination,  hexachloro-para-diketo- 
R-hexene,  which,  with  alcoholic  potash,  is  broken  up  to  perchlor-acroyl- 
acrylic  acid.  The  latter,  as  well  as  hexachloro-para-diketo-R-hexene 
itself,  are  decomposed  by  aqueous  soda  into  dichloro-maleic  acid  and 
trichlor-ethylene  (A.  267,  i)  : 


CO2H  CO,H 

CCI     CC12  CCI  CC12 


CCI     CCI  CCI  CHCI 

\     /  \ 

CO  COaH 

Tetrachloro-          Hexachloro-    Perchlor-acroyl-       Dichloro-       Trichlor- 
p-quinone  p-diketo-  acrylic  acid          maleic  acid      ethyl ene. 

R-hexene 

(3)  From  resorcin,  with  chlorine  and  glacial  acetic  acid,  we  obtain 
pentachloro-resorcin,  and,  from  the  latter,  heptachloro-resorcin. 
Both  m-diketo-chlorides  split  up  in  cold  water  alone.  The  penta- 
chloro-compound  becomes  dichloro-acetyl-trichloro-crotonic  acid,  and 
the  heptachloro-compound  becomes,  with  chlorine  and  water,  trichloro- 
acetyl-pentachloro-butyric  acid.  The  dichloro-acetyl-trichloro-crotonic 
acid,  boiled  in  water,  yields  dichloro-methyl-chloro-vinyl-o-diketone. 
The  trichloro-acetyl-pentachloro-butyric  acid,  treated  with  alkalies, 
splits  into  chloroform  and  pentachloro-glutaric  acid,  as  does  trichloro- 
acetyl-acrylic  acid.  But  on  treating  it  with  boiling  water  it  passes 
into  tetrachloro-diketo-R-pentene,  which,  with  chlorine,  is  trans- 
formed into  perchloro-acetyl-acrylic  chloride.  The  chloride,  with  water, 
yields  the  acid  itself,  which  again,  on  treatment  with  alkalies,  decom- 
poses into  chloroform  and  dichloro-maleic  acid  : 


48 


C(OH) 
CH     CH 


CH     C(OH)      CH 


V 

Resorcin 


CO 

CCI     CC12 
CO 


ORGANIC  CHEMISTRY 

CO2H 
CCI     CC12H    CC1H  CC12H 

II       i       -HI        1 

CH     CO          CH      CO 


+  C02 


12 


CC12  CCI 

Pentachloro-      Dichloro- 
resorcin  acetyl- 

trichloro- 

|  crotonic  acid 

CO  CO2H 

CC12    CC12      CC12    CC13 

I  ->|  I  H 

3HC1  CO 

w 


\S 

Dichloro-methyl- 
chloro-vinyl- 
o-diketone. 


C02H 
/ 
CC12 

HC1  C02H 


+  CHC13 


HC1  CO 
\     / 
CCla 

Hepta-  Trichloro-acetyl-  Pentachloro-  Chloro- 
chloro-  pentachloro-  glutaric  acid  form, 
butyric  acid 


CCla 


resorcn 


CO CC12 

CC1 


CO 


CC13   C02H 

CO  ->CC1     CO2H  +  HCCL 


COC1     CC13     C02H 

dci     co  ->cc\ 

\     /  \     /  \     /          \.     , 

CCI  CCI  CCI  CCI 

Tetrachloro-     Perchloro-      Perchloro-     Dichloro- 

diketo-      acetyl-acrylic  acetyl-acrylic     maleiic 
R-pentene 


chloride 


acid 


Chloro- 
form. 


(4)  The  behaviour  of  resorcin  closely  resembles  that  of  phloroglucin 
or  [i,  3,  5]-trioxy-benzol,  as  this  passes  with  chlorine  into  hexachloro- 
[i,  3,  5]-triketo-R-hexene.  The  triketone,  treated  with  chlorine  and 
water,  decomposes  into  octochloro-acetone,  and,  treated  with  methyl 
alcohol,  into  dichloro-maionic-dimethyl  ester  and  sym.  tetrachloro- 
acetone  ;  and,  treated  with  ammonia,  into  three  molecules  dichloro- 
acetamide  (B.  23,  1706)  : 


C(OH) 


C02CH3 
CCla 

C02CH3 
Dichloro- 


CH 


C(OH)  C(OH) 


CH 

L 


CC12H 
+  CO 

CC12H 

sym.  Tetra-      Phloro- 
malonic    chloro-acetone    glucin 
ester 


C02 

CC13     CC13 
CO 


1 
CO 


CO 

CCla     CC12 
^CO       CO 

\   /         \   / 

CC12  CC12 

Hexachloro-         Octochloro- 
[x»  3»  5]-triketo-  acetyl-acetone.  acetamide. 
R-hexylene 


CONH2 

3  CHC12 
Dichloro- 


2CH3OH 


3NH3 


In  the  four  examples  the  splitting  takes  place  between  a  CO  group 
and  a  CC12  group  of  keto-chlorides.  These  reactions  were  first 
developed  by  Zincke  in  the  naphthalin  series,  and  used  for  splitting 
up  one  of  the  naphthalin  nuclei  and  for  the  transformation  of  naphthalin 
derivatives  into  indene  derivatives.  Later  he  extended  the  process  to 
the  above-mentioned  phenols  and  other  aromatic  compounds.  In  a 
similar  manner  Hantzsch  carried  out  the  splitting  up  of  phenol  with 


BENZENE   RING   SPLITTINGS  49 

chlorine  in  alkaline  solution,  and  its  transformation  into  cyclopentene 
derivatives  (B.  22,  1238). 

3.  Splitting  up  by  reduction  in  alkaline  solution.  —  This  splitting 
occurs  in 

(1)  The  o-phenol-car  boxy  lie  acids  during  reduction  with  Na  in  amyl 
alcohol.     As  intermediate  products  of  the  reduction  we  may  assume 
tetrahydro-acids  and  their  transposition  products — hydro-aromatic-o- 
ketone-carboxylic  acids.     The  latter  take  up  water  and  change  into 
pimelinic  acids  ;   salicylic  acid  yields  almost  quantitatively  n-pimelinic 
acid ;    while  o-,  m-,   and  p-cresotinic  acids  yield  the  three  isomeric 
methyl-pimelinic  acids  (Einhorn  and  Willstatter,  B.  28,  R.  744)  : 

COOH  COOH  COOH  COOH 

C  C  CH  CH2 

/  \  /   \  /\  / 

CH     C.OH  CH2  COH  CH2  CO  CH2  COOH 

CH     CH  ~*  CH2  CH2  ~*  CH2  CH2  CH2  CH2 

\  S  \   /  \/  \/ 

CH  CH2  CH2  CH2 

This  reaction  has  been  transferred  with  equal  success  to  the  naph- 
thalin-o-oxycarboxylic  acids  (see  Naphthalin-ring  splittings). 

(2)  Resorcin  gives,  on  reduction,  dihydro-resorcin,  which,  during 
oxidation  with  potassium  permanganate,  yields  n-glutaric  acid  (Merling, 
A.  278,  32) ;  heating  for  several  hours  with  concentrated  baryta  solution 
to  I5o°-i6o°  splits  up  dihydro-resorcin  to  y-acetyl-butyric  acid  with 
addition  of  H2O  (Vorlander,  B.  28,  2348)  : 


C(OH)  CO  CO 

CH     CH  CH2    CH2  CH2CH3 

CH     C(OH)  CH2    CO  CH2COOH 

\     S  \     /  \  / 

CH  CH2  CH2 

This  reaction  is  reversible. 


1.  The  Single-Nucleus  Benzene 

BENZENE,  phene,  benzol,  C6H6,  m.p.-h5'4°,  b-P-  8o'4°»  is  tne  funda- 
mental hydrocarbon  of  the  aromatic  substances.  It  is  generated  in 
the  dry  distillation  of  coal,  and  is  therefore  found  in  coal-tar,  accom- 
panied by  a  body  most  closely  resembling  it  in  physical  properties, 
viz.  thiophene  (q.v.)  C4H4S,  and  numerous  other  compounds.  Pure 
benzene  is  formed  by  heating  benzoic  acid  or  benzol-polycarboxylic 
acids  with  lime.  Synthetically,  benzene  may  be  produced  from  acety- 
lene by  heating  to  high  temperatures  (Berthelot,  1870). 

Benzene  is  produced  from  coal-tar  by  fractionation,  and  is  separated 

from  thiophene  (q.v.)  by  repeated  shaking  up  with  a  little  concentrated 

sulphuric  acid,  treatment  with  aluminium  chloride,  or  heating  with 

chlorine  sulphide,  formaldehyde,  or  phthalic  anhydride  (B.  29,  R.  1000, 

VOL.  II.  E 


50  ORGANIC   CHEMISTRY 

1152  ;  C.  1902,  II.  737  ;  1909,  II.  666).  Finally  it  is  purified  by 
squeezing  off,  after  being  crystallised  in  a  freezing  mixture. 

Historical  (B.  23,  1271). — Benzene  was  discovered  by  Faraday  in 
1825,  in  compressed  illuminating  gas  prepared  from  oil.  It  was 
obtained  in  1834  by  Mitscherlich  by  distillation  of  benzoic  acid 
with  quicklime,  and  was  discovered  by  A.  W.  Hofmann  in  1845 
in  coal-tar. 

Properties. — Benzene  is  a  mobile  liquid  of  an  odour  resembling 
ether,  D0  0-899,  D20  0-8799.  It  burns  with  a  luminous  flame,  mixes 
with  absolute  alcohol  and  ether,  and  dissolves  resins  and  fats  very  easily, 
also  many  hydrocarbons  capable  of  crystallisation  with  crystal  benzene 
(see  Triphenyl-methane).  Sulphur,  iodine,  and  phosphorus  are  also 
soluble  in  benzene. 

Behaviour  and  Transformations. — (i)  On  conducting  benzene 
through  an  incandescent  tube  it  is  partly  changed  into  diphenyl 
C6H5.C6H5,  and  into  diphenyl  benzols  C6H4(C6H5)2,  and  decomposes 
partly  into  acetylene.  (2)  On  oxidising  benzene  with  Mn  peroxide 
and  H2S04  some  benzoic  acid  is  formed,  obviously  due  to  some  diphenyl 
formed  intermediately  (A.  221,  234),  also  some  o-phthalic  acid  ;  but 
benzene  is  very  stable  against  oxidisers.  By  silver  peroxide  in  the 
presence  of  HN03,  or  by  manganic  sulphate,  it  is  oxidised  to  quinone 
(q.v.)  (B.  38,  3963  ;  C.  1908,  I.  74).  Benzene  is  split  up  by  treatment 
with  C1O3K  and  H2SO4,  passing  into  trichloro-pheno-malic  acid  and 
/?-trichlor-acetyl-acrylic  acid.  On  passing  ozone  through  benzene 
for  some  time,  a  white  amorphous  mass  is  obtained,  the  so-called 
ozobenzol,  a  very  explosive  substance,  of  the  formula  C6H6O9,  decom- 
posed slowly  by  water  with  formation  of  glyoxal  (B.  37,  3431).  (3)  By 
heating  with  HI  to  26o°-28o°  benzene  is  mostly  isomerised  into 
methyl-pentamethylene ;  but  benzene  and  hydrogen  combine  to 
hexahydro-benzol,  on  passing  over  finely  divided  nickel  at  i8o°-200° 
(C.  1901,  I.  817).  (4)  Chlorine  and  bromine  act  upon  benzene  both 
by  addition  and  by  substitution.  (5)  HNO3  transforms  it  into 
nitro-benzol  C6H5NO2 ;  and  (6)  H2SO4  into  benzol-sulpho-acid 
C6H5SO3H.  The  last  two  compounds  are  prepared  industrially  on 
a  large  scale.  With  the  help  of  A12C16  and  halogen  alkyls,  alkyl 
residues  may  be  introduced  into  benzene.  (7)  With  aldehydes, 
benzene  is  condensed  by  H2SO4  to  higher  aromatic  hydrocarbons 
(see  Diphenyl-methane  and  ethane). 

COAL-TAR. 

Dry  distillation  of  coal  also  gives  rise  to  many  alkyl-benzols, 
and  some  higher  condensed  aromatic  bodies  like  naphthalin  C10H8, 
acenaphthene  C12H10,  fluorene  C13H10,  anthracene  and  phenanthrene 
C14H10,  fluoranthene  C15H10,  pyrene  C1GH10,  and  chrysene  C18H12. 
They  are  contained  in  the  "coal-tar"  obtained  in  great  quantities 
in  gas-works  and  coke-ovens.  Besides  illuminating  gas  and  tar, 
ammonia  water  is  formed,  while  coke  remains  in  the  retorts,  forming 
a  fuel  richer  in  carbon  than  coal  itself. 

For  the  rapid  and  brilliant  development  of  aromatic  chemistry  it 
has  been  of  the  greatest  utility  that  the  fundamental  aromatic  sub- 
stances have  been  made  available  to  chemical  investigation,  in  any 


COAL-TAR  51 

desired  quantity,  by  the  industry  concerned.  For,  while  the  paraffins 
were  unsuitable  bases  for  the  building  up  of  aliphatic  substances,  the 
aromatic  hydrocarbons,  with  their  faculty  for  the  most  varied  reactions, 
form  not  only  the  systematic  but  also  the  practical  foundation  for 
the  chemistry  of  aromatic  substances.  Coal-tar,  which  contains  these 
hydrocarbons,  is  the  inexhaustible  source  for  preparing  numberless 
aromatic  compounds,  many  of  which  have  been  most  widely  used  as 
dyes,  perfumes,  and  medicines. 

Working  of  Coal-Tar  for  Aromatic  Hydrocarbons. — Coal-tar,  which, 
besides  the  aromatic  hydrocarbons,  contains  aliphatic  bodies,  thiophene 
and  its  methylated  derivatives,  phenols,  pyridin  bases,  and  other 
compounds,  is  first  distilled  into  three  or  four  fractions  : 

1.  Light  oil  (3  to  5  per  cent.),  lighter  than  water,  boils  at  150°. 

2.  Middle  oil  (8  to  10  per  cent.),  about  the  density  of  water,  boils  at 

I50°-2IO°. 

3.  Heavy  oil   (8  to   10   per  cent.),  heavier  than  water,  boils  at 

2IO°-270°. 

4.  Green  oil,  or  anthracene  oil  (16  to  20  per  cent.),  of  a  green  colour, 
boils  at  270°-400°. 

5.  Residue. — Pitch  (about  60  per  cent.). 

For  the  benzene  compounds  only  light  oil  is  in  question,  which  is 
freed  from  resins,  olefins,  pyridin  bases,  etc.,  by  washing  with  sulphuric 
acid,  and  then  from  phenols  by  washing  with  caustic  soda.  It  is  then 
subjected  to  a  careful  fractional  distillation. 

Besides  benzene,  the  following  benzene  hydrocarbons  occur  in  coal- 
tar  : — Toluol  or  methyl-benzol,  the  three  isomeric  xylols  or  dimethyl- 
benzols  ;  ethyl-benzol,  vinyl-benzol  or  styrol ;  the  three  isomeric  tri- 
methyl-benzols  ;  mesitylene,  pseudo-cumol,  hemi-mellithol,  n-propyl- 
benzol,  the  three  isomeric  toluols,  and  durol  or  tetramethyl-benzol. 
Aromatic  hydrocarbons  are  also  found  freely  in  lignite  tar,  to  some 
extent  in  wood-tar  oil,  in  slate-tar  oil,  and  in  rock-paraffin  oil. 

The  bulk  of  the  benzene  and  toluol  of  to-day  is  obtained  from  the 
coke-oven  gases,  which  contain  about  42  grammes  per  cubic  metre, 
by  treating  the  gases  with  coal-tar  fractionings,  of  higher  boiling- 
points,  in  spraying  towers. 

The  winning  of  aromatic  bodies  by  dry  distillation  should  be  con- 
sidered in  connection  with  their  formation  by  pyrogenic  synthesis  or 
pyro-condensation,  by  conducting  aliphatic  bodies  through  incandescent 
tubes.  In  dry  distillation  the  retort  walls  take  the  place  of  the  tubes 
(cp.  B.  29,  2691  ;  10,  853  ;  20,  660). 

ALKYL-BENZOLS  CnH2nH}. 

The  first  place  among  the  formation  processes  of  alkyl-benzols 
must  be  given  to  the  reactions  of  nuclear  synthesis  (Vol.  I.). 

i.  It  has  been  repeatedly  mentioned  that  various  symmetrical 
trialkyl-benzols  are  formed  by  polymerisation  of  alkyl-acetylenes  in 
the  presence  of  sulphuric  acid,  just  as  benzene  is  produced  by  the 
polymerisation  of  acetvlene. 

cr»  TJ 

Allylene  3CH3.C  =  CH  ~-^  C6H3[i,3,5](CH3)3,  mesitylene.  For 
the  alkyl-acetylenes  we  may  substitute  ketones,  acetone,  ethyl-methyl- 
ketone,  and  treat  them  with  sulphuric  acid. 


52  ORGANIC  CHEMISTRY 

2.  Much  more  general  is  the  reaction  discovered  in  1864  by  Fit  tig  : 
action  of  Na  upon  a  mixture  of  brominated  benzene  hydrocarbons  in 
ether  solution,  with  alkyl-bromides,  and  iodides  (A.  129,  369  ;  131,  303  ; 
B.  21,  3185)  : 

C6H5Br  +CH3I  +2Na=C6H5CH3  +NaI  +NaBr 
C6H4Br.C2H6  +C2H6I  +2Na=C6H/^2*?5  +NaI  +NaBr. 


This  reaction  is  a  very  valuable  generalisation  of  Wiirtz's  synthesis 
of  the  paraffins,  by  the  action  of  sodium  upon  halogen  alkyls  (Vol.  I.). 
A  few  drops  of  acetic  ester  promote  the  reaction,  which  is  the 
smoother,  the  higher  the  molecular  weight  of  the  alkyl  iodide. 

3.  The  synthesis  of  tetramethyl-methane  from  acetone  chloride, 
and  zinc  methyl  (Vol.  I.),  corresponds  to  the  synthesis  of  iso-propyl- 
benzol  out  of  benzol  chloride  and  zinc  methyl  (B.  13,  45),  and  of  one 
amyl-benzol  out  of  benzol  chloride  and  zinc  ethyl  : 

C6H5CHCl2+Zn(C2H5)2=C6H5CH(C2H5)2+ZnCl2. 

4.  Essentially    limited    to    aromatic    compounds,    but    in    these 
of  very  general  utility,  is  the  so-called  aluminium  chloride  synthesis 
discovered  by  Friedel  and  Crafts  in  1877,  and  consisting  in  the  action 
of   alkyl-haloids  upon  benzene  hydrocarbons  in  the  presence  of  Al 
chloride. 

In  some  cases  the  olefins  react  in  the  presence  of  HC1  in  a  manner 
similar  to  the  alkyl-haloids  (C.  1907,  II.  366). 

Similar  action  is  shown  by  zinc  chloride,  and  especially  iron 
chloride  (cp.  Nencki,  B.  32,  2414).  The  Al  chloride  can  sometimes  be 
replaced  by  a  mixture  of  sublimate  and  Al  filings  (see  B.  35,  868). 
Here  it  is  probable  that  the  alkyl-haloids  first  form  organic  compounds, 
which  then  act  upon  the  hydrocarbons  (C.  1900,  I.  756  ;  B.  33,  815). 
In  some  cases  intermediate  products  have  been  preserved.  The 
reaction  between  benzene,  ethyl  chloride,  and  Al  chloride  seems  to 
traverse  the  following  phases  : 

2C6H6  +3C2H6C1  +  A12C16=  A12C16.C6H3(C2H6)3.C6H6  +3HC1 
A12C16.C6H3(C2H5)3.C6H6  +3C2H5C1=  A12C16[C6H3(C2H5)3]2HC1  +2HC1. 

This  reaction  product  on  heating  decomposes  into  triethyl-benzol, 
HC1,  and  the  compound  A12C16.C6H3(C2H5)3,  which  under  the  action  of 
HC1  can  convert  a  fresh  molecule  of  benzene  into  triethyl-benzol,  so 
that  one  may  alkylise  a  large  quantity  of  benzene  with  very  little  Al 
chloride.  Water  decomposes  the  compound  A12C16.C6H3(C2H5)3  in 
A1(OH)2,  HC1,  and  triethyl-benzol  (/.  pr.  Ch.  2,  72,  57).  There  is  no 
difficulty  about  replacing  all  the  H  atoms  of  benzene  by  methyl  and 
ethyl  groups  (B.  14,  2624  ;  16,  1745).  Sometimes  CS2  acts  favourably 
as  a  diluent  (A.  235,  207  ;  cp.  B.  29,  2884)  : 


CH3Cl-fC6H6          ~»     HC1+C6H5CH3 
2CH3C1+C6H6  -^->  2HC1+C6H4(CH3)2 
6CH3C1+C6H6  -^£L->  6HC1+C6(CH3)6. 


ALKYL-BENZOLS  53 

Similar  reactions  with  the  benzene  hydrocarbons  are  shown  by 
very  different  halogen  compounds,  like  chloroform,  and  the  acid 
chlorides.  Ethyl  ether  also  acts,  in  the  presence  of  A12C1C,  upon 
benzene  hydrocarbons  with  formation  of  poly-ethylated  benzols  (C. 
1899,  II.  755). 

Disintegration  reactions.  —  5.  Curiously  enough,  Al  chloride  is  as 
suitable  for  disintegrating  the  alkyl-benzols  as  it  is  for  synthesising 
them.  Under  suitable  conditions  it  is  possible  to  detach,  by  means 
of  Al  chloride,  the  side  chains  from  one  molecule  of  a  hydrocarbon, 
and  introduce  it  into  another  molecule  of  the  same  hydrocarbon.  In 
this  process,  certain  positions  of  the  alkyl  groups  are  preferred,  both 
in  synthesis  and  in  disintegration,  as  shown  by  the  following  scheme 
of  reactions  (Anschiitz  and  Immendorf,  B.  18,  657)  : 


^  C,H4[i,  4l(CHs)2  ^  ^  C.Ha[i,  3,  4,  6](CH,)4  >_ 

C6HSCH,  ^  ^  C.H,[i,  3,  4](CHt),  ^  ^ 

X  C.H4[i,  3](CH,)2  C.H,[i.  3,  4,  5](CH,)4  ^ 


) 
C.H.  ^  C.H,[i,  3,  5](CH,),  *  C.(CH,).. 

In  the  case  of  butyl-  and  amyl-benzols  an  isomerisation  of  the  alkyl 
radicles  is  easily  effected  by  Al  chloride  (C.  1899,  I.  776). 

If  bromine  is  made  to  act  upon  poly-alkalised  benzols,  in  the  presence 
of  Al  bromide,  the  longest  side  chain  is  split  off,  with  bromination  of 
the  resultant  products  (C.  1899,  I.  32). 

6.  Concentrated  sulphuric  acid  acts  similarly,  both  for  synthesis  and 
for  disintegration. 

7.  Dry  distillation  of  a  mixture  of  aromatic  acids,  with  lime  or 
soda-lime,  iron  filings  being  added  to  promote  heat-  conduction.     In 
this  case  all  carboxyls  are  split  off  and  the  fundamental  hydrocarbons 
are  formed  : 

Benzoicacid  .  C6H5CO2H  —  >  CO2+C6H6  Benzol 
Toluylic  acid  CH3C6H4CO2H  —  >  CO2+C6H5CH3  Toluol 
Phthalic  acid  .  C6H4(CO2H)2  --  -»  2CO2+C6H6  Benzol. 

8.  9,  and  10.  Replacement  of  inorganic  residues  in  substitution  products 
by  hydrogen  : 

8.  Treatment  of  diazo-compounds  with  alcohol  and  alkaline  stannous 
oxide  solution  (B.  22,  587).     This  reaction  is  particularly  important 
for   solving   questions    of    constitution.      The    diazo-compounds   are 
obtained  from  amido-compounds,  and  the  latter  from  nitro-compounds, 
produced  by  the  action  of  HNO3  upon  hydrocarbons. 

9.  Treatment  of  sulpho-acids  with  superheated  steam,  and  sulphuric 
acid,  concentrated  HC1,  or  phosphoric  acid,  at  180°. 

10.  Heating  of  oxygen-containing  derivatives,  phenols,  and  ketones, 
with  zinc  dust  (Baeyer,  A.  140,  295)  or  HI  and  phosphorus.     It  is 
notable  that  in  this  reaction  benzo-phenone  C6H5.CO.C6H5  is  easily 
reduced,  but  diphenyl-ether  C6H5.O.C6H5  not  at  all.     A  special  facility 
is  shown  in  the  reduction  of  the  ketones,  on  passing  vapours,  with 
hydrogen,  over  finely  divided  nickel  at  I9o°-i95°  (C.  1905,  I.  29). 

11.  Many  alkyl-benzols,  like  propyl-  and  isopropyl-benzols,  are  best 
produced    by    reduction    of    the    corresponding    olenn-benzols,    like 


54  ORGANIC   CHEMISTRY 

C6H5CH  :  CHCH3  and  C6H5C(CH3)  :  CH2  with  Na  and  alcohol  (B.  36, 
621,  1628,  1632  ;  37,  1721). 

Properties.  —  The  benzene  hydrocarbons  are  mostly  volatile  liquids, 
though  some  polymethyl-benzols  (durol,  penta-  and  hexamethyl- 
benzol,  also  hexa-ethyl-benzol)  are  solid  at  ordinary  temperatures. 
They  possess  a  peculiar,  and  not  unpleasant,  odour,  and  are  insoluble 
in  water,  though  soluble  in  alcohol  and  ether.  They  are  themselves 
good  solvents  for  many  organic  compounds,  which  may  be  precipitated 
from  them  by  means  of  petrol  ether. 

Behaviour  and  Transformations.  —  i.  With  reducing  agents,  especi- 
ally when  the  vapours  are  conducted  with^  hydrogen  over  finely  divided 
nickel,  the  alkyl-benzols  and  benzene  itself  pass  into  hydro-cyclic 
hydrocarbons.  HI  produces  a  transposition  of  the  six-membered  into 
an  isomeric  five-membered  hydrocarbon. 

2.  Of  great  importance  is  the  behaviour  of  alkyl-benzols  in  oxida- 
tion.    Dilute  nitric  acid,  chromic  acid  mixture,  potassium  perman- 
ganate, or  ferricyanide  convert  the  side  chains  of  the  benzene  homo- 
logues  into  COOH  groups.     The  number  of  COOH  groups  produced, 
and  their  mutual  positions,  give  information  concerning  the  number 
and  position  of  the  alcohol  radicles  in  the  oxidised  benzene  carbo- 
hydrates.    By  careful  oxidation,  especially  with  MnO4K,  intermediate 
products  may  be  obtained,  when  the  side  chains  are  long,  the  oxidation 
taking  place  according  to  the  same  rules  as  in  the  fatty  bodies  (cp. 
aromatic  carboxylic  acids). 

3.  Chlorine  and  bromine,  when  cold,  replace  H  atoms  of  the  benzene 
nucleus,  and  on  heating  they  replace  the  H  atoms  of  the  side  chain 
(see  Toluol). 

4.  Concentrated  nitric  acid  yields  nitro-compounds. 

5.  Concentrated  sulphuric  acid  decomposes  alkyl-benzols  to  sulpho- 
acids  on  heating,  and,  from  these,  the  hydrocarbons  can  be  formed 
again  (by  method  9).     A  process  for  separating  out,  and  purifying,  the 
benzols  has  been  based  upon  this. 

6.  Under  the  action  of  ozone  the  alkyl-benzols,  and  benzene  itself, 
yield  explosive  triozonides,  which  are  decomposed  by  water,  with  forma- 
tion of  aliphatic  aldehydes  (A.  343,  369). 

7.  With  chromyl  chloride  CrO2Cl2  the  homologous  benzols  yield 
compounds,  from  which  water  forms  aromatic  aldehydes,  and  ketones 


8.  On  heating  toluol  or  xylols  with  sulphur,  stilbene  C6H5CH  : 
CHC6H5  is  formed,  or  methylated  stilbene,  and  further  transformation 
products  (C.  1903,  I.  502). 

Isomerism.  —  Of  the  first  member  of  the  series,  toluol,  the  theory 
only  allows  of  one  modification,  and  this  is  the  only  one  found.  The 
six  H  atoms  of  benzene  are  equivalent. 

Of  xylol  or  dimethyl-benzol  three  isomers  are  possible,  as  it  is  a 
di-substitution  product  : 


o-Xylol  C.H.  m-Xylo!  C.H.  p-Xylo. 


With  these  three  known  xylols  ethyl-benzol  C6H5C2H5  is  isomeric. 

Of  bodies  with  the  formula  C9H12,  eight  isomers  are  possible,  and 
these  are  all  known  :    (i)  three  trimethyl-benzols  ;    (2)  three  ethyl- 


ALKYL-BENZOLS 


55 


methyl-benzols  ;  (3)  two  propyl-benzols  :  n-propyl-  and  isopropyl- 
benzol. 

The  isomerisms  are  therefore  determined  by  the  position,  number, 
homology,  and  isomerism  of  the  alkyls  entering  the  benzene  in  replace- 
ment of  hydrogen. 

Constitution. — Of  the  syntheses  of  the  alkyl-benzols,  Fittig's  reaction 
(see  above)  is  especially  valuable,  as  regards  conclusions  respecting 
constitution,  since,  as  far  as  we  know,  no  intramolecular  atomic  dis- 
placements occur  in  it,  the  alkyls  taking  the  places  vacated  by  the 
halogen  atom.  Oxidation  also  helps  in  deciding  about  the  number  and 
position  of  the  side  chains. 

The  following  table  shows  the  most  important  alkyl-benzols  : 


Name. 

Formula. 

M.p. 

B.p. 

Density. 

Toluol 

C6H5CH3 

110-3° 

0-8708(13.1/4°) 

Xylols,  Dimethyl-benzols 

C6H4(CH3)2 

o-Xylol    . 

-28° 

142° 

0-8932  (o°) 

m-Xylol,  Isoxylol 

. 

-54° 

139° 

0-8812  (o°) 

p-Xylol    . 

. 

+  15° 

138° 

0-8801  (o°) 

Ethyl-benzol 

GjHjC/HqCHjj                . 

136° 

0-8832  (o°) 

Trimethyl-benzols 

C8H3(CH3)3 

[1,2,3]  =  Hemimellithol 

.  . 

175° 

.  . 

[1,2,4]=  Pseudo-cumol 

. 

.  . 

170° 

[i,3,5]=Mesitylene    . 

164-5° 

0-8694  (9-8/4°) 

Methyl-ethyl-benzols     . 

CaH4(CH3)(C3H  ) 

o-  or  [1,2]- 

.  . 

159° 

0-8731  (16°) 

m-  or  [1,3]- 

. 

.  . 

159° 

0-8690  (20°) 

p-   or  [1,4]- 
n-Propyl-benzol   . 

C6H5CH2CH2CH3        '. 

•• 

162° 
158-5° 

0-8652   (21°) 

0-88  10  (o°) 

Isopropyl-benzol,  Cumol 
Tetramethyl-benzol 

C6H5CH(CH3)2 
C6H2(CH3)4 

153° 

0-8798  (o°) 

[i,2,3,4]  =  Prehnitol  . 

-  4° 

204° 

. 

[i,2,3,5]  =  Isodurol     . 

. 

196° 

0-8961  (0/4°) 

[i,  2.4,5]  =  Durol 

.                              , 

79° 

190° 

Methyl-isopropyl-benzols 

C6H4(CH3)[CH(CH3)2] 

[1,2]-            . 

. 

.  . 

175° 

0-8723  (o°) 

[1.31-         • 

.                              . 

.  . 

175° 

0-8582  (18°) 

[i,4]  =  Cymol    . 

, 

175° 

0-865 

Pentamethyl-benzol 

C6H(CH3)5 

53° 

230° 

Hexamethyl-benzol 
Penta-ethyl-benzol 
Hexa-ethyl-benzol 

C6(CH3)8  . 
C6H(C2H5)5 
C6(C2H5)4 

164° 
129° 

264° 
277° 
298° 

0-8985  (19°) 

From  this  table  it  is  seen  that  the  position  isomers  of  the  same 
formula,  e.g.  the  three  xylols,  have  closely  adjoining  melting-points. 
In  the  dimethyl-benzols  the  o-compound  boils  at  the  highest  tempera- 
ture. Then  come  the  meta-  and  finally  the  para-compound  ;  but  the 
p-compound  has  the  highest  melting-point.  Of  the  tetramethyl- 
benzols,  durol  is  solid  at  ordinary  temperatures,  also  the  pentamethyl-, 
hexamethyl-,  and  hexa-ethyl-benzols. 

The  entry  of  a  methyl  group  produces  in  the  methyl-benzols  an 
elevation  of  the  boiling-point  by  about  24°  to  30°  :  cp.  toluol,  xylols, 
tri-,  tetra-,  penta-,  and  hexamethyl-benzols.  Entry  of  CH3  into  a 
side  chain  raises  the  boiling-point  by  about  24°  :  cp.  toluol,  ethyl- 
benzol,  and  n-propyl-benzol. 


56  ORGANIC   CHEMISTRY 

TOLUOL  C6H5CH3,  so  called  because  it  is  obtained  from  the  dry 
distillation  of  tolu  balsam,  is  found  in  coal-tar  in  company  with  thio- 
tolene  or  methyl-thiophene  (q.v .),  and  is  very  valuable  industrially.  It 
is  formed  according  to  the  general  methods  : 

(1)  From  bromo-benzol,  methyl  iodide,  and  sodium  ; 

(2)  From  benzene,  methyl  chloride,  and  Al  chloride  ; 

(3)  From  the  polymethyl-benzols  and  Al  chloride  ; 

(4)  From  the  three  toluylic  acids,  and  the  methyl-poly carboxylic 
acids,  by  distillation  with  lime,  etc. 

On  reduction,  toluol  passes  into  hexahydro-toluol ;  by  oxidation  with 
dilute  HNO3,  or  chromic  acid,  into  benzoic  acid ;  with  chromyl  chloride, 
CrO2Cl2,  and  water,  or  MnO2,  C12O3,  and  sulphuric  acid,  into  benz- 
aldehyde.  On  nitrogenation  it  gives  o-  and  p-nitro-toluol ;  on  sulphur- 
ising it  yields  much  p-toluol-sulpho-acid,  besides  a  little  o-acid. 

Chlorine  has  a  remarkable  action  upon  toluol.  At  boiling-point 
only  the  hydrogen  of  the  side  chain  is  replaced,  and  we  get : 


Benzyl  chloride  C6H5CH2C1 
Benzal  chloride  C6H5CHC12 
Benzo-trichloride  C6H5CC13. 


In  the  cold,  on  the  other  hand,  o-  and  p-chloro-toluol  are  generated, 
C6H4C1.CH3.  In  the  presence  of  iodine  and  SbCl5  chlorine  only  enters 
the  nucleus,  even  at  boiling-point  (Beilstein  and  Geitner,  A.  139,  311). 
But  a  little  PC15  facilitates  entry  into  the  side  chain  (A.  272,  150).  The 
same  effect  is  produced  by  sunlight. 

Hydrocarbons  C8H10.  —  Ethyl-benzol  is  isomeric  with  the  three  di- 
methyl-benzols. Of  the  three  xylols  occurring  in  coal-tar,  iso-  or  m- 
xylol  is  most  abundant  and  technically  important. 

During  oxidation  with  dilute  HNO3,  o-  and  p-xylol  are  oxidised  to 
o-and  p-toluylic  acid,  and  the  latter  to  o-and  p-phthalic  acid  respectively. 
Metaxylol  is  attacked  with  greater  difficulty.  Potassium  permanganate 
also  oxidises  the  three  xylols  to  the  corresponding  toluylic  acids,  and 
finally  to  phthalic  acids.  H2SO4  dissolves  o-  and  m-xylol  to  xylol- 
sulpho-acids  (B.  10,  1013  ;  14,  2625).  On  distilling  raw  xylol  with 
steam,  p-xylol  passes  over  first. 

o-Xylol  is  also  formed  from  o-bromo-toluol,  CH3I  and  sodium. 
Oxidised  by  MnO4K  it  passes  into  phthalic  acid.  Chromic  acid  burns 
it  to  CO2  and  H2O,  like  many  o-derivatives. 

m-Xylol  or  iso-xylol.  —  The  production  of  m-xylol  from  mesitylenic 
acid,  by  heating  with  lime,  is  theoretically  important.  This  reaction 
genetically  connects  m^xylol  with  mesitylene,  in  which  the  [i,  3,  5]- 
position  of  the  three  methyl  groups  can  be  established.  This  proves 
the  m-position  for  the  toluylic  and  phthalic  acids  generated  by  oxidation 
of  m-xylol. 


H          rH      C  H      MCH^C  H  <  H  .H  /[i]CO,H 

6  "  3  4"C«  - 


Mesitylene     Mesitylenic  acid          Isoxylol         m-Toluylic  acid   Isophthalic  acid 

p-Xylol,  by  distillation  of  camphor  with  ZnCl2,  also  from  p-bromo- 
toluol  and  p-dibromo-benzol,  CH3I  and  Na  (B.  10,  1355).     On  oxidation 


ALKYL-BENZOLS  57 

with  dilute  HNO3  it  gives  first  p-toluylic  acid,  then  terephthalic  acid, 
and  with  CrO3  terephthalic  acid  at  once.  In  fuming  sulphuric  acid 
it  decomposes,  forming  a  well-crystallising  sulpho-acid. 

Ethyl-benzol  C6H5CH2CH3  also  occurs  in  coal-tar  (B.  24,  1955). 
Produced  from  bromo-benzol,  ethyl  bromide,  and  sodium ;  or  benzol, 
ethyl  bromide,  and  Al  chloride  (B.  22,  2662) ;  also  by  reduction  of  styrol 
C6H5CH  =  CH2.  Dilute  HNO3  and  chromic  acid  oxidise  it  to  benzoic 
acid.  CrO2Cl2  produces  phenyl-acetaldehyde  C6H5.CH2.CHO. 

Hydrocarbons  C9H12 — The  isomerism  of  the  eight  compounds  of 
this  formula  has  already  been  pointed  out  above.  For  physical 
constants  see  table. 

Mesitylene,  symmetrical  trimethyl-benzol,  occurs  in  coal-tar,  and  in 
certain  naphtha  fractionate  (C.  1901,  I.  1002),  and  is  prepared  from 
acetone  (Kane,  1837)  or  allylene  with  concentrated  sulphuric  acid  (cp. 
B.  29,  958,  2884).  The  proof  of  its  symmetrical  structure  is  of  funda- 
mental importance  for  the  location  of  the  benzene  substitution  products. 
With  dilute  HNO3,  mesitylene  passes  into  mesitylenic  and  mesidinic 
acids,  or  into  uvitinic  and  trimesinic  acids : 

r[i]CH3                     f[i]C02H  f[i]C02H                     r[i]C02H 

C6H3    [3]CH3 >C6HJ  [3]CH3          — >C6Hj  [3]CO2H >C8H3-  [3]CO2H 

l[5]CH3                       l[5]CH3  l[5]CH3                          l[5]C02H 

Mesitylene               Mesitylenic  acid  Uvitinic  acid               Trimesinic  acid. 

Under  the  influence  of  ozone,  mesitylene  gives  a  triozonide, 
which  is  split  by  water  with  formation  of  methyl-glyoxal  (A.  343, 

37°)  • 

Pseudo-cumol,  [1,3, 4\-trimethyl-benzol,  is  also  contained  in  coal-tar. 

It  is  separated  from  mesitylene  by  means  of  the  less  soluble  sulpho- 
acid  (B.  9,  258).  Also  formed  from  bromo-p-xylol,  and  4-bromo-m- 
xylol,  which  determines  its  constitution. 

Hemi-mellithol,  [i,  2,  ^-trimethyl-benzol,  occurs  in  coal-tar  (B.  42, 
3603)  ;  prepared  from  isodurylic  acid  C6H2(CH3)3COOH,  and  from 
2-bromo-m-xylol  with  CH3I  and  Na. 

The  three  ethyl-toluols  have  been  obtained  from  the  three  bromo- 
toluols  with  ethyl  halides  and  Na.  All  these  isomers  are  found  in 
coal-tar  (B.  42,  3613). 

p-Ethyl-toluol,  m.p.  162°,  has  been  obtained  from  p-methyl-styrol 
and  from  p-cresyl-ketone  by  reduction  (B.  28,  2648  ;  36,  1637). 

n-Propyl-benzol,  from  bromo-benzol,  n-propyl  bromide  or  iodide 
and  Na  ;  from  benzyl  chloride  and  zinc  ethyl ;  from  benzene,  n-propyl 
bromide,  and  A12C16  at  —2°  (B.  24,  768)  ;  and  from  propenyl-benzol 
C8H5CH  :  CHCH3  with  Na  and  alcohol  (B.  36r  622).  Also  found  in 
coal-tar. 

Isopropyl-benzol,  cumol,  C6H5CH(CH3)2,  first  obtained  by  distillation 
of  cuminic  acid  (CH3)  2CHC6H4COOH  with  lime.  Synthetically  from 
benzal  chloride  and  Zn(CH3)2 ;  and  from  benzene,  isopropyl  chloride 
or  bromide,  and  Al  chloride.  Since  heat  transposes  n-propyl  bromide, 
with  A12C16,  into  isopropyl  bromide,  the  Al  synthesis  gives  isopropyl- 
benzol  even  when  n-propyl  bromide  is  used,  unless  the  process  is 
conducted  in  the  cold.  Cumol  is  best  prepared  synthetically  by  the 
reduction  of  isopropenyl-benzol  C6H5C(CH3)  :  CH2  with  Na  and  alcohol 


58  ORGANIC  CHEMISTRY 

(B.  35,  2640).     In  the  animal  body  cumol  is  oxidised  to  propyl-phenol 
(B.  17,  2551). 

In  the  hydrocarbons  C10H14  theory  predicts  22  isomers  : 


C.H2(CH3)4        C. 
3  isomers  6  isomers  3  isomers  6  isomers  4  isomers. 

(a)  Tetramethyl-benzols  C6H2(CH3)4.  —  The  three  possible  isomers 
are  known  : 

Durol,  [i,  2  4,  5]-  or  sym.  tetramethyl-benzol,  is  found  in  coal-tar 
(B.  18,  3034).  Prepared  from  6-bromo-pseudo-cumol  and  4,  6-dibromo- 
m-xylol  with  CH3I  and  Na  ;  from  toluol  and  pseudo-cumol  with  CH3C1 
and  Al  chloride  (B.  35,  868)  ;  and  from  penta-  and  hexamethyl-benzol 
with  A12C16.  On  oxidation  it  passes  into  durylic  acid  and  cumidinic 
acid,  thus  proving  its  constitution  (B.  11,  31).  Concentrated  H2SO4 
converts  durol  into  hexamethyl-benzol  and  the  sulpho-acids  of  prehnitol, 
pseudo-cumol,  and  isoxylol,  which  can  be  separated  by  means  of 
their  amides.  Similar  behaviour  is  shown  by  pentamethyl  and 
penta-ethyl-benzols. 

Isodurol,  [i,  2,  3,  5]-  or  unsym.  tetramethyl-benzol,  from  bromo- 
mesitylene,  CH3I  and  Na  (B.  27,  3441),  which  proves  its  constitution  ; 
also  from  camphor  and  Zn  chloride  or  iodide  (B.  16,  2259).  By  oxida- 
tion it  gives  3-isodurylic  acid  (B.  15,  1853),  and  finally,  mellophanic 
acid. 

Prehnitol,  [i,  2,  3,  4]-  or  v-tetramethyl-benzol,  from  2-bromo-pseudo- 
cumol,  and  from  2,  4-dibromo-m-xylol,  CH3I  and  Na  (B.  21,  2821). 
Oxidised  to  prehnitylic  acid  C6H2(CH3)3COOH  (B.  19,  1214),  and 
prehnitic  acid  C6H2(COOH)4. 

(6)  Dimethyl-ethyl-benzols:  [i,  2,  4],  b.p.  189°,  and  [i,  3,  4],  b.p.  184°; 
[i,  4,  3],  b.p.  185°,  from  camphor  with  ZnCl2  and  iodine,  and  from  the 
corresponding  dimethyl-vinyl-benzols  by  reduction  (B.  23,  988,  2349  > 
36,  1637);  [1,3,5],  b.p.  185°,  from  acetone  and  methyl-ethyl-ketone 
with  SO4H2  (B.  18,  666  ;  25,  1533). 

(c)  Three  diethyl-benzols  oxidise  first  to  ethyl-benzoic  acids  and 
then  to  phthalic  acids.     p-Diethyl-benzol,  b.p.   183°,  has  also  been 
obtained  from  p-ethyl-styrol  by  reduction  (B.  36,  1633). 

(d)  Methyl-n-propyl-benzols.  —  The  most  important  is  the  p-com- 
pound,  cymol.     m-Methyl-isopropyl-benzol  is  found  in  light  resin  oil 
(A.  210,  10).     Also  generated  on  heat  ing  fenc  hone  (q.v.)  with  phosphorus 
pentoxide  (A.  275,  157).     o-Methyl-isopropyl-benzol  has  been  prepared 
from  o-bromo-cumol  with  Na,  and  methyl  iodide  (B.  34,  1950). 

Cymol,  [i,  4]-methyl-isopropyl-benzol  (see  Table,  p.  55),  found  in 
Roman  carraway  oil  from  the  seeds  of  Cuminum  cyminum  besides 
cuminaldehyde,  in  the  oil  from  the  seeds  of  Cicuta  virosa,  in  thyme  oil, 
eucalyptus  oil,  and  many  other  etheric  oils.  Prepared  from  thymol, 
carvacrol,  or  camphor  with  P2S5  (B.  16,  791,  2259)  or  P2O5  (A.  172, 
307)  ;  from  turpentine  oil,  and  other  terpenes,  with  withdrawal  of 
2H,  by  SO4H2  or  iodine.  We  must  note  the  formation  of  cymol  on 
boiling  cumin  alcohol  with  zinc  dust,  and  from  citral.  Synthetically, 
cymol  is  produced  from  p-brom-isopropyl-benzol,  CH3I  and  Na,  which 
fixes  its  constitution  (B.  24,  439,  970,  1362).  Cymol  has  a  pleasant 


HIGHER   HOMOLOGUES   OF  TOLUOL  59 

odour.  The  cymol-sulpho-salt  of  barium  (C10H13SO3)2Ba+3H2O, 
crystallising  in  shiny  scales,  is  characteristic. 

By  dilute  HNO3,  and  chromic  acid  mixture,  cymol  is  converted  into 
paratoluylic  acid  and  terephthalic  acid ;  but  in  the  animal  organism  it 
is  oxidised  to  cuminic  acid,  also  on  shaking  up  with  NaHO  and  air. 
MnO4K  yields  p-oxy-isopropyl-benzoic  acid  (CH3)2C(OH)C6H4COOH. 
The  action  of  concentrated  HNO3  upon  cymol,  produces  p-tolyl-methyl- 
ketone  (B.  19,  588  ;  20,  R.  373). 

(e)  Butyl-benzols  :  n-Butyl-benzol,  b.p.  180°.  Isobutyl-benzol, 
b.p.  167°.  Sec.-butyl-benzol,  b.p.  174°,  by  reduction  of  sec.-butenyl- 
benzol  C6H5C(CH3)  :  CHCH3  (C.  1900,  I.  591  ;  B.  35,  2642).  Teft- 
butyl-benzol,  b.p.  167°.  The  latter  is  not  attacked  by  bromine  in 
sunlight,  in  the  cold  (B.  23,  2412  ;  27,  1610). 

HIGHER  HOMOLOGUES  OF  TOLUOL. 

We  may  mention  the  following  : 

HYDROCARBONS  CUH16. — Pentamethyl  -  benzol  and  hexamethyl- 
benzol  from  toluol,  xylol,  mesitylene,  CH3C1,  and  A12C16  (B.  20, 896) .  For 
behaviour  with  SO4H2  see  Durol.  [1, 3, 5]-Diethyl-methyl-benzol,  b.p. 
200°,  from  a  mixture  of  acetone  and  methyl-ethyl-ketone,  with  sulphuric 
acid.  [1, 2, 4,  5]-Trimethyl-ethyl-benzol,  ethyl-pseudo-cumol,  b.p.  207° 
(B.  25,  1530  ;  36,  1641).  Ethyl-mesitylene,  b.p.  208°  (B.  29,  2459  ; 
36,  1642).  [l,3]-Methyl-tert.-butyl-benzol,  b.p.  i85°-i87°,  occurs  in 
resin  essence,  the  distillation  product  of  fir  resin  ;  prepared  from 
toluol,  isobutyl  bromide,  and  A.\2C\Q.  Its  trinitro-derivative  forms 
artificial  musk  (B.  27,  1606).  The  isomeric  p-tert.-butyl-toluol,  b.p. 
190°,  is  obtained  from  toluol  and  isobutyl  alcohol  with  fuming  sul- 
phuric acid  (C.  1898,  I.  450).  Amyl-benzols,  see  C.  1899,  I.  776  ;  B. 
35,  2644. 

HYDROCARBONS  C12H18. — Hexamethyl-benzol,  by  polymerisation 
of  crotonylene  with  SO4H2  ;  by  heating  xylidin  chloride  with  methyl 
alcohol  to  300°  ;  also  by  analogy  with  durol.  Insoluble  in  SO4H2, 
as  it  cannot  form  a  sulpho-acid.  Potassium  permanganate  oxidises 
it  to  benzol-hexacarboxylic  acid  C6(COOH)6,  mellithic  acid.  p-Di-n- 
propyl-benzol,  b.p.  219°,  from  p-dibromo-benzol,  and  p-n-Propyl- 
isopropyi-benzol,  b.p.  212°,  from  cumyl  chloride  C1CH2.C6H4CH(CH3)2 
with  Zn(C2H5)2.  These  bodies  both  yield  n-propyl-benzoic  acid, 
isomeric  with  cuminic  acid,  on  oxidation  with  HNO3.  Propyl- 
mesitylene,  b.p.  221°  (B.  29,  2459)  ;  Isobutyl-mesitylene,  b.p.  228°  ; 
iso-amyl-mesitylene,  b.p.  241  °,  by  reduction  of  the  corresponding 
acyl-mesitylenes  (B.  37,  1715). 

[1, 3,  5]-Triethyl-benzol,  b.p.  218°,  from  ethyl-methyl-ketone  with 
sulphuric  acid  ;  from  benzene,  ethyl  chloride,  and  A12C16  we  obtain, 
besides -the  sym.  form,  the  as-  or  [i,  2,  4]-triethyl-benzol,  b.p.  218°, 
which  can  be  separated  from  the  former  by  the  greater  stability  of 
its  sulpho-acid,  against  phosphoric  acid,  and  can  also  be  obtained  by 
reduction  of  diethyl- vinyl-benzol  (/.  pr.  Ch.  2,  65,  394 ;  B.  36, 
1634).  [1, 2, 3, 4]-f etraethyl-benzol,  b.p.  251°.  [1, 2, 4, 5]-Tetraethyl- 
benzol,  m.p.  +13°,  b.p.  250°  (B.  36,  1635).  Pentaethyl-benzol. 
Hexaethyl-benzol  from  C6H6,  C2H5Br  or  ether  and  A12C16  (B.  16,  1745  ; 
21.  2819).  Optically  active  Hexyl-benzols  C6H5CH2CH2CH(CH3)C2H5, 


60  ORGANIC   CHEMISTRY 

b.p.  220°,  and  C6H5CH(CH)3.CH2.CH(CH3)2,  b.p.  197°,  s.  B.  37,  654, 
2308.  Active  p-Isopropyl-hexyl-benzol  C3H7.C6H4CH2.CH2.CH(CH3), 
C2H5,  b.p.  265°  (B.  38,  2313).  Heptyl-benzol  C6H5CH(CH3)CH2 
CH2C(CH3)2  (B.  35,  2645).  Tert.-p-butyl-ethyl-benzol,  b.p.  209°, 
from  p-butyl-aceto-phenone  (C.  1905,  I.  29).  Tert.-p-dibutyl-benzol, 
m.p.  76°,  b.p.  236°  (C.  1904,  II.  1112). 

By  Fittig's  method  the  following  mono-  and  di-alkyl-benzols  with 
long  side  chain  were  obtained  from  bromo-benzol  and  bromo-toluol : — 
n-Octyl-benzol,  b.p.  262°.  Cetyl-benzol  C6H5.C16H33,  m.p.  27°,  b.p.15 
230°.  o-Methyl-eetyl-benzol,  m.p.  8°-9°,  b.p.15  239°.  m-Methyl-cetyl- 
benzol,  m.p.  io°-i2°,  b.p.15  237°.  p-Methyl-cetyl-benzol,  m.p.  27°, 
b.p.15  240°.  Octo-decyl-benzol,  m.p.  36°,  b.p.15  249°  (B.  21,  3182). 


2.  Halogen  Derivatives  of   the   Benzene   Hydrocarbons. 

A.  HALOGEN  SUBSTITUTION  PRODUCTS  OF  BENZENE. 

As  a  cyclic  triolefin,  benzene,  in  sunlight,  adds  six  atoms  Cl  or  Br, 
thus  forming  benzene  hexachloride  and  benzene  hexabromide  — 
bodies  which,  as  derivatives  of  cyclohexane,  are  treated  later  in  con- 
nection with  hexahydro-benzol.  But  the  H  atoms  attached  to  the 
benzene  nucleus  are  also  easily  replaced  by  chlorine  and  bromine, 
more  easily  than  the  H  atoms  of  the  paraffins. 

Properties  and  Behaviour. — The  halogen  benzols  are  partly  colour- 
less liquids,  partly  colourless  crystalline  compounds.  They  have  a 
feeble,  but  not  unpleasant,  odour.  They  are  not  soluble  in  water, 
but  easily  in  other  solvents,  and  volatilise  without  decomposition. 
Of  the  dihalogen  benzols  the  para-compounds  are  solid,  at  ordinary 
temperatures.  They  melt  at  higher  temperatures  than  the  ortho- 
and  meta-compounds,  but  boil  at  lower  temperatures. 

There  is  a  remarkably  close  attachment  of  the  halogen  atoms  to 
the  benzene  nucleus.  They  do  not  make  a  double  decomposition 
(or  only  with  great  difficulty)  with  alkaline  hydroxides,  ammonia, 
potassium  cyanide,  etc.  (B.  18,  335  ;  20,  R.  712)  ;  but  metals  like 
Mg,  Na,  and  Cu  extract  halogens,  especially  from  benzol  bromides  and 
iodides.  This  is  of  importance  for  the  synthesis  of  homologous  benzene 
hydrocarbons.  There  is  a  notable  facility  of  reaction  of  chloro-,  bromo-, 
and  iodo-benzol  with  piperidin,  forming  phenyl-piperidin  ;  prolonged 
heating  with  dimethyl-amine  leads  to  dimethyl-aniline  (B.  21,  2279  ; 
C.  1898,  II.  478).  Small  quantities  of  powdered  copper,  or  copper 
salts,  which  act  catalytically,  greatly  favour  the  transformation  with 
ammonia,  and  amines  (C.  1909, 1. 475  ;  B.  40,4541).  Sodium  amalgam 
in  alcoholic  solution,  HI  (C.  1898,  II.  422  ;  /.  pr.  Ch.  2,  65,  564),  and 
phosphorus,  as  well  as  Ni  and  H  at  270°  (C.  1904,  I.  720),  reduce  the 
halogen  benzols  to  benzene. 

Fluoro-benzols  are  formed  from  benzol-diazo-piperididene  by  adding 
hydrofluoric  acid  (Wallach,  A.  243,  221) 

C6H6N=N— NCBH10+2HF1=C6H6F1+N2+NH.C6H10.HF1. 

They  are  formed  from  the  benzol-diazonium  chlorides,  sulphates, 
and  fluorides  (q.v.)  by  decomposition  with  aqueous  solutions  of  HF 
(C.  1898,^1.  1224  ;  1900,  I.  145  ;  1905,  I.  1230). 


HALOGEN   SUBSTITUTION    PRODUCTS   OF   BENZENE     61 


Fluoro-benzol  CeH^F,  m. p. —41-2°,  b.p.  85°,  D4^  1-0236,  has  also 
been  obtained  by  heating  fluoro-benzoic  acid  with  HC1. 

p-Difluoro-benzol  C6H4[i,4]F2,  b.p.  88°,  D  i-n. 

Chloro-benzols. — Modes  of  formation  : — (i)  Free  chlorine  acts  but 
slowly  upon  benzene.  Its  action  is  assisted  by  I,  MoCl5,VCl4  (C.  1904, 
I.  87),  FeCl3  (C.  1899,  II.  287),  or  A1C13.  Chlorination  can  also  be 
accomplished  with  PbCl4.2NH4Cl  (C.  1903,  I.  283,  570). 

(2)  The  hydroxyl  group  of  the  phenols  is  chlorinated  with  difficulty 
by  PC15  ;   in  the  nitro-phenols  this  replacement  is  easier. 

(3)  A   very   important    process   for   forming   chloro-benzols,   and 
aromatic  halogen  derivatives  generally,  is  based  upon  the  transforma- 
tions of   the  so-called  diazo-compounds,  obtained  from   amido-com- 
pounds,  the  reduction  products  of  nitro-compounds.     These  reactions 
involve   no  atomic  displacement,  the  chlorine  taking  the  place  pre- 
viously occupied  by  the  diazo-,  amido-,  or  nitro-group. 

Benzol-diazonium-chlorideC6N5N2Cl=C6H5Cl+N2. 

If,  therefore,  in  the  di-  and  poly-substitution  products  the  consti- 
tution of  one  of  these  bodies  is  known,  the  constitution  of  the  others 
is  determined. 


Name. 

Formula. 

M.p. 

B.p. 

D. 

Monochloro-benzol     . 

C«H5C1 

-45° 

132° 

1-128  (o°) 

"     2]-(o)-Dichloro-benzol    . 

C6H4C12 

1  80° 

;     3]-(m)-Dichloro-benzol  . 

.  . 

172° 

'.     4]-(p)-Dichloro-benzol   . 

.  . 

+53° 

172° 

!     2,  3]-(v)-Trichloro-benzol 
'     2,  4]-(as)-Trichloro-benzol 

C6H3C13 

16° 
63° 

218° 
213° 

'.     3«  5]-(s)-Trichloro-benzol 

54° 

208° 

'.     2»  3»  4]-(v)-Tetrachloro-benzol 

C6H2C14 

46° 

254° 

2»  3>  5]-(as)-Tetrachloro-benzol 

y>l 

246° 

'.     2,  4,  5]-(s)-Tetrachloro-benzol 

244° 

Pentachloro-benzol    . 

C6HC15 

86° 

276° 

Hexachloro-benzol     . 

C6C1, 

226° 

326° 

In  the  chlorination  of  chloro-benzol,  p-dichloro-benzol  is  mostly 
formed,  with  but  little  o-dichloro-benzol  (B.  29,  R.  648) ;  p-dichloro- 
benzol  is  also  obtained  from  p-quinone  (q.v.)  with  PC15.  Further 
chlorination  of  o-,  m-,  and  p-dichloro-benzol  yields  1, 2, 4-trichloro- 
and  1,2,4, 5-tetrachloro-benzol  (C.  1905,  II.  1528).  Characteristic, 
for  the  dichloro-benzols,  is  their  behaviour  on  nitrogenation : 

o-Dichloro-benzol  gives  [i,  2]-dichloro-4-nitro-benzol,  m.p.  43° 
m-Dichloro-benzol  „  [i,  3]-dichloro-4-nitro-benzol,  „  32* 
p-Dichloro-benzol  „  [i,  4]-dichloro-3-nitro-benzol,  „  55°. 

Hexachloro-benzol  (Julin's  "  chlorocarbon  ")  has  also  been  obtained 
by  the  thorough  chlorination  of  many  alkyl-benzols,  and  other  benzene 
derivatives  (B.  29,  875).  It  is  also  formed  on  conducting  CHC12  or 
C2C14  through  an  incandescent  tube. 

Bromo-benzols  have  been  obtained  in  a  manner  quite  similar  to  the 
chloro  substitution  products,  i.e.  (i)  by  direct  substitution,  through 
bromine  carriers,  like  Al  bromide  (B.  10,  971)  or  a  mixture  of  sulphur 
bromide  and  HNO3  (B.  33,  2883  ;  C.  1901,  II.  750)  ;  (2)  from 
phenolene  ;  (3)  from  diazo-compounds  (q.v.). 


62 


ORGANIC   CHEMISTRY 


Name. 

Formula. 

M.p. 

B.p. 

D. 

VIonobromo-benzol 

C6H5Br 

-3i° 

155° 

1-517  (o°) 

"i,  2]  -(o)-Dibro  mo-benzol               j  C6H4Br2 

+   7-8°* 

224° 

"i,  3]-(m)-Dibromo-benzol 

.  . 

-  6-5°  * 

219-4°  * 

:i.4Hi 

.1.2,3. 

3)  -Dibromo-benzol 
-(v)-Tribromo-benzol           C6H3Br3 

89° 

87° 

219° 

1.2,4; 

-  (as)  -Tribromo-benzol 

44° 

275°' 

1.3.5 

-  (s)  -Tribromo-benzol 

.  . 

H9° 

278° 

X2,  3, 

4J-(v)-Tetrabromo-benzol  C6H2Br4 

1,2,  3,5]-(as)-Tetrabromo-benzol        ..                 98 

329°' 

i,  2,  4,  5]-(s)-Tetrabromo-benzol  j 
Pentabromo-benzol           .          .     C6HBr5 

175° 
•      160° 

(6.28,191) 
(C.  1900,  1.  809) 

Hexabromo-benzol  .          .          .     C6Br6 

315° 

Of  the  dibromo-benzols  we  obtain  on  bromination  of  benzene  with 
heat  chiefly  the  p-compounds,  more  rarely  the  o-compounds  (B.  10, 
I345)-  Characteristic  of  the  dibromo-benzols,  as  of  the  dichloro- 
benzols,  is  their  behaviour  on  nitrogenation. 

The  generation  of  tribromo-benzols  from  the  three  dibromo-benzols 
has  been  used  for  constitution  determinations  of  all  these  bodies 
(Kdrner).  Hexabromo-benzol  is  generated  by  heating  CBr4  to  300°. 

Chloro-bromo-benzols,  see  C.  1899,  I.  835  ;  II.  959. 

lodo-benzols  are  obtained  (i)  by  heating  benzene,  iodine,  and 
HI  to  200°  (Kekule).  The  action  is  represented  by  the  equation 
(A.  137,  161)  : 

5C6H6-f4I+I03H=5C6H5I=3H20. 

(2)  By  treating  benzene  with  a  mixture  of  I2S2  and  HNO3  (B.  33, 
2875  ;   C.  1901,  II.  750). 

(3)  More  usually,  iodo-benzols  are  prepared  from  the  corresponding 
amido-compounds  with  the  help  of  the  diazo-com pounds  (q.v.). 

(4)  Bromo-benzol  may  be  transformed  to  iodo-benzol  by  changing 
it  in  ether  solution  to  phenyl-magnesium  bromide,  and  then  treating 
with  iodine  (C.  1903,  I.  318)  : 


C6H6Br 


~>  C6H5MgBr 


C6H5I+MgBrI. 


Name. 

Formula. 

M.p. 

B.p. 

[odo-benzol 

C6H6I 

-30° 

188° 

[  ,  2]-(o)-Di-iodo-benzol 

C6H4I2 

+27° 

286° 

\  ,  3]-(m)-Di-iodo-benzol 

40° 

285° 

,  4J-(p)-Di-iodo-benzol 

129° 

285° 

.2,  3]-(v)-Tri-iodo-benzol 
,2,  4]-(as)-Tri-iodo-benzol 

C6H3I3 

116°  * 
91-4°  * 

'.  •  3.  5]-(s)-Tri-iodo-benzol 
'_  ,  2,  3,  4]-(v)-Tetra-iodo-benzol 
|  ,  2,  4,  6]-(as)-Tetra-iodo-benzol 
,  2,  4,  5]-(s)-Tetra-iodo-benzol 

C6H2I4 

184-4° 
136°* 
148° 
254°* 

see 
•  B.  34,  3343  ; 
C.  1901,  II.  535 

Penta-iodo-benzol 

C6HI5 

172° 

J 

Hexa-iodo-benzol 

C6I8 

I40°-i5o° 

Hexa-iodo-benzoi  C6I6  forms  during  thorough  iodination  of  benzol- 
carboxylic  acids   (benzoic  acid,   terephthalic  acid)   with  iodine  and 


HALOGEN   SUBSTITUTION   PRODUCTS  OF  BENZENE     63 

fuming  sulphuric  acid.  It  forms  reddish-brown  needles  which  melt 
and  decompose  at  I4O°-I5O°  (B.  29,  1631). 

1, 3, 5-Tri-iodo-2-chloro-benzol  (C.  1907, 1. 632).  About  Bromo-iodo- 
benzols  (B.  29, 1405  ;  C.  1899,  II.  371).  1, 3, 5-Tri-iodo-2,  4, 6-tribromo- 
benzols  C6Br3I3,  m.p.  322°  (C.  1898,  II.  972). 

Iodide  chlorides  ;  lodoso-benzol ;  lodo-benzol ;  Diphenyl-iodonium 
hydroxide. — The  iodo-benzols  and  their  homologues,  by  the  action  of 
chlorine  or  substances  easily  liberating  chlorine,  are  transformed  into 
iodide  -  chlorides,  e.g.  phenyl  iodide  -  chloride  C6H6IC12  (Willgerodt, 
1886).  These  contain  chlorine  bound  to  iodine,  and  may  therefore  be 
referred  to  iodine  trichloride  IC13.  The  formation  of  these  peculiar 
compounds  is  useful  for  the  characterisation  of  iodinated  benzene 
derivatives.  The  iodo-chlorides  are  easily  changed  into  iodoso- 
benzols,  and  should  be  regarded  as  the  chlor-anhydrides  of  the  latter. 
From  the  iodoso-benzols  we  arrive  through  oxidation  at  the  iodo- 
benzols,  e.g.  C6H5IO2.  From  iodoso-  and  iodo-benzol  we  finally  obtain 
the  strongly  basic  diphenyl-iodonium  hydroxide. 

Phenyl-iodo-ehloride  C6H5IC12,  yellow  needles,  formed  on  conduct- 
ing chlorine  through  a  solution  of  iodo-benzol  in  chloroform.  By 
heating  it  is  changed  into  p-iodo-chloro-benzol  with  liberation  of 
chlorine  (C.  1907, 1.  1198 ;  II.  43).  Shaken  up  with  water  and  alkalies 
or  other  bases,  it  yields  iodoso-benzol  : 

C6H5IC12+2KOH=C6H5IO+2KI+H2O. 

lodoso-benzol  C6H5IO  is  an  amorphous  substance  exploding  about 
210°  ;  treated  with  acidulated  KI  solution,  it  gives  up  its  oxygen  with 
liberation  of  the  equivalent  quantity  of  iodine : 

C6H5IO+2KI+2CH3COOH-C6H5I+2CH3COOK+2l+H2O. 

It  has  a  basic  character,  and  yields  salts  derivable  from  the  hypo- 
thetical hydrate  C6H5I(OH)2,  like  C6H5I(OOCCH3)2  ;  we  must  there- 
fore regard  C6H5IC12  as  an  iodoso-benzol  chloride. 

Iodo-benzol  C6H5IO2,  by  heating  iodoso-benzol  by  itself,  or  by 
boiling  in  water : 

2C6HBIO=C6HfiI+C6HBIO2 ; 

also  by  oxidation  of  iodoso-benzol  with  hypochlorous  acid,  or  treat- 
ment of  phenyl-iodo-chloride  with  bleaching-powder  solution  (B.  29, 
1567  ;  cp.  B.  33,  853).  It  is  also  formed  direct  from  iodo-benzol  by 
oxidation  with  K  persulphate  and  concentrated  H2SO4  (Caro's  reagent, 
B.  33,  533).  Iodo-benzol  explodes  at  227°-230°.  It  exhibits  the 
behaviour  of  a  super-oxide. 

With  concentrated  HF,  iodo-benzol  yields  benzol-iodo-fluoride 
C6H5IOF2,  which  with  water  regenerates  iodo-benzol  (B.  34,  2631). 

Diphenyl-iodonium  hydroxide  (C6H5)2IOH  is  only  known  in  aqueous 
solution.  Generated  by  shaking  up  a  mixture  of  iodoso-  and^  iodo- 
benzol  with  moist  silver  oxide,  according  to  the  equation 

C6H5IO+C6H5I02+AgOH^(C6H5)2I.OH+I03Ag. 

Its  iodide  is  formed  on  boiling  iodo-benzol  with  KI  solution  (B.  29, 
2008).  Diphenyl-iodonium  hydroxide  has  a  strong  alkaline  reaction, 
and  forms  salts  resembling  those  of  thallium  ;  the  carbonate  and 


64  ORGANIC  CHEMISTRY 

nitrate  are  very  soluble.  The  chloride  and  bromide  form  white 
precipitates. 

Diphenyl-iodonium  iodide  (C6H5)2I.I  is  polymeric  with  iodo-benzol. 
It  forms  yellow  needles  soluble  in  alcohol  with  difficulty.  They  melt 
at  I75°-I76°,  forming  iodo-benzol  (V.  Meyer,  B.  27,  1592  ;  28,  R.  80). 

Fat-aromatic  iodonium  salts  are  obtained  by  transformation  of 
acetylene-silver  chloride  with  aromatic  iodo-chlorides  : 

2C.H6IC12  +HCE=CAg,AgCl  =C1HC  :  CCK 


Dichloro-vinyl-phenyl-iodonium  chloride,  m.p.  174°.  Bromide 
decomposes  at  162°.  The  free  base  is  unstable  (A.  369,  132). 

A  number  of  homologous  and  substituted  iodo-chlorides,  iodoso- 
and  iodo-benzols,  and  iodonium  hydroxides  have  been  prepared  (see 
C.  1900,  I.  761  ;  1902,  II.  1196  ;  B.  34,  3406,  3666  ;  37,  1301  ;  39, 
269). 

B.  HALOGEN  DERIVATIVES  OF  THE  ALKYL-BENZOLS. 

Under  the  same  conditions  as  in  benzene  itself,  in  the  cold,  in  the 
presence  of  I,  MoCl5,  VC14,  FeCl3,  sulphur  bromide,  and  HNO3  (B.  33, 
2885),  so  in  the  alkyl-benzols  the  chlorine  and  bromine  atoms  enter 
almost  solely  into  the  benzene  residue,  and  aromatic  substitution 
products  are  formed.  Thus,  toluol  yields  : 

C6H5CH3 >  C6H4C1.CH3 >  C6H3C12CH3,  etc. 

C6H6CH3 >  C6H4BrCH3 >  C6H3Br2CH3,  etc. 

But  on  conducting  Cl  and  Br  through  the  boiling  alkyl-benzols, 
hardly  anything  but  the  hydrogen  of  the  side  chain  is  replaced,  and 
aliphatic  substitution  products  are  obtained.  Thus,  from  toluol 

C6HBCH3 >  C6H5CH2C1 >  C6H5CHC12 >  C6H5CC13 

Benzyl  chloride      Benzal  chloride    Benzo-trichloride 

are  obtained,  corresponding  to 

CH3CH2C1 >  CH3CHC12 >  CH3CC13 

Ethyl  chloride    Ethylidene  chloride    Methyl  chloroform. 

These  are  dealt  with  in  connection  with  the  corresponding  oxygenated 
compounds  : 

C6H5CH2OH >  C6H5CHO >  C6H5CO2H 

Benzyl  alcohol         Benzaldehyde         Benzoic  acid 

into  which  they  can  be  easily  converted,  and  from  which  they  can  be 
obtained  by  means  of  PC15. 

In  sunlight,  Cl  and  Br  produce  substitutions  of  the  aliphatic  side 
chains  of  the  lower  homologues,  even  when  cold  (B.  20,  R.  530  ;  cp. 
B.  35,  868).  Isopropyl-benzol  is  transformed  by  Cl,  at  boiling-point, 
into  p-chlorisopropyl-benzol  (B.  26,  R.  771).  PC13  also  attacks  the 
alkyles  of  the  alkyl-benzols  when  hot.  In  this  and  many  other 
reactions  the  presence  of  other  substituents,  in  the  benzene  nucleus, 
exercises  an  impeding  influence  (C.  1898,  I.  367,  1019). 


HALOGEN   DERIVATIVES   OF  THE   ALKYL-BENZOLS     65 

The  two  other  methods  for  preparing  the  halogen  derivatives  of 
benzene,  viz.  "  the  action  of  halogen  phosphorus  compounds  upon 
oxy-benzols,  and  the  transformation  of  the  corresponding  diazo-com- 
pounds,  give  alkyl-benzols,  with  substitution  of  halogens  in  the  benzene 
residue.  A  substitution  can  take  place  both  in  the  aromatic  and  the 
aliphatic  residue  of  the  same  alkyl-benzol.  The  halogen  atoms  entering 
the  side  chain  are  always  capable  of  reaction.  They  freely  exchange 
for  radicles,  whereas  the  halogen  atoms  entering  the  benzene  residue 
are  very  strongly  bound.  The  aromatic  monohalogen  derivatives  of 
the  alkyl-benzols,  especially  the  bromalkyl-benzols,  are  often  used 
for  building  up  higher  alkyl-benzols  by  Fittig's  method.  Of  some 
importance  for  recognising  the  constitution  is  the  oxidation  of  the 
side  chains  to  carboxyl  groups,  which  enables  us  also  to  determine  the 
halogen  atoms  in  the  side  chains. 

With  sodium  amalgam  in  alcoholic  solution,  or  with  HI,  the 
halogens  are  replaced  by  hydrogen. 

Of  the  very  numerous  aromatic  halogen  substitution  products  of 
this  kind  we  may  here  enumerate  the  simplest  representatives  of  the 
monohalogen  toluols  : 


Name. 

Formula. 

M.p. 

B.p. 

[I.  2> 

o-Fluoro-toluol 

CH3[i]C6H4[2]F 

n4°  (C.  1906,  II.  1830) 

[i.  3> 

m-Fluoro-toluol 

CH3[i]CBH4f3lF 

H5° 

[i,  41- 

p-Fluoro-toluol 

CH3[i: 

C6H4[4]F 

116° 

[i,  2]- 

o-Chloro-toluol 

CH3[i; 

C6H4[2]C1 

-34° 

156° 

[i,  31- 

m-Chloro-toluol 

CH3[i 

C6H4[3]C1 

-48° 

150° 

[i.  4l- 

p-Chloro-toluol 

CH3[i] 

C6H4[4]C1 

_!_      f° 

1 

163° 

[I,  2]- 

o-Bromo-toluol 

CH.CI 

C6H4[2]Br 

-26° 

181° 

[i.  33- 
[i.  41- 

m-Bromo-toluol 
p-Bromo-toluol 

CH3[iq 

CH3[i; 

C6H4[3]Br 
C6H4[4]Br 

-4o° 

+28° 

183° 
i84° 

[I,  2]- 

o-Iodo-toluol 

CH3[i]C6H4[2]I 

204° 

[i,  31- 

m-Iodo-toluol 

CH3[i]C6H4[3]I 

204<> 

[i,  41- 

p-Iodo-toluol 

CH3[i]C6H4[4]I 

35° 

211° 

o-,  m-,  and  p-Fluoro-toluols  have  been  prepared  by  the  same 
methods  as  fluoro-benzol.  On  chlorinating  or  brominating  toluol  in 
the  cold,  or  in  the  presence  of  iodine  or  FeCl3,  para-  and  ortho-com- 
pounds are  produced,  in  nearly  equal  quantities.  The  p-chloro-toluol 
may  be  separated  from  the  o-compound  by  heating  to  150°  with 
sulphuric  acid,  when  the  o-compound  forms  a  sulpho-acid. 

All  the  monochloro-,  monobromo-,  and  mono-iodo- toluols  may  be 
obtained  pure  by  decomposition  of  the  diazo-compounds  (q.v.)  obtained 
from  the  three  amido-toluols  or  toluidinenes.  The  o-  and  p-chloro- 
toluols  are  easily  obtained  from  the  corresponding  toluidins.  The 
m-bromo-toluol  has  also  been  obtained  by  brominating  aceto-p- 
toluidin  to  m-brom-aceto-p-toluidin  and  then  replacing  the  amido- 
group  by  hydrogen. 

The   m-chloro-toluol  has   also  been   obtained   from   3-methyl-A2- 

keto-R-hexene,  easily  prepared  from   methylene-diaceto-acetic  ester. 

In    this    process    tetrahydro-m-dichloro-toluol    is    first    prepared    by 

means  of  PC15,  and  then  it  splits  into  HC1  and  dihydro-m-chloro-toluol. 

VOL.   n.  F 


66 


ORGANIC   CHEMISTRY 


Bromine  withdraws  two  H  atoms  from  this  body,  and  m-chloro-toluol 
is  formed  (B.  27,  3019)  : 

CH3  CH3  CH3  CH3 

C=CH — CO >  C=CH — CC12 >C=-CH — CC1 ^C=CH— CC1 

CH2— CH2— CH2  CH2— CH2— CH2  CH2— CH2— CH         CH=CH— CH 

If  we  start  from  ethylidene-binaceto-acetic  ester,  we  obtain  [i,  3,  5]- 
chloro-m-xylol  (B.  29,  310) ;  and  [i,  3,  6]-chloro-cymol  has  been 
similarly  obtained  from  menthone  or  keto-hexahydro-p-cymol  (B.  29, 

3*4). 

The  iodoso-  and  iodo-compounds  corresponding  to  p-iodo-toluol 
are  known  (B.  26,  358  ;  27,  1903). 

For  the  halogen  toluols  their  transformation  into  solid  nitro-halogen 
toluols,  and  their  oxidation  to  the  halogen  benzoic  acids  of  known 
constitution,  are  characteristic.  Chromic  acid  oxidises  the  m-  and  p- 
halogen  toluols  to  the  corresponding  carboxylic  acids,  but  it  com- 
pletely burns  up  the  o-halogen  toluols.  By  boiling  with  dilute  HNO3, 
by  potassium  permanganate  or  potassium  ferricyanide,  all  the  three 
isomers,  including  the  ortho-compounds,  are  converted  into  carboxylic 
acids. 

Of  aromatic  di-halogen  toluols  with  similar  halogens  six  isomers  are 
possible.  The  six  isomeric  dichloro-toluols  are  known  (B.  29,  R.  867). 
They  are  isomeric  with  benzal  chloride  C6H5CHC12,  and  the  three 
chloro-benzyl  chlorides  C1C6H4CH2C1.  For  particulars  of  the  higher 
chlorination  products  of  toluol,  see  C.  1902,  II.  1178  ;  1904,  II.  1292, 
etc.  The  six  isomeric  dibromo-toluols  and  di-iodo-toluols  have  all 
been  obtained  (C.  1910,  I.  525).  Pentabromo-toluol  is  prepared  from 
suberane  and  bromine.  The  six  isomeric  tribromo-xylols  are  all 
known  (C.  1906,  II.  1831). 

The  following  table  contains  the  easily  prepared  bromo-derivatives 
of  polymethyl-benzols  : 


Name. 

M.p. 

B.p. 

[i,  2,  4]-Bromo-o-xylol. 

2° 

214° 

[i,  3,  4]-Bromo-m-xylol 

203° 

[i,  2,  4]-Bromo-p-xylol 

+    9° 

200° 

Tribromo-hemimellithol 

245° 

[i,  2,  4,  3]-Monobromo-pseudocumol 

237° 

[i,  2,  4,  3,  6]-Dibromo-pseudocumol 

64° 

293° 

Tribromo-pseudocumol 

224° 

Monobromo-mesitylene 

-    i° 

2^5° 

Dibromo-mesitylene 

+  60° 

285° 

Tribromo-mesitylene 

. 

224° 

Monobromo-prehnitol 

30° 

265° 

Dibromo-prehnitol 

. 

210° 

Monobromo-isodurol 

253° 

Dibromo-isodurol 

. 

20Q° 

Monobromo-durol 

. 

61° 

262° 

Dibromo-durol 

. 

199° 

317° 

Bromo-pentamethyl-benzol    .... 

1  60° 

289° 

It  is  also  remarkable  that  concentrated  sulphuric  acid  can  transfer 
bromine  atoms  instead  of  alkyl  groups.  It  thus  converts  monobromo- 
durol  first  into  dibromo-durol  and  then  into  lurol  (B.  25,  1526). 


NITROGEN  DERIVATIVES  OF  BENZENE  HYDROCARBONS  67 

A  number  of  iodinated  alkyl-benzols  have,  like  iodo-benzol  itself, 
been  prepared  by  means  of  sulphur  iodide  and  HNO3  (see  B.  33,  2875). 

Concerning  the  influence  of  alkyl  groups  in  the  "  reverse  substitu- 
tion "  of  iodine  in  iodinated  benzols,  see  /.  pr.  Ch.  2,  65,  564. 

3.  Nitrogen  Derivatives  of  Benzene  Hydrocarbons  in  which  the 
nitrogenated  residue  is  connected  with  the  benzene  nucleus  by 
nitrogen  linking. 

These  compounds  may  be  classified  by  the  number  of  nitrogen 
atoms  contained  in  the  residues.  The  first  class  is  formed  by  com- 
pounds in  which  the  nitrogen  group  only  contains  one  nitrogen  atom. 
This  is  headed  by  the  mYro-compounds,  so  characteristic  of  the  benzene 
derivatives  in  general,  which  form  the  bases  for  obtaining  the  succeed- 
ing groups.  Then  come  the  amido-compounds,  which  comprise  the 
generators  of  many  coal-tar  dyes  and  aromatic  bodies  of  therapeutic 
importance.  A  link  between  both  groups  is  formed  by  the  nitroso- 
and  the  ft-hydroxylamine  compounds. 

The  second  class  is  formed  by  the  compounds  in  which  the  nitro- 
genated residue  contains  two  or  more  N  atoms  mutually  linked.  Two 
N  atoms  are  carried  by  the  nitro- amines,  the  nitroso-p-hydroxyl- 
amines,  the  nitrosamines,  the  azoxy-compounds^  the  hydrazins,  the 
diazo-  and  the  azo-compounds.  Three  N  atoms  are  carried  by  the 
mVroso-hydrazins,  the  diazo-amido-compounds,  and  the  azo-imido- 
compounds  ;  four  N  atoms  by  the  diazo-kydrazides  or  buzylene  com- 
pounds, and  the  tetrazones  ;  five  N  atoms  by  the  bis-diazo-amido- 
compounds  ;  and  eight  N  atoms  by  the  bis-diazo-tetrazones  or  octazones. 

Our  knowledge  of  some  of  these  classes  of  bodies  has  acquired  the 
greatest  importance,  even  for  the  chemistry  of  the  inorganic  nitrogen 
compounds.  If  we  imagine  these  nineteen  groups  of  aromatic  nitrogen 
compounds  derived  from  the  inorganic  nitrogen  compounds  obtained 
by  replacing  the  aromatic  residues  by  hydrogen,  then  out  of  the  nineteen, 
only  six  occur  free  or  in  inorganic  compounds,  and  these  are  printed  in 
heavy  type  in  the  following  list  : 

1 .  A^ro-compounds  .          .          .   derived  from  H.N02 

2.  Nitroso-compounds         .          .         ,,  „     H.NO 

3.  0-Hydroxylamine-compounds  ,  ,     H.NHOH 

H.NH2 
H.NH.N02 
H.N(OH).NO 
H.NH.NO 
H.N  =  N.OH 

H.NH.NO  or  H.N(OH)  ;  N 
9.  Azo-compounds     .  ,,     H.N=N.H 


4.  Amido-compounds 

5.  Nitro-amines 

6.  Nitroso-ft-hydroxylamines 

7.  Nitrosamines 

8.  .Dia^o-compounds 


10.  A zoxy -compounds 

n.  Hydrazins     .... 

12.  Nitroso-hydrazins 

13.  Diazo-amido-compounds 

1 4 .  Diazo-oxy-amido-compounds  . 

15.  Diazo-imido-compounds 

1 6.  Diazo-hydrazo-  or  Buzylene  com- 

pounds 

17.  Tetrazones    .... 

1 8.  Bis-diazo-amido-compounds    . 

19.  Bis-diazo-tetrazone  or  Octazone 


H.N 


N.H 


H.NH.NH2 

H.N(NO).NH2 
H.N  =  N.NH2 
H.N  =  N  —  NHOH 


H.N  =  N.NH.NH, 
H.NH.N  =  N.NH2 

H.N  =  N  —  NH  —  N  =  N.H 

H.N  :  N.NH.N  :  N.NH.N  :  NH. 


68  ORGANIC  CHEMISTRY 

The  first  three  groups  will  be  dealt  with  in  the  succession  shown, 
but  the  others  will  be  arranged  by  their  genetic  rather  than  their 
systematic  relations,  as  follows  : — Nitroso-jS-hydroxylamines  ;  Amido- 
compounds  ;  Nitroso  -  amines  ;  Nitro  -  amines  ;  Diazo  -  compounds  ; 
Diazo-amido-compounds ;  Bis-diazo-amido-compounds ;  Diazo-oxy- 
amido-  and  Azo-imido-compounds ;  Azoxy-  and  Azo-compounds ; 
Hydrazines  ;  Nitroso  -  hydrazines  ;  Tetrazones ;  Diazo  -  hydrazo-  or 
Buzylene  compounds  ;  and  Octazones. 

i.  NITRO-DERIVATIVES  OF  BENZENE  AND  THE  ALKYL-BENZOLS. 

Benzene  and  the  alkyl-benzols  which  contain  H  atoms  attached  to 
the  nucleus  easily  give  nitro-derivatives  under  the  action  of  nitric  acid  : 

C6H6+N02OH=C6H5N02+H20. 

In  these  compounds  of  a  more  or  less  yellow  colour  the  nitrogen  of 
the  nitro-group  is  directly  linked  with  a  carbon  atom,  as  in  nitro- 
methane,  for  on  reduction  we  obtain  amido-compounds  : 

C6H6N02+6H=C6H5NH2+2H20. 

In  the  previous  chapter  it  was  stated  that  all  the  H  atoms  of  ben- 
zene may  be  replaced  by  chlorine  and  bromine.  This  does  not  apply 
to  the  nitro-groups.  The  two  first  nitro-groups  enter  without  diffi- 
culty, but  the  third  encounters  more  resistance,  and  it  has  not  been 
found  possible  to  introduce  more  than  three  nitro-groups  into  a 
benzene  derivative. 

A  mixture  of  one  part  HNO3  and  two  parts  H2S04  acts  more 
energetically  than  HNO3  alone,  as  the  sulphuric  acid  withdraws  water. 
Di-  and  trinitro-products  are  mostly  obtained  thus.  A  less  complete 
nitrogenation  is  attained  by  first  dissolving  in  glacial  acetic  acid  and 
chloroform  (B.  42,  4151). 

The  more  alkyl  groups  are  contained  in  a  benzene  hydrocarbon, 
the  more  easily  it  is  nitrogenated.  The  production  of  nitro-phenols 
during  such  nitrogenation  may  be  explained  by  assuming  an  addition 
of  HNO3  to  double  links  of  the  benzene  ring,  and  the  liberation  of 
HNO2  on  the  one  hand  and  H2O  on  the  other  (B.  24,  R.  721  ;  42, 4152). 
Such  unstable  addition  products  may  also  be  the  cause  of  the  dark- 
brown  colouring  at  first  observed  during  nitrogenation.  On  heating 
with  dilute  HNO3  the  nitro-group  enters  the  aliphatic  side  chain.  Such 
compounds  are  dealt  with  later  in  connection  with  the  corresponding 
alcohols  (B.  27,  R.  193  ;  C.  1899,  I-  I237)- 

An  admirable  means  of  nitrogenation  has  been  discovered  in  ben- 
zoyl  and  acetyl  nitrate,  suitable  for  some  cases  (B.  39,  3798  ;  C.  1907, 
I.  1025).  It  avoids  the  generation  of  water  which  accompanies  nitro- 
genation with  HNO3  : 

C6H6+C6H5COON02^C6H5N02+C6H6COOH. 

The  action  of  A12C16  upon  the  hydrocarbon  mixed  with  ethyl 
nitrate  can  also  produce  nitro-compounds  (C.  1908,  II.  403). 

From  the  aromatic  amines  obtained  by  reduction  of  the  nitro-com- 
pounds the  latter  may  be  recovered  through  the  intermediary  of  the 
diazo-compounds,  the  nitrites  of  which  yield  nitro-bodies  when  treated 
with  cuprous  oxide.  Nitro-bodies  have  also  been  obtained  by  direct 


NITRO-DERIVATIVES  OF   BENZENE 


69 


oxidation  from  amines,  e.g.  nitro-benzol  from  aniline  with  K  perman- 
ganate, in  which  process  /2-phenyl-hydroxylamine  and  nitroso-benzol 
have  been  obtained  as  intermediate  products  (B.  32, 1675). 

Properties  and  Behaviour. — The  nitre-hydrocarbons  are  only  slightly 
soluble  in  water,  but  they  are  soluble  in  concentrated  HNO3,  and  are 
precipitated  from  this  solution  by  water.  They  are  easily  dissolved  in 
alcohol,  ether,  glacial  acetic  acid,  etc.  The  nitre-products  melt  at  rather 
a  higher  temperature  than  the  corresponding  bromine  derivatives. 

Of  greater  importance  is  the  easy  reduction  of  the  nitre-compounds. 
As  intermediate  products  of  the  reduction  to  amide-compounds  the 
nitroso-compounds  and  the  j3-phenyl-hydroxylamines  have  been  re- 
tained. Both  combine,  under  the  influence  of  an  alkali,  to  azoxy-com- 
pounds,  which  are  further  reduced  to  azo-  and  hydrazo-compounds. 
These  genetic  relations  are  represented  by  the  scheme  : 

C6H5N02 >C6H5NO     >     C6H6NHOH >  C,H5NH2 

Nitroso-benzol      £-Phenyl-hydroxylamine  Aniline 


C'Hf>o- 

CeH5N/ 
Azoxy-benzol 


C,H5N 

"*  C6H5N 
Azo-benzol 


C6H5NH 

C,H5NH 

Hydrazo-benzol. 


During  the  electrolytic  reduction  of  nitre-bodies  dissolved  in  sul- 
phuric acid  we  obtain,  besides  amido-hydrocarbons,  amido-phenols, 
by  transposition  of  the  unstable  j3-phenyl-hydroxylamines  (B.  29, 
R.  230).  In  HC1  solution  p-chloraniline  is  formed  by  a  similar  process 
(B.  29,  1894  ;  C.  1907,  I.  463). 

About  the  electrolytic  reduction  of  nitre-bodies,  see  also  C.I  901, 
I.  105,  149  ;  B.  38,  4006  ;  A.  355,  175,  etc. 

The  easy  reduction  of  nitro-bodies  to  substances  useful  in  the 
manufacture  of  coal-tar  dyes  has  given  them  the  position  of  im- 
portant and  indispensable  intermediate  products. 

By  oxidation  with  alkaline  K  ferricyanide  solution,  the  polynitro- 
benzols  are  easily  converted  into  polynitro-phenols.  Nitro-benzol, 
on  heating  with  powdered  caustic  potash,  yields  o-nitro-phenol  and 
azoxy-benzol ;  m-nitro-toluol  similarly  yields  m-nitro-o-cresol ;  and 
m-dinitro-benzol  yields  2,  4-dinitro-phenol  (B.  32,  3486  ;  34,  2444  ; 
C.  1901,  I.  149). 

By  heating  with  HC1  to  20O°-300°  the  nitro-groups  are  replaced 
by  chlorine  in  many  polynitro-hydrocarbons,  and  in  some  cases  there 
is  a  further  chlorination  (B.  29,  R.  594). 

NITRC-BENZOLS. — The  melting-points  and  boiling-points  of  the 
known  nitro-benzols  are  shown  in  the  following  table  : 


Name. 

Formula. 

M.p. 

B.p. 

tfitro-benzol 

C6H5NO2 

+  5-72° 

209°  (C.  1897,  II. 

547) 

2]-,  o-Dinitro-benzol 

}                         ( 

116° 

319°  (773  mm.) 

3]-,  m-Dinitrc-benzol 

IC6H4(N02)2- 

90° 

303°  (771  mm.) 

4]-,  p-Dinitro-benzol 

j                         I 

172° 

299°  (777  mm-) 

\     2,  4]-,  as-Trinitro-benzol 
3»  5]~f  s-Trinitro-benzol  . 

}C6H3(N02)3{ 

57° 

121° 

!     2>  3»  5]-Tetranitro-benzol 

C,H2(N02)4 

116° 

70  ORGANIC   CHEMISTRY 

Nitro-benzol  C6H5NO2  was  discovered  in  1834  bY  Mitscherlich 
(Pogg.  Ann.  31,  625),  on  treating  benzene  with  nitric  acid.  It  is  also 
formed  during  the  oxidation  of  aniline.  It  is  prepared  in  large  quanti- 
ties industrially,  and  worked  for  aniline  and  azo-benzol.  For  the  in- 
dustrial preparation  of  nitro-benzol  a  mixture  of  HNO3  and  H2SO4  is 
allowed  to  flow  into  benzene  in  cast-iron  tubes,  and  kept  stirred. 
Nitro-benzol  is  a  yellowish,  highly  refractive  liquid  of  density  1-20  at 
20°,  smelling  of  benzaldehyde  or  oil  of  bitter  almonds,  tasting  sweet 
in  dilute  aqueous  solution,  and  acting  as  a  poison,  especially  when 
its  vapour  is  breathed.  Besides  the  dye  industry,  nitro-benzol  is 
also  employed  in  the  perfume  industry,  to  give  soap  an  odour  of  oil 
of  bitter  almonds.  In  the  laboratory  it  is  often  employed  as  a 
solvent  or  an  oxidiser  (see  Rosaniline  and  Quinolin). 

DINITRO-BENZOLS  C6H4(NO2)2. — On  prolonged  boiling  of  benzene 
with  fuming  HNO3,  or  on  short  heating  with  HNO3  and  H2SO4, 
m-dinitro-benzol  is  chiefly  formed,  together  with  the  o-  and  p-forms, 
which  are  more  easily  soluble  in  alcohol  (B.  7,  1372).  The  meta-com- 
pound  is  used  in  the  dye  industry  for  preparing  m-phenylene-diamine. 

p-Dinitro-benzol  is  also  obtained  from  p-quinone  dioxime  by  oxi- 
dation ;  and  o-dinitro-benzol  from  the  residues  of  preparation  of 
m-dinitro-benzol  by  dissolving  in  twice  its  weight  of  boiling  HNO3 
and  pouring  into  the  five-  or  sixfold  volume  of  cold  HNO3,  whereupon 
the  o-dinitro-benzol  separates  out  in  crystals  (B.  26,  266). 

The  dinitro-benzols  are  capable  of  a  lopsided  reduction  to  nitro- 
anilines  (q.v.),  which  form  the  genetic  link  between  phenylene-diamines 
and  dibromo-benzols,  as  well  as  phthalic  acids. 

Ortho-dinitro-benzol  crystallises  in  plates,  yields  o-nitro-phenol  on 
boiling  with  NaHO,  and  o-nitraniline  on  heating  with  alcoholic  ammonia. 
Other  o-dinitro- compounds  behave  in  a  similar  manner. 

Meta-dinitro-benzol,  heated  with  K  ferricyanide  and  NaHO,  or 
with  powdered  KHO,  yields  [i,  OH,  2,  4]  -  dinitro  -  phenol  and 
[i,  OH,  2,  6]  -  dinitro  -  phenol.  On  treating  with  alcoholic  KCy  an 
NO2  group  is  replaced  by  ethoxyl,  with  entry  of  a  cyanogen  group. 
This  produces  [2]  -  nitro  -  [6]  -  ethoxy  -  benzo  -  nitrile  (B.  17,  R.  19) . 
With  alkali  sulphite  it  forms,  with  reduction  and  sulphuration, 
m-nitraniline-p-sulpho-acid  (B.  29,  2448). 

Para-dinitro-benzol,  colourless  needles. 

By  heating  the  dinitro-benzols  with  Cl  or  Br  to  200°  the  nitro- 
groups  are  replaced,  wholly  or  partly,  by  halogens  (B.  24,  3749).  On 
heating  them  with  Na  methylate  or  ethylate,  a  nitro-group  is  replaced 
by  a  methoxy-  or  ethoxy-group  (C.  1899,  I.  1027). 

TRINITRO-BENZOLS. — [i,  3,  5]-,  s-trinitro-benzol,  white  flakes,  from 
m-dinitro-benzol ;  or  by  heating  trinitro-benzoic  acid  ;  or,  syntheti- 
cally, by  oxidation  of  sodium  nitro-malonaldehyde  (B.  28, 2597  ;  C.i899, 
II.  609).  [1,2,4]-  or  0s-trinitro-benzol,  from  p-dinitro-benzol  on 
heating  to  180°  with  HNO3  and  pyro-sulphuric  acid.  The  s-trinitro- 
benzol  may  be  oxidised  to  picric  acid  or  [i,  OH,  2,  4,  6]-trinitro-phenol. 
With  aniline,  naphthalin,  etc.,  it  forms  additive  compounds,  and 
similar  compounds  are  furnished  by  m-  and  p-dinitro-benzol,  trinitro- 
toluol, etc.  (B.  13,  2346  ;  16,  234  ;  39,  76  ;  C.  1906,  II.  1249).  witn 
aqueous  alkalies  the  s-trinitro-benzol  gives  orange-coloured  products, 
probably  through  the  formation  of  unstable  salts  ;  with  Na  alcoholates 


NITRO-DERIVATIVES   OF  BENZENE  71 

it  forms  additive  compounds  of  a  saline  nature,  from  which  water 
regenerates  trinitro-benzol  quantitatively.  They  may  be  interpreted 
as  salts  of  "  quinolic  "  nitro-acids  : 


CH30 


,T^ 


H         N02     H  \ONa 

(cp.  Quinols,  and  A.  323,  219  ;  C.  1903,  I.  707  ;  B.  42,  2119).  On 
heating  with  Na  alcoholate  solution  a  nitro-group  of  the  s-trinitro- 
benzol  is  replaced  by  an  alkoxyl  group  (C.  1901,  I.  1289). 

as-Tetranitro-benzol  C6H2[i,  2,  3,  5](NO2)4,  yellow  needles,  formed 
from  dinitro-dinitroso-benzolby  careful  oxidation  with  HNO3  (B.  34,  56). 

NITRO-HALOGEX-BEXZOLS.  —  Modes  of  formation:  —  (i)  Nitrogenation 
of  F-,  C1-,  Br-,  and  I-benzols  ;  p-mononitro-halogen-benzols  are  formed 
mostly,  also  some  o-compounds.  (2)  Treatment  of  nitro-benzols  with 
bromine  or  chlorine  ;  in  polynitro-compounds  a  nitro-group  is  readily 
replaced  by  halogen.  (3)  Conversion  of  dinitro-benzols  into  nitraniline, 
and  replacement  of  the  amido-group  by  halogens  by  means  of  diazo- 
compounds.  (4)  Formation  from  nitro-phenols  with  PC15,  producing 
chloro-nitro-benzols. 

The  halogen-nitro-benzols  form  the  transition  from  the  dinitro-, 
nitro-amido-,  and  diamido-benzols  to  thehalogen-amido-  and  dihalogen- 
benzols,  and  are  therefore  important  for  recognising  the  relations 
between  the  various  di-substitution  products  of  benzene  : 

N02  r  H  /N02  ~  H  /NO.,  ~  M  /NH2  ~  „  /Br 

-      >- 


When  nitro-groups  enter  the  benzene  nucleus  in  ortho-  or  para- 
position  to  a  halogen  atom,  this  halogen  atom  requires  the  capacity  of 
reacting  with  alkalies,  like  the  halogen  alkyls  (Vol.  I.),  while  a  nitro- 
group  in  the  w^ta-position  does  not  produce  this  effect  (cp.  C.  1903,  I. 
571).  This  rule  is  markedly  shown  by  the  behaviour  of  1,2,4,6- 
tetrachloro-3,  5-dinitro-benzol.  In  this  substance  only  the  halogen 
atoms  2,  4,  and  6  can  be  replaced  by  the  residues  NH2,  NHC6H5, 
OC2H5,  etc.,  but  not  the  chlorine  atom  in  the  m-position  with  regard 
to  the  two  nitro-groups  (C.  1904,  1.  1408).  The  loosening  of  the  halogen 
linking  is  the  more  marked,  the  more  nitro-groups  enter  the  nucleus,  so 
that  i,  3,  5,  6-trinitro-chloro-benzol  or  picryl  chloride  has  the  character 
of  an  acid  chloride.  In  some  cases  it  is  not  the  halogen,  but  a  nitro- 
group,  which  is  split  off;  cp.  sym.  dinitro-chloro-  and  i-Cl-3,  4,  6-trinitro- 
chloro-benzol. 

We  give  here  the  melting-points  of  the  isomeric  mononitro-,  fluoro-, 
chloro-,  bromo-,  and  iodo-benzols  : 

[i,  2]  [i,  3]  [i,  4l 

C6H4F(N02)  -8°  +1-69°  +26-5°  (€.1905,1.29,1230) 

C6H4C1(N02)  32-5°  48°  83°  (C.  1898,  II.  238  ;    1903,  I.  208) 

C6H4Br(N02)  43-1°  56°  126°  (B.  29,  788) 

C6H4I(N02)  49°  36°  171-4°  (B.  29,  1880) 

Meta-chloro-nitro-benzol  occurs  in  two  physical  modifications  :  — 
Cooled  rapidly  after  melting,  it  melts  at  23-7°  ;  but  after  a  short  time 
it  changes  into  the  more  stable  modification  melting  at  44-2°.  A 
similar  behaviour  is  shown  by  p-nitro-fluoro-benzol,  the  two  melting- 
points  being  21-5°  and  26-5°. 


72  ORGANIC   CHEMISTRY 

Of  the  numerous  known  nitro-halogen-benzols,  we  may  mention 
the  [i,  Cl,  3,  4]  -  dinitro  -  chloro  -  benzol,  which  occurs  in  three  very 
similar  modifications,  having  melting-points  36-3°,  37°,  and  38°  (B.  9, 
760  ;  C.  1908,  II.  1425). 

sym.  Dinitro-ehloro-benzol,  m.p.  59°,  formed  by  chlorination  of 
m-dinitro-benzol.  On  heating  with  Na  alcoholate  solution  it  exchanges, 
not  the  Cl  atom,  but  an  NO2  group  for  an  RO  group,  forming  a  nitro- 
chloro-phenol  ether  (C.  1900,  I.  1115  ;  1901,  I.  1289). 

An  analogous  behaviour  is  shown  by  [i,  Cl,  3,  4,  6]-Trinitro-ehloro- 
benzol,  m.p.  116°,  obtained  by  further  nitrogenation  of  [i,  Cl,  3,  4]- 
dinitro-benzol.  By  the  action  of  ammonia,  the  nitro-group  in  the 
3-position  is  replaced  by  the  amido-group  (B.  36,  3953). 

[i,  2,  4,  5]-Diehloro  -  dinitro  -  benzol,  m.p.  114°,  and  [i,  2,  3, 4]- 
Dichloro-dinitro-benzol,  m.p.  55°,  are  formed  together  during  nitro- 
genation of  o-dichloro-benzol.  On  heating  with  ammonia,  the  former 
exchanges  a  nitro-group,  and  the  latter  a  Cl  atom  for  the  NH2  group 
(B.  37,  3892). 

[i,  3,  5,  4,  Cl]-Trinitro-chloro-benzol-picryl-chloride  C6H2C1(NO2)3, 
m.p.  83°,  from  picric  acid  by  means  of  PC15.  The  latter,  with  ammonia 
solution,  gives  picramide  C6H2(NH2)(NO2)3,  and,  on  boiling  with  soda, 
picric  acid  is  generated. 

Picryl  bromide  C6H2(NO2)3Br,  m.p.  123°,  from  bromo-dinitro- 
benzol  with  HNO3  (C.  1903,  I.  963). 

Dinitro-dichloro-benzols  and  their  transformation  products  are 
described,  C.  1902,  II.  513 ;  1903,  I.  503,  511 ;  Dinitro-trichloro- 
benzol,  m.p.  130°,  see  B.  29,  R.  1155. 

Of  the  six  isomeric  dibromo-nitro-benzols,  five  can  be  obtained  by 
direct  nitrogenation  of  the  three  dibromo-benzols  : 

2]-Dibromo-4-nitro-benzol,  m.p.  58°  Chief  product. 

2]-Dibromo-3-nitro-benzol,     ,,     85-2°  By-product. 

3]-Dibromo-4-nitro-benzol,     ,,     61°  Chief  product. 

3]-Dibromo-2-nitro-benzol,     ,,     82°  By-product. 
4]-Dibromo-i-nitro-benzol,     ,,     85° 


o-Dibromo-benzol     i . 


2. 


m-Dibromo-benzol     i . 

2- 

p-Dibromo-benzol          [ 


The  missing  [i,  3]-dibromo-5-nitro-benzol,  m.p.  104-5°,  was  prepared 
by  Korner  (J.  1875,  306)  from  the  dibromo-p-nitraniline  by  eliminating 
the  amido-group.  Concerning  the  transformation  of  the  dibromo- 
nitro-benzols  into  tribromo-benzols,  and  their  significance  concerning 
the  constitution  of  the  three  dibromo-benzols,  see  above. 

NITRO-TOLUOLS.— [i,  2]-,  c-Nitro-toluol  CH3[i]C6H4[2]N02,  two 
modifications,  m.p.  —9°  and  —4°,  b.p.  218° ;  and  [i,  4]-,  p-Nitro-toluol 
CH3[i]C6H4[4]NO2,  m.p.  54°,  b.p.  230°,  by  nitrogenation  of  toluol. 
They  are  separated  by  fractional  distillation,  and,  on  reduction,  they 
yield  the  industrially  important  toluidins.  On  nitrogenation  at  —55°, 
5*5  times  as  much  p-  as  o-nitro-toluol  is  produced  (B.  26,  R.  362),  and 
even  at  higher  temperatures  chiefly  p-nitro-toluol  is  obtained,  with 
fuming  nitric  acid,  while  nitro-sulphuric  acid,  at  low  temperatures, 
gives  about  66  per  cent,  o-nitro-toluol. 

On  further  nitrogenation  of  o-  and  p-nitro-toluol  we  obtain  :  [2,4]- 
dinitro-toluol,  m.p.  70° ;  [2,5]-dinitro-toluol,  m.p.  48°  ;  and  [2,4,6]- 
trinitro-toluol,  m.p.  82°  (B.  21,  433  ;  22,  2679). 

We  must  note  the  transformation  of  o-nitro-toluol  into  anthranilic 
acid  by  heating  with  an  alkaline  hydroxide,  whereby  o-nitroso-benzyl 


NITRO-PRODUCTS   OF   ALKYL-BENZOLS  73 

alcohol  and  anthranile  have  been  isolated  as  intermediate  products 
(C.  1908,  II.  210).     The  reaction  passes  through  the  following  phases  : 


Similarly,  we  obtain  from  o-nitro-toluol-sulpho-acid  anthranile 
sulpho-acid  (C.  1903,  I.  371),  and,  by  heating  o-nitro-toluol  with  Br  to 
170°,  dibromo-anthranilic  acid. 

On  boiling  with  HgO  in  an  alkaline  solution,  o-nitro-toluol  yields 
a  mono-  and  a  di-mercuric  compound.  The  latter  probably  has  the 
formula  NO2[i]C6H4[2]CH<^:g^>O.  It  forms  dark-yellow  crystals,  which 

decompose  above  220°,  and  may  be  smoothly  split  up  in  the  cold  by 
means  of  concentrated  HC1  into  HgCl2  and  anthranile  (q.v.)  (B.  40, 
4209  ;  C.  1908,  I.  1346)  : 


p-Nitro-  and  2,  4-dinitro-toluol  also  react  with  HgO. 

[1,3]-,  m-Nitro-toluol  CH3[i]C6H4[3]NO2,  m.p.  16°,  b.p.  230°,  is 
formed  on  nitrogenating  aceto-p-toluidin  and  replacing  the  amido- 
group  by  hydrogen  (B.  22,  831).  On  further  nitrogenation  of  m-nitro- 
toluol  we  obtain  [3,4]-dinitro-toluol,  m.p.  61°,  and  [3,5]-dinitro-toluol, 
m.p.  92°  (B.  27,  2209). 

NITRC-PRODUCTS  OF  ALKYL-BENZOLS. 

On  account  of  the  facility  with  which  the  aromatic  nitro-compounds 
are  produced,  many  of  them  are  suitable  for  determining  their  funda- 
mental hydrocarbons.  Some  of  them  may  here  be  enumerated  : 

[4]-Nitro-o-xylol  NO2[4]C6H3[i,  2](CH3)9,  m.p.  29°  (B.  17,  160  ; 
18,  2670).  [4,5]-  and  [4,  6]-Dinitro-o-xylol,  m.p.  116°  and  76° 
(B.  35,  628). 

[5]-Nitro-m-xylol,  m.p.  74°.  [2,  4]-Dinitro-m-xylol,  m.p.  82°. 
[2,  6]-Dinitro-m-xylol,  m.p.  93°.  [2,4,6]-Trinitro-m-xylol,  m.p.  182° 
(B.  17,  2424).  [4,  5,  6]-Trinitro-m-xylol,  m.p.  125°  (C.  1906,  II.  29; 
1909,  I.  1320). 

[2]-Nitro-p-xylol,  b.p.  239°  (B.  18,  2680).  [2,  6]-Dinitro-p-xylol, 
m.p.  123°,  and  [2,  3]-Dinitro-p-xylol,  m.p.  93°,  form  a  double  compound 
of  m.p.  99°  (B.  15,  2304).  [2,  3,  6]-Trinitro-p-xylol,  m.p.  137°  (B. 

19,145). 

[2,  4]-Dinitro-  ethyl  -benzol,  b.p.10  163°.  [2,  4,  6]  -Trinitro  -  ethyl- 
benzol,  m.p.  37°  (B.  42,  2633). 

Nitro-mesitylene  NO2[2]C6H2[i,  3,  5](CH3)3,  m.p.  44°  (6.33,3625). 
Dinitro-mesitylene,  m.p.  86°.  Trinitro-mesitylene,  m.p.  232°  (B.  29, 
2201). 

Nitro-pseudocumol  NO2[5]C6H2[i,  2,  4](CH3)3,  m.p.  71°.  Dinitro- 
pseudocumol  (XO2)2[3,5]C6H[i,2,4f(CH3)3,  m.p.  172°.  [3,  5,  6]-Trinitro- 
pseudocumol  (NO2)3[3,  5,  6]C6[i,  2,  4l(CH3)3,  m.p.  185°  (B.  42,  3608). 

[4,  5,  6]-Trinitro-v-trimethyl-benzol  (NO2)3[4,  5,  6]C6[i,  2,  3]  (CH3)3, 
m.p.  209°  (B.  19,  2517). 


74  ORGANIC   CHEMISTRY 

Nitro-prehnitol  NO2[5]C6H[i,  2,  3,  4](CH3)4,  m.p.  61°  (B.  21,  905). 
Dinitro-prehnitol,  m.p.  178°.  Dinitro-isodurol  (NO2)2[4, 6]C6[i,  2,  3,  5] 
(CH3)4,  m.p.  156°.  Dinitro-durol  (NO2)2[3,  6]C6[i,  2,4,  5](CH3)4,  m.p. 
205°. 

Nitro-pentamethyl-benzol,  m.p.  154°  (B.  42,  4162). 

[2,  4,  6]-Trinitro-<H>utyl-toluol  (NO2)3[2,  4,  6]C6H[i]CH3[3]C(CH3)3, 
m.p.  96°-  97°,  smells  intensely  of  musk,  and  is  marketed  as  "  artificial 
musk  "  (B.  24,  2832). 

NITRO-HALOGEN  DERIVATIVES  OF  THE  ALKYL-BENZOLS. 

A  large  number  of  such  compounds  have  been  prepared. 

2-Chloro-5-nitro-toluol,  m.p.  44°,  and  4-ehloro-2-nitro-toluol,  m.p. 
38°,  by  nitrogenation  of  o-  and  p-chloro-toluol  respectively  (B.  19, 
2438 ;  20,  199).  3-Chloro-4-nitro-toluol,  m.p.  55°,  from  nitro-m- 
toluidin.  For  further  halogen-nitro-toluols,  see  B.  37,  1018. 

2, 4, 6-Trinitro-5-chloro-toluol,  m.p.  148°,  is  formed,  besides  the 
2,  4-dinitro-compound,  on  nitrogenation  of  m-chloro-toluol.  It  is  a 
homologue  of  picryl  chloride.  Here  also  the  halogen  is  exceedingly 
reactive,  and  exchangeable  for  numerous  other  groups. 

Nitro-bromo-durol,   m.p.    178°,   by  nitrogenation   of  bromo-durol 
with  nitro-sulphuric  acid  in  chloroform  solution.     Very  peculiar  is  the 
action  of  fuming  nitric  acid  upon  bromo-durol,  leading  to  dinitro- 
durylic  bromide,  with  displacement  of  the  bromine  atom  and  oxidation  : 
TT  CH3     CH3  CH3  COBr 

H  CH3     CH3  Br  -    -*  N°2  CH3     CH3  N0*- 

RULES  OF  SUBSTITUTION. 

Formation  of  Di-derivatives. — Chlorination  and  bromination  of 
benzene  and  toluol,  nitrogenation  of  monohalogen  benzols  and  of 
toluol,  give  rise  almost  entirely  to  p-  and  o-di-derivatives,  while  nitro- 
genation of  benzene  produces  chiefly  m-dinitro-benzol.  Phenol  and 
aniline  behave  like  toluol :  p-  and  o-di-derivatives  are  mainly  formed. 
On  the  other  hand,  benzol  sulpho-acid  C6H5SO3H,  benzoic  acid 
C6H5COOH,  benzaldehyde  C6H5CHO,  benzo-nitrile  C6H5CN,  aceto- 
phenone  C6H5CO.CH3,  and  a  few  other  compounds,  with  so-called 
side  groups,  form  mostly  m-combinations.  The  substituents  contained 
in  the  mono-derivatives  therefore  determine  the  place  of  further  sub- 
stitution. And  it  is  not  immaterial  in  what  succession  the  substituents 
are  introduced.  Nitrogenation  of  chloro-benzol  yields  chiefly  p-nitro- 
chloro-benzol,  while  chlorination  of  nitro-benzol  produces  mainly 
m-nitro-chloro-benzol. 

Concerning  the  dependence  of  substitution  processes  upon  atomic, 
and  radicle,  magnitudes  of  the  substituents,  see  B.  23,  130. 

The  following  rule  is  given  by  Crum  Brown  and  J.  Gibson  : — If  the 
hydrogen  link  of  the  atom  or  radicle  attached  to  the  benzene  nucleus 
in  the  mono-derivative  cannot  be  oxidised  direct,  i.e.  in  one  operation, 
to  the  corresponding  hydroxyl  compound,  a  further  substitution  gives 
o-  and  p-derivatives,  otherwise  m-derivatives  (B.  25,  R.  672). 

The  following  rule  attempts  an  explanation  of  the  various  regu- 
larities of  substitution.  The  second  substituent  enters  the  o-  or  p- 
position  when  the  first  substituent  is  attached,  with  much  valence 


NITROSO-DERIVATIVES   OF   BENZENE  75 

energy,  to  the  benzol-hydrocarbon  atom,  since  there  is  then  a  greater 
amount  of  surplus  energy  attached  to  the  C  atom  ;  when  the  first 
substituent  is  loosely  bound,  the  m-position  has  more  surplus  energy, 
and  the  substitution  will  take  place  there  (/.  pr.  Ch.  2,  66,  321  ;  cp. 
C.  1906,  I.  458). 

Formation  of  Tri-derivatives.  —  On  further  substitution  (chlorination, 
nitrogenation)  of  the  ortho-  and  para-di-derivatives,  the  substituent 
groups  enter  the  para-  and  ortho-positions  respectively,  so  that  the 
di-derivatives  [i,  2],  and  [i,  4]  become  tri-derivatives  [i,  2,  4]  (A.  192, 
219).  From  the  meta-di-derivatives  [i,  3]  the  [i,  3,  4]  and  [i,  2,  3]- 
tri-derivatives  are  obtained.  If  both  substituent  groups  are  of  strongly 
acid  character,  as  in  m-dinitro-benzol  [1,3,  5]  -derivatives  are  formed. 

Formation  of  Tetra-derivatives.  —  If  further  substitution  takes  place 
in  an  unsymmetrical  tri-derivative  [1,2,4],  unsymmetrical  tetra- 
derivatives  [i,  2,  4,  6]  are  usually  produced.  Aniline,  phenol,  etc., 
become  trichloro-  or  trinitro-derivatives,  in  which  the  entering  groups 
are  in  the  meta-position  [2,  4,  6]  =  [i,  3,  5]  with  respect  to  each  other. 
If  from  these  the  groups  OH  and  NH?  are  eliminated,  symmetrical 
tri-derivatives  C6H3X3  [i,  3,  5]  are  obtained. 

2.  NITROSO-DERIVATIVES  OF  BENZENE  AND  THE  ALKYL-BENZOLS. 

Mononitroso-derivatives  of  benzene  hydrocarbons  cannot  be 
obtained  from  the  benzols  by  substitution.  They  are  produced  : 

(1)  by  oxidation  of  the  corresponding  j8-hydroxylamine  derivatives 
with  K  bichromate  and  sulphuric  acid,  ferric  chloride,  or  atmospheric 
oxygen  : 

C6H5NHOH+0=C6H5NO+H20  ; 

(2)  from  anilines  by  oxidation  with  sulpho-mono-per-acid  (B.  32,  1675)  ; 

(3)  by   electrolytic  reduction  of  nitro-benzol  without  a  membrane, 
using  neutral  electrolytes,  e.g.  solutions  of  Na,  Mg,  or  Al  sulphate. 
The  formation  of  nitroso-benzol  seems,  in  this  case,  to  be  secondary, 
the   primary  jS-phenyl-hydroxylamine  formed   at   the   cathode   being 
oxidised  to  nitroso-benzol  at  the  anode  (C.  1908,  1.  911).     The  nitroso- 
compounds  form  colourless  crystals  of  great  volatility,  coloured  green, 
when  melted  or  dissolved.     This  change  of  colour  is  probably  due  to 
the  fact  that  the  molecules,  dimeric  in  the  solid  state,  become  dis- 
sociated into  simple  molecules  on  melting  or  dissolving  (B.  34,  3877). 
By   oxidation   the  nitroso-benzols   give  nitro-bodies  ;    by   reduction, 
amido-bodies.      With   aromatic  amines  they  condense   to  azo-bodies 
with  elimination  of  water  ;   with  jS-phenyl-hydroxylamines,  to  azoxy- 
bodies  ;  with  hydroxylamine,  to  so-called  isodiazo-benzols  ;  with  phenyl- 
hydrazine,  to  diazo-oxy-amido-compounds  ;   with  the  salts  of  nitro- 
hydroxylaminic  acid  (Vol.  I.),  or  benzol-sulpho-hydroxamic  acid,  they 
form  j3-phenyl-nitroso-hydroxylamines  (Bamberger,  B.  28,  245,  1218  ; 
29,  102  ;    32,  3554  ;    C.  1904,  I.  24)  : 

C6H5NO+NH2.C6H5         =C6H5N  :  N.C6H6+H2O 
C6H5NO+NH(OH).C6H5=C6H5N~  -  -NC6H5+H2O 


C6H5NO  +NH2.OH  =  C6H5N  :  N.OH  +H2O 

C6H5NO+NH2.NHC6H5  =  C6H5N(OH)N  :  NC6H5(+2H) 
C6H5NO+HON  :  NO2Na  =  C6H5N(OH)NO+NO,Na. 


76  ORGANIC   CHEMISTRY 

With  substances  containing  CH2  groups  which  have  become  reactive 
through  the  vicinity  of  acid-forming  radicles,  the  nitroso-benzols  yield 
ketone-aniles  with  elimination  of  water,  e.g. 

<p-\r 
H=C6H5N  : 


(B.  34,  494).  By  concentrated  H2SO4  the  nitroso-benzols  are 
polymerised  like  aldol,  forming  p-nitroso-diphenyl-hydroxylamines 
NOCeH4N(OH)C6H5  (B.  31,  1513;  32,  219).  Nitroso-benzol  in  these 
reactions  strikingly  resembles  the  aldehydes,  especially  benzaldehyde 
C6H5CHO  (q.v.),  from  which  it  is  distinguished  by  the  CH  group  being 
replaced  by  a  nitrogen  atom.  With  diazo-methane  (Vol.  I.)  the  nitroso- 
benzols  form  addition  products,  which  give  off  N,  and  pass  into  the 
N-phenyl-ether  of  glyoxime  (B.  30,  2791). 

NITROSO-BENZOL  C6H5NO,  m.p.  68°,  first  obtained  in  solution  by 
the  action  of  nitrosyl  bromide  upon  mercury  diphenyl  (v.  Baeyer,  1874). 
Now  prepared  by  oxidation  of  j8-phenyl-hydroxylamine  or  aniline,  or  by 
electrolytic  reduction  of  nitro-benzol.  Produced  in  small  quantities 
with  other  bodies  by  oxidation  of  diazo-benzol  chloride  ;  also  from 
diazo-benzol  perbromide  with  alkalies,  and  by  distillation  of  azoxy- 
benzol  (B.  27,  1182,  1273).  Illumination  completely  decomposes 
nitroso-benzol  in  benzene  solution  :  besides  some  resins,  azoxy-benzol, 
nitro-benzol,  aniline,  and  o-oxyazo-benzol  are  formed  (B.  35,  1606). 

o-,  m-,  p-Nitroso-toluol  CH3.C6H4.NO,  m.p.  72°,  53°,  48°.  2,  3-, 
2,  4-,  2,  5-,  2,  6-,  and  3,  4-Nitroso-xylol  (CH3)2C6H3NO  melt  at  91°,  41°, 
101°,  141°,  and  45°.  Nitroso-mesitylene  (CH3)3[2,  4,  6]C6H2NO,  m.p. 
122°,  best  obtained  from  amido-mesitylene  (mesidin)  with  sulpho-mono- 
per-acid  (A.  316,257,  etc.).  p-Chloro-  and  p-Bromo-nitro-benzol,  m.p. 
87°  and  92°. 

o-,  m-,  and  p-Nitro-nitroso-benzol,  m.p.  126°,  90°,  and  119°,  by 
oxidation  of  the  three  nitranilines  with  sulpho-mono-per-acid  (B.  36, 
3803  ;  38,  4011).  o-  and  p-Nitro-nitroso-benzol  are  also  obtained  by 
reduction  of  o-  and  p-dinitro-benzol  by  hydroxylamine  and  stannous 
oxide,  in  strongly  alkaline  methyl-alcoholic  solution.  This  at  first  gives 
strongly  coloured  alkali  salts  of  a  dinitronic  acid  resembling  quinone, 

C6H4^NOOK,  from  which  acidulation  liberates  water  and  produces  the 

nitro-nitroso-benzols.  Similarly,  o-nitro-nitroso-p-xylol,  m.p.  130-5°, 
from  o-dinitro-p-xylol.  m-Dinitro-benzol  is  not  reduced  under  similar 
conditions,  but  undergoes  substitution  with  formation  of  dinitro-amido- 
compounds  (B.  39,  2526,  2533). 

Trinitro-nitroso-benzol  (NO2)3[2,  4,  6]-C6H2NO,  m.p.  198°  (B.  34, 

59)- 

2-Nitro-6-nitroso-toluol,  m.p.  117°,  2-Nitro-4-nitroso-toluol,  m.p.  87° 

(B.  40,3331). 

p-Dinitroso-derivatives  are  formed  by  oxidation  of  p-quinone  di- 
oximes  in  alkaline  solution  with  potassium  ferricyanide,  e.g.  p-Dinitroso- 
toluol  CH3[i]C6H3[2,  5](NO)2,  m.p.  133°,  from  tolu-quinone  dioxime 
CH3C8H3(NOH)2,  yellow  needles  with  a  suffocating  odour  of  quinone, 
converted  by  fuming  nitric  acid  into  p-dinitro-toluol,  and  by  hydro- 
xylamine chloride  into  tolu-quinone  dioxime  (B.  21,  734,  3319). 

o-Dinitroso-derivatives  are  obtained  from  o-nitro-diazo-imides,  by 
heating,  and  elimination  of  N. 


jS-ALPHYL-   OR  ARYL-HYDROXYLAMINES  77 

o-Dinitroso-benzol  C6H4[i,  2](NO)2,  m.p.  72°,  from  o-nitro-diazo- 
benzol-imide  at  90°,  yields  on  reduction  o-quinone  dioxime  (A.  307,  28). 

m-Dinitroso-benzol  C6H4[i,  3](NO)2,  m.p.  146-5°,  formed,  besides 
m-nitro-nitroso-benzol,  during  reduction  of  m-dinitro-benzol,  with  zinc 
dust,  and  glacial  acetic  acid  in  alcoholic  solution  (B.  38,  1899). 

1,  2,  3,  4-Tetranitroso-benzol  C6H2(NO)4,  m.p.  93°,  from  diquinoyl- 
tetroxime  by  oxidation  with  sodium  hypochlorite  (B.  32,  505). 

Dinitro-dinitroso-benzol  C6H2(NO2)2(NO)2,  m.p.  133°,  golden  flakes, 
from  picrvl  chloride  with  hydroxylamine  in  acetic  solution.  By  oxida- 
tion it  yields  as-tetranitro-benzol  (B.  34,  55). 

3.  j3-ALPHYL-  OR  ARYL-HYDROXYLAMINES.* 

These  very  reactive  substances  are  obtained  as  intermediate  pro- 
ducts in  the  reduction  of  nitro-  and  nitroso-benzols.  They  are  very 
sensitive  to  alkalies  and  acids,  and  they  are  therefore  prepared  by 
means  of  neutral  reducing  agents,  as  by  the  action  of  zinc  dust,  and 
sal  ammoniac  solution,  upon  nitro-benzols,  or  of  Al  amalgam  and  water 
on  the  etheric  solutions  of  nitro-benzols  (B.  29,  494,  863,  2307). 

Particularly  straightforward  is  the  electrolytic  reduction  of  the 
nitro-com pounds  in  acetic  solution  with  Na  acetate  (B.  38,  3076). 
With  alcoholic  ammonium  sulphide  it  is  easy  to  obtain  /S-aryl-hydro- 
xylamine.  Polynitro-compounds  in  this  case  yield  nitro-aryl-hydro- 
xylamines  by  partial  reduction  (B.  41,  1936).  Aniline  is  oxidised  to 
jS-phenyl-hydroxylamine  by  mono-sulpho-per-acid  (B.  32,  1675). 

The  aryl-hydroxylamines  reduce  ammoniacal  silver  solution  and 
Fehling's  solution.  They  energetically  absorb  atmospheric  oxygen  in 
aqueous  solution,  especially  in  the  presence  of  alkali.  Hydrogen  per- 
oxide is  thus  generated,  and  the  hydroxylamines  are  first  oxidised  to 
nitroso-benzols,  which,  however,  mostly  combine  with  the  unchanged 
aryl-hydroxylamine  to  azoxy-benzols  : 

C6H5NO+C8H5NHOH=C6H5N, -NC,H5+H,O. 

\O/ 

By  ortho-  and  />flra-position  methyl  groups  this  reaction  is  retarded, 
and  in  mesityl-hydroxylamine  it  is  entirely  suspended  (A.  316,  257). 

With  diazo-benzol  solutions  the  aryl-hydroxylamines  yield  diazo- 
oxy-amido-compounds,  e.g.  C6H5N(OH)N2C6H5 ;  this  reaction  is  also 
hindered  by  o-  and  p-methyl  groups. 

Sulphuric  acid  transposes  phenyl-hydroxylamine,  and  hydro- 
xylamines in  a  free  para-position,  into  p-amido-phenols  : 

C6H5NHOH  -      -->  HO[4]C6H4[i]NH2. 

If  the  para-position  is  occupied  by  a  methyl  group,  transposition 
occurs  all  the  same  ;  but  so-called  "  quinols  "  are  produced  with  rejec- 
tion of  NH3.  These  quinols  are  closely  related  to  the  quinones  (q.v.),  and 
may  easily  pass  by  further  atomic  displacement  into  methylated  hydro- 
quinones,  e.g. 

CH3  H     H  NHOH 

3  H     H 

*  "  Alphenyl  "  is  a  contraction  of  "  alkyl  phenyl  "  C;/H2,,+JC6H4  (Bamberger) . 
The  word  "  aryl  "=  aromatic  radicle  has  been  lately  proposed  for  these  residues 
(Vorlander,  J.'pr.  Ch.  2,  59,  247). 


78  ORGANIC  CHEMISTRY 

Concentrated  sulphuric  acid  transforms  phenyl-hydroxylamine  into 
p-amido-phenol-o-sulpho-acid.  Concentrated  nitric  acid  transforms 
m-tolyl-hydroxylamine  into  chloro-toluidines  (B.  33,  3600  ;  34,  61  ; 
35,  3697).  Cp.  the  similar  transpositions  of  aromatic  nitramines, 
nitrosamines,  and  chloramines,  into  p-nitro-,  nitroso-,  and  chlor-aniline. 

With  aldehydes,  e.g.  benzaldehyde,  the  aryl-hydroxylamines  reject 

C  H  N CHC  H 

water,  and  form  n-aryl-ether  from  aldoximes,  e.g.          "  \o/ 

(C.  1905,  II.  764).     But  formaldehyde  gives  methylene-diaryl-hydro- 

xylamines,  e.g.  CH2[N(OH)C6H5]  2.    Methylene-diphenyl-hydroxylamine 

is  easily  converted  into  the  n-phenyl-ether  of  glyoxime,  but  under  the 

influence  of  anhydrous  SO4Cu  it  passes  into  diphenyl-oxy-formamidin 

CH/N(OH)C6H5 

\NC6H6 

Acid  chlorides  acidulate  the  aryl-hydroxylamines  in  their  nitrogens, 
e.g.  N-Formyl-phenyl-hydroxylamine  C6H5N(CHO)OH,  m.p.  71°;  N- 
Acetyl-phenyl-hydroxylamine  C6H5N(COCH3)OH,  m.p.  67°;  N-Benzol- 
sulphono-phenyl-hydroxylamine  C6H5N(SO2C6H5)OH  (B.  34,  243  ;  35, 
1883). 

j8-Phenyl-hydroxylamine  C?H5NHOH,  m.p.  81°.  Chlorohydrate, 
white  crystalline  flakes,  precipitated  from  ether.  With  metals  it  also 
forms  salts  :  C6H5NHONa  from  phenyl-hydroxylamine  with  Na  in  ether. 

To  the  above  transpositions  of  ^-phenyl-hydroxylamine  we  may 
add  the  formation  of  nitroso-phenyl-hydroxylamine  with  N2O3,  and  of 
phenyl-sulphaminic  acid  C6H5NSO3H  with  SO2  (in  etheric  solution)  ; 
in  aqueous  solution,  phenyl-hydroxylamine,  with  SO2,  gives  o-aniline- 
sulpho-acid  (cp.  B.  34,  246).  For  the  action  of  BrCN  upon  /?-phenyl- 
hydroxylamine,  see  B.  37,  1536. 

o-,  m-,  p-Tolyl-hydroxylamine  CH3C6H4NHOH,  m.p.  44°,  68°,  94°  ; 
2, 3-,  2, 4-,  2,5-,  2, 6,  and  3, 4-Xylyl-hydroxylamine  (CH8)2CGH8.NHOH, 
m.p.  74°,  64°,  91°,  98°,  and  101° ;  Mesityl-hydroxylamine  (CH3)3 
[2,  4,  6]C6H2NHOH,  m.p.  116°. 

jS-Chloro- phenyl-hydroxylamine  C1C6H4NHOH,  m.p.  88°.  m- 
Nitro-phenyl-hydroxylamine  NO2C6H4NHOH,  m.p.  119°,  by  electro- 
lytic reduction  of  m-dinitro-benzol  (B.  38,  3078).  3, 5-Dinitro-phenyl- 
hydroxylamine  (NO2)2CeH3NHOH,  m.p.  i35°-i37°,  from  sym.  trinitro- 
benzol  by  reduction  with  H2S  (C.  1905,  II.  1330).  2,  4,  6-Trinitro- 
phenyl  -  hydroxylamine  (NO2)3C6H2NHOH,  m.p.  174°,  from  picryl 
chloride  with  hydroxylamine  chlorohydrate.  On  heating  with  caustic 
soda  it  passes  into  an  iso-picric  acid,  isomeric  with  picric  acid 
(B.  34,  57). 

Diphenyl-hydroxylamine  (C6H5)2NOH  has  not  up  to  the  present 
been  isolated  ;  but  it  probably  forms  the  first  product  of  the  splitting 
of  tetraphenyl-hydrazin  (q.v.)  with  concentrated  acids  (B.  41,  3482). 

o,  p-Dinitro-diphenyl-hydroxylamine  (NO2)2[2, 4]C6H3N(OH)C6H5, 
m.p.  114°  with  decomposition,  orange-coloured  needles,  from  i,  2,  4- 
bromo-nitro-benzol  and  j8-phenyl-hydroxylamine.  Also  formed  on 
treating  tetranitro-tetraphenyl-hydrazin  with  concentrated  sulphuric 
acid.  With  alkalies,  it  forms  salts,  of  a  brownish-red  colour,  which, 
perhaps,  belong  to  the  quinoid  type  : 


jS-ALPHYL-NITROSO-HYDROXYLAMINES  79 

In  concentrated  SO4H2  it  dissolves  without  change,  with  an  intense 
violet  colour  (B.  39,  3038). 

p-Nitroso-diphenyl-hydroxylamine  NOC6H4N(OH)C6H5,  shiny  bronze 
scales,  melting  at  I47°-I52°  with  active  decomposition,  produced  by 
action  of  concentrated  SO4H2  upon  nitroso-benzol.  The  deep-red  salts, 
and  the  methyl  ester  derived  from  them  (m.p.  138°),  may  be  referred 
to  the  quinoid  form  HON  :  C6H4  :  NOC6H5.  By  boiling  with  dilute 
SO4H2  or  NaOH  it  is  split  back  into  nitroso-benzol  (B.  39,  3036). 

4.    /3-ALPHYL-NlTROSO-HYDROXYLAMINES. 

j8-Phenyl-nitroso-hydroxylamineC6H5N(OH).NO  or  C6H6NO(:NOH), 
m-P-  59°,  produced 

(1)  From  ice-cold  hydrochloric  j8-phenyl-hydroxylamine  solution 
with  solution  of  Na  nitrite  ; 

(2)  By  action  of  hydroxylamine  and  Na  alcoholate  upon  nitro- 
benzol  (C.  1899,  II.  371)  ; 

(3)  From  nitroso-acet-anilide,  or  from  potassium-n-diazo-benzol  by 
oxidation  with  alkaline  H  peroxide  solution  (B.  42,  3568,  3582) ; 

(4)  By  conducting  nitric  oxide  into  an  etheric  solution  of  phenyl- 
magnesium  bromide  (A.  329,  190) ; 

(5)  By  transposition  of  nitroso-benzol  with  the  Na  salts  of  nitro- 
hydroxylaminic  acid  HON  :  NO2H  (Vol.  I.  194)  or  benzol-sulphydr- 
oxamic   acid    (C.    1904,   I.    24).     Ammonium   salt,    m.p.    164°.     The 
slightly  soluble  iron  salt  is  characteristic.     j8-Phenyl-nitroso-hydroxyl- 
amine   is   a    very   unstable   body,   decomposing   spontaneously   into 
nitroso-benzol,   diazo-benzol  nitrate,   and  other  substances,   such   as 
p2-dinitro-diphenylamine  NH(C6H4NO2)2.     By   methylating  its  salts 
with  methyl  iodide,  or  the  free  substance  with  diazo-methane,  a  methyl 
ether,  m.p.  38°,  is  generated,  probably  referable  to  the  tautomeric  form 
C6H5NO(:  NOH),  since  reduction  with  Al  amalgam  transforms  it  into 
diazo-benzol-methyl  ester  C6H5N  :NOCH3  (B.  31,  574). 

p-Chloro-  and  p-Bromo-j8-phenyl-nitroso-hydroxylamme,  m.p.  74*5° 
and  87°. 

5.  AMIDO-DERIVATIVES  OR  ANILINES. 

The  aromatic  amido-compounds  are  derivable  from  benzene,  and 
the  alkyl-benzols,  by  replacing  hydrogen  by  amido-groups  : 

C6H5.NH2  C6H4(NH2)2  C6H3(NH2)3 

Aniline,  amido-benzol         Diamido-benzol  Triamido-benzol. 

On  the  other  hand,  we  may  regard  them  as  derivatives  of  ammonia, 
which  indicates  the  existence  of  primary,  secondary,  and  tertiary 
amines  of  the  benzene  series  : 

C6H5.NH2  (C6H5)2NH  (C6H5)3N 

Phenylamine  Diphenylamine  Triphenylamine 

C6H5NHCH3  C6H5N(CH3)2 

Phenyl-methylamine  Phenyl-dimethylamine. 

If,  on  the  other  hand,  the  hydrogen  in  the  side  chains  of  the  benzene 
homologues  is  replaced  by  the  amido-group,  the  true  analogues  of  the 


8o  ORGANIC   CHEMISTRY 


fatty   amines   are  produced,   like   CgHg.CHg.NHg   benzylamine,    and 
these  are  considered  in  connection  with  the  corresponding  alcohols. 

A.  PRIMARY  PHENYLAMINES. 

Formation  of  the  primary  phenylamines,  in  which  the  amido-groups 
are  joined  to  the  benzene  nucleus. 

Reduction  Reactions. 

i.  The  amido  -  derivatives  are  prepared  almost  exclusively  by 
reduction  of  the  corresponding  nitro-compounds  : 

C6H5N02+6H=C6H5NH2+2H2O. 

As  intermediate  products  of  the  reduction,  some  conditions  yield  the 
j8-phenyl-hydroxylamines  and  nitroso-benzols. 
The  most  important  methods  of  reduction  are  : 

(a)  Action  of  ammonium  sulphide  in  alcoholic  solution  (Zinin,  1842)  : 

C6H5.N02+3H2S=C6H5.NH2+2H20+3S. 

In  the  polynitro-compounds  only  one  nitro-group  is  easily  reduced 
in  this  way,  and  nitro-amido-  compounds  are  produced. 

In  the  chloro-nitro-benzols  the  nitro-group  is  only  reduced  by 
Am2S  if  it  is  not  in  the  neighbourhood  of  chlorine,  or  of  another  nitro- 
group  ;  otherwise  chlorine,  or  another  nitro-group,  is  replaced  by 
sulphur  or  SH  (B.  11,  1156,  2056).  Generally  speaking  nitro-groups 
in  ortho  position  with  reference  to  other  substituents  are  not  reducible 
by  Arn2S,  but  the  reduction  can  usually  be  brought  about  by  stannous 
chloride  (B.  35,  2073  ;  C.  1905,  II.  1330,  but  cp.  C.  1902,  I.  115). 
On  the  reduction  of  nitro-compounds  with  fixed  sulphur  alkalies,  see 
C.  1903,  I.  746  ;  1907,  I.  404. 

(b)  Action   of   zinc   and  HC1   upon   alcoholic   solutions  of   nitro- 
bodies  (A.  W.  Hofmann)  ;    action  of  iron  filings  and  acetic  or  hydro- 
chloric acid.     Iron  and  HC1  are  used  industrially  for  producing  aniline, 
and  o-  and  p-toluidin. 

(c)  Action  of  tin  and  HC1  or  acetic  acid  (B.  15,  2105)  ;  or  a  solution 
of  stannous  chloride  in  HC1  : 

C6H5NO2+3Sn      +6HCl=C6H5NH2+3SnCl2-h2H2O 
C6H5N02+3SnCl2+6HCl=C6H5NH2+3SnCl4+2H20. 

The  last  reaction  may  serve  for  the  quantitative  determination  of 
the  nitro-groups.  By  adding  to  the  alcoholic  solution  of  a  polynitro- 
compound,  an  alcoholic  hydrochloric  solution  of  the  calculated  amount 
of  SnCl2,  one  is  able  to  obtain  a  step-by^step  reduction.  In  the  case 
of  o-  p-,  [2,  4]-dinitro-toluol  the  [4]-NO2  group  is  thus  reduced,  while 
with  alcoholic  Am2S  the  [2]-NO2  group  is  reduced  (B.  19,  2161  ;  cp. 
B.  35,  2073).  In  the  reduction  with  Sn  and  HC1  an  addition  of  graphite 
favours  the  reaction  (/.  pr.  Ch.  2,  65,  579).  On  the  speed  of  reaction 
with  SnCl2  and  HC1,  see  Z.  phys.  Ch.  56,  i. 

(d)  Electrolytic  reduction  in  mineral  acid  solution  converts  nitro- 
compounds  into  amido-compounds.     In  concentrated  H2SO4  solution 
the  chief  product  is  p-amido-phenol,  generated  by  transposition  of  the 


PRIMARY   PHENYLAMINES  Si 

/?-phenyl-hydroxylamine  first  formed.  For  a  summary  of  literature, 
see  A.  355,  175. 

In  many  cases  the  following  reducing  agents  have  been  used  with 
advantage : 

(e)  Titanium  trichloride,  and  HC1,  especially  for  quantitative 
determinations  of  the  nitro-groups  (B.  36,  1554). 

(/)  Sodium  arseniate  (/.  pr.  Ch.  2,  50,  563). 

(g)  Zinc  dust  in  alcoholic,  or  ammoniacal,  solution. 

(h)  Ferric  sulphate  with  baryta  water  (B.  24,  3193),  or  ammonia 
(B.  15,  2294),  for  reducing  nitro-bodies  soluble  in  water  or  alkalies. 

(i)  Molecular  hydrogen  reduces  nitro-bodies  smoothly  to  anilines, 
if  the  former  are  conducted  at  higher  temperatures  (2OO°-4OO°)  over 
finely  divided  metals,  such  as  copper,  nickel,  etc.  (C.  1901,  II.  681)  ; 
or  if  in  the  presence  of  colloid  metals,  especially  palladium  and  platinum 
at  ordinary  temperatures,  they  are  treated  with  hydrogen  in  alcoholic, 
or  etheric,  solution  (B.  40,  2209). 

2.  By  reduction   of   nitroso-compounds ;    see  Nitroso-benzol  and 
Nitroso-dimethyl-aniline. 

3.  By  reduction  of  hydrazo-compounds,  and  hydrazins  (q.v.). 

Exchange  Reactions. 

4.  By  replacing  a  halogen  atom   or   nitro-group,  an  hydroxyl   or 
an  alkoxyl  group,  by  an  amido-group,  the  halogen  benzols,  heated  by 
themselves  in  ammonia,  only  yield  traces  of  amido-compounds.     But 
the  transformation  is  readily  effected  in  the  presence  of  small  quantities 
of  copper  salts  (C.  1909,  I.  475).     The  reaction  is  the  readier  without 
a  catalyser  the  more  nitro-groups  are  also  introduced,     [i,  2]-Chloro- 
benzol,  bromo-nitro-benzol,  [i,  2]-dinitro-benzol,  [i,  2]-nitro-phenol  and 
its   alkyl   ethers,    [i,  4]-chloro-    and   bromo-nitro-benzol,    [i,  4]-nitro- 
phenol  and  its  alkyl  ethers,  when  heated  with  ammonia,  give  nitro- 
amido-compounds.     The  [i,  3]-  or  w^te-compounds  do  not  react  (B.  21, 
1541  ;  A.  174,  276). 

Phenols  can  be  directly  converted  into  primary  (and  secondary) 
amines,  by  heating  with  ZnCl2.NH3  to  3OO°-35o°  (B.  16,  2812  ;  17, 
2635  ;  19,  2916  ;  20,  1254).  An  easier  reaction  .than  that  of  the 
phenols  is  shown  by  the  naphthols : 

C10H7.OH+NH3   —- '-»  C10H7NH2-f-H20 
Naphthol  Naphthylamine. 

5.  By  heating  the  halogen  derivatives  and  the  alkaline  sulphonates 
with  Na  amide,  NaNH2  (B.  39,  3006). 

6.  A  replacement  of  the  carboxyl  group  of  aromatic  carboxylic 
acids  by  the  amine  group  may  be  brought  about  through  the  inter- 
mediary of   (a)  the  amides,  (b)  the  azides,  of   these  acids  as  in  the 
aliphatic  carboxylic  acids  (Hofmann,  Curtius).     To  this  may  be  added 
(c)  Beckmann's  transformation  of  the  oximes  of  aromatic  ketones  into 
acidulated  aromatic   amines   (Vol.    L),   from   which   the  amines  are 
obtained  by  saponification : 

CGH5C(NOH)CH3  -     -->  C6H5NH.COCH3 >  C6H5NH2. 

7.  A  direct  introduction  of  the  amido-group  into  benzene  hydro- 
VOL.  II.  a 


82  ORGANIC  CHEMISTRY 

carbons  may  be  effected  by  heating  the  latter  with  hydroxylamine 
chlorohydrate,  and  Al  or  Fe  chloride  (B.  34,  1778)  : 


C6H6+NH2OH   --U  C6H5NH2+H20. 
But  this  only  gives  a  small  amount  of  anilines. 

///.  Separation  Reactions. 

8.  By  heating  amido-carboxylic  acids  : 

(NH2)2C6H3C02H=C02+C6H4(NH2)2 
Diamido-benzoic  acids  Phenylene-diamine. 

9.  By  heating  secondary,  and  tertiary,  amines  with  HC1,  and  from 
the  quaternary  Am  salts,  by  quick  heating,  without  additions  : 


,  , 

ry  Am  salts,  by  quick  heating, 

C6H5.NHCH3+HC1=C6H5.NH2 
C6H5.NHC2H5.HBr=C6H6.NH2 

IV.  Nuclear  Snthese 


2+CH3C1 
2+C2H5Br. 


IV.  Nuclear  Syntheses. 

10.  On  heating  aniline  with  methyl  chloride,  monomethyl-aniline 
chloride  is  first  formed,  and,  at  higher  temperatures,  this  splits  again 
into  methyl  chloride  and  aniline  ;  at  340°  methyl  chloride  brings  about 
the  replacement  of  nuclear  H  in  aniline  by  methyl,  thus  producing 
toluidin    chlorohydrate.     Phenyl-trimethyl-ammonium    iodide    gives 
mesidine  iodo-hydrate  : 

C6H4NH2HC1  /CH3 

NH.HC1  -  >  I  C6H5N—  CH3  -  >  C6H2(CH3)3.NH2HI 

CH3  I  \CH3 

Phenyl-methylamine  Toluidin        Phenyl-trimethyl-   Mesidin-iodo-hydrate. 

chlorohydrate  chlorohydrate     ammonium  iodide 

In  this  way  secondary,  and  tertiary,  aromatic  bases  may  be  converted 
into  isomeric  primary  ones.  Instead  of  the  halogen  salts  of  the 
secondary,  and  tertiary,  bases,  one  can  also  heat  the  salts  of  primary 
bases  with  suitable  alcohols  to  300°  (B.  13,  1729)  : 

C6H5NH2HC1      +     C4H9OH  =  C4H9.C6H4NH2.HC1+H2O 
Aniline  chlorohydrate  Isobutyl-alk.  Amido-tertiary-butyl-benzol. 

Or  free  bases  are  heated  with  paraffin  alcohols,  and  zinc  chloride,  to 
250°  (B.  16,  105). 

11.  The  oximes  of  many  hydro-aromatic  ketones,  such  as  those 
of  methyl-  and  dimethyl-cyclo-hexenone,  trimethyl-cyclo-hexenone,  or 
iso-aceto-phenone,  yield  primary  anilines  on  heating  with  HC1,  with 
atomic  displacement  (A.  322,  379). 

PROPERTIES  AND  TRANSFORMATIONS  OF  PHENYLAMINES. 

The  primary  amines  are  colourless  compounds  of  a  peculiar,  and 
not  unpleasant,  odour,  and  can  be  distilled,  without  decomposition, 
at  ordinary  pressures.  As  regards  formation  of  salts  they  resemble 
alkylamines  (Vol.  I.),  but  they  are  much  feebler  bases  than  the  primary 
alkylamines,  have  no  alkaline  reaction,  and  are  but  slightly  soluble 
in  water,  though  volatile  with  water  vapour. 


PROPERTIES   OF   PHENYLAMINES  83 

The  basic  character  of  primary  phenylamines  is  further  weakened 
by  the  entry  of  negative  groups  ;  the  salts  of  the  di-substituted  anilines, 
such  as  C6H3C12.NH2  and  C6H3(NO2)2.NH2,  are  decomposed  by  water 
alone,  and  cannot  survive.  The  compounds  resemble  the  carboxylic 
amides  in  chemical  behaviour,  just  as  the  corresponding  oxy-com- 
pounds,  or  phenols,  have  the  character  of  acids. 

Hydrogen  reduces  the  amido-compounds  to  the  corresponding 
hexahydro-anilines,  on  leading  their  vapours  over  finely  divided 
nickel,  at  190°,  or  on  heating  at  high  pressure  in  presence  of  nickel. 
The  resulting  bodies  again  show,  as  cyclo-alkylamines,  the  strongly 
basic  character  of  the  aliphatic  amines. 

Aniline  will  be  studied  in  detail  as  the  type  of  primary  phenyl- 
amines. But  first  the  following  general  reactions  of  the  amido-group 
will  be  specified  : 

1.  Alkali  metals  dissolve  on  heating,  with  liberation  of  H.     From 
aniline   we   obtain   potassium    anilide   C6H5NHK,    and   dipotassium 
anilide  C6H5NK2. 

2.  Halogen  alky  Is  combine  with  the  anilines  to  secondary,  tertiary, 
and  finally  to  quaternary  ammonium  compounds  (Vol.  I.). 

3.  One  molecule  of  an  aldehyde  combines  with  one  or  two  mole- 
cules of  a  primary  amine,  with  liberation  of  water  (B.  25,  2020).    With 
furfurol  all  primary  anilines  give  intensely  red  compounds. 

4.  Of    extreme    importance,    for    the    development    of    aromatic 
chemistry,  has  been  the  behaviour  of  free  primary  anilines,  and  their 
salts,   with   nitrous   acid.      Diazo-amido-   and   diazo-compounds   are 
produced,  the  latter  forming  the  links  in  the  conversion  of  nitro-  and 
amido-compounds,  into  the  most  diverse  substitution  products. 

5.  With   thionyl   chloride  the  primary  anilines  behave  like  the 
primary  aliphatic  amines  (Vol.  I.) ;  thionyl-anilines  are  thus  produced. 

6.  A  hydrogen  atom  of  the  amido-group  is  very  easily  replaced 
by  acid  residues,  acid  anilides  being  thus  formed,  which  correspond 
to  the  acid  amides  (Vol.  I.).     The  easily  crystallised  acetic  compounds 
are  formed  with  special  frequency. 

7.  Like  the  primary  aliphatic  amines  (Vol.  I.),  the  primary  anilines 
give,  with  chloroform,  and  alkaline  hydroxides,  carbyl-amines. 

8.  With  CS2  the  primary  anilines  combine  to  di-aryl-sulpho-uric 
compounds,  with  liberation  of  SH2,  while  the  primary  aliphatic  amines 
yield  ammonium  alkyl-dithio-carbaminates  (Vol.  I.). 

9.  Of  significance   for    the   development   of    quinolin    chemistry 
has  been  the  synthesis  of  quinolin  (q.v.),  and  other  bases  containing 
quinolin  nuclei,  on  heating  aniline,  and  other  primary  aromatic  bases, 
with  glycerin,  sulphuric  acid,  and  nitro-benzol.     Quinolin  derivatives 
are  also  produced  by  condensation  into  fatty  aldehydes  by  HC1  or 
H2SO4. 

10.  Primary    aromatic    bases,    heated    with    a-halogen-keto-com- 
pounds,  yield  indols  (q.v.),  sometimes  with  dihydro-pyrazin  derivatives 
fe».). 

ANILINE,  phenylamine  [aminophene]  [amino-benzene)  C6H6NH2, 
m.p.  —8°,  b.p.  184°,  D0  1-0361,  is  an  oil  of  a  feebly  aromatic  odour, 
soluble  at  12-5°,  in  31  parts  water  (B.  10,  709). 

Historical. — Aniline  was  first  discovered  in  1826,  by  Unverdorben, 
during  distillation  of  indigo,  and  was  called  "  crystalline  "  on  account 


84  ORGANIC  CHEMISTRY 

of  the  crystallising  power  of  its  salts.  In  1834  Runge  found  it  in  coal- 
tar,  and  called  it  "  cyanol,"  on  account  of  its  blue  colour  in  bleaching- 
powder  solution.  In  1841  Fritzsche  prepared  a  base,  by  distillation  of 
indigo  with  KHO,  and  called  it  "  aniline  "  from  the  name  of  the  indigo 
plant,  Indigo/era  anil.  In  the  same  year  Zinin  prepared  "  benzi- 
dame  "  by  reducing  nitro-benzol  with  Am2S.  The  identity  of  the 
four  bases  was  proved  by  A.  W.  Hofmann  in  1843  (A.  47,  37). 

Industrially,  aniline  is  obtained  on  a  large  scale  by  reduction  of 
nitro-benzol  with  iron,  and  about  one-fortieth  of  the  HC1  required 
according  to  the  equation  : 

C6H5N02+2Fe+6HCl=C6H5NH2+Fe2Cl6+2H20. 

Probably  only  FeCl2  is  formed  at  first,  and  its  presence  brings  about 
a  reduction  of  the  nitro-benzol  by  iron  and  water,  the  ferrous  chloride 
serving  as  a  carrier.  The  finely  divided  moist  metal  is  the  immediate 
reducing  agent  (B.  27,  1436,  1815). 

C6H5NO2+3Fe+6HCl=C6H5NH2+3FeCl2+2H2O 
C6H5N02+2Fe+4H20=C6H5NH2+Fe2OH)6. 

The  other  means  which  can  be  used  for  reducing  nitro-benzol  to 
aniline  have  been  explained  above,  where  aniline  has  been  usually 
chosen  as  the  primary  phenylamine.  The  same  applies  to  the  other 
reactions.  Aniline  is  almost  as  much  used  in  reactions  as  ammonia, 
and  is  the  generator  in  numerous  aromatic  compounds.  In  spite  of 
its  feeble  basicity,  it  precipitates  zinc,  aluminium,  and  ferrous  salts, 
and  displaces  ammonia  from  its  salts  on  account  of  being  less  volatile. 

Aniline  is  a  poison.     It  is  a  solvent  for  many  bodies,  e.g.  indigo. 

Aniline  is  very  sensitive  to  oxidisers.  It  gradually  colours  brown 
in  air,  and  becomes  resinous.  Bleaching-powder  solution  colours 
aniline  purple- violet  (B.  27,  3263).  With  sulphuric  acid,  and  a  few 
drops  of  potassium  bichromate,  aniline  colours  red,  and,  afterwards,  an 
intense  blue.  On  oxidising  aniline  with  hot  chloride  of  lime,  or  with 
cold  MnO4K,  it  can  be  reconverted  into  nitro-benzol,  through  a  series 
of  intermediate  products  (B.  26,  496  ;  31,  1522).  With  chromic 
acid  it  yields  quinone  (q.v.) ;  with  chlorides,  in  the  presence  of  certain 
metallic  salts,  it  gives  aniline  black  (q.v) . 

With  nitroso-benzol  aniline  combines  to  azo-benzol,  and  with 
caustic  potash  and  nitro-benzol  it  gives  azo-benzol,  and  phenazin 
oxide  (B.  34,  2442). 

Aniline  is  used  in  preparing  numerous  dyes  and  medicines,  such 
as  aniline  black,  fuchsin,  etc.,  and  antifebrin,  antipyrin,  etc. 

Aniline  salts.  —  Chlorohydrate  is  obtained  quite  pure  and  dry  by  con- 
ducting HC1  through  an  etheric  aniline  solution,  m.p.  198°,  b.p.  245° 
(B.  31,  1698)  ;  industrially  it  is  called  "  aniline  salt."  In  water  it 
rapidly  dissolves.  Platinum  chloride  double  salt,  yellow  needles,  from 
alcohol.  Stannous  and  stannic  chloride  double  salt  SnCl2.2C6H5. 
NH2.HC1  +  2H2O  and  SnCl4.2C6H5.NH2.HCl  -f  2H2O.  Sulphate 
(C6H6NH2)2SO4H2.  Thiosulphate  S2O3H2(CGH5NH2)2  :  only  primary 
anilines  form  normal  thiosulphates,  not  secondary  or  tertiary  ones 
(C.  1902,  I.  303).  Nitrate  forms  rhombic  plates  ;  oxalate,  rhombic 
prisms.  Not  only  the  chlorohydrate  but  also  free  aniline  forms  double 


PROPERTIES   OF   PHENYLAMINES  85 

salts  with  some  salts.  It  also  combines  additively  with  trinitro- 
benzol. 

Potassium  anilide :  C6H5NHK  and  C6H5NK2  are  unknown  in  a 
pure  condition.  The  formation  of  di-  and  trimethylamine,  by  action 
of  bromo-benzol  upon  the  reaction  product  of  K  upon  aniline,  proves 
that  the  hydrogen  of  the  amido-group  is  replaced  by  K.  Na  does 
not  act  upon  aniline  below  200°.  Small  quantities  of  Cu,  CuO,  etc., 
facilitate  the  formation  of  the  Na  salt  (C.  1909,  II.  1512).  Cp.  also 
acetanilide,  and  monomethyl-aniline. 

Magnesium  haloid  compounds  of  aniline  (like  C6H5NHMgI)  are 
obtained  in  the  shape  of  crystalline  precipitates  by  the  action  of 
aniline  upon  an  etheric  solution  of  alkyl-magnesium  haloids  (C.  1903, 
I.  1024)  : 

C6H5NH2+CH3MgI=C6H5NH.MgI+CH4. 

They  strongly  absorb  CO2,  forming  salts  of  carbaminic  acid  (B.  37, 
3978)  ;  with  acid  esters  they  give  the  corresponding  acid  anilides 
(C.  1904,  I.  201  ;  1906,  I.  1000). 

Amido-methyl-benzols. — Some  representatives  of  this  group  are 
of  great  importance  in  the  dye  industry,  especially  o-  and  p-toluidin. 
Most  of  the  bases  are  liquid  at  ordinary  temperatures,  but  easily 
yield  acetic  compounds,  on  boiling  with  glacial  acetic  acid,  or  treating 
with  acetyl  chloride  or  acetic  anhydride.  These  substituted  aceta- 
mides  are  easily  crystallising  bodies,  of  definite  melting-point,  very 
suitable  for  characterisation  of  the  bases,  from  which  they  are  easily 
obtained.  The  melting-point  of  the  acetic  compound  is  therefore,  in 
what  follows,  added  to  the  m.p.  or  b.p.  of  the  base.  Amido-methyl- 
benzols  are  obtained  by  the  reduction  of  the  corresponding  nitro- 
compounds,  and  by  heating  chlorides  of  the  bases,  methylated  as 
regards  the  nitrogen,  like  dimethyl-aniline  C6H5N(CH3)2,  under  pressure, 
at  high  temperature. 

Toluidin  CH3.C6H4NH2.— The  three  toluidins  are  isomeric  with 
benzyl-amine  C6H5CH2NH2  (treated  in  connection  with  benzyl- 
alcohol)  and  with  methyl-aniline  C6H5NHCH3.  They  are  obtained  by 
reduction  of  the  three  nitro-toluols.  m-Toluidin  is  also  prepared  by 
reduction  of  m-nitro-benzol  chloride,  a  transformation  product  of 
m-nitro-benzaldehyde  (B.  15,  2009 ;  18,  3398).  p-Toluidin  was 
discovered  in  1845  by  A.  W.  Hofmann  and  Muspratt  (A.  54,  i). 

o-Toluidin,  liquid  .  b.p.  197°  ;  Acet-o-tolnide,  m.p.  110°,  b.p.  296° 
m-Toluidin,  ,,  .  „  199° ;  Acet-m-toluide,  ,,  65°,  ,,  303° 
p-Toluidin,  m.p.  45°  „  198° ;  Acet-p-toluide,  ,,  153°,  „  307° 

p-Toluidin  unites  with  one  molecule  of  water  to  a  monohydrate 
CH3C6H4.NH2.H2O,  m.p.  41-5°,  which  may  be  used  for  isolating,  and 
purifying,  the  base  (C.  1908,  I.  2092). 

The  chlorohydrates  of  o-,  m-,  and  p-toluidin  melt  at  215°,  228°,  and 
243°  respectively,  and  boil  without  decomposition  at  242°,  250°,  and 
257°  respectively  (B.  31,  1698). 

Separation  of  o-  and  p-toluidin. — Nitrogenation  of  toluol  forms 
o-  and  p-nitro-toluol,  from  which  the  industrially  important  toluidins  are 
obtained.  The  o-toluidin  is  separated  from  the  p-toluidin  by  treat- 
ing the  mixed  bases  with  an  amount  of  sulphuric  acid  insufficient  for 


86 


ORGANIC  CHEMISTRY 


complete  neutralisation,  and  distilling.  The  stronger  p-base  remains 
behind,  as  a  sulphate.  Or  we  can  utilise  the  greater  solubility  of  the 
o-toluidin  oxalate  (/.  pr.  Ch.  2,  14,  449).  Aniline,  o-  and  p-toluidin 
may  also  be  separated  by  the  different  behaviour  of  their  chloro- 
hydrates  towards  mono-sodium  phosphate  (B.  19,  1718,  2728  ;  cp. 
B.  29,  R.  434). 

In  the  aniline  dye  industry  there  is  a  distinction  between  : 

Aniline  oil  for  blue  :  pure  aniline. 

Aniline  oil  for  red :   molecular  quantities  of  aniline,  o-   and 

p-toluidin. 
Aniline  oil  for  safranin:    aniline   and  o-toluidin,  from   the 

distillate  of  the  fuchsin  mixture. 

The  free  toluidins  are  easily  transformed,  by  oxidation,  into  azo- 
compounds  (B.  26,  2772).  If  the  amido-group  is  protected  from  oxi- 
dation, by  introducing  an  acid  radicle,  e.g.  the  acetyl  group,  the  methyl 
group  may  be  oxidised  to  a  carboxyl  group  with  potassium  per- 
manganate, and  o-aceto-toluide  may  thus  be  converted  into  o-acet- 
amido-benzoic  acid  (B.  14,  263).  In  the  chlorination,  bromination,  or 
nitrogenation  of  the  aceto-toluides,  the  negative  substituent  is  mostly 
placed  in  the  o-position  with  respect  to  the  acet-amido  group  (see 
Rules  of  Substitution). 

o-Toluidin,  like  aniline,  is  coloured  violet  by  chloride  of  lime  solu- 
tion and  HC1,  but  p-toluidin  is  not.  Iron  chloride  separates,  from  the 
hydrochloric  o-toluidin  solution,  a  blue  body,  known  as  toluidin  blue. 

Xylidins  (CH3)2C6H3NH2.     All  the  six  possible  isomers  are  known  : 


v-o-Xylidin,  liquid,  b.p.  223° 
as-o-Xylidin,  m.p.  49°,  ,,  226° 
v-m-Xylidin,  liquid  ,,  216° 
as-m-Xylidin  ,,  ,,  212° 

s-m-Xylidin  „  „  220° 

p-Xylidin,  m.p.  15°  „  213° 


corresponding  Acetoxylide,m 


P-  134° 
,  99° 
,  170° 

,  120° 
,  144° 

180° 


For  melting-  and  boiling-points  of  the  chlorohydrates,  see  B.  31, 
1699. 

The  xylidin  used  industrially  for  making  azo-dyes,  and  obtained 
from  dimethyl-aniline,  is  chiefly  m-xylidin  and  p-xylidin  (B.  18,  2664, 
2919).  Concerning  the  separation  of  isomeric  xylidins  from  each  other, 
see  C.  1899,  II.  1113. 

Amido  -  polymethyl  -  benzols  (CH3)3C6H2NH2.  The  product  in- 
dustrially obtained  by  heating  xylidin  chloride,  with  methyl  alcohol, 
to  250°,  under  pressure,  consists  essentially  of  s-pseudo-cumidin  and 
mesidin,  and  is  used  for  preparing  red  azo-dyes  (B.  15,  ion,  2895). 

s-Pseudo-cumidin  [5NH2, 1,2,4],  m-P-  68°;  b.p.  235°;  acetic  com- 
pound, m.p.  164°  (B.  18,  92,  2661). 

Mesidin  [2NH2,  1,3,5],  liquid,  b.p.  230°;  acetic  compound,  m.p. 
216°  (B.  18,  2229  ;  24,  3546). 

Duridin  [3NH2,  i,  2,  4,  5],  m.p.  75°,  b.p.  26i°-262°  ;  acetic  com- 
pound, m.p.  207°  (B.  42,  4160). 

Isoduridin  [4NH2,  i,  2,  3,  5],  m.p.  23°,  b.p.  255°;  acetic  compound, 
m.p.  215°  (B.  18,  1149). 


SECONDARY   AND   TERTIARY   PHENYLAMINES         87 

Prehnidin  [5NH2,  i,  2,  3,  4],  m.p.  64°,  b.p.  260°  ;  acetic  compound, 
m.p.  170°  (B.  21,  644,  905). 

Amido-pentamethyl-benzol,  m.p.  151°,  b.p.  277°  ;  acetic  compound, 
m.p.  213°  (B.  18,  825). 

Aniline  homologues  with  larger  alcohol  radicles  are  obtained 
not  only  from  the  corresponding  nitro-compounds  by  reduction,  but 
also  from  aniline  itself  by  a  nuclear  synthesis,  when  aniline  is  heated 
to  250°-28o°,  with  aliphatic  alcohols,  and  zinc  chloride.  The  alkyl 
takes  up  the  p-position  with  respect  to  the  amido-group.  If  iso-butyl 
and  iso-amyl  alcohol  are  used,  p-terti-butyl-  and  p-terti-amyl  aniline  are 
produced,  water  being  probably  first  given  off,  with  formation  of 
iso-butylene,  and  ^3-iso-amylene,  respectively,  which,  under  the  influence 
of  the  condensing  agent,  attach  themselves  to  the  p-carbon  atom  of 
the  aniline. 

p-Amido-ethyl-benzol  C2H5C6H4NH2,  m.p.  -5°,  b.p.  216°  (B.  22, 
1847). 

p-Amido-propyl-benzol,  b.p.  225°  ;  acetic  compound,  m.p.  87°  (B. 
17,  1221). 

p-Amido-iso-propyl-benzol,  b.p.  225°  ;  acetic  compound,  m.p.  102° 
(B.  21,  1159). 

p-Amido-tert.-butyl-benzol,  m.p.  17°,  b.p.  240°  ;  acetic  compound, 
m.p.  172°  (B.  24,  2974). 

p-Amido-oetyl-benzol,  m.p.  19°,  b.p.  310°  ;  acetic  compound,  m.p. 
93°  (B.  18,  135). 

B.  SECONDARY  AND  TERTIARY  PHENYLAMINES  AND  PHENYL- 
AMMONIUM  BASES. 

Phenyl-alkylamine.  —  Modes  of  formation  :  —  (i)  The  alkyl  products 
of  aniline,  and  its  homologues,  are  formed,  like  the  aliphatic  amines 
(Vol.  L),  by  the  action  of  alkyl  bromides  and  alkyl  iodides  upon  primary 
bases,  mostly  even  at  ordinary  temperatures.  They  can  also  be  ob- 
tained by  heating  aniline  chlorohydrate,  or,  better,  aniline  bromo- 
hydrate  (B.  19,  1939),  with  alcohols,  to  250°,  alkyl  chlorides  or  bro- 
mides being  first  formed,  which  then  act  upon  the  aniline. 

(2)  The  above  method  yields  the  haloid  salts  of  mono-  and  di- 
alkyl-aniline  together.  To  obtain  mono-alkyl-anilines  separately,  a 
start  is  made  from  the  aceto-compounds  of  the  primary  bases.  These 
are  dissolved  in  toluol  or  xylol,  and  the  calculated  quantity  of  sodium 
is  introduced  into  the  solution.  Hydrogen  is  developed,  and  white 
solid  Na  acetanilide  is  formed,  and  transformed  smoothly  with  iodo- 
alkylene.  By  saponification  of  the  alkyl  acetanilide,  the  alkyl-aniline 
is  obtained  : 


Separation  of  the  Primary,  Secondary,  and  Tertiary  Bases.  —  From 
the  acid  solution  of  a  mixture,  the  secondary  bases  are  precipitated,  by 
sodium  nitrite,  as  oily  nitrosamines,  while  the  primary  ones  become 
diazonium  chlorides  soluble  in  water,  and  the  tertiary  amines  become 
chlorohydrates  (also  soluble)  of  p-nitroso-dialkyl-anilines.  From  the 
precipitated  nitrosamines  the  secondary  bases  can  be  recovered,  by 
means  of  tin  and  HC1.  Hydro-ferro-cyanic  salts  (A.  190,  184),  and 


88  ORGANIC   CHEMISTRY 

meta-phosphates,  may  also  be  used  for  this  separation  (B.  10,  795  ; 
22,  605  ;  26,  1020). 

Phenyl-alkyl-ammonium  Bases.— The  tertiary  phenyl-alkylamines, 
like  C6H5N(C2H5)2,  may  be  combined  with  alkyl  haloids  to  Am  com- 
pounds, from  which  Am  hydroxides  are  generated  by  action  of  moist 
silver  oxide  or  lime  : 

C6H5N(C2H5)3I     gives     C6H5N(C2H5)3OH. 

In  homologous  anilines,  containing  the  substituents  in  ortho-position 
with  respect  to  the  amine  group,  the  formation  of  quaternary  Am 
bases  is  partly  difficult,  and  partly  impracticable  (B.  33,  345  ;  cp.  34, 
1129)  ;  this  accords  with  a  number  of  other  impediments  to  reaction 
set  by  ortho-substituents.  A  number  of  phenyl-alkyl-ammonium 
bases  with  three  different  alkyl  radicles,  e.g.  phenyl-methyl-alkyl-ethyl- 
ammonium  hydroxide,  may  be  decomposed  by  fractional  crystallisa- 
tion, of  their  bromo-camphoro-sulphonic  salts,  into  optically  active 
nitrogen  compounds.  Their  solutions,  especially  in  solvents  con- 
taining hydroxyl,  show  a  strong  tendency  to  auto-racemisation,  thus 
tending  to  a  gradual  loss  of  optical  activity. 

Di-alkyl-aniline  Oxides. — Prepared  from  the  di-alkyl-anilines,  by 
oxidation  with  hydrogen  peroxide,  or  sulpho-mono-per-acid  (B.  35, 
1082).  They  correspond  to  trimethyl-amino-oxide  (CH3)3NO  (Vol.  I.), 
and  the  alkyl-piperidin  oxides  (q.v.).  Methyl  groups,  in  the  o-position, 
retard  the  formation  of  dialkyl-aniline  oxides  (B.  39,  4285).  With 
acids  they  form  additive  salts,  e.g.  Dimethyl-phenyl-oxy-ammonium- 

chlorohydrate  CGH5N(CH3)2/°H.    They  easily  part  with  their  oxygen, 

\v_/l 

and,  therefore,  act  as  oxidisers.  On  heating  dimethyl-aniline  oxide, 
or  its  chlorohydrate,  it  breaks  up  into  dimethyl-aniline  and  oxygen. 
But  the  latter  acts  as  an  oxidiser  on  the  former,  so  that  a  number  of 
other  decomposition  products  are  formed.  On  heating  dimethyl- 
aniline  oxide  with  concentrated  sulphuric  acid,  o-  and  p-dimethyl- 
amido-phenol  are  generally  formed  (B.  34,  12).  With  nitrous  and 
sulphurous  acids,  addition  products  are  first  formed,  which,  however, 
are  immediately  transposed  into  nuclear  substitution  substances  : 
nitro-dimethyl-aniline  and  dimethyl-aniline-sulpho-acid  (B.  32,  342, 
1882). 

Methyl-ethyl-aniline  oxide  C6H5(CH3)(C2H,j)NO  has  been  split 
up,  by  means  of  bromo-camphoro-sulpho-acid,  into  a  dextro-rotatory 
and  a  lasvo-rotatory  base.  This  is  the  first  case  of  a  compound  of 
5-valent  nitrogen  occurring  in  optically  active  forms,  in  which  not  all 
the  five  valencies  are  saturated  by  different  radicles. 

Properties  and  Transformations. — The  most  important  compounds 
of  this  class  are  the  methyl-  and  ethyl-anilines.  Freshly  distilled, 
they  are  colourless,  highly  refractive  liquids,  which  gradually  turn 
brown  in  the  light.  They  smell  somewhat  like  aniline,  but  less  pleasant. 

The  secondary  phenyl-alkylamines  recall  in  their  behaviour  the 
dialkylamines  (Vol.  I.),  (i)  They  form  salts,  and  combine  with  the 
halogen  alkyls  to  form  haloid  salts  of  the  tertiary  amines.  (2)  By 
acid  chlorides,  and  acid  anhydrides,  the  imide  hydrogen  is  made  to 
give  way  to  acid  radicles.  (3)  With  nitrous  acid  they  yield  nitros- 
amines  (Vol.  I.). 


SECONDARY   AND  TERTIARY   PHENYLAMINES         89 

The  tertiary  phenyl-dialkylamines  containing  an  aromatic  H  atom 
in  para-position  to  the  dialkyl-amido-group,  show  a  remarkable  mobility 
of  this  H  atom,  which  enables  it  to  produce  a  variety  of  reactions  im- 
possible, or  difficult,  in  the  case  of  the  primary  and  secondary  anilines. 
The  greatest  theoretical  and  technical  importance  is  attached  to  the 
behaviour  of  phenyl-dialkylamines  towards  nitrous  acid.  The  latter 
converts  the  phenyl-dialkylamines  into  p-nitroso-compounds. 

The  primary,  secondary,  and  tertiary  aromatic  amines  differ  in 
their  behaviour  towards  nitrous  acid  in  the  following  particulars  : 

(1)  Primary    phenylamines    gives    diazo-compounds,    and    diazo- 
amido-compounds. 

(2)  Secondary  phenyl-alkylamines  give  nitrosamines. 

(3)  Tertiary  phenyl-dialkylamines  give  />-m>oso-compounds. 
Some  other  reactions    of   phenyl-dialkylamine  are  mentioned  in 

connection  with  dimethyl-aniline. 

The  methyl-  and  ethyl-anilines  have  the  following  boiling-points 
and  densities  : 

Monomethyl-aniline,  liquid,       b.p.  192°,     D.  0-976    (15°) 
Dimethyl-aniline,       m.p.  0-5°,    ,,    192°,      ,,  0-9575  (2o°-24°) 
Ethyl-aniline,  liquid,         ,,    206°,      ,,  0-954    (18°) 

Diethyl-aniline,  „  „    213-5°,  „  0-939    (18°). 

The  methylated  anilines  are  used  in  industry  for  the  production  of 
aniline  dyes,  and  are  obtained  by  heating  aniline  chlorohydrate  and 
methyl-alcohol  to  220°,  or  by  leading  methyl  chloride  into  boiling 
aniline. 

Methyl-aniline  C6H5NHCH3,  by  reduction  of  phenyl-carbylamine 
and  formaldehyde- aniline.  Chlorohydrate,  m.p.  122°,  obtained  from 
the  etheric  solution  of  the  base  with  dry  HC1  (B.  30,  3134  ;  C.  1898, 
II.  479).  Not  coloured  by  chloride  of  lime.  On  heating  to  330°  it 
passes  into  p-toluidin.  For  methyl-phenyl-nitrosamine  and  methyl- 
acetanilide,  see  below. 

By  oxidation  with  hydrogen  peroxide  or  monopersulphonic  acid  the 
alkyl  groups  are  split  off,  from  methyl-  and  ethyl-aniline,  and  we  obtain 
jS-phenyl-hydroxylamine,  nitroso-  and  nitro-benzol,  azoxy-  and  azo- 
benzol  (B.  35,  703). 

With  formaldehyde  and  HC1,  methyl-  and  ethyl-aniline  form 
C6H5N(CH3)CH2C1  and  C6H5N(C2H5)CH2C1,  which,  by  reduction,  can 
be  converted  into  dimethyl-  and  methyl-ethyl-aniline  (C.  1902,  II.  340  ; 
1905,  I.  227). 

Dimethyl-aniline  C6H5N(CH3)2  is  also  formed  on  heating  bromo- 
or  iodo-benzol  with  dimethylamine  to  25o°-26o°  (C.  1898,  II.  478). 
With  dry  HC1  it  yields  a  mono-  and  a  dichlorohydrate,  C6H5N(CH3)2. 
HC1  and  C6H5N(CH3)2.2HC1,  crystalline  bodies  deliquescing  in  moist 
air,  which  easily  give  off  HC1  (B.  30,  3134).  lodo-hydrate,  m.p.  112°, 
cp.  C.  1898,  II.  479.  Not  coloured  by  hypochlorite.  With  methyl 
iodide  it  combines  to  form  trimethyl-phenylium  iodide  C6H5N(CH3)3I. 
Treated  with  nitrous  acid  it  passes  into  p-nitroso-dimethyl-aniline,  and, 
with  nitric  acid,  into  p-nitro-dimethyl-aniline.  With  acetyl  and 
benzoyl  bromides  it  gives  acetyl-  and  benzoyl-monomethyl-aniline, 
besides  trimethyl-phenyl-ammonium  bromide  (B.  19,  1947).  By 
hydrogen  peroxide  and  monopersulphonic  acid  it  is  oxidised  to  : 


go  ORGANIC   CHEMISTRY 

Dimethyl-aniline  oxide  C6H5N(CH3)2O,  m.p.  153°.  Picrate,  m.p. 
135°  ;  chlorohydrate,  m.p.  125°. 

Dimethyl-aniline  has  been  introduced  into  a  number  of  condensa- 
tion reactions.  With  chloral  it  combines  to  p-amido-mandelic  acid 
(CH3)2N[4]C6H4[i]CH(OH).CCl3.  With  phosgene  it  passes  into 
tetramethyl-p-diamido-benzo-phenone  [(CH3)2N[4]C6H4[i]]2CO ;  with 
formic  ester  and  zinc  chloride,  into  hexamethyl-p-leukaniline  CH 
[C6H4N(CH3)2]3;  and  with  benzo-trichloride,  into  malachite  green  (q.v.). 

The  homologous  mono-  and  dialkyl- anilines  behave  similarly.  We 
may  mention  Methyl-ethyl-aniline  C6H5N(CH3)(C2H5),  b.p.  201°.  Its 
compound  with  CH3I  is  identical  with  dimethyl-aniline-ethyl  iodide  ; 
from  which,  and  others,  theoretical  conclusions  can  be  drawn  with 
regard  to  the  equivalence  of  the  five  nitrogen  affinities  (cp.  B.  33,  1003). 
By  heating  with  KHO,  the  higher  alkyl  is  split  off  from  these  Am 
iodides. 

Methyl-ethyl-anffine  oxide  C6H5(CH3)(C2H5)NO,  from  methyl-ethyl- 
aniline  and  hydrogen  peroxide ;  colourless  and  very  hygroscopic 
prisms.  Chlorohydrate,  m.p.  124°;  picrate,  m.p.  148°.  On  the  split- 
ting of  the  base  into  optically  active  components,  see  above. 

Alkylene-mono-  and  dianilines  are  obtained  from  dibromo-paraffins 
with  anilines  ;  [i,  4]-dibromides  react  with  formation  of  cyclic  alkylene 
imides,  or  pyrrolidins  (Vol.  I.),  unless  a  substituent  is  in  the  ortho- 
position  to  the  amido  group  ("  steric  hindrance,"  see  B.  32,  848,  2251). 

Ethylene-monophenyl-diamine  NH2.CH2.CH2.NHC6H5,  b.p.  263°, 
from  phthalimide  of  potassium  (B.  24,  2191).  Ethylene-diphenyl- 
diamine  C6H5NH.CH2.CH2.NHC6H5,  m.p.  65°.  Trimethylene-diphenyl- 
diamine  C6H5NH[CH2]3NHC6H5,  b.p.iq  28o°-285°,  besides  Trimethylene- 
phenylimine,  from  trimethylene  bromide  and  aniline.  1, 4-Pentylene- 
di-o-toluidin  CH3C6H4NH.CH2.CH2CH2CH(CH3)NHC6H4CH3,  b.p.23 
I9i°-i93°. 

Further   cyclic   alkylene-dianilines  like  [CH2]2/N(c'Hs)\CH2,   m.p. 

\N(C6H5)/ 

124°,  and  [CH2]3/^^^)\cH2,  m.p.    87°,   Diphenyl-hydro-glyoxalins 

\JN  (U6tL5)  / 

and  -pyrimidins,  have  been   obtained  from   alkylene-dianilines  with 
aldehydes  (B.  31,  328  ;   32,  2256). 

Alkylidene-dianilines  are  easily  obtained,  in  cold  aqueous  solutions, 
from  fatty  aldehydes  (i  mol.)  and  anilines  (2  mols.).  They  are  decom- 
posed by  mineral  acids.  The  methylene-dianilines,  heated  with 
concentrated  HC1,  or  the  corresponding  aniline  chlorohydrates,  are 
transformed  into  diamido-diphenyl-methanes  (B.  41,  2145)  : 

C6H5NH.CH2.NHC6H5  ->  [C6H3NH.CH2.C6H4NH2]  ->  NH2C6H4.CH2.CCH4NH2. 

The  simpler  alkylene-dianilines  easily  pass  into  the  alkylidene-mono- 
anilines,  or  their  transformation  products. 

Methylene-diphenyl-diamine  CH2(NHC6H5)2,  m.p.  65°,  b.p.12  160°, 
oxidised  with  monopersulphonic  acid,  gives  several  fission  products, 
and  also  diphenyl-oxy-form-amidin  (B.  35,  714).  Methylene-o2-  and 
p2-ditolyl-diamine,  m.p.  52°  and  89°.  Ethylidene-diphenyl-diamine 
CH3CH(NHC6H5)2,  m.p.  51°.  Trichlor  -  ethylidene  -  diphenyl  -  diamine 
CC13CH(NHC6H5)2,  m.p.  107°. 

Alkylidene-monoanilines  are  formed  by  an  energetic  reaction,  by 


SECONDARY   AND  TERTIARY   PHENYLAMINES         91 

combination  of  equimolecular  amounts  of  fatty  aldehydes  and  anilines, 
with  elimination  of  water  ;  the  simple  bodies  are  mostly  unstable  oils, 
which  at  once  either  polymerise,  like  formaldehyde-aniline,  or  condense, 
like  aldol. 

With  sulphurous  acid  and  sodium  disulphite,  the  alkylidene-anilines 
act  like  the  aldehydes,  but  the  reaction  is  more  complicated  in  the 
higher  homologues  of  the  aldehyde  derivatives ;  from  ethylidene-aniline 

we  obtain  CH3CH/^^H5'  the  Na  salt  of  which  is  also  formed  from 

\SO3H 

acetaldehyde  sodium  bisulphite,  with  aniline.  The  simple,  as  well  as 
the  polymeric,  alkylidene-anilines  easily  add  hydrocyanic  acid,  with 
formation  of  the  nitrites  of  a-anilido-carboxylic  acids,  also  obtained 
by  direct  transformation  of  aniline  salts,  with  aldehydes,  and  CNK 
(B.  37,  4073  ;  39,  986,  2796).  The  aldoloid  condensation  products, 
on  the  other  hand,  do  not  add  HCN  ;  they  behave  like  di-acid,  di- 
secondary  bases  ;  they  do  add  bromine,  and  must  therefore  be  regarded 
as  probably  dianiline  derivatives  of  the  olefin-glycols,  e.g.  CH3CH 
(NHC6H5)CH  :  CH(NHC6H5).  These  bodies  are  easily  condensed  with 
further  elimination  of  aniline  to  quinolin  derivatives  (B.  25,  2020  ; 
A.  316,  89  ;  318,  58  ;  C.  1902,  I.  911). 

Anhydro-formaldehyde-aniline  (CH2NC6H5)3,  m.p.  140°,  obtained 
by  mixing  formaldehyde  solution  with  aniline  in  the  cold.  May  be 
reduced  to  methyl-aniline.  Gives  with  HCN  anilido-aceto-nitrile.  With 
aromatic  amines  the  anhydro-formaldehyde  anilines  condense,  in  the 
presence  of  chlorohydrates,  to  amido-benzyl-anilines  (C.  1900, 1.  496)  : 

C6H5N  :  CH2+C6H5NH2 >  C6H5NH.CH2C6H4NH2. 

Ethylidene-aniline  CH3CH  :  NC6H5,  an  oil,  easily  adds  hydrocyanic 
acid  to  a-anilido-propio-nitrile,  and  easily  condenses  to  two  stereo- 
isomeric  modifications  of  j8-anilido-butylidene-aniline  CH3CH(NHC6H5). 
CH  :  CHNHC6H5,  m.p.  126°  and  85°,  the  latter  being  easily  transformed 
into  the  former.  On  heating  with  HC1  or  acetic  acid  both  give 
quinaldin.  With  HNO2  they  yield  two  dinitroso-compounds  of  m.p.  161° 
and  120°.  Aldonaniline  CH3CH(OH)CH2CH  :  NC6H5,  from  aldol  and 
aniline,  is  a  reddish,  easily  decomposed  oil ;  by  treatment  with  Am2S 
it  is  transformed  into  thio-aldo-aniline  CH3.CH(OH)CH2CH  NC6H5, 

\S/ 

m.p.  92°  (B.  29,  59).  For  higher  homologues,  alkylidene-anilines, 
and  aldol-anilines,  see  B.  33,  3460  ;  34,  509  ;  C.  1901,  II.  582,  etc. 

C.  POLY-PHENYLAMINES. 

The  modes  of  formation,  and  the  behaviour,  of  these  compounds 
are  to  be  illustrated  by  di-  and  triphenylamine. 

Diphenylamine  NH(C6H5)2,  m.p.  54°,  b.p.  310°.  (i)  This  com- 
pound, of  importance  in  the  aniline-dye  industry,  was  first  obtained 
by  A.  W.  Hofmann,  by  heating  aniline  blue,  rosaniline,  and  similar 
dyes  (A.  132,  160).  (2)  By  heating  aniline  with  aniline  chlorohydrate 
to  140°,  a  large-scale  industrial  process  : 

C6H5NH2HCl+C6H5NH2=NH(C6H5)2-hNH4Cl. 

In  a  similar  manner  ditolyl-amines  have  been  prepared  (C.  1903, 1.  85). 
(3)  By  heating  aniline  with  bromo-benzol  and  copper  powder,  or 


92  ORGANIC   CHEMISTRY 

cuprous  iodide,  good  quantities  of  diphenylamine  are  obtained.  It  is 
well  to  start  from  acetanilide,  and  obtain,  first,  the  acetyl  compound, 
from  which  the  free  base  is  easily  separated.  (4)  By  heating  aryl- 
anthranilic  acids,  with  liberation  of  CO2  (A.  355,  312).  The  last  two 
methods  are  very  suitable  for  preparing  asymmetrical  and  substituted 
diphenylamines  (B.  40,  4541). 

Diphenylamine  is  a  crystalline  body,  of  pleasant  odour.  In  water 
it  is  nearly  insoluble,  but  easily  soluble  in  alcohol  and  ether. 

It  is  but  a  weak  base,  the  salts  of  which  are  dissolved  by  water. 
The  imide  hydrogen  may  also  be  replaced  by  metals :  potassium- 
diphenyl-amine  (CeH5)2NK  (C.  1898,  II.  1252). 

Oxidation  of  diphenylamine  with  potassium  permanganate,  or  lead 
peroxide,  in  acetone,  or  benzol  solution,  gives  tetmphenyl-hydrazin 
(B.  39,  1500).  In  alkaline  solution  it  is  oxidised  by  potassium  per- 
manganate to  diphenyl-p-azophenylene,  or  quinone-dianile  C6H5N 
=  [i]C6H4[4]=NC6H5  (B.  20,  R.  719).  Chlorine  and  bromine  change 
diphenylamine  into  tetra-  or  hexahalogen  substitution  products  ; 
HNO3  into  the  hexanitro-products.  H2SO4  dissolves  diphenylamine, 
and  the  solution  colours  blue  with  traces  of  HNO3  (test  for  the  latter). 

/  C^  TT  \ 

Heating  with  sulphur  gives  thio-diphenylamine,  NH<(^C6]  yS  (q.v.), 
the  fundamental  body  of  the  thionin  dyes  ;  heating  with  aliphatic 

/P  TT  \ 

acids  to  300°  gives  acridines  (q.v.)  like  N    C6H*    CH. 

Diphenylamine  is  used  for  preparing  triphenyl-rosaniline  (q.v.),  or 
aniline  blue. 

Methyl-diphenylamine  CH3N(C6H5)2,  b.p.  292°  (A.  235,  21). 

Phenyl-p-toluidin  C6H5NHC6H4CH3,  m.p.  87°;  Phenyl-m-xylidin 
C6H5NHC6H3(CH3)2,  m.p.  43°,  by  methods  3  and  4. 

Triphenylamine  (C6H5)3N,  m.p.  127°,  distils  without  decomposition, 
formed  by  heating  dipotassium-aniline,  or  from  sodium-diphenylamine 
with  bromo-benzol  (B.  18,  2156).  The  easiest  method  is  by  heating 
diphenylamine  with  iodo-benzol  and  some  powdered  copper  ;  or  from 
diphenyl-anthranilic  acid  by  splitting  off  CO2  (B.  40,  2448).  It 
crystallises  from  ether  in  large  plates.  It  dissolves  in  hot  H2SO4  with 
intense  blue  coloration.  It  does  not  form  salts  with  acids.  Nitro- 
genation  give.s  a  trinitro-product,  from  which,  by  reduction,  triamido- 
triphenylamine  is  formed  (B.  19,  759).  Phosgene  gives  hexaphenyl- 
rosaniline  (q.v.). 

p-Tritolyl-amine  (CH3C6H4)3N,  m.p.  117°,  from  p-ditolyl-amine 
and  p-iodo-toluol.  With  Br,  PC15,  SbCl5,  etc.,  it  gives  dark-blue, 
unstable  addition  products,  decomposed  by  water  with  restoration  of 
tritolyl-amine  (B.  46,  4268). 

D.  ANILINE  DERIVATIVES  OF  INORGANIC  ACIDS. 

Aromatic  thionylamines  (Michaelis). — These  compounds,  corre- 
sponding to  the  alkyl- thionylamines  (Vol.  I.),  are  obtained  by  the  action 
of  thionyl  chloride  upon  primary  bases,  a  reaction  characteristic  of 
these  compounds. 

The  thionyl-anilines  are  mostly  yellow  liquids,  not  decomposing 
when  boiling,  even  under  increased  pressure.  They  have  an  aromatic 
odour,  pervaded  by  the  sulphur  chloride  smell. 


ANILINE   DERIVATIVES   OF   INORGANIC  ACIDS        93 

Thionyl-aniline  C6H5N  :  SO,  b.p.  200°,  D15  1-236.  Thionyl- 
o-chloraniline,  b.p.46  207°  ;  m-compound,  b.p.  233°  ;  p-compound, 
m.p.  36°,  b.p.  237°.  Thionyl-o-bromaniline,  b.p.46  210° ;  m-compound, 
m.p.  32° ;  p-compound,  m.p.  60°.  Thionyl-o-nitraniline,  m.p.  32°. 

Thionyl-o-toluidin,  b.p.10o  I84°  ;  m-compound,  b.p.  220° ;  p-com- 
pound, m.p.  7°,  b.p.  224°  (A.  274,  201),  etc. 

Phenyl-sulphaminic  acid  C6H5NHSO3H,  known  only  in  its  salts, 
formed  (i)  by  the  action  of  SO3  or  C1SO3H  upon  aniline,  in  chloroform 
solution  (B.  24,  360)  ;  (2)  by  heating  aniline  with  amido-sulphonic 
acid  (B.  27,  1244)  ;  (3)  by  combining  jS-phenyl-hydroxylamine  with 
SO2 ;  (4)  by  action  of  sodium  bisulphite,  or  hydro-sulphite,  upon 
aqueous  solutions  of  benzol  (C.  1904,  I.  1380  ;  1906,  II.  37). 

C6H5NO2+3HSO3Na=C6H5NHSO3Na-f2SO4HNa. 

By  dilute  acids  phenyl-sulphaminic  acid  is  easily  split  up,  with 
formation  of  aniline  salts ;  while  concentrated  acids  produce  transposi- 
tion into  the  o-  and  p-aniline-sulpho-acid  (B.  30,  2274). 

p-Tolyl-sulphaminie  acid  is  precipitated  from  solution  of  its  Am 
salts  by  acids  (B.  28,  3161).  p-Chloro-phenyl-sulphaminic  acid 
C1C6H4NHSO3H  is,  on  heating,  transposed  into  p-Chloraniline-o- 
sulphonic  acid  (B.  34,  2748).  For  formation  of  phenyl-sulphaminic 
acids  from  anilines  with  SO2,  see  C.  1898,  II.  195.  Sulphanilide 
S02(NHC6H5)a  (B.  28,  362). 

The  aromatic  nitroso-amines  and  nitro-amines  are  dealt  with  later, 
before  the  diazo-compounds. 

Phosphoro-phenylamines.  Phosph-azo-benzol  chloride  C6H5N  :  PCI, 
m.p.  I36°-I37°,  by  action  of  PC13  upon  aniline  chlorohydrate.  With 
phenol  it  yields  Phenoxyl-phosphazo-benzol  C6H5N  :  P(OC6H5).  With 
aniline,  Phosphazo-benzol-anilide  C6H5N  :  P.NHC6H5  (B.  27,  490). 
Anilido-phosphoric  dichloride  C6H5NH.POC12,  m.p.  84°,  from  POC13 
and  aniline  chlorohydrate  (B.  26,  2939).  Ortho-phosphoric  anilide 
(C6H5NH)3PO,  m.p.  208°  (A.  229,  334).  Oxy-phosphazo-benzol- 
anilide  C6H5NH.PO  :  NC6H5,  m.p.  357°,  is  the  final  product  of  the 
action  of  POC13  upon  aniline  (B.  29,  716  ;  A.  326,  129).  From  aniline 
chlorohydrate  and  PC15  we  get  trichloro-phosphanile  C6H5N.PC13 
(B.  28,  2212  ;  cp.  C.  1902,  II.  355). 

Sulpho-phosphazo-benzol  chloride  C6H5N :  PSC1,  m.p.  149°,  b.p. 
28o°-290°,  from  PSC13,  and  aniline  chlorohydrate  (B.  29,  1239). 

Arseno-phenylamines  are  produced  by  the  action  of  arsenious 
chloride  or  bromide  upon  aniline  in  ether  or  chloroform. 

Arsen-anilido-dichloride  C6H5NHAsCl2,  m.p.  87°.  Arsen-anilido- 
dibromide,  m.p.  112°.  Arsen-dianilido-monoehloride  (C6H5NH)2AsCl, 
m.p.  127°.  Arsen-anilido-dimethyl-ether  C6H5NHAs(OCH3)  2,  b.p.12  55° 
(A.  261,  279). 

Siiieo-tetraphenylamide  Si(NHC6H5)4,  m.p.  137°  (B.  22,  R.  746), 
passes  on  heating  into  Silico-diphenylimide  Si(NC6H5)2  (C.  1903, 1.  572). 

E.  CARBOXYLIC  DERIVATIVES  OF  THE  AROMATIC  PRIMARY  AND 
SECONDARY  AMINES. 

In  the  introduction  to  the  fatty  acids,  it  was  explained,  by  the 
example  of  acetic  acid,  which  nitrogen  derivatives  could  be  obtained 


94  ORGANIC  CHEMISTRY 

by  changes  in  the  carboxyl  group.  The  first  category  of  compounds 
are  the  carboxylic  amides,  which  may  be  variously  interpreted, 
according  to  the  formulae  : 

LR'-C\NH2    and    ILR/-C<SHH- 

The  imido-ethers  are  derived  from  formula  II. 

Many  such  fatty-acid  derivatives  have  been  obtained,  by  starting 
from  aniline  and  its  primary  homologues.  For  the  acid  amides  x>f 
secondary  bases  only  formula  I.  need  be  considered.  In  a  primary 
amine  the  two  H  atoms  may  be  replaced  by  acid  radicles. 

The  introduction  of  the  second  acidyl  group  is  facilitated  by 
o-substituents  in  the  aniline  nucleus,  which  otherwise  retard  the 
entry  of  the  first  acidyl  group  (C.  1901,  I.  836). 

To  the  acid  amides  correspond  the  thiamides  and  iso-thiamides  : 

LRC\NH2     and     n'R<NH- 

These  classes  of  bodies  are  followed  by  the  amido-chlorides,  the 
imido-chlorides,  and  the  amidins. 

Anilides  of  mono-basic  fatty  acids. — The  anilides  or  phenylamides 
of  the  fatty  acids  are  produced  by  the  same  methods  (Vol.  I.)  as  the 
acid  amides  themselves  :  (i)  by  heating  the  aniline  salts  of  the  fatty 
acids  ;  (2)  by  the  action  of  aniline  upon  esters  ;  (3)  upon  acid  chlorides  ; 
(4)  upon  acid  anhydrides  ;  (5)  by  action  of  acid  esters  upon  C6H5 
NHMgl  (C.  1904,  II.  201). 

The  acid  amides  are  very  stable ;  they  mostly  distil  without  decom- 
position, and  can  be  chlorinated,  brominated,  and  nitrogenated  direct. 
TJiey  serve  for  the  simple  and  quick  identification  of  the  aromatic 
bases.  By  heating  with  alkalies,  or  with  HC1,  the  anilides  are  again 
split  into  their  components.  Boiling  with  sulphur  converts  them 
into  benzol- thiazols  (q.v.). 

The  secondary  anilides,  like  the  secondary  alkyl-anilines,  form 
nitroso-anilides  with  nitrous  acid.  With  phenol,  and  sulphuric  acid, 
they  give  the  nitrosamine  reactions,  but  they  are  much  less  stable 
than  the  nitrosamines  of  the  secondary  anilines  ;  by  reducing  agents 
the  nitroso-group  is  split  off  again.  With  hypochlorous  and  hypo- 
bromic  acids,  the  hydrogen  attached  to  the  nitrogen  of  the  anilides 
may  be  replaced  by  halogens :  C6H5.NC1.COCH3 ;  these  nitrogen 
haloids  are  easily  transposed  under  the  influence  of  HC1,  or  sunlight, 
into  anilines  with  nuclear  substitution,  e.g. 

C6H5NC1(COCH3)  -   — >  C1[4]C6H4NHCOCH3 

(B.  32,  3573  ;  C.  1903,  I.  21,  141). 

Formanilide  C6H5NH.CHO,  m.p.  46°,  b.p.  284°  (A.  270,  279),  is 
produced  on  boiling  aniline  with  formic  acid,  or  during  rapid  heating 
of  aniline  with  oxalic  acid.  It  is  soluble  in  water,  alcohol,  and  ether. 

Salts  and  alkyl  derivatives. — From  the  aqueous  solution,  NaHO 
precipitates  Sodium  formanilide  C6H6N  :  (CHONa),  in  a  crystalline 
form,  and  with  methyl  iodide  this  gives  Methyl  formanilide 

C«H5N<\C^°,  m.p.  12-5°,  b.p.  253°.  By  heating  with  alcoholic  potash, 
or  HC1,  the  latter  is  split  into  acid,  and  methyl- aniline  (B.  21,  1107). 


CARBOXYLIC  DERIVATIVES   OF  AROMATIC   AMINES     95 

Silver  formanilide  C6H6N  :  CH(OAg)  is  precipitated  from  the  alcoholic 
solution  of  the  sodium  compound  with  silver  nitrate,  and  passes,  in 
the  presence  of  methyl  iodide,  into  Methyl  iso-formanilide  C6H5.N  : 
CHOCH3,  b.p.  196°,  which,  on  heating,  is  transposed  into  the  isomeric 
methyl  formanilide  (B.  23,  2274,  R.  659).  But  the  silver  salt  gives  N 
derivatives  with  acid  chlorides,  like  benzoyl  chloride  (B.  29,  R.  1141). 
Ethyl  iso-formanilide,  ethoxy-methylene- aniline,  C6H5N  :  CHOC2H5, 
b.p.  212°,  is  also  obtained  by  prolonged  boiling  of  aniline  with 
ortho-formic  ester,  besides  diphenyl  formamidin  (A.  287,  360). 

Acetanilide,  antifebrin  CeH5NHCOCH3,  m.p.  114°,  b.p.  295°,  gene- 
rated by  boiling  aniline  with  glacial  acetic  acid  (B.  15,  1877)  ;  or 
from  aniline  with  acetyl  chloride,  acetic  anhydride,  or  thio-acetic 
acid ;  the  last  of  these  agents  has  been  found  very  useful  for  intro- 
ducing acetyl  groups  into  aniline  (B.  35,  no). 

Acetanilide  is  also  formed  from  malon-anilic  acid  by  rejection  of 
CO2.  A  notable  method  is  by  treating  the  isomeric  aceto-phenone 
oxime  with  sulphuric  acid  at  100°  (B.  26,  2581) : 

C6H5C:(NOH).CH3 >  C6H5NH.CO.CH3. 

Crystallised  from  water,  in  which  it  is  not  easily  soluble  in  the  cold, 
acetanilide  does  not  form  white  flakes.  It  is  used  as  an  anti-pyretic 
and  anti-rheumatic.  For  action  of  PC15  see  A.  184,  86.  Heating 
with  sulphur  produces  bis-thiazol  (q.v.). 

Brom-aeetanilide,  m.p.  131°,  yields  indigo  (q.v.)  on  melting  with 
caustic  potash  in  air. 

Salts. — The  chlorohydrate  is  decomposed  by  water.  On  heating, 
it  passes  into  diphenyl-acet-amidin,  flavanilin  (q.v.)  and  dimethyl- 
quinolin  (B.  18,  1340).  With  sodium  ethylate,  on  heating,  it  is  con- 
verted into  ethyl- aniline  and  sodium  acetate  (B.  19,  R.  680). 

Sodium  aeetanilide  C6H5N  :  C(ONa)CH3,  by  action  of  sodium  upon 
the  xylol  solution  of  acetanilide,  yields  mono-alkyl-acetanilides  with 
alkylene  iodide,  and  from  these  the  mono-alkyl-anilines  may  be  obtained 
(B.  10,  328  ;  23,  2587).  The  same  acetanilides  are  produced  by  the 
action  of  acetic  anhydride  upon  the  secondary  bases.  But  acetanilide, 
heated  with  silver  oxide,  methyl  iodide,  or  dimethyl  sulphate,  yields 

Aeeto-phenyl-imido-methyl-ether  CH3c^^  b.p.  197°  (C.  1901,  I. 
1043;  A.  333,  293).  Mercurio-acetanilide  (C36H5NCOCH3)  2Hg  (B.  28, 
R.  113). 

Methyl-acetanilide,  exalgin,  m.p.  101°,  b.p.  253°  (anti-neuralgic). 
Ethyl-aeetanilide,  m.p.  54°,  b.p.  258°.  n-Propyl-acetanilide,  m.p.  47°, 
b.p.  266°  (B.  21,  1108). 

Substituted  Acetanilides. — The  action  of  Cl,  Br,  and  HNO3  upon 
acetanilide  produces  o-  and  p-derivatives. 

Formyl  aeetanilide  C6H5N(COH)(COCH3),  m.p.  56°,  from  mercurio- 
formanilide  and  acetyl  chloride  (B.  29,  R.  1155). 

Diacetanilide  C6H5N(COCH3)2,  m.p.  37°,  b.p.1]L  142°,  by  heating 
acetanilide  with  acetyl  chloride  to  i7O°-i8o°,  or  with  acetic  anhydride  ; 
also  by  boiling  phenyl-mustard  oil  with  acetic  anhydride  (B.  27,  91  ; 
28,  1665).  Its  physiological  effects  are  similar  to  those  of  acetanilide 
(B.  31,  2788). 

Concerning   transpositions    of    diacetanilide    into    p  -  Acetamido  - 


96  ORGANIC   CHEMISTRY 

aeetophenone,  (CH3CO)  2NC6H5 >  CH3CONHC6H4COCH3,  see  C. 

1902,  II.  355  ;  1903,  I.  1222. 

The  acetic  compounds  are  distinguished  for  their  power  of  crystal- 
lisation. They  serve  as  means  of  recognising  many  primary  and 
secondanr  aromatic  bases.  Hence  the  melting-points  of  many 
acetic  compounds  have  been  quoted  in  connection  with  the  bases 
concerned. 

Thio-anilides  are  formed  from  the  anilides  with  P2S5  ;  or  from 
amidins  and  isonitrites  with  H2S  ;  or  from  phenyl-mustard  oil  with 
magnesium-alkyi  iodides. 

Thio-formanilide  C6H5NHCHS  melts  at  137°,  with  decomposition 
into  H2S  and  phenyl  iso-cyanide  (B.  11,  338  ;  A.  192,  85).  For 
homologous  thio-formanilides,  see  B.  18,  2292. 

Thio-aeetanilide,  m.p.  75°,  oxidised  with  potassium   ferricyanide, 

passes  into  Amido-thio-phenol  C6H4<f^C.CH3  (B.  19,  1072).  Thio- 
anilides  of  homologous  fatty  acids,  B.  36,  587.  Methyl-thio-acetanilide, 
m.p.  59°,  b.p.  290°. 

Methyl-iso-thio-acetanilide  C8H5N:C<(^,  b.p.  245°,   Ethyl-iso- 

thio-acetanilide,  b.p.  250°,  formed  by  action  of  sodium  alcoholate  and 
alkyl  iodides  upon  thio-acetanilide.  On  shaking  with  HC1  they 
decompose  into  aniline  chlorohydrate  and  thio-acetic  ester  (Vol.  I.) 
(B.  12,  1061). 

F.  PHENYLATED  AMIDINS  OF  FORMIC  ACID  AND  ACETIC  ACID. 

Besides  the  general  methods  of  amidin  formation,  enumerated 
in  Vol.  I.,  the  phenylated  amidins  are  prepared  by  action  of  PC13  or 
HC1  upon  a  mixture  of  aniline  and  anilide,  with  liberation  of  water 
(B.  15,  208,  2449) : 

C6H5NHCOCH3  +C0H6NH2  = 

They  are  feeble  bases,  and  combine  with  i  equiv.  HC1  to  form 
salts.  On  boiling  with  alcohol  they  decompose  into  aniline  and 
acid  anilides. 

Diphenyl  -  f ormamidin,  methenyl  -  diphenyl  -  diamine  C6H5N  :  CH. 
NHC6H5,  m.p.  135°,  by  heating  aniline  to  180°  with  chloroform  or 
formic  acid;  from  hydrocyanic  sesqui-chlorohydrate  (CHN)2(HC1)3 
with  aniline  (B.  35,  2498)  ;  or  by  boiling  phenyl-iso-cyanide  C6Hg.NC 
with  aniline.  It  crystallises  from  alcohol  in  long  needles,  and  distils 
at  about  250°,  with  partial  decomposition,  into  benzo-nitrile  and 
aniline. 

Di-aryl-form amidins  are  distinguished  from  the  amidins  of  the 
higher  carboxylic  acids  by  their  superior  power  of  reaction.  With 
the  CH2  group  of  malonic  ester,  aceto-acetic  ester,  and  similar  sub- 
stances, they  react  with  liberation  of  aniline,  and  formation  of 
aniline-methylene  derivatives  like:  C6H5NHCH  :  C(CO2R)2  Anilino- 
methylene- malonic  ester,  C6H5NHCH  :  C(COCH3)CO2R  Anilino- 
methylene-aeetic  ester,  etc.  (B.  35,  2505). 

Diphenyl-oxy-f ormamidin  melts  without  water  at  131°  ;    formed 


PHENYLATED  CARBYLAMINES          97 

from  methyl-iso-formanilide  with  j3-phenyl-hydroxylamine  •  also  from 
methylene-diphenyl-hydroxylamine  by  withdrawing  H2O,  by  means 
of  anhydrous  copper  sulphate.  Acetic  anhydride  transposes  it  into 
diphenyl-urea  C6H5NH.CO.NHC6H5  (B.  35,  1451,  1874). 

Diphenyl-ethenyl-amidin  melts  at  131°,  formed  by  addition  of 
CH3.MgI  to  carbo-diphenyl-imide  (q.v.). 

Phenyl-ethenyl-amidin  C6H5.N  :  C(NH2).CH3,  from  aceto-nitrile  and 
HCl-aniline  (A.  184,  362  ;  192,  25)  (Vol.  I.)  is  liquid. 

Phenylisuretin  CgHgNH-CH :  NOH,  m.p.  138°,  from  formyl- 
chloridoxime  (Vol.  I.)  with  aniline  (B.  27,  R.  745). 

PHENYLATED  CARBYLAMINES  (Vol.  I.). — Phenyl-isoeyanide,^n>'J- 
carbylamine,  boils,  at  atmospheric  pressure,  at  166°  with  strong  poly- 
merisation, below  20  mm.  at  64°  without  change.  The  colourless 
liquid,  D15  0-977,  soon  colours  a  light  blue,  then  dark  blue,  and  turns 
resinous.  Phenyl-isocyanide  is  formed  from  aniline  and  chloroform, 
with  alcoholic  potash,  also  by  heating  thio-formanilide.  Phenyl- 
carbylamine  has  an  abominable  and  clinging  odour,  tastes  bitter,  and 
causes  headache  and  flow  of  saliva.  It  behaves  as  follows  : — Heating 
to  220°  transposes  it  into  benzo-nitrile  C6H5CN.  Nascent  H  converts 
it  into  methyl-aniline.  With  HC1  in  dry  ether  it  gives  phenyl-imido- 
formyl-chloride  ;  with  glacial  acetic  acid,  formanilide  ;  with  SH2  at 
100°,  thio-formanilide ;  with  sulphur  at  130°,  mustard  oil ;  with  aniline 
at  170°,  diphenyl-formamidin  ;  with  chlorine,  isocyano-phenyl-chloride 
or  phenyl-amido-carbonyl-chloride;  with  phosgene,  meso-xanil-amido- 
chloride  ;  with  acetyl  chloride,  pyro-racemic  anilide  chloride  (Nef , 
A.  270,  274).  o-Tolyl-isoeyanide,  b.p.16  75°,  D24  0-968.  p-Tolyl- 
isocyanide,  b.p.32  99°  (B.  27,  R.  792). 

PHEXYLAMIXE  DERIVATIVES  OF  OXY-ACIDS. — These  compounds  are 
capable  of  some  condensation  reactions,  in  which  the  benzene  H  atom, 
in  ort/jo-position  to  nitrogen,  often  takes  part,  so  that  heterocyclic 
compounds  are  formed.  The  acids  are  obtained  by  heating  the  corre- 
sponding halogen  fatty  acids  with  anilines  (cp.  B.  30,  2303,  2464,  3169  ; 
31,  2678).  Their  nitriles  are  formed  :  (i)  by  addition  of  HCN  to  the 
alkylidene-anilines  ;  (2)  from  the  bisulphite  addition-products  of  the 
latter  with  CNK  (C.  1902,  II.  315  ;  B.  37,  4073)  ;  (3)  by  heating  the 
aldehyde  and  ketone  cyano-hydrins  with  aniline  ;  (4)  by  direct  trans- 
formations of  aniline  salts  with  aldehydes,  or  ketones,  and  CNK  (B.  39, 
986,  2796). 

Anilido-aeetie  acid,  phenyl-glycocoll,  phenyl-glycin  C6H5NHCH2 
COOH,  m.p.  127°,  by  heating  chloro-  or  bromo-acetic  acid  with  aniline 
and  water  (B.  10,  2046  ;  21,  R.  136).  Its  alkyl  esters  are  obtained  by 
heating  aniline  with  chloracetic  ester  or  dichloro-vinyl  ether  in  aqueous 
suspension  (C.  1908,  I.  1006  ;  II.  358),  or  by  action  of  diazo-acetic 
ester  upon  aniline.  Its  nitrile,  m.p.  43°,  is  formed  (i)  from  anhydro- 
formaldehyde-aniline  with  absolute  HCN  ;  (2)  from  its  bisulphite  com- 
pounds with  CNK  ;  (3)  from  formaldehyde-cyanhydrin  with  aniline  ; 
(4)  from  aniline  chlorohydrate,  formaldehyde,  and  CNK  (C.  1902,  II. 
315  ;  1903,  I.  208  ;  1904,  I.  1308).  By  heating  the  free  acid  to 
150°  we  obtain  Diphenyl-glycin-anhydride  or  diphenyl-diacipiperazine 
C6H5N^^— CO\NC6H6,  m.p.  263°  (B.  25,  2270).  Phenyl-glycin 

-LAJ — L,rl2/ 

possesses  industrial  importance,  since,  on  melting  with  caustic  potash, 
VOL.  II.  H 


98  ORGANIC   CHEMISTRY 

or,  better,  sodium  amide,  it  passes  into  indoxyl  C6H4<^  (        yCH,  which, 

in  air,  easily  oxidises  to  indigo. 

Distillation  of  calcium  anilido-acetate  with  Ca  formate  gives  indol 

</-"TT  vx 
l^tl  \pTT 
NH/C 

Besides  phenyl-glycin  we  obtain  from  aniline  and  chloracetic  acid 
Diglycol-phenyl-amidic  acid,  anilino-diacetic  acid  C6H5N(CH2COOH)2, 
m.p.  I5o°-i55°.  Oxidised  with  MnO4K  it  gives  Formyl-phenyl-glycin 
C6H5N(CHO)CH2COOH,  m.p.  125°.  It  is  better  obtained  from  phenyl- 
glycin  by  heating  with  formic  acid  (B.  34,  1647). 

Diglycol-phenyl-amidic  anhydride  C6H5N(CH2CO)2O,  m.p.  148° 
(B.  25,  2272)  ;  imide,  C6H5N(CH2CO)2NH,  m.p.  158°  (B.  22,  1809)  ; 
anile  C6H5N(CH2CO)2NC6H5,  m.p.  152°  (B.  22,  1802).  Isomeric  with 

diglycol-phenyl-amidic  acid  is  Diglycol-anilic   acid  O/CH2CONHC6H5, 

\CH2CO2H 

m.p.  118°,  from  diglycolic  anhydride  and  aniline.  With  acetyl  chloride 
it  passes  into  Diglycolic  anile  O(CH2CO)2NC6H5,  m.p.  116°,  isomeric 
with  diglycol-phenyl-amidic  anhydride  (A.  273,  66).  Thio-diglyeol- 
anilic  acid  and  anilide,  see  A.  273,  70. 

Methyl-phenyl-glycin  C6H5(CH3)NCH2COOH,  by  heating  methyl- 
aniline  with  chloracetic  acid.  The  nitrile,  b.p.  266°,  is  obtained  by  the 
action  of  methyl-aniline  upon  formaldehyde-cyano-hydrin.  Amide, 
m.p.  163°  (B.  37,  2636). 

Dimethyl-phenyl-betamC6H5N(CH3)2CH2COO+H2O,  m.p.  124°,  by 
the  action  of  chloracetic  acid  upon  dimethyl-aniline.  On  heating  it  is 
transformed  into  Methyl-phenyl-glyeocoll-methyl  ester,  b.p.10  141°. 

o-Nitro-phenyl-glyein  NO2[2]C6H4[i]NHCH2CO2H,  m.p.  193°. 

a-Anilido-propionic  acid,  phenyl-alanin  C6H5NHCH(CH3)COOH, 
m.p.  162°,  is  obtained  from  its  nitrile,  the  transformation  product  of 
ethylidene-cyano-hydrin  with  aniline,  and  of  ethylidene-  aniline  with 
HCN  (B.  15,  2036  ;  23,  2010  ;  25,  2032).  a-Anilido-butyric  acid 
C6H5NHC(CH3)2COOH,  m.p.  185°;  nitrile,  m.p.  94°  (B.  39,  989). 
^-Anilido-propionic  ester,  b.p.ls  175°,  from  jS-iodo-propionic  ester  (B. 
29,  514).  j8-Anilido-aliphatic  acids  are  also  formed  by  attachment  of 
aniline  to  olefin-carboxylic  acids  (B.  36,  1262). 

Dianilido-acetic  acid  (C6H5NH)2CHCOOH,  m.p.  880-o,3°,  by  action 
of  aniline  upon  diacetyl-glyoxylic  acid.  It  easily  splits  off  i  mol. 
aniline  and  forms  anyl-glyoxylic  acid.  Heating  with  aniline  and  its 
chlorohydrate,  it  is  transformed  into  p,  p-diamido-diphenyl-acetic  acid 
(q.v.)  (B.  41,  3031,  4264). 

ANILINE  DERIVATIVES  OF  KETONE-CARBOXYLIC  ACIDS.  —  Pyro- 
racemic  anilide  CH3.CO.CONC6H5,  m.p.  104°.  Pyro-racemic  anilide 
chloride  CH3.CO.CC1  :  NC6H5,  m.p.  136°,  from  phenyl-carbylamine 
(q.v.)  and  acetyl  chloride  (A.  270,  299).  Anile-pyro-raeemic  acid 

C6H6N  :  C<>  ni.p.  122°  with  decomposition,  formed  from  aniline 


and  pyro-racemic   acid  in  ether   (A.    263,    126)  ;   passes   easily  into 
anile-uvitoninic  acid,  a  derivative  of  quinolin. 

Aceto-acetic  anilide  CH3CO.CH2CONHC6H5,  m.p.  85°,  formed  from 
aceto-acetic  ester  and  aniline  at  130°.  May  be  condensed  to  y-methyl- 
carbostyrile  (q.v.).  Anile-aceto-acetic  ester,  p-pfonyl-imido-butyric  ester 


ANILINE  DERIVATIVES   OF   CARBONIC  ACID          99 


C6H6N  :  c/CH»co«c»H",   or    6-Anilido-erotonic   ester 

\CH3 

b.p.16  165°,  from  aniline  and  aceto-acetic  ester  at  ordinary  tempera- 
tures. It  adds  HCN,  like  the  alkylidene-anilines,  which  speaks  for 
the  anile  formula  (B.  35,  2080).  By  alkalies,  and  acids,  it  is  split  up 
into  its  generators.  By  heating  at  ordinary  pressures  it  may  be  con- 
densed to  y-oxy-quinaldin  (q.v.)  and  phenyl-lutidone-carboxylic  acid 
(q.v.)  (B.  20,  947,  1398  ;  22,  83).  A  similar  behaviour  is  shown  by  the 
tolyl-amido-compounds. 

ANILINE  DERIVATIVES  OF  CARBONIC  ACID.  —  The  numerous  com- 
pounds of  this  class  are  treated  in  the  same  order  as  the  amine  and 
alkylamine  derivatives  of  carbonic  acid,  with  which  they  can  be  thus 
most  conveniently  compared  (see  Vol.  I.). 

Carbanilic  acid,  phenyl-carbaminic  acid,  is  unknown  in  the  free  state. 
Its  salts  are  obtained  by  the  action  of  very  dilute  alkalies,  or  alkaline- 
earth  hydroxides,  upon  phenyl  isocyanate.  On  acidulating,  even 
with  carbonic  acid,  the  salts  immediately  break  up  into  aniline  and 
CO2.  Their  esters,  the  Phenyl-urethanes,  are  obtained  :  (i)  from 
aniline  and  chloro-carbonic  acid  esters  (B.  18,  978)  ;  (2)  from  car- 
banile  and  alcohols  (B.  3,  654)  ;  (3)  from  urea  chlorides  and  alcohols 
(B.  24,  2108)  ;  (4)  from  benzoyl  azide  with  alcohols  (cp.  Vol.  I.,  and 
B.  29,  R.  181). 

Methyl  ester  C6H5NH.CO2CH3,  m.p.  47°,  with  sulphuric  acid  passes 
into  amido-sulpho-benzoic  ester  (B.  18,  980).  Ethyl  ester,  m.p.  52°. 

Urea  chlorides  are  formed  from  secondary  aromatic  bases,  and 
phosgene  in  benzene  solution  (B.  23,  424).  Phenyl-urea  chloride 
C6H5NH.COC1,  m.p.  59°,  and  bromide,  m.p.  67°  (B.  28,  R.  777). 
Methyl-phenyl-urea  chloride  (CH3)(C6H5)N.COC1,  m.p.  88°,  b.p.  280°. 
Diphenyl-urea  chloride  (C6H5)2N.COC1,  m.p.  85°.  With  benzene  and 
Al  chloride  they  pass  into  the  amides  of  benzoic  acid  (B.  20,  2118  ; 

24,  2108)  ;  cp.  the  syntheses  of  aromatic  carboxylic  acids.     Sodium, 
in  ether,  converts  di-p-tolyl-urea  chloride,  m.p.   102°,  into  a  tetra- 
substituted  oxamide  (B.  25,  1819,  1825). 

PHENYLATED  UREAS.—  Phenyl-urea  NH2CONHC6H5,  m.p.  144°  :  (i) 
from  cyanic  acid  and  aniline,  by  evaporation  of  a  solution  of  aniline 
chlorohydrate  with  potassium  isocyanate  (B.  9,  820)  ;  (2)  from  am- 
monia and  carbanile. 

Sym.  alkyl-phenyl-ureas  are  produced  by  the  action  of  aniline 
upon  isocyanic  ester,  or  of  phenyl  isocyanate  upon  alkylamine. 
Sym.  alkyl-phenyl-urea  C2H5NHCONHC6H5,  m.p.  99°. 

Asym.  alkyl-phenyl-ureas  from  alkyl-aniline  chlorohydrate  and 
potassium  isocyanate,  as  ethyl-phenyl  urea,  m.p.  62°. 

Sym.  diphenyl-urea,  carbanilide  CO(NHC6H5)2,  m.p.  235°,  b.p. 
260°,  formed  (i)  from  phosgene  and  aniline  (B.  16,  2301)  ;  (2)  from 
phenol  isocyanate  and  aniline  (A.  74,  13)  ;  (3)  from  s-diphenyl- 
sulpho-urea,  with  mercuric  oxide,  or  alcoholic  potash  (A.  70,  148)  ; 
(4)  from  aniline,  and  urea  at  170°  ;  (5)  from  monophenyl-urea,  and 
aniline  at  190°  (B.  9,  820)  ;  (6)  from  diphenyl  carbonate,  with  aniline, 
at  170°  (B.  18,  516)  ;  (7)  from  oxanilide,  by  heating  with  HgO  (M. 

25,  375)  ;    (8)  from  phenyl  isocyanate  and  water,  carbanilide  forms 
needles  of  a  silky  lustre,  easily  soluble  in  alcohol  and  ether,  slightly 
soluble  in  water. 


TOO  ORGANIC  CHEMISTRY 

as-Diphenyl-urea  C6H5NH.CO.N(C6H5)2,  m.p.  132°,  and  Tetra- 
phenyl-urea  (C6H5)2N.CO.N(C6H5)2,  m.p.  183°,  are  also  obtained 
from  diphenyl-urea  (B.  37,  963). 

CYCLIC  ALKYLENE-PHENYL-UREA  DERIVATIVES  (cp.  Vol.  I.).— 
Ethylene-phenyl-urea,  see  B.  24,  2192.  Trimethylene-phenyl-urea 
(B.  23,  1173). 

Ethylene-carbanilide  OO^J^S'-  m-P-  l83°  (B-  20>  784)-    Trl- 

\IN(C6H.6)CJdL2 

methylene-carbanilide,  m.p.  153°  (B.  20,  783). 

Ureids  of  the  Phenylated  Ureas  of  Mono-carboxylic  Acids. — Acetyl- 
phenyl-urea  CH3CONH.CO.NHC6H5,  m.p.  183°,  from  phenyl-urea 
with  acetic  anhydride  or  acetyl  chloride  (B.  8,  1181),  and  from 
phenyl  isocyanate  and  aceto-chloramide  (C.  1904,  I.  241).  Acetyl- 
carbanilide  C6H5NH.CO.N(COCH3)C6H5,  m.p.  115°  (B.  17,  2882). 

Ureids  of  Oxy-acids. — Glycol-phenyl-urea,  phenyl-hydanto'in,  m.p. 
194°,  from  phenyl-glycin  and  urea  at  160° ;  also  from  chloracetyl- 
urethane  with  aniline  (C.  1899,  II.  420  ;  /.  pr.  Ch.  2,  66,  231  ;  homo- 
logues,  see  C.  1906,  I.  461).  Diphenyl-hydantom,  m.p.  139°  (B.  25, 
2274). 

Phenylated  Pseudo-Urea  Derivatives  are  obtained  from  phenylated 
cyanamides,  with  alcohols  and  HC1,  as  are  the  imido-ethers  from 
nitriles. 

Methyl-phenyl-iso-urea  C6H5NHC(OCH3)  :  NH,  see  C.  1901,  II. 
919.  Ethyl  -  phenyl -iso- urea  C6H5NH.C(OC2H5)  :  NH,  b.p.19  138°. 
Ethyl-phenyl-methyl-iso-urea  C6H5N(CH3).C(OC2H5)  :  NH,  b.p.21  137° 
(B.  32,  1494;  33,  807).  Ethyl-diphenyl-iso-urea,  anilido-phenyl- 
carbaminic  ethyl  ether  C6H5N  :  C(OC2H5)NHC6H5,  an  oil,  b.p.2;)  200°. 
Methyl-ditolyl-iso-urea,  m.p.  48°,  b.p.n  199°,  generated  from  the  car- 
bodi-phenylimides  with  alcohol  at  i8o°-i9O°,  or,  better,  with  Na 
alcoholates,  give  with  HC1  addition  products.  By  acids  they  are 
easily  split  up,  but  with  alkalies  and  amines  they  are  stable  (C.  1899, 

I.  828).    Triphenyl-ehloro-carbamidin  CIC\^*H)S>  m-P-  92°,  formed 

by  action  of  PC15  upon  triphenyl-urea  ;  gives,  with  Na  ethylate, 
ethyl-iso-triphenyl-urea  C6H5N  :  C(OC2H5)N(C6H5)2,  m.p.  49°  (B. 
37,  964). 

Phenylated  Ureids  of  Carbonic  Acid. — Phenyl  -  allophanie  ester 
C6H6NH.CO.NHCO2C2H5,  m.p.  120°  (/.  pr.  Ch.  2,  32,  18).  Diphenyl- 
allophanic  acid,  see  B.  4, 246.  Sym.  Phenyl-biuret  C6H5.N  :  (CONH2)2, 
m.p.  192°,  from  phenyl-urea  and  PC13.  as-Phenyl-biuret  C6H5NH. 
CONH.CO.NH2,  m.p.  167°  (A.  352,  73).  Diphenyl-biuret  C6H5NH. 
CONH.CO.NHC6H5,  m.p.  210°  (B.  4,  265),  by  heating  phenyl-urea 
with  excess  of  phosgene.  Triphenyl-biuret,  m.p.  147°  (B.  4,  250). 

PHENYLATED  HYDROXYLAMINE  AND  HYDRAZIN  DERIVATIVES  OF 
UREA.— Phenyl-hydroxyl-urea  C6H5NH.CO.NHOH,  melts  at  140°  with 
decomposition,  formed  from  carbonile  and  hydroxylamine  chloro- 
hydrate  (A.  263,  264). 

Phenyl  -  semicarbazide,  phenyl  -  carbaminic  hydrazide  C6H5NH. 
CO.NH.NH2,  m.p.  120°,  isomeric  with  carbaminic  hydrazide  (q.v.), 
formed  (i)  from  its  acetyl  derivative,  m.p.  169°,  formed  on  boiling 
benzo-acid  with  aceto-hydrazide  in  acetone,  with  liberation  of  nitrogen  : 

C6H5CON8-i-NH2NH.COCH3=C6H5NH.CO.NHNH.COCH3-fN2; 


DERIVATIVES   OF  THIO-CARBAMINIC   ACIDS         101 

(2)  by  splitting  up  acetone  phenyl-semicarbazone  (CH3)2C  :  NNH. 
CO.NHC6H5,  which  is  easily  obtained  by  heating  aniline  with  acetone 
semi-carbazone  (B.  38,  831)  ;  (3)  from  phenyl-urea  with  hydrazin 
hydrate. 

Hydrazi-diearbon-anilide  C6H5NH.CO.NHNH.CONHC6H5,  m.p. 
245°,  from  phenyl-semicarbazide  by  heating  ;  it  is  oxidised  to  azo- 
di-carbon-anilide  C6H5NHCO.N  :  N.CONHC6H5,  m.p.  183°.  Phenyl- 
carbamic  azide  C6H5NH.CON3,  m.p.  104°.  In  contrast  with  other 
carboxylic  azides  it  is  split  by  water,  or  alcohol,  into  nitrogen  hydride, 
and  carbaminic  acid,  and  their  esters  (/.  pr.  Ch.  2,  58,  205). 

PHENYLATED  DERIVATIVES  OF  THE  THIO-CARBAMINIC  ACIDS  AND  OF 
THIO-UREA.— Phenyl-carbaminic  thio-methyl  ester  C6H5.NH.COSCH3, 
m.p.  83°,  and  ethyl  ester,  m.p.  74°,  fromdiphenyl-amidin-thio-alkylene, 
heated  with  dilute  sulphuric  acid  to  180°  (B.  15,  339). 

Phenyl-sulphur-ethane,  xanthogen-anilide,  thio-carbanilic  ethyl  ester 
C6H5NHCS.OC2H5  or  C6H5N  :  C(SH)OC2H5,  m.p.  71°,  from  phenyl- 
mustard  oil,  with  alcohol  at  120°,  or  with  alcoholic  potash.  With 
primary  and  secondary  bases  it  changes  into  phenyl-sulpho-ureas. 
On  distilling,  it  decomposes  into  phenyl-mustard  oil  and  alcohol 
(B.  15,  1307,  2164).  Oxidised  with  alkaline  potassium  ferri- 
cyanide,  it  passes  into  ethoxy-mustard  oil  and  ethoxy-benzo-thiazol 

C.H4<^;  C.OC2H5.  In  alkalies  it  dissolves  like  the  phenol-thio-ureas, 
and  makes  metallic  compounds  with  silver,  mercury,  and  lead. 

Phenyl-imido-thio-carboxylic  acid  C6H5N :  c/^   [  is  unknown.     Its 

\brl 

ethers  are  formed  by  the  action  of  alkyl  iodides  upon  the  metallic  com- 
binations of  the  phenyl-sulphur-ethanes  and  upon  the  free  phenyl- 
sulphur-ethanes.  A  similar  behaviour  is  shown  by  the  thio-acetanilides 
and  the  phenyl-sulpho-ureas.  Ethyl-methyl  ester  C6H5N : 

b.p.  260°.     Diethyl  ester,  m.p.  30°  (A.  207,  148). 

PHENYL-DITHIO-CARBAMINIC  ACID  DERIVATIVES. — The  free  acid, 
precipitated  from  the  potassium  salt,  decomposes  into  aniline  and 
SC2.  Its  potassium  salt,  C6H5NHCSSNH4,  is  formed  from  aniline, 
CS2,  and  aqueous  ammonia  (/.  pr.  Ch.  2,  65,  369).  For  further 
aryl-dithio-carbaminates,  see  B.  40,  2970. 

Phenyl-dithio-carbaminie  methyl  ester,  m.p.  87°,  and  phenyl-dithio- 
urethane,  m.p.  60°,  formed  by  heating  phenyl-mustard  oil  with  mer- 
captans,  which  split  again  at  higher  temperatures.  They  dissolve  in 
alkalies. 

Ethyl-phenyl-dithio-urethane  (C2H5)C6H5NCSSC2H5,  m.p.  68°,  b.p. 
310°,  from  diphenyl-pseudo-ethyl-thio-urea,  with  CS2  at  160°.  This 
compound  is  very  stable,  does  not  dissolve  in  alkalies,  and  is  not  freed 
from  sulphur  by  HgO,  or  alkaline  lead  solutions.  On  heating  with 
methyl  iodide  the  phenyl-dithio-urethanes,  like  phenyl-sulphur-ethane, 
and  diphenyl-sulpho-urea,  form  addition  products. 

Phenyl-thiuram-sulphide  S(CSNHC6H5)2,  m.p.  137°  (B.  24,  3023). 

Methyl-phenyl-thio-carbamine  chloride  (CH3)C6H5N.CSC1,  m.p.  35°, 
from  methyl-aniline  and  thio-phosgene  (B.  20,  1631). 

PHENYL  -  SULPHO  -  UREAS. — Phenyl  -  sulpho  -  urea,  sulpho-carbanile- 
amide  NH2CSNHC6H5,  m.p.  154°, from  phenyl-mustard  oil  and  ammonia, 


102  ORGANIC   CHEMISTRY 

or  from  ammonium  phenyl-dithio-carbaminate  with  Pb  carbonate 
(/.  pr.  Ch.  2,  65,  369).  On  boiling  with  silver  nitrate  it  passes  into 
phenyl-urea  ;  with  HgO  into  phenyl  cyanamide  ;  with  bromine,  in 
chloroform  solution,  phenyl- thio-urea  gives  the  bromide  of  a  disulphide 
C6H5N  :  C(NH2)SSC(NH2)  :  NC6H5,  m.p.  128°  (B.  34,  3130)  ;  with 
methyl  iodide  it  combines  to  form  the  iodo-hydrate  of  n-phenyl- 
methyl-pseudo-thio-urea.  With  acetic  anhydride  the  unstable  as- 
phenyl-aeetyl-thio-urea,  m.p.  145°,  is  formed  at  first,  which,  on  heating 
above  the  m.p.,  is  transformed  into  the  symmetrical  variety 
C6H5.NH.CSNH.COCH3,  m.p.  171°  (C.  1902,  I.  1300;  1908,  I.  1541). 
These  reactions  are  generally  applicable  to  aromatic  thio-ureas. 

s-Diphenyl-sulpho-urea,  sulpho-carbanilide  CS(NHC6H5)2,  m.p. 
151°,  brilliant  colourless  flakes,  easily  soluble  in  alcohol  (B.  19,  1821). 
Formed  :  (i)  from  phenyl-mustard  oil,  and  aniline,  in  alcoholic  solution  ; 
(2)  by  boiling  aniline  with  CS2,  and  withdrawing  SH2.  The  formation 
of  the  urea  is  greatly  favoured  by  the  addition  of  sulphur  or  hydrogen 
peroxide  (B.  39,  4369). 

Reactions  of   sulpho-carbanilide  are  known  in  great  number  : — 

(1)  Iodine  converts  it  into  sulpho-carbanile  and  a-triphenyl-guanidin. 

(2)  Boiling  with  concentrated  HC1  splits  it  up  into  phenyl-mustard  oil, 
and  aniline  (B.  16,  2016).     (3)  Extraction  of  sulphur  with  HgO  pro- 
duces the  symmetrical  diphenyl-urea.     (4)  In  benzene  solution  with 
HgO,  carbo-diphenyl-imide  is  formed.     (5)  With  ammonia,  and  Pb2O, 
we  obtain  diphenyl-guanidin  ;   with  aniline,  triphenyl-guanidin  ;   with 
hydroxylamine,     oximido-diphenyl-urea     (C6H5NH)2C  :  NOH  ;      with 
hydrazin   hydrate,    in    the    presence    of    alkalies,    amido  -  diphenyl- 
guanidin,  etc. 

Phenyl-  and  symmetrical diphenyl-sulpho-ureas,  dissolved  in  alkalies, 
form  salts  in  which  the  metal  adheres  to  the  sulphur  (cp.  thio- 
acetanilide). 

As  to  alkyl-phenyl-sulpho-ureas,  see  B.  17,  2088  ;  23,  815  ;  26, 1686. 
as-Diphenyl-sulpho-urea,  m.p.  198°,  from  diphenyl-amine-rhodanide 
(B.  26,  R.  607).  Triphenyl-thio-urea,  m.p.  152°  (B.  17, 2092).  Tetra- 
phenyl-thio-urea  (C6H5)2N.CS.N(C6H5)2,  m.p.  195°,  is  generated  by 
heating  triphenyl-guanidin  with  CS2  (B.  15,  1530). 

Phenyl-sulpho-hydantoins. — While  the  product  formerly  taken  for 
thio-  or  sulpho-hydantoin  has  turned  out  to  be  pseudo-hydantoin, 
aromatic  phenyl-sulpho-hydantoins  have  become  known  (B.  24,  3278). 

Phenyl-a-methyl-sulpho-hydantoin  SC<^HS)  £O 

\  .N  H CrlCrl3 

m.p.    184°,   by   melting  phenyl-mustard   oil 

x-g 

and  alanin  together. 

PHENYLATED  PSEUDO  -  SULPHO  -  UREA  DERIVATIVES. — Such  com- 
pounds are  obtained,  e.g.,  from  phenyl-  and  symmetrical  diphenyl- 
sulpho-urea  by  the  action  of  alkyl  iodides  and  caustic  potash,  or, 
better,  by  heating  with  alkyl  iodides  or  bromides  in  alcoholic  solution 
(B.  25,  48).  In  the  latter  case  we  get  the  iodo-hydrate  of  a  base 
which  is  precipitated  by  sodium-carbonate  solution,  and  may  again 
add  halogen  alkyl.  On  heating  with  alcoholic  potash,  the  imido- 
phenyl-carbaminic  thio-ester  splits  off  mercaptans. 

n-Phenyl-methyl-pseudo-thio-urea,    imido-phenyl-carbaminic    thio- 


PHENYLATED   DERIVATIVES   OF  THIO-UREA        103 

methyl  ester  C«H5^^CSCH3,  m.p.  71°.  Sym.  diphenyl  -  pseudo  - 
methyl  -  thio  -  urea,  phenyl-imido-phenyl-carbaminic  thio-methyl  ester 

;")C.SCH3,  m.p.  110°.     On  heating  with  dilute  sulphuric  acid, 
C6H5N-^ 

both  yield  phenyl-carbaminic  thio-methyl  ester,  which  proves  the 
adhesion  of  the  methyl  to  sulphur.  With  alcoholic  ammonia  at  120°, 
phenyl-guanidin  and  mercaptan  are  formed.  Heated  with  CS2,  the 
diphenyl-pseudo-methyl-thio-urea  passes  into  phenyl-mustard  oil  and 
phenyl-dithio-carbaminic  ester  (B.  15,  343).  Phenyl-pseudo-methyl- 
thio-urea  gives,  with  acetyl  chloride,  an  as-acetyl  derivative,  m.p.  86°, 
which,  on  heating,  passes  into  the  symmetrical  form  (C.  1902,  I.  1300). 
With  CH2I2,  CH2Br.CH2Br,  and  CH2Br.CH2.CH2Br,  diphenyl- 
thio-urea  gives  cyclic  derivatives  of  pseudo-sulpho-urea  (B.  21,  1872)  : 

C.H6N:C/N<C'H*>>CH2    C,H5N  :  C/N(C.H5).CH2    ^^  .  c  /N(C  HS).CH, 
\S  '  \S  -  Cri2  ^S  —  CH2~Cri2 

The  ethylene  derivative  contains  the  so-called  thi-azol  ring  ;  the  tri- 
methylene  derivative,  the  next  higher  penthi-azol  ring,  which  is  homo- 
logous with  the  thi-azol  ring. 

Triphenyl-pseudo-thio-urea  (C^2^)c.s.c6H5,  m.p.  i85°-i88°,  by 

transformation  of  triphenyl-chloro-carbamidin  with  sodium-thiophenol 
(B.  36,  965). 


Pseudo-phenyl-thiohydantoinic  acid  HN  :  c/:5    .  m.p.   150° 

\SCH2CO2H 

(C.  1898,  II.  296),  and  Pseudo  -  diphenyl  -  thiohydantoinic  acid 
C6H5N  :  C<^(^6C^)5  H>  formed  from  phenyl-  and  diphenyl-thio-urea  with 

chloracetic  acid.  By  rejecting  water,  these  compounds  pass  into 
pseudo-hydantoins  :  unstable  Pseudo  -  phenyl  -  thiohydantoln 
HN  .  c</N(CeH5).co  ^  mp  I48o^  from  Rhodan-acetanilide  CNS.CH2 

CONHC6H5,  m.p.  91°,  by  heating  to  100°,  and  on  further  heating  it 
forms  a  stable  isomeric  C6H5N  :  C/^H'^  m.p.  178°  ;  on  boiling  with 

NO 


HC1,  the  latter  splits  up,  to  form  pseudo-phenyl-thiohydantomic  acid, 
and,  subsequently,  forms  a  mixture  of  aceto-iso-thiocyanic  acid  and 
phenyl-aceto-iso-thiocyanic  acid  co/^^^£°  (C.  1902,  II.  792). 
The  latter  is  also  formed  by  the  breaking  up  of  Pseudo-diphenyl- 
thiohydantoln  C6H5N  :  c<^c«Hs)-<;O  ,  m.p.  I76°. 

\o  -  v^.H-2 

HYDROXYLAMINE  AND  HYDRAZIN  DERIVATIVES  OF  THE  PHENY- 
LATED THIO-UREAS.  —  Phenyl  -  hydroxyl  -  thio  -  urea  C6H5NHCSNHOH, 

m.p.  106°,  from  hydroxylamine  and  phenyl-mustard  oil,  is  easily 
decomposed  into  water,  sulphur,  and  phenyl  cyanamide  (B.  24,  378). 

Phenyl-thio-semiearbazide,  phenyl-thiocarbaminic  hydrazide  C6H5 
NH.CS.NH.NH2,  m.p.  140°,  from  phenyl-mustard  oil  and  hydrazin 
hydrate  ;  or  from  diphenyl-sulpho-urea  with  hydrazin  hydrate  in 
alcoholic  solution  (B.  33,  1058).  With  aldehydes  it  is  transformed  into 
phenyl-thio-semicarbazones.  Its  acyl  derivatives  easily  yield  thio- 
bi-azolins  (q.v.)  with  rejection  of  water.  A  peculiar  behaviour  is  shown 
by  the  benzoyl  derivative,  which,  when  deprived  of  H2O  by  means 


104  ORGANIC   CHEMISTRY 

of  acetyl  chloride,  yields  a  phenyl-imido-phenyl-thio-bi-azolin  ;  or  by 
means  of  benzoyl  chloride,  a  diphenyl-triazol  mercaptan  (B.  29,  2914)  : 

C6H6N  :  c/NH~N  ^-C6H5NH.CS.NHNH.COC6H5~>C6H5N  <C(C6H5)  :  N. 

XS  -  C.C6H6  HSC  --  N 


Phenylated  Guanidin  Derivatives.—  Phenyl-guanidin  NH  :  c 

m.p.  60°,  from  cyanamide  and  aniline  chlorohydrate.  By  an  analogous 
process  we  obtain  Diphenyl-guanidin,  melanilin  NH  :  C(NHC6H5)2, 
m.p.  147°,  from  cyananilid  (p.  106)  and  aniline  chlorohydrate,  and  also 
by  the  action  of  C1CN  upon  dry  aniline.  Both,  like  guanidin  itself,  are 
mono-acid  bases.  CS2  decomposes  diphenyl-guanidin  into  diphenyl- 
sulpho-urea  and  KSCN. 

a-Triphenyl-guanidin  C6H5N  :  C(NHC6H5)2,  m.p.  143°,  formed  on 
heating  diphenyl-urea  or  diphenyl-sulpho-urea,  by  itself,  or  with 
copper,  to  140°,  also  by  warming  the  alcoholic  solution  of  diphenyl- 
sulpho-urea  and  aniline  with  Pb(OH)2  (C.  1902,  II.  795)  or  HgO,  or 
by  boiling  it  with  iodine  solution.  CS2  splits  it  up  into  diphenyl- 
sulpho-urea  and  phenyl-mustard  oil. 

j8-Triphenyl-guanidin  NH  :  c/^*1^,  m.p.  131°,  has  been  obtained 

-^  Jriv^g  Jri-c 

by  heating  cyano-anilide  with  diphenyl-amine  chlorohydrate.  CS2 
breaks  it  up  into  diphenyl-amine,  phenyl-mustard  oil,  and  hydrogen 
sulpho-cyanide. 

Sym.  Tetraphenyl-guanidin  NH  :  C[N(C6H5)2]2,  m.p.  130°,  by  action 
of  CNC1  upon  diphenyl-amine  at  170°. 

as-Tetraphenyl-guanidin  C6H5N  :  c/^1^?2,  m.p.  140°,  and  Penta- 

\JNrlC6rl5 

phenyl-guanidin  C6H5N  :  C[(NC6H5)2]2,  m.p.  179°,  obtained  by  trans- 
formation of  aniline  and  diphenyl-amine,  respectively,  with  triphenyl- 
chloro-carbamidin  (B.  36,  964). 

Amido-diphenyl-guanidin  C6H5N  :  C(NHC6H5)NH.NH2,  m.p.  99°, 
formed  from  diphenyl-thio-urea  with  hydrazin  hydrate  in  alcoholic 
alkaline  solution  (without  alkali,  phenyl-thio-semicarbazide  is  formed)  ; 
it  is  a  strong  base.  With  anilines  it  gives  addition  products;  with 
carboxylic  acids,  and  with  HNO2,  it  condenses  to  triazol  and  tetrazol 
derivatives  respectively  (B.  33,  1058  ;  35,  1710,  1716). 

Diphenyl-oxyguanidin,  oximido-diphenyl-urea  HON  :  C(NHC6Hs)2, 
m.p.  151°,  from  diphenyl-thio-urea  with  alcoholic  hydroxylamine 
solution  and  PbO  (B.  32,  2238). 

PHENYL-BIGUANIDES.—  a-Phenyl-biguanide    ™*  ")C.NH.C<^ 

JNrl2/  \JNrlL/6rl5 

chlorohydrate,  m.p.  237°,  by  heating  aniline  chlorohydrate  with 
dicyano-diamide  (C.  1905,  I.  730  ;  II.  1530).  a-Diphenyl-biguanide 

™  /C-NH-C\NH<^H5'  m'p'  l67°'  from  sulpho-carbanilide  and 
guanidin  (see  A.  310,  335  ;  B.  34,  2594). 

G.  Phenylated  Nitriles  and  Imides  of  Carbonic  Acid. 

Phenyl  isocyanate,  carbanile  C6H5N  :  CO,  b.p.  166°,  a  liquid  with  an 
acrid  odour,  formed  (i)  by  distillation  of  oxanilides  ;  (2)  by  distillation 
of  carbanilic  esters  with  P2O5  (B.  25,  2578)  ;  (3)  from  diazo-benzol 


NITRILES   AND    IMIDES   OF   CARBONIC   ACID          105 

salts  by  the  action  of  potassium  cyanate  and  copper  (B.  25,  1086)  ; 
(4)  from  phenyl-mustard  oil  C(}H5.N  :  CS  by  heating  with  HgO  to  170° 
(B.  23,  1536)  ;  (5)  by  the  action  of  thionyl  chloride  upon  benzo- 
hydroxamic  acid  (q.v.)  in  benzene  solution  (C.  1907,  I.  633)  ;  (6)  by 
warming  benzoyl  azide  (q.v.)  or  benzoyl  chloride  and  sodium  azide, 
in  neutral  solvents  (B.  42,  3133,  3359)  ;  (7)  by  the  action  of  HNO2 
upon  monophenyl-urea,  with  excess  of  HC1  (C.  1906,  II.  510)  ;  (8)  by 
action  of  phosgene  upon  aniline,  or  its  chlorohydrate.  By  methods 
6,  7,  and  8  a  series  of  substituted  carbaniles  could  also  be  prepared 
(C.  1900,  I.  30  ;  1902,  II.  554). 

Carbanile  behaves  very  similarly  to  the  isocyanic  alkyl  esters.  With 
water  it  becomes  diphenyl-urea,  with  alkalies  it  forms  salts  of  phenyl- 
carbaminic  acid  (/.  pr.  Ch.  2,  73,  177).  With  alcohols  and  phenols  it 
combines  to  form  carbanilic  esters,  a  reaction  useful  for  proving  the 
presence  of  alcoholic  hydroxyls  (B.  18,  2428,  2606).  It  reacts  similarly 
with  the  SH  group,  and  with  the  hydroxyl  group  of  the  aldoximes  and 
ketoximes.  With  the  groups  C  :  O  and  C  :  S  carbanile  does  not  react 
(B.  25,  2578)  ;  but  it  unites  with  I,  3-dicarbonyl  compounds,  like 
acetyl-acetone,  aceto-acetic  ester,  malonic  ester,  etc.,  in  the  presence 
of  small  quantities  of  alkali,  to  form  C-carbanilide  derivatives,  e.g. 
C6H5NHCOCH(COCH3)CO2R,  which,  in  contrast  with  O-carbanilide 
derivatives,  have  an  acid  nature  and  show  the  ferric  chloride  reaction 
(B.  37,  4627). 

With  NH3  we  obtain  phenyl-urea.  With  diazo-amido-compounds 
C6H5N2NHR'  mixed  ureas  are  formed,  in  which  the  hydrogen  of  the 
NH  group  is  represented  by  the  residue — CONHC6H5  (B.  22,  3109). 
For  action  upon  dicarboxylic  acids,  see  C.  1906,  I.  1017  ;  upon  oxy- 
acids,  C.  1903,  I.  564. 

All  these  phenyl-cyanate  reactions,  if  taking  place  in  the  absence 
of  a  solvent,  usually  take  place  normally  without  transpositions,  and 
are  therefore  suitable  for  determinations  of  constitution  (B.  23,  2179  ; 
38,  22).  By  heating  of  carbanile  with  benzene  and  A12C16,  we  obtain 
benzoyl  anilide  (see  synthesis  of  benzoic  acid). 

o-,  m-,  p-Tolyl  isocyanate  CH3C6H4N  :  CO,  m.p.  186°,  183°,  187°, 
by  method  7. 

Triphenyl  isocyanurate  C3O3(NC6H5)3,  m.p.  275°,  formed  (i)  by 
polymerisation  of  carbanile,  on  heating  with  potassium  acetate  (B. 
18, 3225)  ;  (2)  by  the  action  of  concentrated  HC1  at  150°  upon  triphenyl- 
iso-melamin. 

Triphenyl  cyanurate  C3N3(OC6H5)3,  m.p.  224°,  by  the  action  of 
cyanic  or  cyanuric  chloride  upon  sodium  phenol. 

Isocyano-phenyl  chloride,  phenyl-imido-carbonyl  chloride  C6H5N  : 
CC12,  b.p.  209°,  a  colourless  oil,  of  acrid  odour,  formed  from  phenyl 
isocyanide  and  chlorine  in  chloroform  solution  ;  also  from  phenyl- 
mustard  oil  and  chlorine  (B.  26,  2870).  With  aniline  it  passes  into 
a-triphenyl-guanidin  (A.  270,  282). 

Phenyl  sulpho-cyanide  C6H5S.CN,  b.p.  131°,  is  isomeric  with  phenyl- 
mustard  oil  and  methenyl-amido-thio-phenol  C6H4<^S^;CH  (see  Amido- 

thio- phenols).  Formed  by  action  (i)  of  HSCN  upon  diazo-benzol 
sulphate,  and  (2)  of  cyanogen  chloride  upon  lead  thio-phenol.  It 
behaves  like  the  alkyl  sulpho-cyanic  esters. 


106  ORGANIC  CHEMISTRY 

Phenyl-mustard  oil,  sulpho-carbanile,  iso-thio-cyanic  phenyl  ester 
C6H5N  :  CS,  b.p.  222°,  is  a  colourless  liquid  smelling  of  mustard  oil. 
Formed  (i)  from  diphenyl-sulpho-urea  by  splitting  off  aniline  with 
hot  sulphuric  acid  or  concentrated  HC1,  or,  best,  with  concentrated 
phosphoric  acid  (B.  15,  986)  ;  (2)  besides  triphenyl-guanidin,  from 
diphenyl-sulpho-urea  with  alcoholic  iodine  solution  ;  (3)  by  action  of 
thio-phosgene  upon  aniline  ;  (4)  by  action  of  HNO2  upon  phenyl- 
sulpho-urea  (C.  1906,  II.  510). 

Heating  with  copper  or  zinc  dust  converts  it  into  benzo-nitrile, 
the  phenol-iso-nitrile  first  formed  transposing  into  benzo-nitrile  at  the 
temperature  of  reaction.  Heated  with  dry  alcohols  to  120°,  or  in 
alcoholic  potash  solution,  it  becomes  phenyl-sulphur-ethane  (C.  1900, 
I.  289) ;  with  ammonia,  aniline,  hydrazin,  or  hydroxylamine  it  becomes 
phenyl-sulpho-urea  ;  with  chlorine,  iso-cyano-phenyl  chloride.  With 
sodium-malonic  ester  it  combines  to  form  thio-carbanilino-malonic 
ester  (C.  1908,  I.  1929).  Combines  with  aromatic  hydrocarbons, 
phenol  ethers,  and  thio-phenol  ethers  under  the  influence  of  Al  chloride 
to  thio-anilides  of  carboxylic  acids  (/.  pr.  Ch.  2,  59,  572). 

With  alkyl-magnesium  iodides  (Vol.  I.),  phenyl-mustard  oil  com- 
bines to  form  salts  which,  on  decomposition  with  acids,  yield  thio- 
anilides  of  fatty  acids,  e.g.  NH.CS.CH3  (B.  36,  585).  By  reduction 
with  zinc  and  HC1,  it  is  decomposed  into  aniline  and  thio-formaldehyde, 
but  by  Al  amalgam  into  sulpho-carbanilide  and  methyl  mercaptan 
(B.  34,  2033). 

PHENYLATED  CYANAMIDE  DERIVATIVES  (cp.  Cyanamide,  Vol.  I.)-— 
Phenyl-cyanamide,  cyananilide  C6H5NHCN-f-JH2O,  m.p.  47°,  loses 
its  water  of  crystallisation  in  the  drying  oven,  liquefies,  and  re-forms 
the  hydrate  in  air.  On  standing,  or  heating,  it  polymerises  to  tri- 
phenyl-iso-melamine.  Formed  (i)  by  conducting  CNC1  into  an  ether 
solution  of  aniline  ;  (2)  by  heating  phenyl-sulpho-urea,  with  HgO  or 
lead  acetate  and  alkali  (B.  18,  3220).  It  is  easily  soluble  in  alcohol 
and  ether,  and  combines  again  with  H2S  to  form  phenyl-sulpho-urea. 
For  substituted  cyananilides,  see  C.  1905,  I.  441  ;  1907,  I.  543. 

Phenyl-methyl  cyanamide  C6H5N(CH3)CN,  m.p.  30°,  from  cyan- 
anilide, ICH3  and  NaOC2H5  (B.  33,  1383)  ;  or  from  mono-,  or  even 
dimethyl-aniline,  with  CNBr.  The  latter  process  has  yielded  a  number 
of  homologous  phenyl-alkyl  cyanamides  (B.  33,  2728  ;  35,  1279). 

Diphenyl  cyanamide  (C6H5)2NCN,  m.p.  73°,  from  as-diphenyl-thio- 
urea  with  ammonia,  and  silver  solution  (B.  26,  R.  607). 

Carbo-diphenyl-imide  C6H5N  :  C  :  NC6H5,  a  thick  liquid,  b.p.30  218°. 
On  distillation,  at  ordinary  pressures,  carbo-diphenyl-imide  transposes 
into  a  polymeric  modification  melting  at  161°,  and  having  triple 
molecular  weight  (B.  28,  1004). 

Carbo-diphenyl-imide  is  formed  (i)  by  action  of  HgO  upon  a 
solution  of  symmetrical  diphenyl-sulpho-urea  in  benzene ;  (2)  by 
distillation  of  a-triphenyl-guanidin  ;  (3)  by  heating  phenyl  isocyanate 
to  180°,  with  rejection  of  CO2  (B.  41,  1125).  With  water  it  combines 
to  form  a  symmetrical  diphenyl-urea ;  with  H2S,  to  a  symmetrical 
diphenyl-sulpho-urea ;  with  aniline,  to  a-triphenyl-guanidin  ;  with 
phenol,  to  diphenyl-iso-urea  phenyl  ether  (C.  1909,  II.  426).  On  con- 
ducting HC1  into  a  benzene  solution  of  carbo-diphenyl-imide  we 
obtain  the  compounds  C6H5N  :  CC1.NHC6H5  and  C6H5NH.CC12.NHC6H5 


ANILIDES   OF   DICARBOXYLIC  ACIDS  107 

(B.  28,  R.  778)  ;  with  malonic  ester,  and  similar  bodies,  carbo-diphenyl- 
imide  forms  substances  like  C6H5NH.C(NC6H5).CH(CO2C2H5)2  (B.  32, 
3176).  It  also  combines  with  aliphatic  and  thio-aliphatic  acids  to 
form  compounds  like  acetyl-diphenyl-urea  and  acetyl-diphenyl-thio-urea 
(J.  pr.  Ch.  2,  64,  261). 

Alkyl-magnesium  iodides  give  Mg  compounds,  which,  with  acids, 
decompose  into  diphenyl-amidines. 

Carbodi-p-tolyl-imide  (C7H7N)2C,  m.p.  57°-59°. 

Triphenyl-melamine,  triphenyl-cyanuro-triamide 

r  H  N  •  r/NH.C(NHC.H.K 
C6H5N    C  > 


m.p.  228°,  by  the  action  of  cyanuro-chloride  upon  aniline,  or  by  heating 
tri-thia-cyanuric  methyl  ester  with  aniline  to  25O°-30O°  (B.  18,  3218). 

Hexaphenyl-melamine,  C3N3[N(C6H5)2]3,  m.p.  300°,  from  cyanuric 
chloride  and  diphenyl-amine. 

Triphenyl-isomelamine    NH  • 


by  polymerisation  of  phenyl  cyanamide  ;  also  by  the  action  of 
cyanogen  bromide  upon  aniline.  On  heating  with  HC1  the  NH  groups 
are  successively  replaced  by  oxygen,  with  final  formation  of  isocyanuric 
triphenyl  ester. 

Besides  the  normal  and  iso-triphenyl-melamines,  unsymmetrical 
triphenyl-melamines  are  also  known  (B.  18,  228). 

ANILIDES  OF  DICARBOXYLIC  ACIDS.  —  Oxalic  acid  and  its  homo- 
logues,  as  well  as  the  unsaturated  dicarboxylic  acids,  form  anilic  acids 
and  dianilides,  corresponding  to  the  amino-acids  and  the  diamides. 
Those  dicarboxylic  acids  capable  of  forming  anhydrides  yield  also 
aniles  or  phenyl-imides  corresponding  to  the  imides. 

The  anilic  acids  are  obtained  (i)  by  partial  decomposition  of  the 
dianilides  ;  (2)  on  mixing  the  ethereal  or  chloroform  solutions  of  the 
anhydrides  with  aniline  (B.  20,  3214)  ;  (3)  by  the  breaking  down  of 
the  aniles.  The  latter  are  re-formed  from  the  anilides  by  treatment 
with  PC15  (B.  21,  957),  or  with  acetyl  chloride.  They  also  appear 
on  heating  the  acids  or  anhydrides  with  aniline.  A  large  number  of 
these  compounds  have  been  mentioned  in  the  first  volume,  in  connection 
with  their  respective  acids. 

PHENYL-AMINE  DERIVATIVES  OF  OXALIC  ACID.  —  Oxanilic  acid  C6H5 
NH.CO.CO2H,  m.p.  150°  (see  A.  270,  295,  for  an  isomeric  acid,  m.p. 
210°),  is  formed  by  heating  oxalic  acid  and  aniline  to  140°  (B.  23, 
1820),  by  the  action  of  alcoholic  potash  upon  oxanilide,  and  when 
citracon-anilic  acid  is  oxidised  with  MnO4K  (B.  23,  747).  Methyl 
ester,  m.p.  114°  (A.  254,  10)  ;  ethyl  ester,  66°  ;  chloride,  82°  (B.  23, 
1823). 

Oxanilic  acid  nitrile,  cyano-formanilide  C6H5NHCOCN,  m.p.  120°, 
prepared  by  adding  hydrocyanic  acid  to  phenyl  isocyanate.  On 
heating  above  its  m.p.  it  decomposes  into  its  constituents.  On  careful 
saponification  it  passes  into  phenyl-oxamide  C6H5NHCOCONH2, 
m.p.  224°  ;  by  addition  of  H2S  it  becomes  oxanilic  acid  thio-amide 
C6H5NHCOCSNH2,  m.p.  176°  (B.  38,  2977). 

Oxanilide   (CONHC6H5)2,   m.p.   245°,  is   also   obtained  from  the 

isomeric  glyoxime-N-phenyl-ether   c6H6Nc  —  >CH—  CH<-  —  /NC6H5)  m.p. 

\CK  XX 


io8  ORGANIC   CHEMISTRY 

183°,  by  transformation  with  glacial  acetic  acid  and  acetic  anhydride. 
The  latter  is  formed  (i)  from  nitroso-benzol  with  diazo-methane  ; 
(2)  from  j8-phenyl-hydroxylamine  with  glyoxal  or  with  formaldehyde 
(B.  30,  2871  ;  35,  1833). 

A  number  of  sulphuretted  derivatives  of  oxanilic  acid  are  obtained 
by  action  of  P2S5  upon  the  corresponding  compounds  of  oxalic  acid. 
They  are  distinguished  by  their  intense  yellow  or  reddish-yellow 
colour  (B.  37,  3708). 

Thio-oxanilic  acid  C6H5NHCSCOOH,  m.p.  102°.  Thio-oxanilide 
C6H5NHCS.CONHC6H5,  m.p.  145°.  Both  compounds  are  easily 
converted  into  derivatives  of  benzo-thiazol  (q.v.). 

Thio-oxanilic  thio-amide  C6H5NHCS.CSNH2,  m.p.  98°. 

Dithio-oxanilide  (CSNHC6H5)2,  m.p.  134°,  is  also  generated  by  the 
action  of  H2S  upon  oxanilide  chloride  (C.  1902,  II.  121). 

Tetra-p-tolyl-oxamide  [CON[4](C6H4[i]CH3)2]2,  m.p.  127°,  from 
p-ditolyl-urea  chloride. 

Oxanilide  dioxime  [C  :  (NOH)(NHC6H5)]2,  m.p.  215°  with  decom- 
position, from  dibromo-glyoxime  peroxide.  Semi-ortho-oxalic-dianilido- 
methyl  ester  CO2CH3.C(NHC6H5]2OCH3,  and  Phenyl-imido-oxalie 
dimethyl  ester  CO2CH3C  iNCgHgfOCHg),  m.p.  111°,  from  dichlor-oxalic 
ester  (B.  28,  60)  and  aniline.  Phenyl-oxaminic  diphenyl-amidine 

C6H6NHCO.C^^?JH5,   m.p.   134°,  from   semi-ortho-oxalic    ester    and 

vWCxjtlg 

from  oxanile  dichloride  acid  ethyl  ester  (A.  184,  268). 

The  corresponding  nitrile,  carbo  -  diphenyl  -  imide  -  hydrocyanide, 
NC.C(NHC6H5)  :  NC6H5,  generated  from  carbo-diphenyl-imide  by  union 
with  hydrocyanic  acid,  yields,  with  yellow  Am2S,  a  thiamide  NH2CS. 
C(NHC6H5)  :  NC6H5,  which  can  be  easily  converted  into  isatin  anilide 
and  indigo. 

o-Nitro-oxanilic  acid,  m.p.  112°. 

o-Dinitro-oxanilide,  see  A.  209,  369. 

Malon-anilic  acid  C6H5NHCOCH2CO2H  melts  at  132°,  with 
decomposition  into  CO2  and  acetanilide.  It  is  also  formed  by  a 
peculiar  transposition  of  sodium  acetyl-phenyl-carbaminate  from 
sodium  acetanilide  with  CO2,  on  heating  to  140°  (B.  18,  1359). 
With  PC15  it  forms  trichloro-quinolin  (B.  18,  2975). 

Malon-anilide  CH2(CONHC6H5)2,  m.p.  223°  (B.  17,  135,  235). 
Malonic  methyl-anilide  (B.  31,  1826).  Dithio-malon-anilide  CH2 
(CSNHC6H5)2,  m.p.  149°,  from  malon-anilide,  with  P2S5  (B.  39,  3300). 

Succin-anilic  acid,  succin-anile,  see  Vol.  I. :  Succinimide. 

Fumar-anilic  acid,  fumar-anilic  chloride,  fumaric  dianilide,  malein- 
anilic  acid,  malein-anile,  dichloro-malein-anile,  dichloro-malein-anile 
dichloride,  dichloro-malein  -  anile  -  dimethyl  ester,  dichloro  -  malein- 
imidanile,  diehloro-malein-dianile,  citracon-anilic  acid,  citracon-anile, 
itacon-anilic  acid,  see  Vol.  I.  in  connection  with  the  corresponding 
carboxylic  acids. 

ANILIDO  -  CARBOXYLIC  ACIDS. — Anilido  -  malonic  acid  C6H5NH. 
CH(COOH)2  melts  at  119°,  with  rejection  of  CO2,  and  formation  of 
phenyl-glycin.  Its  esters  (methyl,  m.p.  68° ;  ethyl,  m.p.  45°)  are 
formed  from  the  bromo-malonic  esters,  with  aniline,  and  behave  like 
malonic  esters  in  having  their  C  atom  alkylated,  and  in  forming 
addition  products  with  a,  j8-olefin-carboxylic  ester,  etc.  (see  Vol.  I.). 


ANILINE   HALOIDS  109 

On  heating  to  26o°-265°  they  condense  to  indoxyl-acetic  esters, 
which  can  easily  be  converted  into  indigo  (B.  35,  54).  For  the  effect 
of  nitrous  acid,  see  C.  1902,  II.  1318. 

For  phenyl-asparagin-anilic  acid,  phenyl-asparagin-anile,  3-anilido- 
pyro-tartaric  acid,  and  pseudo-itaeon-anilic  acid,  see  Amido-succinic 
acids,  Vol.  I. 

PHENYLATED  UREIDS  OF  DICARBOXYLIC  ACIDS.  —  Phenyl-parabanic 

acid  co<^£:6H5)~9?,  m.p.  208°,  and  diphenyl-parabanic  acid,  m.p. 

\  JN  xd.    ......  x>vJ 

204°,    from    the    corresponding   carbamides   with   ethoxalic   chloride 
(/.  pr.  Ch.  2,  32,  20). 


m.p.  238°,  formed  by  the  action  of  malonyl  chloride  upon  carbanilide. 

As  uric  acid  is  obtained  from  malonyl-urea  (Vol.  I.),  so  from 
diphenyl-malonyl-urea,  through  the  intermediacy  of  diphenyl-violuric 
acid,  m.p.  227°,  we  obtain  diphenyl-uramile,  m.p.  195°;  diphenyl- 
j/r-uric  acid,  m.p.  217°  ;  and  1,  3-diphenyl-uric  acid,  m.p.  above  300° 
(C.  1907,  II.  1065). 

ANILINE  SUBSTITUTION  PRODUCTS.  —  It  is  only  the  aniline  derivatives, 
among  the  substitution  products  of  the  primary  phenyl-amines,  which 
deserve  particular  consideration,  for  it  was  with  them  that  the  re- 
gularities of  substitution  obtaining  among  the  aromatic  amido-bodies 
were  observed,  and  they  were  the  intermediate  stages  in  numerous 
instances  where  constitution  was  to  be  determined. 

ANILINE  HALOIDS.  —  Formation  :  —  (i)  Aniline,  like  phenol,  is  more 
readily  substituted  than  benzene.  When  chlorine  or  bromine  acts 
upon  the  aqueous  solutions  of  aniline  salts,  the  halogen  atoms  enter 
the  [2,  4,  6]-position.  Concerning  the  additive  intermediate  products 
preceding  substitution,  see  A.  346,  128  ;  B.  38,  2159.  Starting  with 
acetanilide,  chlorine  and  bromine  produce  first  p-  and  o-mono-sub- 
stitution  products;  these  are  immediately  converted  into  o-p-di-sub- 
stitution  derivatives.  If,  however,  chlorine  or  bromine  be  allowed 
to  act  upon  aniline,  in  the  presence  of  concentrated  sulphuric  or  hydro- 
chloric acid,  m-compounds  will  be  produced.  By  combining  with  the 
strong  acids  the  amido-group  acquires  a  negative  character.  Con- 
cerning further  substitutions  in  meta-substituted  anilines,  see  B.  15, 
1328  ;  C.  1899,  II.  1049. 

Iodine  can  substitute  the  anilines  directly  ;  the  resulting  hydriodic 
acid  combines  with  the  excess  of  base  : 

2C6H6.NHa+I2=C6H4LNHI+C,H5.NHa.HI. 

(2)  The  mono-halogen  anilines  can  be  readily  obtained  from  the 
mono-halogen-nitro-benzols,  which  in  turn  are  derived  from  the 
nitro-amido-derivatives.  The  change  is  effected  through  the  diazo- 
bodies. 

p-Chloraniline  is  a  stronger  base  than  the  o-  and  m-bodies 
(B.  10,  974).  It  has  also  been  obtained  by  the  electrolytic  re- 
duction of  nitro-benzol  in  concentrated  hydrochloric  acid  solution. 
It  is  very  probable  that  C6H5.NHC1  is  formed  at  first,  but  sub- 
sequently rearranges  itself  into  p-chloraniline  (B.  29,  1895  ;  C.  1904, 

n.  95). 


no 


ORGANIC   CHEMISTRY 


[I.  2]-,  0- 

[i.  3]-,  m- 

[i,  4l-.  P- 

M.p. 

B.p. 

M.p.    |     B.p. 

M.p.    |    B.p. 

F1C6H4NH_ 

liquid 

188° 

(A.  243,  222) 

C1C6H4NH2 

liquid 

207° 

liquid 

230° 

?o° 

230° 

(A.  176,  27) 

BrC6H4NH2 

3i° 

229° 

18° 

251° 

66° 

.  . 

(B.  8,  364) 

IC6H4NH2 

56° 

27° 

63° 

•• 

(B.  17,  487) 

Of  the  higher  halogen  substitution  products  of  aniline  we  may 
mention  the  following  : — 

From  acetanilide  : 

a-[i  NH2, 2, 4]-Dichloraniline,  m.p.  63°,  b.p.  245°  (B.  7,  1602). 
a-[i  NH2, 2, 4]-Dibromaniline,  m.p.  79°  (A.  121,  266). 

From  the  nitro-compounds  : 

jS-[i,4,2NH2]-Dichlorannine,  m.p.  54°,  b.p.  250°  (A.  196,  215). 
j3-[i,4,2NH2]-Dibromaniline,  m.p.  51°  (A.  165,  180). 

[i  NH2, 2, 6]-Di-iodaniline,  m.p.  122°  (C.  1904,  II.  319). 

[i  NH2, 2, 4]-Di-iodaniline,  m.p.  96°  (C.  1904,  II.  590). 

From  aniline  with  Cl  and  Br  : 

[iNH2,2,  4, 6]-Trichloraniline,  m.p.  77°,  b.p.  262°  (/.  pr.  Ch.  2, 

16,  449  ;  B.  27,  3151). 

[i  NH2, 2, 4, 6]-Tribromaniline,  m.p.  119°  (B.  16,  635). 
[iNH2,  3,4,  5]-Tribromaniline,  m.p.  ii8°-ii9°  (C.  1898,  I.  939). 
[iNH2,2,4,6]-Tri-iodaniline,  m.p.  184°  (C.  1910,  I.  526). 

The  five  benzene-hydrogen  atoms  in  aniline  can  be  replaced  by 
chlorine  or  bromine  : 

Penta-ehloraniline,  m.p.  232°.  Penta-bromaniline,  m.p.  222°. 
Halogen  benzols  are  produced  by  eliminating  the  amido-group  by 
means  of  the  diazo-compounds. 

For  di-,  tri-,  and  tetra-iodanilines  and  their  transformation  products, 
see  B.  34,  3343. 

For  further  aniline  haloids,  see  C.  1907,  II.  1784  ;  A.  346, 160. 

NITRANILINES  NO2C6H4NH2  are  isomeric  with  diazo-benzolic  acid 
C6H5NHNO2.  Aniline  is  strongly  attacked  by  nitric  acid,  and  easily 
resinified.  (i)  In  order  to  obtain  mono-  and  di-substitution  products, 
acetanilide  is  nitrated.  The  acetyl  group  protects  the  amido-group, 
and  p-  and  o-nitro-acetanilide  are  first  formed,  with  an  excess  of  nitric 
acid,  chiefly  the  p-compound ;  while  with  the  calculated  amount  of 
HNO3,  in  glacial  acetic  acid  with  addition  of  acetic  anhydride,  we 
obtain  chiefly  the  o-nitro-acetanilide  (B.  39,  3903)  But  if  aniline  is 
nitrogenated  in  the  presence  of  cold  concentrated  sulphuric  acid,  meta- 
nitraniline  is  also  formed,  besides  the  p-  and  o- varieties  (B.  10,  1716  ; 
17,  261),  and  its  amount  increases  with  the  quantity  of  sulphuric  acid 
present.  There  is  here  the  linking  of  an  amido-group  and,  so  to  speak, 
transformation  into  an  acid  group,  which  produces  meta-substitution. 
The  three  isomers  are  separated  by  their  basicities.  On  neutralising 
their  acid  solutions,  o-nitraniline  precipitates,  first  o-,  then  p-,  and  then 


NITRANILINES  in 

m-nitraniline  (B.  28,  1954).     In  a  similar  manner  the  nitroacetanilides 
can  be  separated  (B.  39,  3903). 

(2)  The  nitranilines  can  also  be  obtained  by  heating  the  nitro- 
benzol  haloids  to  I5o°-i8o°  with  alcoholic  ammonia  ;  also  by  heating 
the   nitre-phenol  ethers,   like  C6H4(NO2).O.C2H5,  with   aqueous   am- 
monia.    In  both  cases  it  is  only  the  para-  and  or^o-derivatives  which 
react,  but  not  the  w^a-derivatives. 

(3)  The  direct  introduction  of   an  amido-group  into  the  o-  or  p- 
position,  with  respect  to  the  nitro-groups  present,  may  be  effected  by 
the  action  of  an  alcohol-alkaline  hydroxylamine  solution. 

(4)  By  partial  reduction  of  poly-nitro-compounds. 

(5)  By  heating  nitro-amido-benzol-sulphonic   acids  with   HC1   to 
170°  (B.  18,  294  ;  C.  1905,  I.  416). 

(6)  o-  and  p-nitraniline  are  produced  by  transposition  of  diazo- 
benzolic  acid  : 

[i,  2]-,    o-Nitraniline,    m.p.    71°  ;    Acet.    m.p.    92°.      o-Nitro- 

dimethyl-aniline,  see  B.  32,  1066. 
[i,  3]-,  m-Nitraniline,  m.p.  114°  ;  Acet.  m.p.  142°. 
[i,  4]-,  p-Nitraniline,  m.p.  147°  ;        „     m.p.  207°. 

The  nitro-anilmes  link   the  diamido-   and   dinitro-benzols   to  the 
nitro-haloid,  amido-haloid,  and  dihaloid  benzols  : 

NH.     r  „  /NO.     r  w  /NO.    p  „  /NO.    r  „  /NH.    r  „  /Br 
-  ~ 


When  ortho-  and^ara-nitranilines  (not  meta-)  are  boiled  with  alkalies, 
they  part  with  NH3,  and  are  converted  into  their  corresponding  nitro- 
phenols  C6H4(NO2).OH  ;  the  di-  and  tri-nitranilines  react  even  more 
readily. 

The  nitranilines  approach  in  character  the  acid  amides  as  the  number 
of  nitro-groups  in  them  increases. 

Ammonia  converts  the  corresponding  dinitro-phenols  or  poly- 
nitro-haloid-benzols  into  : 

a-[i  NH2,2,  4]-Dinitraniline,  m.p.  182°.  0-[i  NH2,  2,  6]-DinitranUine, 
m.p.  138°. 

[i  NH2,2,  4,  6]-Trinitraniline  C6H2(NO2)3.NH2,  picramide,  is  obtained 
from  picric  acid  through  its  ether,  or  by  means  of  picryl  chloride. 
The  latter  reacts  with  ammonia,  even  in  the  cold.  It  forms  orange-red 
needles,  m.p.  186°.  It  forms  picric  acid  when  heated  with  alkalies  : 

C6H2(N02)3.NH2+KOH=C6H2(N02)3.OK+NH3. 

Sym.  Trinitro-xylidine,  m.p.  206°,  from  trinitro-chloro-xylol  and  NH3 
(B.  28,  2047). 

NITRO-DIPHENYL-AMINES  are  obtained  by  the  transformation  of 
benzol-nitro-haloids  with  aniline,  or  of  the  nitranilines  with  bromo- 
benzols  and  addition  of  copper  bronze  or  copper  iodide.  o-Nitro- 
bromo-benzol  and  the  polynitro-halogen-benzols  react  with  aniline 
even  without  a  catalyst.  In  a  similar  manner  the  aryl-sulphonic 
esters  of  o-nitro-phenol,  and  its  derivatives,  yield  nitro-diphenyl- 
amines  with  aniline  (B.  41,  1870).  Numerous  nitro-diphenyl-amines 
have  also  been  obtained  by  nitrogenating  nitroso-  or  benzoyl-diphenyl- 


ii2  ORGANIC   CHEMISTRY 

amine,  and  breaking  up  the  resulting  compounds  with  dilute  SO4H2 
(C.  1906,  I.  28). 

The  nitro-diphenyl-amines  are  pale  -yellow  compounds.  They 
yield  dark-red  alkali  salts,  with  a  stability  increasing  with  the  number 
of  nitro-groups  they  contain. 

Hexanitro-diphenyl-amine  dissolves  in  aqueous  alkalies,  with  a 
purple  colour.  Its  ammonium  salt  is  a  brick-red  powder.  Before 
the  introduction  of  the  azo-dyes,  it  was  used  under  the  name  of 
"  aurantia  "  for  dyeing  wool  and  silk.  At  present  it  is  only  used  for 
making  photographic  colour-filters.  The  corresponding  salt  of  penta- 
nitro-diphenyl-amines  possesses  no  dyeing  power. 

These  strongly  coloured  alkali  salts  probably  possess  a  quinoid 
structure  : 


The  nitro-diphenyl-amines  probably  therefore  belong  to  the  class 
of  pseudo-acids  (Vol.  I.).  They  form  two  series  of  alkyl  derivatives  : 
pale-yellow,  stable  nitrogen  ethers  corresponding  to  the  free  nitro- 
phenyl-amines  ;  and  dark-violet,  unstable  oxygen  esters  corresponding 
to  the  dark-coloured  alkali  salts,  and  possessing,  like  the  latter,  a 
quinoid  structure  (aci-nitro-derivatives)  : 

I.   (N02)3C6H2.N(CH3)C6H2(N02)3  II.   (NO2)3C6H2N  :  C6H2(NO2)2  :  NOOCH3 

Pale  yellow.  Deep  violet. 

o-,  m-,  and  p-Nitro-diphenyl-amine  NO2C6H4NHC6H5,  m.p.  75°, 
112°,  132°  (B.  15,  826  ;  22,  903  ;  40,  4545). 

o,  o-,  p,  p-,  and  o,  p-Dinitro-diphenyl-amine  N02C6H4NHC6H4NO2, 
m.p.  167°,  214°,  219°  (B.  15,  826). 

[2,  4,  6]  -  Trinitro  -  phenyl  -  phenyl  -  amine,  m.p.  175°,  from  picryl 
chloride  (B.  3,  126).  Trinitro-xylyl-phenyl-amine,  m.p.  175°  (B.  28, 
2047).  Similar  compounds,  see  B.  33,  594  ;  C.  1898,  II.  342. 

Pentanitro-diphenyl-amine,  m.p.  194°.  Hexanitro-diphenyl-amine, 
m.p.  238°. 

N-Methyl-2,4-dinitro-diphenyl-amine  C6H5N(CH3)C6H3(NO2)2,  m.p. 
167°,  from  i,  2,  4-chloro-dinitro-benzol  and  methyl-  aniline,  gives,  on 
further  nitrogenation,  N  -  methyl  -  hexanitro  -  diphenyl  -  amine,  m.p. 
236°,  yellow  flakes.  The  isomeric  o-methyl-aci-hexamtro-diphenyl- 
amine,  in  violet-black  crystals  decomposing  at  141°,  is  obtained  by 
the  action  of  ICH2  upon  the  silver  salt  of  hexanitro-diphenyl-amine. 
Traces  of  alcoholic  HC1  rapidly  saponify  the  ester.  But  acetyl  chloride 
gives,  with  the  silver  salt,  an  N-acetyl-hexanitro-diphenyl-amine,  pale- 
yellow  crystals  melting  at  240°  (B.  41,  1745). 

p-Nitro-phenyl-amine  NO2C6H4N(C6H5)2,  m.p.  144°,  from  p-nitro- 
iodo-benzol  and  diphenyl-amine,  in  presence  of  copper  bronze  (B.  41, 
35n). 

H.  p-NlTROSO-DERIVATIVES  OF  THE  PRIMARY,  SECONDARY, 
AND  TERTIARY  AROMATIC  AMINES. 

Formation.  —  (i)  When  the  nitrosamines  of  monomethyl-aniline 
or  diphenyl-amine  are  treated  with  alcoholic  hydrochloric  acid,  they 
rearrange  themselves  into  p-nitroso-compounds  (B.  19,  2991).  (2) 
The  p-nitroso-bodies  are  also  produced  when  nitrous  acid  acts  upon 


p-NITROSO-DERIVATIVES   OF  AROMATIC  AMINES     113 

the  tertiary  dialkyl-anilines,  or  sodium  nitrite  upon  their  hydro- 
chlorides  (Baeyer  and  Caro,  B.  7,  963).  (3)  When  the  nitroso-phenols 
are  fused  with  ammonium  acetate  and  ammonium  chloride,  they  yield 
p-nitroso-anilines  (B.  21,  729). 

Behaviour. — When  the  p-nitroso-derivatives  of  the  secondary  and 
tertiary  aromatic  amines  are  heated  with  caustic  soda,  they  break 
down  into  sodium  nitroso-phenate  and  alkylamines  (I.  163).  Most 
chemists  consider  the  nitroso-phenols  to  be  the  monoximes  of  the 
paraquinones.  And  in  connection  with  this  mode  of  formulation 
of  the  nitroso-phenols,  many  are  disposed  to  view  the  p-nitroso- 
derivatives,  of  the  secondary  and  tertiary  aromatic  amines,  as  quinine 
derivatives  : 

r[i]  :  O  r[i]  :  N.OH  |[i]  :  N  =  (CH3)2 

C«M[4]:0  C'M[4]:0  C«H*i[4]:N>0 

p-Quinine.  p-Quinone-monoxime       p-Nitroso-dimethyl-aniline. 

Nitroso-phenol . 

p-Nitroso-aniline  NO[4]C6H4[i]NH2,  m.p.  174°,  crystallises  in 
steel-blue  needles  (B.  21,  729  ;  28,  R.  735). 

p-Nitroso-monomethyl-aniline  NO[4]C6H4[i]NHCH3  forms  blue 
lustrous  flakes,  and  melts  at  118°  C.  It  is  soluble  in  dilute  sodium 
hydroxide,  and  is  again  liberated  from  its  solution  by  carbon  dioxide. 

When  heated  with  sodium  hydroxide,  p-nitroso-methyl-aniline  is 
decomposed  into  sodium  nitroso-phenate  and  methyl-aniline. 

p-Nitroso-monoethyl-aniline,  m.p.  78°. 

o-,  m-,  and  p-Nitroso-acetanilide  NOC6H4NHCOCH3,  m.p.  107°, 
ni°,  173°,  by  oxidation  of  the  three  mono-acetyl-phenylene-diamines 
with  monopersulphonic  acid.  The  p-nitroso-acetanilide  exists  in  a 
grey  and  a  colourless  modification,  m.p.  173°  and  181°  (C.  1908, 
I.  2027). 

p-Nitroso-dimethyl-aniline  NO[4]C6H4[i]N(CH3)2,  m.p.  85°,  con- 
sists of  large  green  flakes.  Potassium  permanganate  and  ferro- 
cyanide  of  potassium  oxidise  it  to  p-nitro-dimethyl-aniline.  Upon 
reduction  it  yields  p-amido-dimethyl-aniline,  which  is  so  important 
in  the  dye  manufacture.  Sodium  hydroxide  resolves  it  into  nitroso- 
phenol  and  dimethyl-aniline.  Its  hydrochloride  dissolves  with  diffi- 
culty in  cold  water. 

p-Nitroso-diethyl-aniline,  m.p.  84°. 

p-Nitroso-diphenyl-amine,  m.p.  143°,  consists  of  green  plates,  and 
is  produced  when  hydrochloric  acid  gas  acts  upon  diphenyl-nitros- 
amine.  Dissolves  in  concentrated  aqueous  alkalies  with  formation 
of  dark-brown  alkali  salts,  derivable  from  the  anile  of  quinone-mon- 
oxime  C6H5N  :  C6H4  :  NOH  (B.  20,  1252  ;  21,  R.  227). 

5#.  Diamines. 

Formation. — The  aromatic  diamines,  whose  amido-groups  are 
attached  to  the  benzene  nucleus,  are  formed  (i)  by  the  reduction  of 
the  three  dinitro-benzols  or  nitro-anilines  with  tin  and  hydrochloric 
acid  ;  (2)  the  monamines  can  be  converted  into  the  diamines  by  first 
changing  them  to  amido-azo-compounds,  and  then  decomposing  the 
latter  by  reduction  : 

CGH5N^N[4]C6H4[i]NH2+4H=C6H5NH2+NH2[4]C6H4[i]NH2. 

VOL.  II.  I 


ii4  ORGANIC  CHEMISTRY 

(3)  They  can  be  obtained,  also,  from  the  diamido-benzoic  acids,  by 
the  loss  of  carbon  dioxide,  when  they  are  treated  with  baryta.  This 
reaction  has  become  of  particular  importance  in  ascertaining  the  con- 
stitution of  the  three  phenylene-diamines.  (4)  Phenylated  diamido- 
benzols  are  formed  by  the  semidin  transposition  of  hydrazo-benzols  ; 
thus,  o-amido-ditolyl-amine  is  formed  from  hydrazo-toluol.  (5)  Di- 
phenylated  diamido-benzols  C6H4(NH.C6H5)2  are  produced  when  dioxy- 
benzols — e.g.  resorcinol  and  hydroquinone — are  treated  with  aniline 
and  CaCl2  or  ZnCl2. 

Properties. — The  diamines  are  colourless  solids  volatilising  without 
decomposition,  but  on  exposure  to  the  air  they  become  coloured. 
They  are  di-acid  bases,  forming  well-defined  salts.  Ferric  chloride 
imparts  an  intense  red  colour  to  their  solution.  The  amide  hydrogen 
atoms  can  be  replaced  in  the  same  manner  as  in  the  mon amines. 

Diamido-benzols,  or  phenylene-diamines,  C6H4(NH2)2.  The  o-body 
is  derived  from  o-nitraniline  by  reduction  with  caustic  soda  and  zinc 
dust  (B.  28,  2947).  The  m-derivative  is  most  easily  accessible  through 
m-dinitro-benzol.  The  p-compound  is  obtained  by  the  decomposition 
of  amido-azo-benzol,  or  by  heating  p-dichloro-benzol  with  NH3  in 
presence  of  copper  sulphate  (Z.f.  Ch.  1866,  136  ;  C.  1908,  II.  1221). 

[i,  2]-,  o-Phenylene-diamine,  m.p.  102°,  b.p.  252° 
[i,  3]-,  m-Phenylene-diamine,  ,,  63°,  ,,  267° 
[i,  4]-,  p-Phenylene-diamine,  ,,  147°,  ,,  267°. 

o-Phenylene-diamine  is  coloured  red,  in  hydrochloric  acid  solution, 
by  ferric  chloride,  with  the  production  of  diamido-phenazine  hydro- 
chloride  (B.  27,  2782).  Oxidation  with  PCO2  or  Ag20  gives  o-quinone- 
di-imine,  which  immediately  polymerises  to  O2-diamido-benzol.  In 
the  table  (see  below),  showing  the  numerous  o-condensations  of  which 
the  o-diamines  are  capable,  it  is  o-phenylene-diamine  which  appears 
most  frequently  as  the  example. 

o-Amido-phenyl-urethane  melts  at  86°. 

o-Amido-diphenyl-aniline,  b.p.  217°  (B.  32,  1903).  4,  6-Dinitro- 
o-phenylene-diamine,  m.p.  215°,  deep-red  needles,  by  reduction  of 
picramide  with  alcoholic  Am2S  (B.  41,  3093). 

m-Phenylene-diamine  with  nitrous  acid  becomes  triamido-diazo- 
benzol,  or  Bismarck  brown.  It  imparts  an  intense  yellow  colour  to 
a  very  dilute  solution  of  nitrous  acid,  and  can  therefore  be  used  for  the 
colorimetric  estimation  of  the  latter  in  water  (B.  14,  1015)  ;  if  the 
nitrite  solution  is  allowed  to  flow  quickly  into  the  hydrochloric  solu- 
tion of  the  m-phenylene-diamine,  we  obtain,  besides  Bismarck  brown, 
1,  2,  4-Nitroso-m-phenylene-diamine  NOC6H3(NH2)2,  garnet-red  flakes 
of  m.p.  210°  (B.  37,  2276).  Concerning  the  action  of  COC12,  CS2,  and 
oxalic  ester,  cp.  B.  7, 1263  ;  21,  R.  521 ;  24,  2113  ;  36, 411. 

Tetramethyl-m-phenylene-diamine,  b.p.  267°  (B.  36,3110).  Tetra- 
phenyl-phenylene-diamines  C6H4[N(C6H5)2]2  are  produced  from  the 
dichloro-benzols  by  heating  with  potassium  diphenyl-amine  (B.  32, 
1912).  m-Phenylene-carbyl-amine  C6H4[i,  3](N  :  C)2  is  transposed 
to  isophthalic  nitrile  by  heating  (C.  1902,  I.  463). 

o-Nitro-  and  o-Amido-phenyl-m-phenylene-diamine  NH2[2]C6H4. 
NH.C6H4[3]NH2,  see  B.  34,  3089.  4-Nitro-m-phenylene-diamine,  see 


DIAMINES  115 

C.  1906,  I.  517.    2,  4-Dinitro-m-phenylene-diamine,  m.p.  254°  (B.  39, 

2538). 

p-Phenylene-diamine  oxidises  in  air  to  the  dark  garnet-red  crystals 

of    Tetra-amido-diphenyl-p-azo-phenylene  CA 


m.p.  231°  with  decomposition  (B.  27,  480).  By  Ag2O  it  is  turned 
into  quinone  di-imine  (q.v.),  by  MnO2  and  sulphuric  acid  into  quinone 
(q.v.),  by  chloride  of  lime  into  quinone  dichlorimine  (q.v.). 

p-Amido-dimethyl-aniline  NH2[4]C6H4[i]N(CH3)2,  m.p.  41°,  b.p. 
257°,  is  obtained  by  reduction  of  p-nitroso-  or  p-nitro-dimethyl-aniline, 
or  by  splitting  up  helianthin  or  p-dimethyl-amido-azo-benzol  (B.  16, 
2235)  .  In  acid  solution  it  gives  with  SH2  and  ferric  chloride  a  dark-blue 
colour  —  methylene  blue  (q.v.)  —  and  therefore  is  used  as  a  sensitive  reagent 
for  SH2.  N,  N^dimethyl-p-phenylene-diamine  CH3NH[i]C6H4[4] 
NHCH3,  m.p.  53°,  b.p.17  150°,  is  oxidised  by  Ag2O  to  quinone  dimethyl- 
imine  (B.  38,  2248). 

Thionyl-  and  formyl-p-amido-dimethyl-aniline,  see  B.  27,  602  ; 
31,  2179.  p-Phenylene-dicarbyl-amine  (CJHJfi^JfN  :  C),  yields,  on 
heating,  terephthalic  acid  nitrile  (C.  1902,  I.  463).  Nitro-p-phenylene- 
diamine,  m.p.  135°,  lustrous  green  needles,  from  [i,  2,  4]-dinitraniline 
(B.  28,  1707  ;  29,  2284). 

DIAMIDO-TOLUOLS,  ToLUYLENE-DiAMiNES.  —  All  the  six  isomers 
predicted  by  theory  are  known  : 

1.  [i  CH3,  2,  3]-Toluylene-diamine,  m.p.    61°,  b.p.  255°  (A.  228,243) 

2.  [i  CH3,  3,  4]-Toluylene-diamine,     „      88°,    „    265° 

3.  [i  CH3,  2,  4]-Toluylene-diamine,     „      99°,    „    280° 

4.  [i  CH3,  2,  6]-Toluylene-diamine,     „    103°,  (B.  17,  1959) 

5.  [i  CH3,  3,  5]-Toluylene-diamine,  liquid,          „    284°  (A.  217,  200) 

6.  [i  CH3,  2,  5]-Toluylene-diamine,  m.p.    64°,    „    273°. 

[1,  3,  4]-Toluylene-diamine  is  the  most  accessible  o-diamine.  It  is 
prepared  from  p-aceto-toluidin  : 

,rilCH  r[i]CHs  r[i]CH3  f[i]CH3 

C«H<    u  NH  COCH  —  >C*H*\  [3JNO*  —  >C6H3|  [3JNO,—  *C,HJ  [3]NH, 

'Ha  l[4]NHCOCH3  l[4]NH,  l[4]NHa 

1,  2,  4-Toluylene-diamine  is  the  fundamental  body  for  the  prepara- 
tion of  toluylene  red  (q.v.). 

Xylylene-diamine.  —  The  eleven  theoretically  possible  diamido-xylols 
have  all  been  obtained,  and  four  of  them  are  derivable  from  o-phenylene- 
diamine:  (NH2)2[i,  2](CH3)2[3,  4],  m.p.  89°;  -[4,5]-,  m.p.  126°; 
-[3,  5]-,  m.p.  78°  ;  -[3,  6]-,  m.p.  75°. 

Four  derivatives  from  m-phenylene-diamine  :  (NH2)2[i,3](CH3)2 
[4,  5]-,  m.p.  67°  ;  -[2,  4]-,  m.p.  66°  ;  -[4,  6]-,  m.p.  105°  ;  -[2,  5]-,  m.p. 
103°;  and 

Three  derivatives  from  p-phenylene-diamine  :  (NH2)2[i,  4](CH3)2 
[2,  3]-,  m.p.  116°;  -[2,  6]-,  m.p.  104°;  -[2,  5]-,  m.p.  150°  (B.  35,  636). 

[1,  2,  3,  5,  6]-o-Diamido-pseudo-cumol,  m.p.  90°  ;  p-Diamido-pseudo- 
cumol,  m.p.  78°  (B.  24,  1647).  Diamido-mesitylene,  m.p.  90°  (A.  141, 
134  ;  179,  176,  etc.). 

In  the  phenylene-diamines  with  a  methylated  nucleus,  the  amidyl  in 
para-position  to  a  methyl  is  more  easily  acidulated  than  the  o-  and 
m-position  amidyls  (B.  35,  681).  Concerning  the  influence  of  nucleus- 


n6  ORGANIC   CHEMISTRY 

alkylene  upon  the  alkylation  of  the  phenylene-diamines  at  the 
nitrogen,  see  C.  1902,  I.  1279. 

p-Amido-diphenyl-amine  NH2[4]C6H4[i]NHC6H5,  m.p.  75°,  by 
reduction  of  p-nitroso-diphenyl-amine  with  (NH4)2S.  It  also  forms 
during  the  electrolytic  reduction  of  nitro-benzol  in  hydrofluosilicic  acid 
solution.  Ferric  chloride  oxidises  it  to  emeraldin  (q.v.)  (B.  40,  289). 

p2-Diamido-diphenyl-amine,  m.p.  158°,  by  semidin-transposition  of 
p-amido-hydrazo-benzol  (C.  1906,  I.  232). 

p-Amido-triphenyl-amine  NH2[4]C6H4[i]N(C6H5)2,  m.p.  i45°-i48°, 
by  reduction  of  the  corresponding  nitro-compound.  A  p-Chloranilino- 
triphenyl-amine,  m.p.  77°-8i°,  is  formed  by  a  complex  reaction  in  the 
breaking  up  of  tetraphenyl-hydrazin  with  HC1  (B.  41,  3507). 

THE  CONDENSATIONS  OF  THE  O-DIAMINES. 

The  o-diamines  possess  the  power  in  a  remarkable  degree  of  forming 
condensation  products.  These  usually  consist  of  ring-systems  con- 
taining five  or  six  atoms,  and  will  be  discussed  in  connection  with  the 
heterocyclic  carbon  derivatives.  The  m-  and  p-diamines  do  not 
possess  this  power.  The  condensation  occurs  in  that  hydrogen  atoms 
of  both  amido-groups  of  an  o-diamine  are  replaced  by  polyvalent 
atomic  groups.  Frequently,  when  this  occurs,  the  nitrogen  atoms 
occupying  the  o-position  unite  with  one  another. 

1.  Sulphur  dioxide  and  selenium  dioxide  convert  the  o-diamines 
into  piazo-thiols  (q.v.)  and  piazo-selenols  (q.v.). 

2.  Nitrous  acid  produces  azimides  (q.v.). 

3.  The  cyclic  amidines  are  directly  produced  from  the  o-diamines 
on  heating  them  with  acids,  their  chlorides  and  anhydrides,  as  well 
as  with  aldehydes.      Anhydro-bases  or  aldehydins  (Ladenburg).     These 
are  substances  nearly  related  to  the  glyoxalins  or  imidazols,  and  will 
be  treated  later  in  connection  with  these.     Such  condensations  have 
been  observed  also   in  the   reduction  of   acidylated   o-nitro-amido- 
compounds  (Hobrecker). 

4.  Cyclic  ureas  and  thio-urea  derivatives  are  formed  from  COC12  and 
SCC12  or  CS2,  also  by  condensation  with  urea  and  thio-urea,  as  well  as 
with  ammonium  sulpho-cyanide. 

5.  Cyclic  guanidin  derivatives  are   obtained  by  means   of  carbo- 
di-imides  and  phenyl-mustard  oils. 

6.  A  very  interesting  condensation  of  the  o-diamines  is  that  with 
glyoxal  and  other  a-dicarbonyl  derivatives,  as  well  as  with  grape- 
sugar,  when  quinoxalins  result,  with  rejection  of  water   (Hinsberg) 
(I-  321). 

Related  six-membered  rings  are  produced  : 

7.  When  o-diamines  condense  with  cyanogen  ; 

8.  By  condensation  with  o-dioxyl-benzol. 

9.  Unsym.    diamido-phenazin    is    produced    by    the    oxidation    of 
o-phenylene-diamine. 

10.  Dibenzol-sulphone  derivatives  of  o-phenylene-diamine  condense 
with   alkylene   dihaloids — e.g.    methylene   iodide,    ethylene   bromide, 
trimethylene  bromide.     The  products  are  cj^clic  diamines,  from  which 
the   corresponding  phenylene-alkylene-diamines   are   obtained   by  the 
splitting  off  of  the  benzol-sulphone  groups  (B.  28,  R.  756). 


CONDENSATIONS   OF  THE   o-DIAMINES 


117 


ii.  The  o-phenylene-diamines  condense  also  with  oxalic  acid,  and 
the  homologous  paraffin-dicarboxylic  acids,  as  well  as  o-phthalic  acid, 
to  rings  of  a  higher  number  of  members  (A.  327,  9). 


so, 


NO,H 


[2]N/ 


~»C.H< 


HCO»H  •         „„    / [i]NH\rHBenzimidazol; 

-»C.H4  ^2-jN    ^ctl  o-Phenylene-formamidin 


COC1, 


C(NC.H.)t 


[i]NH 


„       [i]NH 
§    4[a]N 


Benzimidazolone 
o-Phenylene-urea 


-->C.H4 


CHOCHO 


CN.CN 


>C4H4  J  LIJN     »«  Ouinoxalin 
\[2]N=CHV 


OH[i]C.H4[2]OH 


/[i]N==CNH, 
^  [2]N=CNHj 


C8H4 


BrCH.CHjBr 


]^!']  \ 


c,H,(NHs),  as-Diamido-phenazin 


C.H4 


HOCO.COOH 


WNH—  CH,  Tetrahydro-quinoxalin 
WNH  —  CH, 


/WN= 

\[2]N  = 


COH 
COH 


a,  /3-Dioxy-quinoxalin. 


The  o-amido-phenols,  the  o-amido-thio-phenols,  and  the  o-dioxy- 
benzols  show  condensations  similar  to  those  observed  with  the  o- 
diamines. 

DIFFERENCES  BETWEEN  THE  o-,  m-,  AND  P-DIAMINES. 

1.  The  /)aya-diamines  are  capable  of  yielding  various  dyestuffs. 
Mixed  with  primary  amines  (or  phenols)  and  oxidised  at  the  ordinary 
temperature,  they  are  converted  into  indoamine  and  indophenol  dye- 
stuffs  ;    at  higher  temperatures  the  so-called  safranins  are  produced. 
When  oxidised  with  ferric  chloride  in  the  presence  of  H2S,  the  para- 
diamines,  containing  a  free  NH2  group,  yield  sulphurised  dyes  of  thio- 
diphenyl-amine  (Lauth's  dyestuffs).     Manganese  dioxide  and  sulphuric 
acid  oxidise  the  p-diamines  to  quinones,  recognisable  by  their  odour. 
Ferric  chloride  (B.  17,  R.  431)  imparts  colour  to  the  diamines.     See 
above,  o-Phenylene-diamine. 

2.  The  or^o-diamines,  when  acted  upon  by  nitrous  acid,  yield 
azimido-compounds,  e.g.  azimido-benzol.     The  wtfta-diamines,  on  the 
contrary,  yield  yellow-brown  azo-dyes,  of  the  type  of  phenylene  brown. 
Test  for  nitrous  acid  (B.  11,  624,  627).     In  every  acid  solution,  and 
when  there  is  an  excess  of  acid  (nitrous),  the  meta-diamines   form 
bis-diazo-derivatives.     Nitrous  acid  (or  NaNO2)   converts   the   para- 
diamines  (their  salts)  into  bis-diazo-compounds. 

3.  When    the     chlorohydrates     of     the     three     isomerides     are 
digested    with     ammonium     sulphocyanide,     disulphocyanides,     like 


C.H4- 


NH2.HSCN 
NH2.HSCN 


,    are    produced.      On    heating    these    to    120°    we 


discover  that  the  ortho-diamines  are  changed  to  cyclic  sulpho-ureas 


n8  ORGANIC  CHEMISTRY 


CS.     These   are   not   desulphurised   by   digestion   with  an 

alkaline  lead  solution  ;  while  the  derivatives,  obtained  from  the  meta- 
and  para-diamines,  are  immediately  blackened  by  the  alkaline  lead 
solution  (reaction  of  Lellmann,  B.  18,  R.  326). 

4.  The  diamines  unite  in  a  similar  manner  with  the  mustard  oils. 
If  these  products  be  fused,  those  from  the  ortho-diamines  decompose 
into  cyclic  phenylene-sulpho-urea  and  dialkyl-sulpho-ureas  ;  the  fused 
mass  soon  becomes  crystalline.     The  meta-diamine  derivatives  melt 
without  decomposition,  while  those  of  the  para-,  after  fusion,  are 
completely  broken  up  (B.  18,  R.  327  ;  19,  808). 

5.  The  o-diamines  show  a  series  of  other  condensation  reactions, 
which  have  been  tabulated  above;  and  as  the  m-  and  p-diamines 
behave  differently  in  these  transpositions,  they  will  answer  for  the 
distinction   of   the   o-derivatives   from   the   other   two   classes.     The 
behaviour  towards  phenanthraquinone  is  used  for  the  detection  of  the 
o-diamines.     A  more  delicate  test  is  that  with  croconic  acid  (B.  19,  2727). 
Both  tests  are  based  upon  the  formation  of  quinoxalin  derivatives. 

Triamines.  —  The  three  triamido-benzols  possible  theoretically  are 
known,  although  the  symmetrical  body  only  in  the  form  of  its  salts. 

The  adjacent  [1,2,3]  is  obtained  from  triamido-benzoic  acid  (from 
chrysanisic  acid),  m.p.  103°,  b.p.  330°  (A.  163,  23).  The  unsymmetrical 
[1,2,4],  m-P-  I32°>  b.p.  340°,  is  obtained  by  the  decomposition  of 
chrysoidine  (B.  10,  659  ;  15,  2196),  or  diamido-azo-benzol,  and  from 
the  corresponding  nitro-amido-derivatives  (B.  19,  1253).  When 
oxidised  by  air  it  changes  to  a  eurhodine  dyestuff  (B.  22,  856). 
[iCH3,  2,  3,  4]-Triamido-toluol  (B.  14,  2657). 

Triamido-mesitylene,  m.p.  118°,  see  C.  1898,  II.  539.  Di-,  terra-, 
and  hexamethylated  triamines,  see  B.  29,  1053  ;  30,  3110. 

Tetramines.  —  v-,  [l,2,3,4]-Tetra-amido-benzol  is  obtained  by  the 
reduction  of  diquinol  tetroxime  (B.  22,  1649).  The  symmetrical 
(1,2,4,5)  variety  is  formed  by  the  reduction  of  dinitro-m-phenylene- 
diamine.  It  exhibits  all  the  reactions  of  the  ortho-  and  para-diamines 
(B.  22,  440). 

Asym.  [1,2,  3,  5]-tetramido-benzol,  from  tetra-nitro-benzol,  see 
B.  34,  57- 

Pentamines.  —  Penta-amido  -  benzol,  from  trinitro-m-phenylene- 
diamine. 

Penta-amido-toluene  CH3.C6(NH2)5  is  formed  from  trinitro-s- 
toluylene-diamine  (B.  26,  2304). 

As  the  number  of  amido-groups  increases  the  polyamines  become 
more  unstable. 

In  the  sym.  triamido-benzols  the  NH2  groups  may  be  replaced 
by  OH  groups,  by  heating  with  HC1  ;  sym.  triamido-benzol  becomes 
phloro-glucin  (M.  21,  20  ;  22,  983). 

6.  Phenyl-Nitrosamines. 

Nitroso-compounds  are  obtained  when  potassium  nitrite  acts  upon 
the  hydrochlorides  of  secondary  aromatic  bases.  This  procedure  is 
similar  to  that  employed  with  the  aliphatic  nitrosamines.  It  is  a 
reaction  which  can  be  used  to  distinguish,  and  separate,  secondary 


PHENYL-NITROSAMINES  119 

from  primary  and  tertiary  bases,  as  the  nitrosamines  are  precipitated, 
as  oils,  from  the  acid  solution  of  a  mixture  of  bases.  The  phenyl- 
nitrosamines  in  alcoholic  or  ethereal  solution,  when  treated  with  hydro- 
chloric acid  gas,  pass  into  p-nitroso-anilines  : 

C^3  »   NO[4]C.H4[i]NHCH3 

Methyl-phenyl-nitrosamine      p-Nitroso-monomethyl-aniline. 

They  change  into  hydrazins  upon  reduction,  or  break  down  into 
ammonia,  and  the  original  secondary  bases.  They  are  volatile  with 
steam  (B.  10,  329  ;  22,  1006  ;  A.  190,  151),  but  decompose  upon  dry 
distillation. 

The  nitrosamines  are  not  only  intimately  related  to  the  secondary 
amines  and  hydrazins,  but  also  to  the  diazo-compounds.  Potassium 
diazo-benzol  may  be  readily  rearranged  into  potassium  iso-diazo- 
benzol,  which  yields  phenyl-methyl-nitrosamine  with  methyl  iodide. 
Unsym.  phenyl-methyl-hydrazin  results  from  the  reduction  of  phenyl- 
methyl-nitrosamine.  Potassium  diazo-benzolate  is  formed  by  the 
oxidation  of  potassium  iso-diazo-benzol.  The  latter,  and  methyl 
iodide,  combine  to  phenyl-methyl-nitramine,  which  can  be  reduced 
to  phenyl-methyl-nitrosamine,  and  unsym.  phenyl-methyl-hydrazin. 
These  genetic  relations  are  indicated  in  the  following  diagram  : 

C  H  N   OK Potassium      c  H  N/NO  c  H  N/NH2 

8    5    2'  "Tlso-diazo-benzol  T  xCH   "        "*         5    \CH 

Potassium 

diazo-benzol  Methyl -phenyl-       as-Methyl-phenyl- 

nitrosamine  hydrazin 

C6H5(N20S)K 

Potassium  Methyl-phenyl- 

diazo-benzolic  acid  nitro-amine. 

Phenyl-methyl-nitrosamine  C6H5N(CH3)NO,  m.p.  i2°-i5°  (B.  27, 
365,  footnote),  also  from  nitroso-phenyl-glycin  C6H5N(NO)CH2COOH, 
on  boiling  with  water  (B.  32,  247).  The  methyl  group  is  replaced  by 
potassium  when  the  substance  is  fused  with  caustic  potash  ;  potassium 
iso-diazo-benzol  results.  In  the  cold,  phenyl-methyl-nitrosamine  forms 
in  HC1,  in  alcohol,  a  chlorohydrate  [C6H5N(NO)CH3]HC1,  which,  on 
boiling  or  heating,  is  transposed  into  the  isomeric  p-nitroso-methyl- 
aniline  (B.  35,  2975). 

Phenyl-ethyl-nitrosamine  C6H5N(C2H5)NO  is  a  yellow  oil,  with 
an  odour  like  that  of  bitter  almond  oil  (B.  7,  218). 

Diphenyl-nitrosamine  (C6H5)2NNO,  m.p.  66°,  consists  of  pale- 
yellow  plates.  It  dissolves  in  concentrated  sulphuric  acid  with  a 
dark-blue  colour. 

For  other  aromatic  nitrosamines,  see  B.  33,  100. 

NITROSANILIDES. — These  bodies  are  even  more  closely  allied  to  the 
diazo-compounds  than  are  the  phenyl-alkyl-nitrosamines.  They  are 
formed  (i)  from  the  anilides  in  glacial  acetic  acid  solution  with  nitrous 
acid  ;  (2)  from  the  diazo-alkali  salts  (normal  and  iso-)  with  acid 
chlorides  in  alkaline  solution.  Gaseous  HC1  breaks  them  up  again 
into  anilides  and  nitrosile  chloride  NOC1,  and  the  anilides  are  always 
restored  by  reduction  also  ;  alkalies,  on  the  other  hand,  split  off  the 


120  ORGANIC  CHEMISTRY 

acidyl  group  even  at  low  temperatures,  diazo-alkali  salts  being  formed. 
With  potassium  sulphite,  nitroso-acetanilide  forms  benzol-diazo- 
sulphonic  acid  and  phenyl-hydrazin-disulphonic  acid.  With  benzene, 
nitrous  acetanilide  yields  diphenyl  with  evolution  of  nitrogen  (B.  30, 
366  ;  A.  325,  226). 

Nitroso-formanilide  C6H5N(NO)CHO,  m.p.  39° ;  Nitroso-acetanilide 
C6H5N(NO)COCH3,  m.p.  40° ;  p-Bromo-nitroso-acetaniiide,  yellow 
needles,  exploding  at  88°.  Nitroso-phenyl-urea  C6H5N(NO)CO.NHC6H5, 
m.p.  82°  with  decomposition,  behaves  like  the  nitroso-anilides. 

7.  Phenyl-Nitramines. 

Diazo-benzolic  acid,  nitranilide,  phenyl  -  nitramine  C6H5NH.NO2 
or  C6H5N  :  NOOH,  m.p.  46°,  colourless  crystals,  formed  :  (i)  by  oxida- 
tion of  normal  diazo-  and  iso-diazo-potassium-benzol  with  potassium 
ferricyanide  or  permanganate  (B.  28,  R.  82),  besides  the  isomeric  nitroso- 
phenyl-hydroxylamine  C6H5N(NO)OH  (B.  42,  3568)  ;  (2)  by  nitro- 
genation  of  aniline  by  means  of  nitrogen  pentoxide  (B.  27,  584  ;  cp.  29, 
1015  ;  A.  311,  91)  ;  (3)  by  the  action  of  sodium  upon  an  etheric  solution 
of  aniline  and  ethyl  nitrate  (C.  1905,  II.  894)  ;  (4)  by  decomposition  of 
diazo-benzol  per  bromide  with  alkalies,  besides  nitroso-benzol  (B.  27, 
1273  ;  28,  R.  31)  ;  (5)  from  nitrite  chloride,  and  aniline  (B.  27,  668)  ; 
(6)  from  aniline  nitrate  and  acetic  oxyhydride,  with  splitting  off,  as 
in  the  case  of  acetanilide,  from  aniline  acetate  (A.  311,  99).  A  number 
of  substituted  diazo-benzolic  acids  have  been  prepared  by  the  above 
methods. 

Properties  and  Behaviour. — In  the  light,  on  heating,  and  in  contact 
with  mineral  acids,  diazo-benzolic  acid  is  transformed  into  a  mixture 
of  o-  and  p-nitraniline,  with  which  it  is  isomeric.  It  is  probable  that, 
during  nitrogenation  of  aniline,  diazo-benzolic  acid  occurs  as  an  inter- 
mediate product.  By  reduction  with  sodium  amalgam  it  passes  into 
sodium-iso-diazo-benzol,  and  the  latter  easily  into  phenyl-hydrazin 
(B.  27,  1181).  With  zinc  and  acetic  acid  it  yields  diazo-benzol.  It 
forms  salts  :  a  potassium  salt  C6H5H2O2K,  and  a  sodium  salt  of  brilliant 
white  flakes.  With  ICH3  the  sodium  salt  gives  the  a-methyl  ester, 

Phenyl-methyl-nitramine  C6H5N<^™3,  m.p.  39°,  which,  with  sulphuric 

^•NC/2 

acid,  changes  into  o-  and  p-nitro-methyl-aniline,  yields  methyl-aniline 
on  heating  with  KHO,  and  may  be  reduced  to  methvl-phenyl-nitros- 
amine,  unsym.  methyl- phenyl-hydrazin,  and  monomethyl- aniline. 
With  methyl  iodide  the  silver  salt  gives  jS-Diazo-benzolic  methyl 
ester  C6H5N  :  NOOCH3,  a  yellowish-brown  oil,  smelling  of  heliotrope 
(B.  27,  359  J  cp.  B.  31,  177,  574). 

Homologous  Diazo-benzolic  Acids. — The  symmetrical  tri-substituted 
phenyl-nitramines  in  which  the  o-  and  p-positions,  with  reference  to 
the  amido-group,  are  occupied,  do  not  undergo  the  transposition  into 
nitraniline.  They  are  stable  in  the  presence  of  mineral  acids,  and 
may  therefore  be  obtained  by  direct  nitrogenation  of  the  corresponding 
anilines  with  concentrated  NO3H. 

o-Diazo-toluolic  acid,  a  colourless  oil.  p-Diazo-toluolic  acid,  m.p. 
52°.  Diazo-pseudo-cumolic  acid,  m.p.  87°.  o-,  m-,  p  -  Nitro  -  diazo- 
benzolic  acid,  m.p.  65°,  86°,  m°  (B.  28,  399).  Dinitro-p-tolyl-methyl- 


DIAZO-COMPOUNDS  121 

nitramine  (NO2)?C6H2(CH3).N(CH8)NO2,  m.p.  138°,  is  obtained  by 
the  action  of  nitric  acid  upon  dimethyl-p-toluidin  (B.  29,  1015). 

2,  4,  6-Trichloro-phenyl-nitramine,  m.p.  135°.  2,  4,  6-Tribromo- 
phenyl-nitramine,  m.p.  144°  (C.  1905,  I.  1231).  2,  4-Dinitro-phenyl- 
nitramine,  m.p.  ioi°with  decomposition,  by  the  action  of  concentrated 
nitric  acid  upon  o-  and  p-nitraniline  or  2,  4-dinitraniline  (A.  339,  229). 

2,  4,  6-Trinitro-phenyl-nitramine,  extremely  explosive,  generated  as 
a  by-product  during  nitrogenation  of  aniline  (B.  41,  3094  ;  42,  2959). 

8.  Diazo-compounds. 

The  aromatic  diazo-derivatives,  because  of  their  ready  conversion 
into  the  most  varied  substitution  products  of  the  aromatic  hydro- 
carbons, and  as  intermediate  steps  in  the  formation  of  azo-dyes,  are 
equally  important  both  from  a  scientific  and  technical  standpoint. 

The  behaviour  of  the  primary  aliphatic  amines  towards  nitrous 
acid  was  particularly  emphasised.  As  is  known,  the  amido-group  can, 
by  this  means,  be  replaced  by  hydroxyl  ;  it  is  a  change  corresponding 
to  that  of  ammonia  itself  by  nitrous  acid  into  nitrogen  and  water  : 

NH3+NOOH=H2O-fN2+H2O 
C2H5NH2+NOOH=C2H5OH+N2+H2O. 

Among  the  nitrogen-containing  derivatives  of  the  aldehydo-acids 
we  observed  a  body,  in  the  reaction  product  resulting  from  nitrous 
acid  and  glycocoll  ester,  in  which  the  group  —  N=N  —  had  joined 
itself  to  carbon.  This  substance  has  been  termed  diazo-acetic  ester, 
produced  according  to  the  equation  : 

CO2C2H5.CH2NH2+NOOH-CO2C2H5.CH(N2)+2H2O. 

The  moderated  action  of  nitrous  acid  upon  the  salts  of  aromatic 
primary  amines  is  analogous  to  its  action  upon  aliphatic  a-amido- 
acid  esters.  It  was,  however,  observed  long  before  the  latter.  When 
nitrous  acid  acts  upon  the  aqueous  solution  of  salts  of  primary  aromatic 
amines  without  cooling  the  mixture,  there  follows,  as  in  the  case  of 
the  aliphatic  amines,  a  replacement  of  the  amido-group  by  hydroxyl  : 

C6H5NH2HCl+NOOH-C6H5OH4-N2+H2O-hHCl. 

Upon  cooling  the  solution,  however,  the  three  hydrogen  atoms  will 
be  replaced  by  a  nitrogen  atom,  thus  : 

C6H5NH3C1  +  NOOH  =  C6H6NC1=N  +  2H2O 

Diazo-benzol  chloride 


C6H5NH3ONO2     +  NOOH  =  C6H5N(O.NO2)=N    +  2H2O 

Diazo-benzol  nitrate 


C3H5NH3OSO3H  +  NOOH  =  C6H5N(O.SO3H)=N  +  2H,O 

Diazo-benzol  sulphate. 

These  aromatic  diazo-bodies  differ  from  the  aliphatic,  in  that 
the  bivalent  group  N2  is  linked,  not  with  both,  but  only  with  one, 
affinity  to  the  carbon  atom.  The  second  affinity  is  joined  to  another 
univalent  radicle.  Bodies  of  this  class,  when  boiled  with  water, 
yield  oxy-compounds  : 

C02C2H5.CHN2+H20=C02C2H5.CH2OH+N2 
C6HBN2C1+H20=C6H6OH+HC1+N2. 


122  ORGANIC   CHEMISTRY 

Formation  of  Diazo-benzols.  —  (la)  Gaseous  nitrous  acid,  made  by 
digesting  arsenious  acid  with  nitric  acid,  is  conducted  into  a  paste  of 
the  salt  to  be  diazotised.  The  mixture  is  cooled  all  the  while  with 
ice.  The  solution  of  the  diazo-compound  is  precipitated  by  a  mixture 
of  alcohol  and  ether,  (ib)  Add  acid  to  the  cooled  solution  of  the 
salt  to  be  diazotised  sufficient  (B.  8,  1073  ;  25,  1974,  footnote  ;  29, 
R.  1158)  to  liberate  the  nitrous  acid  from  sodium  or  potassium  nitrite, 
the  well-cooled  solution  of  which  is  gradually  introduced  into  the 
acidified  liquid  : 

C6H5NH2.HCl+HCl-fNO2K-C6H5N2Cl+2H20+KCl. 

(ic)  Feebly  basic  amines,  e.g.  dinitraniline,  which  are  incapable  of 
forming  stable  salts  in  aqueous  solution,  are  dissolved  in  concentrated 
nitric  acid,  and  the  amount  of  potassium  metabisulphite  required  for 
reducing  i  mol.  nitric  acid  to  nitrous  acid  is  introduced  (B.  42,  2956) : 

2C6H5NH2.HNO3+K2S2O6-f2NO3H=2C6H5N2NO34-K2S2O7+4H2O. 

(2)  As  the  diazo-benzol  salts  are  more  freely  soluble  in  water  than 
in  alcohol,  in  order  to  obtain  solid  diazo-salts  the  diazotising,  where 
practicable,  should  be  made  with  alkyl  nitrites  (Vol.  I.)  dissolved  in 
alcohol  or  glacial  acetic  acid  (cp.  B.  34,  3338  ;  C.  1898,  I.  295  ;  II.  742). 

Sometimes  a  peculiar  migration  of  the  diazo-groups  takes  place, 
on  mixing  the  solution  of  an  aniline  salt  with  a  diazo-salt  solution. 
Thus,  toluol  diazo-chlorides  and  ni tramlines  (B.  29,  287)  arise  from 
nitro-diazo-benzol  chlorides  and  toluidins  : 

N02C6H4N2C1+C6H4(CH3)NH2=N02C6H4NH2+C6H4(CH3)N2C1. 

(3)  Another    procedure,    occasionally    applicable    in    diazotising, 
consists  in  letting  zinc  dust  and  hydrochloric  acid  act  upon  the  nitrate 
of  the  diazo-derivative  (B.  16,  3080)  : 

C6H5NH2.NO3H+Zn+3HCl-C6H5N2Cl+ZnCl2+3H20. 

(4)  By  the  action  of  hydroxylamine  upon  the  nitroso-benzols  : 

C6H6NO+H2NOH=C6H5N1OH+H20. 

(5)  Diazo-benzol  nitrate  is  precipitated  upon  conducting  nitric 
oxide  into  a  chloroform  solution  of  nitroso-benzol  (B.  30,  512). 

(6)  By  the  saponification  of  nitroso-acetanilide  with  caustic  alkali. 

(7)  By  the  action  of  mercuric  oxide  upon  the  phenyl-hydrazins. 

(8)  From  phenyl-hydroxylamine,  benzol-sulphydroxamic  acid,  and 
caustic  soda  (B.  37,  290)  : 

CeH6NHOH+C6H6S02.NHOH+NaOH=CaH6N2OH+C8H6S02Na+2H20. 

(9)  From  phenyl-hydrazin   salts  with  H2O,  or  by  the  action  of 
chlorine  and  bromine  upon  the  alcoholic  solution  of  free  phenyl-hydra- 
zins at  low  temperatures.     This  last  method  is  very  suitable  for  pre- 
paring solid  diazonium  salts. 

(10)  From  thionyl-phenyl-hydrazone  with  thionyl  chloride,  acetyl 
chloride,  and  other  acid  chlorides  (A.  270,  116)  : 

CeH5NH,N  ;  SO+CH3COC1=C6H6N2C1+ S+ CH3CO2H. 


DIAZO-COMPOUNDS  123 

Properties.—  The  acid  salts  of  the  diazo-compounds  are  mostly 
crystalline,  colourless  bodies,  which  speedily  brown  on  exposure  to  the 
air.  They  are  readily  soluble  in  water,  slightly  in  alcohol,  and  are 
precipitated  from  the  latter  solution  by  ether.  Consult  B.  28,  1734, 
2020,  for  their  electric  conductivity  and  cryoscopic  behaviour.  They 
are  generally  very  unstable  (B.  24,  324),  and  decompose  with  a  violent 
explosion  when  they  are  heated,  or  struck  by  a  blow. 

The  diazo-derivatives  are  very  reactive,  and  enter  numerous, 
readily  occurring  reactions,  in  which  nitrogen  is  liberated,  and  the 
diazo-group  in  the  benzene  nucleus  directly  replaced  by  halogens, 
hydrogen,  hydroxyl,  and  other  groups. 

History  and  Constitution.—  The  diazo-compounds  were  discovered 
at  the  close  of  the  '5o's  by  Peter  Griess  (A.  137,  39),  who  regarded 
their  salts  as  additions  of  C6H4N2  and  acids,  e.g.  HC1.  Kekule 
demonstrated  that  the  azo-group  only  replaced  one  hydrogen  of  benzene, 
and  held  on  the  opposite  side  the  radicle  of  the  acid,  e.g.  C6H5  —  N 
=N.C1  (Z.  f.  Ch.  N.F.  (1866)  2,  308  ;  Chemie  der  Benzolderivate, 
1,  223).  Blomstrand,  A.  Strecker,  and  E.  Erlenmeyer,  sen.,  however, 
viewed  the  diazo-salts  as  ammonium  salts,  e.g.  C6H5N(C1)  =  N. 

The  proof  of  the  fact  that  the  azo-group  N2  replaces  one  benzene 
hydrogen  atom  is  supposed  to  be  found  in  the  existence  of  such  bodies 

/N    \ 
as    tetrabromo-benzol-sulphanile-diazide    C«BIV\SQ  /    (B.    10,  1537). 

The  relations  of  the  diazo-benzol  salts  to  the  hydrazins  (E.  Fischer, 
A.  190,  100),  and  to  the  mixed  azo-compounds,  argued  in  favour  of 
Kekule  's  hypothesis. 

In  recent  years  Blomstrand's  formula  has  been  accepted  for  the 
acid  salts  of  the  diazo-bodies  (B.  29,  R.  93,  783).  Comparative  studies 
of  the  cryoscopic  behaviour,  and  the  electric  conductivity,  of  diazo- 
salt  solutions  on  the  one  side,  and  ammonium  and  alkali  salts  on  the 
other  (B  28,  1734,  2020),  have  contributed  to  this  assumption.  The 
diazo-salts  are  compared  to  the  quaternary  ammonium  salts  : 

C6H5N  :  N  C8H6N  }  (CH3)3 

Cl  Cl 

and  therefore  are  termed  diazonium  salts.  From  a  chemical  standpoint 
this  view  would  indicate,  among  other  things,  the  power  of  the 
diazonium  haloids  to  form  additive  compounds  with  the  halogens  —  a 
property  which  they  would  hold  in  common  with  quaternary  ammonium 
halides  as  well  as  with  certain  alkali  metals  —  e.g.  caesium,  rubidium. 
This  formula  also  permits  of  the  easy  conversion  of  the  aniline  salts 
by  means  of  nitrous  acid  into  diazo-salts,  without  being  compelled  to 
assume,  as  is  necessary  in  the  Kekule  formula,  the  migration  of  the 
acid  residue  from  the  aniline  nitrogen  to  the  nitrogen  atom,  which  has 
but  recently  entered  : 


The  basic  hydrates  corresponding  to  the  diazonium  salts  are  very 
unstable  (cp.  B.  31,  340,  1612  ;  33,  2147),  as  they  probably  transform 
themselves  into  compounds  of  Kekule's  diazo-type  (see  above)  with 
atomic  displacement,  The  chemical  character  of  these  transposed 


124  ORGANIC  CHEMISTRY 

hydrates  (incapable  of  isolation)  is  thereupon  changed :  they  are  acids, 
forming  metallic  salts  such  as  C6H5N  :  NOK,  which  can  be  handled. 
By  mineral  acids,  these  metallic  salts  are  changed  back  into  the 
diazonium  salts  of  the  acids.  The  diazo-alkali  salts,  or  alkaline  diazo- 
tates,  are  transposed  into  the  more  stable  iso-diazotates,  partly  at 
ordinary  temperatures,  partly  on  heating  (B.  29,  455).  These  are 
distinguished  by  the  difficulty  with  which  they  "  couple  "  in  alkaline 
solution,  when  efforts  are  made  to  form  azo-dyes,  with  aromatic  amines 
or  phenols  (Schraube  and  Schmidt,  B.  27,  514).  To  these  iso-diazo- 
tates the  structure  C6H5NMe.NO  was  originally  ascribed.  They  were 
derived  from  the  "  nitrosamine  "  form  of  the  diazo-bodies,  since,  with 
methyl  iodide,  they  yielded  phenyl-methyl-nitrosamine.  But  it  has 
been  found  possible,  in  several  cases,  to  obtain,  from  the  iso-diazotates, 
acid  hydrates  containing  hydroxyl,  by  acidulating  them.  But  these, 
as  a  rule,  change  rapidly  into  the  more  stable  "  nitrosamine"  forms 
ArNH.NO  (cp.  Vol.  I.,  Pseudo-acids,  and  B.  35,  2964). 

According  to  Hantzsch  (Die  Diazoverbindungen,  Stuttgart,  1902), 
the  isomerism  of  the  diazo-metallic  salts  of  identical  structure  is  based 
upon  stereo-isomerism  (see  Vol.  I.,  Stereo-isomerism  of  ethylene  deriva- 
tives, and  Vol.  II.,  Benzaldoxime),  according  to  the  formula  : 

C6H5N  C6H5N 

KOlSr  NOK 

Syn-diazo-benzol-potassium         Anti-diazo-benzol-potassium. 

The  difference  in  the  coupling  power  (see  above),  and  in  other 
reactions  of  the  normal  and  the  iso-diazotates,  respectively,  is  attributed 
by  Hantzsch  to  the  larger  energy  content  of  the  former,  in  comparison 
with  the  latter ;  the  two  groups  of  diazotates  might  therefore  also  be 
distinguished  as  the  "  unstable  "  and  "  stable  "  groups  respectively 
(see  also  Vol.  I.,  Dynamic  isomerism). 

There  are  therefore  four  classes  of  diazo-bodies,  also  more  or  less 
convertible  into  one  another  :  (i)  diazonium  salts ;  (2)  normal, 
"  syn-,"  or  "unstable"  diazotates;  (3)  iso-,  "  anti-,"  or  "stable" 
diazotates  ;  (4)  primary  nitrosamines.  Their  transitions  correspond 
to  the  following  scheme  : 

C6H5N(OH)N  ^±  C6H5N  :  N(OH)  ^±  C6H5NH.NO. 

As  of  the  diazo-metallic  salts,  so  also  of  the  diazo-benzol-sulphonic 
salts,  and  especially  of  the  diazo-cyanides  (see  below),  isomeric  series 
have  been  discovered:  ArN2CN  may  be  diazonium  cyanide  as  well 
as  unstable,  or  stable,  diazo-cyanide  (benzol-azo-cyanide,  cp.  nomen- 
clature, B.  33,  2556). 

i.  DIAZONIUM  SALTS. — Diazo-benzol  chloride  C6H5NC1  =  N,  colour- 
less needles  (B.  23,  2996  ;  28,  2053).  The  platinum  salt,  [C6H5N2C1]2 
PtCl4,  consists  of  yellow  prisims.  The  gold  salt,  C6H5N2Cl.AuCl3 
(A.  137,  52).  Mercury  salt,  C6H5N2Cl.HgCl2,  consists  of  white  needles, 
decomposing  at  122°. 

Diazo-benzol  bromide  C6H5.N2Br  separates  in  white  laminae,  if 
bromine  be  added  to  the  ethereal  solution  of  diazo-amido-benzol. 
Tribrom-aniline  remains  in  solution. 

Diazo-benzol   bromide    cuprous    bromide    C6H5N2Br.Cu2Br2,   con- 


DIAZONIUM   SALTS  125 

sisting  of  reddish-yellow  needles,  is  decomposed  by  water  into  cuprous 
bromide,  nitrogen,  and  bromo-benzol  (B.  28,  1741).  Concerning 
Benzol-diazonium  fluorides  like  C6H5N2F.HF,  and  benzol-diazonium- 
azides  like  NO2C?H4N2.N3,  see  B.  36,  2056,  2059. 

Diazo-per-halides.  — The  diazonium  halides  readily  add  two  halogen 
atoms,  but  of  the  ten  possible  combinations  with  the  halogens,  chlorine, 
bromine,  and  iodine,  the  trichloride  is  the  only  one  that  has  not  been 
prepared.  It  may  be  remarked  that  the  compound  C6H5N2BrICl 
can  be  prepared  both  from  the  chloride  and  BrI,  and  from  the  bromide 
and  C1I  (B.  28,  2754). 

Diazo-benzol  perbromide  C6H5.N2Br3  is  precipitated  from  the 
aqueous  solution  of  diazo-benzol  nitrate  or  sulphate  by  bromine  in 
HBr  acid  or  NaBr.  It  is  a  dark-brown  oil,  which  quickly  becomes 
crystalline.  It  is  insoluble  in  water  and  ether,  and  crystallises  from 
cold  alcohol  in  yellow  laminae.  Continued  washing  with  ether  con- 
verts it  into  diazo-benzol  bromide.  In  moist  air  it  decomposes, 
forming  phenol  and  tribromo-phenol.  Chemically,  it  behaves  like  a 
mixture  of  diazo-benzol  bromide  and  free  bromine.  Many  compounds 
may  thus  be  brominated  with  diazo-benzol  perbromide,  with  simul- 
taneous formation  of  HB  and  benzol-diazonium  bromide.  It  is 
changed  by  aqueous  ammonia  to  diazo-benzol  imide.  Alkalies  decom- 
pose it  into  nitroso-benzol  and  potassium-diazo-benzol.  Boiling 
alcohol  converts  it  into  bromo-benzol. 

Diazo-benzol  nitrate  C6H5N2O.NO2  consists  of  long,  colourless 
needles,  which  explode  with  greater  violence  than  fulminating  mercury 
or  nitrogen  iodide  when  they  are  gently  heated,  struck,  or  subjected 
to  pressure. 

Diazo-benzol  sulphate  C6H5.N2.SO4H  consists  of  colourless  needles 
or  prisms,  which  dissolve  readily  in  water.  It  explodes  at  100°.  It 
is  prepared  either  by  diazotising  aniline  sulphate  or  by  allowing 
sulphuric  acid  to  act  upon  diazo-benzol  nitrate  (B.  28,  2049). 

Diazo-benzol  perchlorate  C6H5N2O.C1O4  is  distinguished  by  its 
difficult  solubility,  like  potassium  perchlorate.  On  adding  perchloric 
acid  to  an  aqueous  solution  of  diazo-benzol  chloride,  it  precipitates 
in  the  form  of  prismatic  needles,  which  explode  with  extreme  violence, 
even  in  a  moist  condition. 

Oxalate  (B.  28,  2059). 

Carbonate,  nitrite,  acetate  (B.  28,  1741). 

Diazonium  cyanides,  corresponding  to  diazonium  haloids,  have 
been  obtained  in  the  form  of  their  silver  double  cyanides,  e.g. 
p-bromo-diazonium  silver  cyanide  BrC6H4N(CN)N.AgCN  (B.  30, 
2546  ;  cp.  also  anisol-diazonium  cyanide,  B.  34,  4166)  ;  the  diazonium 
cyanides  are  equally  isomerised  to  diazo-cyanides. 

Diazo-benzol  sulphoeyanide  C6H5N2.SCN  is  a  yellow,  very  explosive 
mass,  obtained  from  diazo-benzol  chloride  and  potassium  sulpho- 
cyanide. p-Chloro-diazo-benzol  sulphocyanide  C1[4]C6H4N2.SCN  re- 
arranges itself  with  ease  into  p-Sulphoeyano-diazo-benzol  chloride 
CNS[4]C6H4N2C1  (B.  29,  947).  Such  a  change  of  place  between 
nucleus-substituting  atoms,  and  the  acid  residue  of  the  diazonium  group, 
has  become  known  in  a  number  of  further  cases  ;  it  only  occurs  in  the 
o-  and  p-positions  of  the  nucleus  substituent ;  thus,  2,  4-dibromo- 
benzol-diazonium  chloride  yields  a  chloro-bromo-diazonium  bromide  ; 


126  ORGANIC   CHEMISTRY 

and  2,  4,  6-tribromo-diazonium  chloride,  a  dibromo-chloro-diazonium 
bromide  (B.  31,  1253  ;  33,  505  ;  36,  2069). 

p-Phenylene-bis-diazo-chloride  C6H4(N2C1)2  consists  of  yellow- 
coloured,  very  explosive  needles  (B.  30,  92). 

2.  NORMAL  DIAZO-HYDRATES  are  not  known  in  a  free  state.  In 
attempting  to  separate  them  by  acids  from  their  potassium  salts, 
yellow-coloured,  exceedingly  explosive,  and  unstable  precipitates  are 
obtained,  under  certain  conditions.  These  appear  to  be  not  hydrates, 
but  anhydrides,  e.g.  diazo-benzol  anhydride  [C6H5N2]2O  ;  p-ehloro- 
diazo-benzol  anhydride  [C1C6H4N2]2O.  These  bodies  redissolve  in 
acids  to  diazonium  salts,  in  alkalies  to  diazo-metallic  salts,  in  ammonia 
to  bis-diazo-amido-bodies,  in  anilines  to  diazo-amido-compounds 
(B.  29,  451),  in  HCN,  diazo-cyanides,  and  with  benzol-sulphinic  acid, 
diazo-sulphones  (B.  29,  451  ;  31,  637). 

Normal  diazo-benzol  potassium  C6H5N2OK  is  produced  on  intro- 
ducing a  saturated  aqueous  solution  of  diazo-benzol  chloride  into  an 
excess  of  highly  concentrated  caustic  potash  (B.  29,  461).  It  forms 
white,  pearly  flakes  which  can  be  quantitatively  reconverted  into 
diazo-benzol  chloride.  Normal  sodium-diazo-benzol  is  formed  in 
small  quantities  by  the  action  of  sodium  amide  upon  nitro-benzol 
(B.  37,  629),  or  of  NH2OH  upon  nitro-benzol  in  alkaline  solution  (B. 
38,  2056).  It  yields  diazo-esters  in  the  cold,  with  alcohols  (B.  29, 
488)  ;  see  B.  30,  339,  for  the  reduction  of  potassium  diazo-benzol  to 
phenyl-hydrazin.  When  alkaline  diazo-benzol  solutions  are  oxi- 
dised with  potassium  ferricyanide  or  potassium  permanganate,  the 
principal  product  is  diazo-benzol  acid,  together  with  a  little  nitroso- 
benzol,  nitro-benzol,  azo-benzol,  and  diphenyl.  Benzoyl  chloride  and 
sodium  hydroxide  change  normal  potassium  diazo-benzol  into  nitroso- 
benzanilide  C6H5N(NO).CO.C6H5  (B.  30,  214).  Salts  of  the  heavy 
metals  with  diazo-benzol  are  obtained  by  the  precipitation  of  solu- 
tions of  potassium  diazo-benzol  with  metallic  salts  (B.  23,  3035  ; 
28,  226). 

Diazo-benzol  methyl  ether  C6H5N2.OCH3,  isomeric  with  methyl- 
phenyl-nitrosamine,  is  obtained  from  normal  or  iso-diazo-benzol  silver 
and  methyl  iodide,  as  well  as  from  diazo-benzol  potassium  and  methyl 
alcohol.  It  is  a  yellow,  volatile  oil,  rapidly  turning  dark  in  colour, 
possessing  a  penetrating,  stupefying  odour,  and  decomposing  shortly 
after  its  liberation.  Boiling  dilute  sulphuric  acid  decomposes  it  into 
nitrogen-methyl  alcohol,  and  phenol  (B.  28,  227,  236).  o-  and  p- 
Nitro-diazo-benzol  methyl  ether  NO2.C6H4N2.OCH3  (B.  28,  236). 

On  saponification  with  alkali  in  the  cold,  the  diazo-ethers  give 
normal  diazo-alkali  salts  (B.  36,  4361). 

Di-p-nitro-phenyl-diazo-sulphide  [NO2[4]C6H4N2]2S  is  precipitated 
as  an  egg-yellow,  very  explosive  mass,  on  adding  hydrogen  sulphide 
to  a  neutral  solution  of  the  diazo-chloride.  With  benzene  it  forms 
nitro-diphenyl,  nitrogen,  and  sulphur  ;  di-p-nitro-diphenyl  disulphide 
is  formed  simultaneously.  In  an  acid  solution  with  an  excess  of 
hydrogen  sulphide  there  is  produced,  along  with  the  diazo-sulphide, 
p-Nitro-phenyl-diazo-mercaptan  hydrosulphide  NO2.C6H4N2SH.SH2, 
consisting  of  red,  brilliant,  metallic-looking  needles,  which  dissolve 
with  a  deep-red  colour  in  the  alkalies.  They  decompose,  when  fused, 
with  the  formation  of  nitro- phenyl-hydrazin,  nitraniline,  sulphur, 


ISO-DIAZO-HYDRATES  127 

and  dinitro-phenyl  disulphide.  Non-explosive  Di  -  p  -  nitro  -  phenyl  - 
diazo-disulphide  [NO2C6H4N2]2S2  is  finally  the  third  product  in  the 
action  of  hydrogen  sulphide.  It  is  insoluble  in  alkali.  It  consists  of 
sulphur-yellow  needles,  soluble  in  acetone  (B.  29,  272).  See  Thio- 
phenol  for  diazo-benzol-thio-phenyl  ether. 

3.  ISO-DIAZO-HYDRATES  are  liberated  from  their  potassium  salts  by 
acetic  acid.     They  are  very  easily  decomposed.     Those  of  benzene 
and  toluol  are  colourless  oils.     These  substances  are  mostly,  however, 
not  the  real  hydrates,  but  their  pseudo-forms  :  primary  aryl-nitros- 
amines  ArNH.NO.     In  some   cases,   as   in   the   dibrom-anisol-diazo- 
hydrate,  the  hydroxyl  forms  have  been  isolated  as  unstable  precipitates 
easily   passing   into   nitrosamines.     In   undissociating   solvents   they 
react  energetically  with  NH3,  acetyl  chloride,  and  PC15,  whereas  the 
nitrosamine  forms  remain  indifferent  (B.  35,  2964). 

Potassium  iso-diazo-benzol  C6H5N2OK  is  formed  on  digesting 
potassium  diazo-benzol  for  a  brief  period  at  I30°-I35°  with  concen- 
trated caustic  potash  ;  and  when  fused,  caustic  potash  acts  upon  phenyl- 
methyl-nitrosamine,  into  which  it  returns  upon  treatment  with  methyl 
iodide  (B.  27,  514,  672,  680).  Sodium  amalgam  reduces  it  with  ease 
to  phenyl-hydrazin  (B.  29,  473  ;  30,  339).  With  benzoyl  chloride 
and  sodium  hydrate,  as  well  as  during  oxidation,  it  behaves  like  the 
normal  diazotate,  but  differs  from  the  latter  qualitatively  by  the 
omission  of  dye-formation,  e.g.  on  mixing  with  j3-naphthol  in  alkaline 
solution  (B.  27,  517).  Potassium  iso-diazo-benzol  is  also  formed  direct 
from  aniline  and  phenyl-hydrazin  by  the  action  of  alkyl  nitrite  and 
alkali  alcoholate,  liberating  nitrous  oxide  in  the  latter  case  (B.  33,  3511  ; 
41,  2808)  ;  it  has  also  been  obtained  from  oxy-azoxy-benzol  C6H5 
(N2O)C6H4OH  by  oxidising  decomposition  with  MnO4K  (B.  33,  1957). 
Potassium  iso-p-diazo-toluol  results  when  its  isomeride  is  exposed  to 
the  air  (B.  29,  1385).  Sodium  iso-p-nitro-diazo-benzol  C6H4(NO2) 
N2ONa+2H2O  yields  nitro-phenyl-methyl-nitrosamine  with  methyl 
iodide,  whereas  the  silver  salt  forms  the  corresponding  diazo-ester 
(B.  29,  1384). 

4.  DIAZO-BENZOL    SULPHONIC    ACID,    benzene   azo-sulphonic   acid 
C6H5N2SO3H,  is  very  decomposable  (B.  30,  75).     Its  potassium  salt 
is  produced  upon  introducing  diazo-benzol  nitrate  into  a  cold,  neutral, 
or  feebly  alkaline  solution  of  di-potassium  sulphite  ;  the  liquid  solidi- 
fies to  a  yellow,  crystalline  mass.     Under  other  conditions  a  more 
easily   decomposable,   orange-coloured  salt   is   formed   (B.   27,   1715, 
2930).     For  the  sensitivity  of  the  diazo-benzol  sulphonates  to  light, 
and  their  application  in  photography,  consult  B.  23,  3131.     Mono- 
potassium  sulphite  reduces  diazo-benzol  nitrate  to  potassium  phenyl- 
hydrazin    sulphonate,  which    mercuric  oxide   oxidises  to   potassium 
diazo-benzol  sulphonate  (B.  27,  1245). 

p-Nitro-diazo-benzol  nitrate  and  one  molecule  of  K2SO3  yield 
potassium  p-nitro-diazo-benzol  sulphonate,  which  also  appears  to  exist 
in  two  forms.  The  acid  crystallises,  with  four  molecules  of  water,  in 
ruby-red  prisms  (B.  30,  90).  On  using  two  molecules  of  potassium 
sulphite  the  product  is  potassium  p- nitro -phenyl-hydrazin  disul- 
phonate  C6H4(NO2)N(SO3K)NH.SO3K  (B.  29,  1829).  p-Chloro-  and 
p-bromo-benzol-diazo-sulphonic  acid  (B.  30,  75). 

The  diazonium  salts  and  benzene-sulphinic  acid  combine  to  Benzene- 


128  ORGANIC  CHEMISTRY 

diazo-sulphones  C6H5N2SO2C6H5,  which  are  resolved  by  hydro- 
chloric acid  into  diazonium  chlorides  and  sulphinic  acids  (B.  30,  312). 

With  substances  containing  the  grouping  C6H5N  :  NX,  e.g.  benzol- 
diazo-cyanides  and  the  azo-compounds,  benzol-sulphinic  acid  forms 
colourless  addition  products,  mostly  stable  in  water  and  acids  : 
C6H5N(SO2C6H5)NHX.  These  should  be  regarded  as  derivatives  of 
hydrazo-benzol,  and  are  split  up  into  their  components  by  alkalies 
(B.  30,  2548).  The  action  of  SO2  upon  p-nitro-diazo-benzol  hydrate 
produces  p-Nitro-phenyl-diazo-p-nitro-phenyl  sulphone  NO2C6H4N  : 
NSO2C6H4N02  (B.  35,  661). 

5.  DIAZO-BENZOL  CYANIDE  C6H5N2CN  appears  as  an  unstable  oil, 
on  adding  a  potassium  cyanide  solution  to  the  solution  of  a  diazo- 
benzol  salt.  If,  however,  the  reverse  be  done — the  diazo-salt  be  added 
to  the  potassium  cyanide  solution — a  prussic  acid  additive  product, 
C6H5N2CN.HCN,  will  separate  as  a  yellow  precipitate,  m.p.  70°.  Ben- 
zene-diazo-carboxyl-amide,  phenyl-azo-carbamide  C6H5N  :  NCONH2, 
results  from  the  oxidation  of  phenyl-semicarbazide  (/.  Ch.  Soc.,  1895, 
i,  p.  1067  ;  B.  28,  1925,  2599).  It  consists  of  reddish-yellow  needles, 
m.p.  114°.  The  anilide  C6H5N2CONHC6H5,  from  i,  4-diphenyl-semi- 
carbazide  (B.  29, 1691),  m.p.  122°. 

Two  isomerides  have  been  obtained  from  p-chloro-  and  p-nitro- 
diazo-benzol  cyanide,  and  in  each  instance  the  one  body  is  unstable 
and  the  other  stable.  The  unstable,  low-melting  modifications  only 
form  at  lower  temperatures,  decompose  easily,  especially  in  contact 
with  copper  powder,  give  up  nitrogen  with  the  formation  of 
benzene  cyanides,  form  azo-dyes  with  aromatic  amines  or  phenols, 
and  change  rapidly,  particularly  in  alcoholic  solution,  or  in  sun- 
light, into  the  stable  isomerides  (C.  1906,  II.  1054).  This  trans- 
position is  influenced  by  the  nature  and  position  of  the  nuclear 
substituents.  With  a  less  straightforward  course  it  can  also  be 
obtained  through  the  intermediary  of  benzol-sulphinic  addition 
products  (B.  30,  2553). 

Unstable  p-chloro-  and  p-nitro-diazo-benzol  cyanide  melt  at  28° 
and  29°  respectively,  the  stable  forms  at  106°  and  86°  respectively. 
2, 4, 6-Tribromo-benzol-diazo-cyanide,  unstable  form,  m.p.  6p° ;  stable 
form,  m.p.  147°.  The  stable  cyanides  approach,  in  their  behaviour, 
the  azo-bodies.  With  prussic  acid  they  readily  combine  to  form 
imido-cyanides  (see  above)  ;  with  water,  diazo-carboxyl  amides  ;  with 
alcohols,  amido-ethers,  from  which,  by  saponification,  the  potassium 
salts  of  the  corresponding  diazo-benzol-carboxylic  acids  are  obtained  ; 
the  acids  are  very  easily  decomposed  (B.  28,  670,  2072  ;  30,  2529). 
Tribromo-benzol-azo-carboxylic  acid  C6H2Br3.N2COOH  is  obtained 
from  its  amide,  the  oxidation  product  of  tribromo-phenyl-semi- 
carbazide  (B.  28,  1929). 

CHIEF  DECOMPOSITIONS  OF  THE  DIAZO-BENZOL  SALTS. 

The  decompositions  of  diazo-salts  in  which  atoms  of  metal- 
loids or  atomic  groups  take  the  place  of  nitrogen  and  expel  the 
latter,  are  of  the  greatest  importance  for  the  relations  of  many 
different  di-  and  poly-substitution  products  of  benzene,  and  its 
homologues. 


CHIEF   DECOMPOSITIONS   OF   DIAZO-BENZOL   SALTS    129 

1.  Replacement  of  the  Diazo-group  by  Hydrogen. — (a)  On  heating 
diazonium  salts  with  alcohols,  two  reactions  may  take  place  : 

I.  C6H5N2C1+C2H5OH=C6H5OC2H5+HC1+N2 
II.  C6H5N2C1+C2H5OH  =C6H6+C2H40-fHCl+N2. 

Reaction  I.  yields  phenol-ether,  and  reaction  II.  benzene-hydro- 
carbons with  aldehyde  as  a  by-product  (A.  137,  69  ;  217,  189  ;  B. 
9,  899  ;  17,  1917  ;  18,  65).  Often  these  two  reactions  are  simultane- 
ous :  solid  benzol-diazonium  chloride  or  sulphate,  with  absolute  methyl- 
alcohol,  gives  anisol ;  with  ethyl-alcohol,  phenetol  and  a  little  benzene  ; 
in  the  negatively  substituted  benzols,  the  replacement  of  the  diazo- 
group  by  hydrogen  steps  into  the  foreground.  Multi-valent  alcohols, 
on  the  other  hand,  only  appear  to  form  phenol-ether  (B.  34,  3337  ; 
35,  998  ;  36,  2061).  Sunlight  favours  reaction  I.  (C.  1905,  II.  129). 

Heating  with  phenols  also  converts  diazonium  salts  partly  into 
phenyl-ether,  with  evolution  of  nitrogen  ;  but  oxy-diphenyls  are  mainly 
generated  (C.  1903,  I.  705). 

(b)  The   aryl-hydrazins   formed   by  reduction   of   the   diazo-com- 
pounds  (cp.  phenyl-hydrazin)  are  so  oxidised  by  boiling  with  copper 
sulphate,  ferric  chloride,  potassium  chromate,  or  sodium  hypochlorite 
that  an  H  atom  takes  the  place  of  the  hydrazin  group,  with  evolution 
of  nitrogen : 

C6H5NHNH2+0=C6H6+N2+H20. 

The  intermediate  formation  of  hydrazins,  subsequently  oxidised 
by  unchanged  diazo-compounds  (B.  36,  813),  is  probably  also  the 
cause  of  the  following  reactions  in  which  H  displaces  the  diazo-group  : 

(c)  Boiling  of  diazonium  chlorides  with  stannous  chloride  solution 
(B.  22,  R.  741). 

(d)  Action  of  hypo-phosphonic  acid  upon  diazonium  salts  (B.  35, 
162  ;  A.  320,  143). 

(e)  Solution  of   the  diazo-compound   in   caustic  soda,   and  soda- 
stannous  oxide  (B.  36,  813).     Iso-diazotates  are  not  reduced  by  the 
latter  (B.  36,  2065). 

(/)  Boiling  with  formic  acid  converts  diazonium  salts,  almost  ex- 
clusively, into  the  corresponding  hydrocarbons : 

C6H5N2C1+HCOOH=C6H6+N2+CO2+HC1. 

Glacial  acetic  acid  yields  nothing  but  acetyl-phenols  (B.  23,  1632  ; 
C.  1907,  I.  1031). 

2.  Replacement  of  the  Diazo-group  by  Halogens.— (a)  The  diazo- 
benzol  salts  are  treated  with  haloid  acids.     Of  the  four  acids  of  this 
class,  hydriodic  acid  reacts  most  readily  : 

C6H5N2.OS03H+HI=C6H5I+N2+SO4H2. 

The  haloid  acids  are  frequently  applied  in  glacial  acetic  acid  solution. 
The  hydro-bromides  or  hydro-iodides  of  the  bases  can  also  be  treated 
with  nitric  acid. 

(b)  Concentrated  haloid  acids  are  allowed  to  act  upon  the  diazo- 
amido-derivatives.  This  reaction  is  especially  recommended  for  the 
preparation  of  fluoro-  or  chloro-derivatives  (B.  21,  R.  97)  : 

C6H5.N  :  N-NH.C6H5+2HF1=C6H5F1+N2+F1H.NH2.C6H5. 

VOL.  II.  K 


130  ORGANIC  CHEMISTRY 

(c)  Chloro-  and  bromo-derivatives  are  formed,  if  the  PtCl4-  and 
PtBr4-  double  salts  are  heated  alone  ;  or,  which  is  better,  with  dry 
soda  or  salt  : 

(C6H5N2Cl)2PtCl4-:2C6H5Cl+2N2+Pt+2Cl2. 

(d)  When  the  diazo-perbromides  are  boiled  with  alcohol  (the  latter 
is  oxidised  to  aldehyde),  bromo-benzols  are  formed  : 

C6H5N2Br3+CH3CH2OH=C6H5Br+N2+2HBr+CH3CHO. 

The  reactions  indicated  under  a,  b,  c,  and  d  were  all  observed  by 
P.  Griess.  Another  reaction  belongs  to  this  group  ;  it  was  discovered 
by  Sandmeyer  (B.  17,  2650  ;  23,  1880),  and  is  capable  of  far  greater 
generalisation.  It  is  based  upon  the  fact  that  diazo-salts  are  decom- 
posed by  cuprous  salts  : 

(e)  When  cuprous  chloride  is  added  to  an  aqueous  solution  of  diazo- 
benzol  *  chloride,  an   addition   product,  C6H5N2ClCu2Cl2,  is  formed  at 
first,  but  upon  the  application  of  heat  this  decomposes  into  C6H5C1 
(B.  19,  810  ;  23,  1628  ;  33,  2544)  : 

C6H5N2Cl(Cu2Cl2)-C6H5Q+N2+Cu2Cl2. 

Cuprous  bromide  and  cuprous  iodide  act  similarly  upon  the  corre- 
sponding diazo-benzol  salts.  If  cuprous  bromide  acts  upon  a  diazo- 
nium  salt,  the  corresponding  bromo-benzol  is  produced  under  suitable 
conditions,  which  proves  that  the  cuprous  haloid  takes  an  essential 
part  in  the  process. 

A  modification  of  the  method  consists  in  treating  the  diazo-deriva- 
tives  in  the  presence  of  hydrochloric,  hydrobromic,  or  hydro-iodic  acid 
with  copper  powder  (B.  23,  1218  ;  25,  1091,  footnote).  The  latter 
seems  to  act  catalytically. 

3.  Replacement  of  the  Diazo-group  by  Hydroxyl.  —  When  the  salts 
(sulphates  are  best)  are  boiled  with   water,  the  diazo-group  will  be 
replaced  by  hydroxyl  : 

C6H5N2Br      +H20=C6H5OH+N2+HBr 
C6H5N2N03   +H20=C6H5OH+N2+N03H 
C6H5N2S04H+H20=C6H5OH+N2+S04H2. 

This  method  often  fails  in  negatively  substituted  diazonium  salts. 
But  it  also  succeeds,  in  these  cases,  on  replacing  the  water  by  a  mixture 
of  dilute  sulphuric  acid  and  sodium  sulphate  (C.  1905,  II.  617). 

On  decomposing  diazo  -nitrates,  nitro-phenols  are  formed  as  by- 
products. On  the  velocity  of  phenol  splitting,  see  A.  325,  292  ;  B. 
31,  35I9- 

4.  Replacement  of  the  Diazo-group  by  the  Sulphydrate  Group.— 
On  digesting  the  diazide  of  sulphanilic  acid  (q.v.),  a  cyclic  diazo-salt, 
with  alcoholic  potassium  sulphide,  the  potassium  salt  of  p-thio-phenol- 
sulphonic  acid  will  be  produced  (B.  20,  350)  : 


r[i]Na  x  r[i]SK 

QH4  1  [4]S03/      K2S  :  :  CfiH4  \  [4]S03K  + 
In  the  same  manner,  when  mercaptan  acts  upon  diazo-benzol- 


CHIEF  DECOMPOSITIONS   OF  DIAZO-BENZOL   SALTS    131 

sulphonic  acid,  a  compound  results  which,  upon  standing  or  warming, 
decomposes  into  thio-phenol-ethyl-ether-p-sulphonic  acid  : 


r  H  /N2  \   C,H.SH  /N2SC,H5     -N. 

C"H4\S03/  C«H*\S03H  C« 

With  xanthogenic  salts  (Vol.  I.)  the  diazonium  salts  form  aromatic 
xanthogenic  acid  esters,  like  C6H5S.CSOC2H5,  which,  on  saponification, 
yield  thio-phenols  (/.  pr.  Ch.  2,  41,  184). 

For  the  reaction  of  diazonium  salts  with  thio-glycolic  acid,  see 
C.  1908,  I.  1221. 

5.  Replacement  of  the  Diazo-group  by  the  Sulphinic  Acid  Residue 
is  brought  about  by  conducting  sulphurous  acid  through  solutions  of 
diazonium  sulphates,  or  treating  them  with  alcoholic  SO2  solution, 
bisulphite,  and  Cu  powder  (B.  32,  1136  ;  C.  1902,  I.  959)  : 

C6H5N2(S04H)+S02-hCu=C6H5S02H+N2+S04Cu. 

6.  Replacement  of  the  Diazo-group  by  the  Nitro-group.  —  The  diazo- 
benzol  nitrite  solution  is  added  to  freshly  precipitated  cuprous  oxide, 
or  the  solutions  of  diazonium,  and  mercury  nitrites,  are  decomposed 
with  Cu  powder  (B.  33,  2551). 

7.  In  a  few  cases  the  diazo-group   may  be  replaced  by  amine 
residues,  e.g.  in  the  diazide  of  amido-anthra-quinone-sulphonic  acid 
by  treatment  with  ammonium  carbonate  or  amines  (B.  35,  2593). 

8.  Replacement  of  the  Diazo-group  by  the  Cyanogen  Group.  —  This 
reaction  connects   by  easy  stages   the  nitro-amido-benzols  with  the 
nitro-benzoic  acids,  and  the  latter  with  the  phthalic  acids.     The  im- 
portance of  this  fact  has  been  mentioned.     Add  the  diazo-benzol 
chloride  solution  to  a  copper  sulphate  solution  mixed  with  potassium 
cyanide  (B.  20,  1495  ;  23,  1630)  : 

C6H5N2CN=C6H5CN+N2. 

9.  Sulpho-cyanides  (rhodanides)  result   when  the  diazo-salts  are 
boiled  with  potassium,  and  cuprous  sulpho-cyanides  (B.  23,  770). 

10.  When  a  solution  of  diazo-benzol  sulphate  is  mixed  with  potas- 
sium cyanate,  and  reduced  copper  is  then  added  (B.  25,  1086),  phenyl 
iso-cyanide  or  carbanile  will  result. 

11.  Formation  of  Diphenyl  Compounds  from  Diazo-derivatives.  — 
Diphenyl  derivatives  frequently  appear  as  by-products  in  the  treat- 
ment of   diazo-bodies  with   reducing  agents  —  e.g.   stannous   chloride 
(B.  18,  965),  alcohol,  and  reduced  copper  (B.  23,  1226),  alcohol  alone 
or  sodium  ethylate  (B.  28,  R.  389)  —  as  well  as  in  the  action  of  water, 
of  phenol  (B.  23,  3705),  and  of  potassium  ferricyanide  (B.  26,  471). 
Into  aromatic  hydrocarbons   and  heterocyclic  compounds  —  e.g.  thio- 
phene,   pyridin,   and   quinolin  —  diazo-benzol   chloride  introduces  the 
phenyl  group.     This  occurs  very  easily  in  the  presence  of  aluminium 
chloride  (B.  26,  1994)  : 


C6H5N2C1  +  C6H6         >  C6H5C6H5  +  N2  +  HCL 
The   diazo-residue  in  the   diazo-oxides,  diazo-sulphides,  and  iso- 


132  ORGANIC  CHEMISTRY 

diazo-hydrates  is  readily  replaced  by  cyclic  residues  (B.  28,  404  ;  29, 
165,  274,  452)  : 

[N02C6H4N2]2S  +2C6H8  =2N02C6H4.C6H6  +N2 +H2S 
C6H6N2OH+C6H5N  (pyridin)  =CeH6.C6H4N+N2+H2O. 

12.  On  treating   diazonium  salts  with  amm.  cuprous  oxide  solu- 
tion, they  are  mostly  converted  into  azo-benzols  with  evolution  of  N  : 

2C6H5N2Cl+Cu20-C6H5N  :  NC6H5-f  N2+CuCl2+CuO  ; 

whereas  the  diazonium  salts,  from  o-  and  p-nitraniline,  usually  give 
the  corresponding  diphenyl  derivatives  (A.  320, 122). 

13.  The  reactions    n    and  12  are   simultaneous  when  saturated 
potassium  ferrocyanide  solution  acts  upon  diazonium  salts,  the  azo- 
compounds  of  the  diphenyl  series  being  produced  (C.  1907, 1.  1789). 

Other  Reactions  of  Diazo-derivatives,  in  which  nitrogen  is  not 
set  free : 

1.  Phenyl-hydrazins  are  produced  in  the  reduction  of  diazo-salts. 
The  action  of  benzol-diazonium  chloride  upon  zinc-ethyl,  in  etheric 

solution,   produces    ethylated   phenyl-hydrazins    and    also    diethyl- 
benzidin  (B.  35,  4179  ;  C.  1905,  I.  79). 

2.  When  diazo-compounds  are  oxidised  in  alkaline  solution,  they 
are  converted  into  nitroso-benzol  and  phenyl-nitro-amine  or  diazo- 
benzol  acid. 

3.  The  behaviour  of  diazo-bodies  toward  ammonia,  alkylamines, 
aniline,    and   related   bases,    when    diazo-imido-,    diazo-amido-,    and 
mixed  azo-derivatives  arise,  is  worthy  of  special  note.     These  very 
important  reactions  will  be  given  in  detail,  with  the  individual  classes. 

4.  Hydrazones  result  when  diazo-benzol,  in  alkaline  solution,  acts 
upon  bodies  containing  the  group  CH2CO.     The  primarily  formed 
hydrazones  often  rearrange  themselves,  with  additional  quantities  of 
the  diazo-benzol  salt,  into  formazyl  derivatives,  which  belong  to  the 
class  of  amidines  (B.  27, 147,  320, 1679  ;  29, 1386  ;  31,  3122  ;  32,  2880). 

9.  Diazo-amido- compounds. 
10.  Dis-diazo-amido-compounds. 

The  diazo-amido-compounds  are  derived  from  the  unknown  hydride 
NH=N — NH2,  in  which  the  hydrogen  of  the  imide  group  is  replaced 
by  an  aromatic  residue — e.g.  phenyl,  tolyl,  etc. — and  the  hydrogen 
of  the  amido-group  by  aliphatic  or  aromatic  residues :  mixed 
and  true  aromatic  diazo-amido-compounds.  The  dis-diazo-amido- 
bodies  are  also  derivatives  of  an  unknown  nitrogen  hydride, 
NH=N— NH— N=NH. 

Formation  of  Diazo-amido-derivatives. — They  result  from  the 
transposition  of  primary  and  secondary  amines  with  diazo-salts  : 

la.  Primary  aromatic  amines  yield  diazo-amido-  or  dis-diazo- 
amido-bodies,  depending  upon  the  conditions  of  experiment.  Diazo- 
amido-compounds  are  formed  when  equimolecular  quantities  of  diazo- 
salt  and  primary  amine  interact  : 

:  N.NHC6H5+HC1. 


DIAZO-AMIDO-COMPOUNDS  133 

Substituted  anilines  containing  the  substituent  in  p-  or  o-position 
react  essentially  like  aniline  itself,  but  in  meta-substituted  anilines, 
like  m-toluidin,  the  formation  of  amido-azo-compounds  becomes  pro- 
minent (/.  pr.  Ch.  2,  65,  401). 

Diazo-amido-compounds  are  also  produced  when  an  alkali  nitrite, 
in  the  absence  of  mineral  acids,  acts  upon  the  salts  of  primary  amines  : 

2C6H5NH2HC1+N02K=C6H5N  :  N.NH.C6H5+KC1+HC1+2H2O. 

ib.  A  dis-diazo-compound  results  if  a  molecule  of  aniline  be 
allowed  to  act,  in  alkaline,  alcoholic  solution,  upon  two  molecules  of 
a  diazo-benzol  salt.  It  can  also  be  obtained  by  transposing  diazo- 
benzol  chloride  with  diazo-amido-benzol  (B.  27,  703)  : 


2CaH5N2Cl+C6H5NH2  -    «5  NCeH5  +  2HC1 

V^jJtlgJN  I  JN/ 

C6H5N2C1+C.H5N  :  N.NHC,H5  =    «*  :       >NC.H.  +  HC1. 


Primary  aliphatic  amides  react,  with  special  readiness,  with  diazo- 
benzol  chloride,  forming  dis-diazo-amido  -  compounds,  so  that  the 
isolation  of  the  simple  aliphatic-aromatic  diazo-amido-compounds 
only  succeeds  under  special  conditions  (B.  38,  2328). 

When  a  diazo-benzol  salt  solution  is  allowed  to  flow  into  cold, 
concentrated  ammonia,  dis  -  diazo  -  benzol  -  amide  C6H5N  :  N.NH.N  : 
NC6H5  (B.  28,  171)  will  be  produced. 

The  normal  diazo-alkali  salts  also  yield  diazo-amido-compounds 
(B.  29,  289).  The  iso-diazo-salts,  due  to  the  transposition,  are,  how- 
ever, generally  incapable  of  reactions. 

ic.  Secondary  aromatic  and  aliphatic  bases  yield  secondary 
aromatic,  or  mixed  aliphatic-aromatic,  diazo-amido-compounds  (B. 
8,  148,  843  ;  C.  1905,  I.  1539). 

2.  Diazo-amido-compounds  are  also  produced  by  the  action  of  free 
nitrous  acid  upon  alcoholic  solutions  of  free  primary  amines,  the  free 
diazo-benzol  hydrate  or  anhydride  first  formed  turning  into  aniline  : 

C6H5N2.OH+NH2C6H5=C6H5N  :  N.NHC6H5+H2O. 

If  nitrites,  such  as  silver  nitrite,  act  upon  free  aniline,  salts  of  the 
diazo-amido-compounds  are  generated  (B.  29,  R.  1158). 

3.  A  method  specially  useful  for  preparing  mixed  fatty-aromatic 
diazo-amido-compounds  is  based  upon  the  action  of  organo-magnesium 
compounds  upon  the  aryl  esters  of  nitrogen  hydride.     Addition  pro- 
ducts containing  Mg  are  first  formed,  and  from  these  water  liberates 
the  diazo-amido-compounds  (D.  38,  683)  : 

/N 
C6H5.N<^  i)  +  CH3.Mg.I  =  C8H5.N  :  N.N(MgI)CH3 

CflH5N  :  N.N(MgI)CH3  +  H2O  =  C6H5N  :  N.NHCH3+MgI(OH). 

4.  Nitrosamines,    and   primary   amines,    also    yield   diazo-amido- 
compounds  (B.  27,  655). 

Nitroso-acetanilide  undergoes  transposition  with  aniline,  acetic 
acid  and  diazo-amido-benzol  being  formed.  If  i  mol.  aniline  is  used 


134  ORGANIC   CHEMISTRY 

for  every  2  mols.  nitroso-acetanilide  in  an  alkaline  solution,  an  aro- 
matic dis-diazo-amido-compound  is  obtained  : 

—  NO+NHaCeH6  =  C,H6NH—  N=NC6H6+CH3COOH 


Course  of  the  Reaction  in  the  Formation  of  Diazo-amido-deriva- 
tives.  —  It  is  an  interesting  fact  that  the  same  diazo-benzol-p-amido- 
toluol  is  formed,  e.g.,  from  diazo-benzol  chloride  and  p-toluidin,  as 
from  diazo-p-toluol  chloride  and  aniline,  although  different  com- 
pounds might  well  have  been  expected  : 

C,H6N2Cl+NH2[4]CeH<[i]CH3  -  >    I.  C6H5N=N.NH[4]C6H4[i]CH3 
CH3[i]CaH4[4]N2Cl+NH2CeH6  --  *  II.  CH3[i]C6H4[4]N==N.NHC6H6. 

By  method  3,  the  transposition  of  phenyl-azide  with  p-tolyl-mag- 
nesium  bromide,  and  of  p-tolyl-azide  with  phenyl-magnesium  bromide, 
identical  products  are  also  obtained. 

The  constitution  of  the  substances  produced  is  best  determined  by 
transposing  them  into  phenyl  iso-cyanate.  Thus,  diazo-benzol-p- 
amido-toluol  forms  a  urea  with  this  reagent,  and  this  new  compound 
will  have  either  formula  I'.,  corresponding  to  I.,  or  II'.,  corresponding 
to  formula  II.,  depending  upon  the  constitution  of  the  diazo-amido- 
body  : 

NHC6H5 

I'.  CO/     /[4]C6H4[i]CH3  --  -CC<(NHCeH5  +C(5H6OH+N2 

XJN\  _  N=N.C  H  \NH[4]C6H4[i]CH3 

NHC6H6 

II'.  C0<(     /C6H5  - 

\N=N[4]C6H4[i]CH3 

On  decomposing  the  urea  with  dilute  sulphuric  acid,  the  products 
will  be  phenyl-p-tolyl-urea,  phenol,  and  nitrogen  ;  whereas,  accord- 
ing to  formula  II'.,  they  should  be  sym.  diphenyl-urea,  p-cresol,  and 
nitrogen.  Therefore,  diazo-benzol-amido-p-  toluol  is  constituted  ac- 
cording to  formula  I.  The  imide  group  apparently  combines  with 
the  more  negative  radicle  (B.  21,  2578  ;  40,  2395). 

DlAZO-AMIDOCOMPOUNDS   FROM   PRIMARY  AROMATIC   BASES. 

Diazo  -  benzol  -  amide,  phenyl  -  triazene  C6H6N  :  N.NH2,  m.p.  50° 
with  decomposition.  Diazo-benzol-amide  is  the  simplest  conceivable 
diazo-amido-compound.  Its  formation,  by  the  action  of  ammonia 
upon  benzol-diazonium  chloride,  is  not  practicable,  only  dis-diazo- 
benzol-amide  being  formed.  It  is  obtained  by  reduction  of  diazo- 
benzol-imide  with  stannous  chloride  and  HC1  in  ether  at  —  18°  : 


C6H6N<(j|+2H=C6H5N  :  N.NH, 


The  cupro-salt  forms  yellow  prismatic  crystals.  Diazo-benzol- 
amide  is  exceedingly  unstable.  It  decomposes  spontaneously  in  a 
short  time,  but  instantly,  in  contact  with  acids,  in  aniline,  and  nitrogen. 


DIAZO-AMIDO-COMPOUNDS  135 

It  combines  with  phenyl  iso-cyanate  to  form  benzol-azo-phenyl-urea 
C6H5N  :  N.NHCO.NHC6H5.  Oxidisers  like  potassium  hypobromite, 
or  ammoniacal  silver  solution,  turn  it  into  diazo-benzol-imide  (B. 
40,  2376). 

Diazo  -  amido  -  benzol,  benzol  -  diazo  -  anilide,  diazo  -  benzol  -  anilide 
(B.  14,  2443,  footnote)  C6H5.N2.NH.C6H5,  melts  at  96°,  and  explodes 
when  it  is  heated  to  higher  temperatures.  It  is  obtained  by  the  action 
of  nitrous  acid  on  the  cold  alcoholic  solution  of  aniline  (Griess,  A.  121, 
258)  ;  by  mixing  diazo-benzol  nitrate  with  aniline  (B.  7,  1619)  ;  and 
by  pouring  a  slightly  alkaline  sodium  nitrate  solution  upon  aniline 
hydro-chloride  (B.  8,  1074)  or  sulphate  with  cold  sodium  nitrite  (B. 
17,641  ;  19,  1953;  20,  1581). 

The  combination  of  diazo-benzol-imide  with  phenyl-magnesium 
bromide  gives  a  salt  of  diazo-amido-benzol,  of  the  formula  C6H5N2N 
(MgBr)C6H5,  where  it  can  be  liberated  by  water  (B.  36,  910). 

Diazo-amido-benzol  consists  of  golden-yellow,  shining  laminae  or 
prisms.  It  is  insoluble  in  water,  sparingly  soluble  in  cold,  but  readily 
in  hot  alcohol,  ether  and  benzene.  Its  transpositions  will  be  dis- 
cussed later;  the  most  remarkable  one  is  its  rearrangement  into  iso- 
meric  amido-azo-benzol. 

Its  salts  are  very  unstable,  although  it  forms  a  double  salt, 
(C12H11N3.HCl)2.PtCl4,  with  hydrochloric  acid  and  PtCl4.  It  crys- 
tallises in  reddish  needles.  When  the  alcoholic  solution  is  mixed 
with  silver  nitrate,  the  compound  C6H5.N2NAg.C6H5  separates  in 
reddish  needles. 

Sodium,  in  ethereal  solution,  converts  it  into  C6H5NNaN==N.C6H6, 
which  is  decomposed  by  water  (B.  27,  2315).  Cuprous  salt,  C.  1900, 

I.  659. 

Benzene-diazo-acetanilide  C6H5N=N— N(COCH3)C6H5  melts  with 
decomposition  at  130°,  and  is  formed  when  diazo-amidc-benzene 
stands  with  acetic  anhydride  in  toluene  solution  (B.  24,  4156). 

The  para-variety  of  the  three  diazo  -  amido  -  toluenes  is  alone 
stable.  The  ortho-  and  meta-iorms  (from  ortho-  and  meta-toluidine) 
immediately  pass  into  isomeric  amido-azo-derivatives. 

Diazo  -  amido  -  compounds  containing  two  different  residues  : 
Mixed  diazo-amidc-compounds,  like  Diazo-benzol-p-amido-bromc- 
benzol,  melting  at  91°  (B.  20,  3012). 

o-,  m-,  p-Dinitro-diazo-amido-benzol,  m.p.  196°,  194°,  228°  (B. 
27,  2201  ;  28,  R.  303),  diazo-benzol-p-amido-toluol,  can  be  obtained 
from  the  diazo-derivatives  of  the  two  components  with  the  free  amido- 
derivatives — e.g.  Diazo-benzol-p-amido-toluol  equally  well  from  the 
diazo-benzol  salt  with  p-toluidin,  as  from  p-diazo-toluol  salt  and 
aniline. 

Dis- diazo -benzol -amide  (C6H5N  :  N)2NH  (B.  27,  899)  is  ex- 
tremely decomposable.  Dis  -  diazo  -  benzol  -  anilide  C6H5N=N — N 
(C6H5) — N=NC6H5  consists  of  shining  yellow  flakes  which  explode 
at  8o°-8i°  in  a  capillary  tube  (B.  27,  703,  2597  ;  C.  1905, 1.  517). 

MIXED  FATTY-AROMATIC  DIAZO-AMIDC-COMPOUNDS. 

Diazo  -  benzol  -  methyl-amide,  methyl  -  phenyl  -  triazene  C6H5N  :  N. 
NHCH3,  colourless  plates,  m.p.  37°,  obtained  from  diazo-benzol- 


136  ORGANIC   CHEMISTRY 

imide  and  methyl-magnesium  iodide.  With  water  vapour  it  volati- 
lises without  decomposition.  With  acids  it  is  decomposed  into  ani- 
line, nitrogen,  and  the  ester  of  methyl-alcohol.  With  phenyl  iso- 
cyanate  it  forms  a  urea  of  m.p.  104°,  which  is  split,  by  HC1,  into 
benzol-diazonium  chloride,  and  methyl-phenyl-urea. 

Copper  -  methyl  -  phenyl  -  triazene  C6H5N3CuCH3,  orange  -  yellow 
prisms,  m.p.  187°  with  decomposition. 

Acetyl-methyl-phenyl-triazene  C6H5N  :  N.N(COCH3)CH3,  m.p.  35° 
(B.  38,  678).  Diazo-benzol-ethyl-amide,  colourless  crystals,  m.p.  31°. 
p-Tolyl-methyl-triazene  CH3C6H4N  :  N.NHCH3,  m.p.  81-5°  (B.  40,2397). 
Diazo-benzol-dimethyl-amine  C6H5N==N.N(CH3)2,  a  yellowish  oil  (B. 
8,  148).  Diazo-benzol-piperidin  C6H5N=N.NC5H10,  m.p.  43°.  The 
diazo-piperidins  are  useful  for  preparing  fluorine  compounds. 

Benzol  -  azo  -  cyanamide,  phenyl-cyano-triazene  C6H5N  :  N.NHCN 
or  C6H5NH.N  :  N.CN,  colourless  flakes  puffing  off  at  72°.  The  potas- 
sium salt  is  formed  by  heating  diazo-benzol-imide  with  KCN  in  alcohol. 
Acids  split  it  up  into  diazo-benzol  and  urea  : 

C6H5N  :  N.NHCN+2H2O-C6H5N2OH+CO(NH2)2. 

Methylation  of  the  potassium  salt  yields  methyl-phenyl-cyano- 
triazene  C6H5(CH3)N.N  :  NCN,  m.p.  6g°-^o°,  decomposed  by  acids  into 
methyl-aniline,  nitrogen,  and  cyanic  acid  (B.  37,  2374). 

Dis- diazo-benzol- methyl -amine  (C6H5N=N)2NCH3,  light-yellow 
needles,  m.p.  112°.  Dis-diazo-benzol-ethyl-amine,  m.p.  70°  (B.  22, 
934). 

THE  REARRANGEMENTS  OF  THE  DIAZO-AMIDOCOMPOUNDS. 

1.  The  most  remarkable  property  of  the  diazo-amido-compounds, 
containing  a  replaceable  hydrogen  atom  in  the  p-position  with  refer- 
ence to  the  NH  group,  is  their  ability  to  rearrange  themselves  into 
isomeric  p-amido-azo-derivatives.     In  the  amido-azo-body  the  amido- 
group  holds  the  p-position  with  reference  to  the  point  of  union  : 

C6H5N=N— NHC6H5 >  C6H5N=N[i]C6H4[4]NH2. 

This  rearrangement  completes  itself  in  the  course  of  a  few  days, 
when  a  small  quantity  of  an  aniline  salt  is  present.  It  may  be 
assumed  that  in  the  conversion  a  quantity  of  aniline,  equal  to  that  actu- 
ally needed  for  the  change,  is  produced  ;  consequently  a  comparatively 
small  amount  of  the  aniline  salt  will  be  sufficient  to  rearrange  a  large 
quantity  of  diazo-amido-benzol  into  amido-azo-benzol  (Kekule,  Z.  f. 
Ch.  (1866),  689  ;  B.  25,  1376).  The  rapidity  of  the  conversion  is 
proportional  to  the  strength  of  the  acid  whose  aniline  salt  is  employed 
(B.  29,  1899).  A  strong  base,  such  as  amido-azo-benzol,  is  obtained 
from  a  body  indifferent  to  acids — e.g.  diazo-amido-benzol.  Various 
intramolecular  atomic  rearrangements,  such  as  the  preceding,  in  which 
indifferent  compounds  are  rearranged  as  strong  bases  or  strong  acids, 
are  known — e.g.  the  rearrangement  of  hydrazo-benzol  as  benzidin, 
of  benzol  into  benzilic  acid,  etc.  (I.  54  ;  II.  116,  118). 

2.  The  imide  hydrogen  of  the  diazo-amido-benzol  can  be  replaced 
by  acid  radicles,  through  the  action  of  acid  anhydrides  (see  Benzene- 
diazo-acetanilide) . 


DIAZO-AMIDO-COMPOUNDS  137 

3.  The  diazo-amido-compounds  and  phenyl  iso-cyanate  combine 
with  urea  derivatives. 

In  the  preceding  reactions  the  diazo-amido-bodies  are  not  decom- 
posed. This  occurs  very  readily  (4)  on  treating  them  with  con- 
centrated haloid  acids  ;  the  diazo-amido-derivatives,  like  the  diazo- 
benzol  salts,  then  change  to  haloid  benzols  ;  the  side  products  are 
salts  of  the  bases  previously  in  combination  with  the  diazo-residue. 
Therefore  the  diazo-amido-compounds,  in  the  presence  of  acids,  are 
fully  converted  by  nitrous  acid  into  diazo-benzol  salts.  This  method 
is  not  suitable  for  the  determination  of  the  constitution  of  unsym. 
diazo-amido-compounds,  since  it  is  ambiguous.  Thus,  on  treating 
benzol-diazo-amido-p-toluol  with  dilute  sulphuric  acid,  p-toluidin, 
phenol,  and  p-cresol  are  formed.  The  behaviour  of  the  diazo-amido- 
bodies  towards  concentrated  hydrofluoric  acid,  with  the  addition 
of  diazo-piperidins,  proved  itself  particularly  well  adapted  for  the 
preparation  of  fluoro-benzols  (A.  243,  220) : 

C6H5N=N.NC5H10+2HF1  =  C6H6F1+N2+HF1.HNC6H10. 

5.  Boiling  water  converts  the  diazo-amido-compounds  into  phenols 
and  bases. 

6.  The  reduction  of  the  diazo-amido-bodies  has  not  led  to  hydrazo- 
amido-derivatives — e.g.  C6H5NH — NH.NH.C6H5 ;  a  decomposition  into 
phenyl-hydrazin  and  aniline  has  been  the  regular  result. 

7.  On  boiling  the  alcoholic  solution  with  sulphurous  acid,  the  diazo- 
group  is  replaced  by  the  sulpho-group  : 

C6H5N2NHC6H5+2S02+2H20   =  C6H6SO3H+N,+C6H5NH2.SO3H2. 

11.  Diazo-oxy-amido-compounds. 

These  compounds  are  formed  (i)  from  diazo-compounds  with 
j3-alkyl-  and  alphyl-hydroxylamines  (cp.  B.  32,  1546  ;  A.  353,  228)  ; 
(2)  from  phenyl-hydrazins  and  nitroso-benzols,  in  the  latter  case  with 
liberation  of  hydrogen.  If  a-alkylated  phenyl-hydrazins  are  used, 
we  get  bodies  like  C6H5N(CH3)N^-^/NC,H6  or  C8H5N(CH3)N :  N( :  O)CaH6, 

i.e.  analogous  to  azoxy-compounds. 

Diazo-oxy-amido-benzol  C6H5N2.N(OH)C6H5,  m.p.  127°,  yellowish 
needles  of  silky  lustre,  from  nitroso-benzol  with  phenyl-hydrazin,  or 
from  diazo-benzol  with  phenyl-hydroxylamine. 

Benzol-diazo-oxy-amido-methane  C6H5N2.N(OH)CH3,  m.p.  70°, 
from  /3-methyl  -  hydroxylamine  and  diazo-benzol  chloride  (B.  30, 
2278).  Other  compounds,  see  B.  32,  3554  ;  C.  1909,  II.  18. 

12.  Diazo-imido-compounds. 

The  diazo-imido-compounds  are  ethers  of  hydro-nitric  acid — 
hydrazoic  acid.  They  are  produced  : 

i.  By  the  action  of  aqueous  ammonia  upon  diazo-benzol  per- 
bromides : 

C,H5N2.Br3+NH3   = 


138  ORGANIC   CHEMISTRY 

2.  By  the  action  of   hydroxylamine   upon  diazo-benzol  sulphate 
(B.  25,  372  ;  26,  1271) : 

C6H5N2OSO3H+NH2OH  =  C6H5N3+H2O+S04H2. 

The  hydroxylamines  can  sometimes  be  replaced  by  the  salts  of 
hydroxylamine-di-sulphonic  acid  (B.  33,  3408). 

3.  By  the  action  of   sodium   nitrite   upon  the  hydrochloric  acid 
solution  of  phenyl-hydrazin,  when  the  nitroso-phenyl-hydrazins  first 
produced  lose  water  and  form  phenyl-diazo-imides  : 

C'H'N<(NO°  =  c«H 

4.  From  phenyl-hydrazin  and  diazo-benzol  sulphate  (B.  20,  1528  ; 
21,  3415)  : 

C6H5NHNH2     r  H  M/NH2  r  w  V/N  ,  r  „  MTT 

C^N2OS03H  ~        '  C«H'N\N :  NC6H5  "        '  C8H5N<^ +C6H5NH2. 

5.  Hydrazin  and  diazo-benzol  sulphate  yield,  on  the  one  hand, 
diazo-benzol-imide  and  ammonia;  upon  the  other,  aniline  and  azo- 
imide  or  hydro-nitric  acid,  as  by-products.     These  reactions  are  due 
to  the    breaking    down    of    a    non-accessible    intermediate    product, 
C6H5N=N— NH.NH2  (B.  26,  88,  1271)  (cp.  buzylene  derivatives) : 

NH3+C6H5N3< C6H5N  :  N.NH.NH2 >C6H5NH2+N3H. 

6.  By  the   action  of    sodium    hypochlorite  upon  j3-phenyl-semi- 
carbazide,  the  latter  being  first  oxidised  to  phenyl-azo-carboxyl-amide, 
then  transposed  into  diazo-benzol-amide,  and  finally  converted  into 
diazo-benzol-imide : 

/N 

C6H5NH.NH.CONH2 >  C6H5N :  N.CONH2 >  C6H5N  :  N.NH2 >  C6H5.N/  || 

\N 

Analogous  reactions  are  given  by  a  number  of  substituted  phenyl- 
semicarbazides  (B.  40,  3035). 

7.  By    oxidation   of    diazo-benzol-amide   with    potassium   hypo- 
bromite,  or  ammoniacal  silver  solution  (B.  40,  2388). 

Diazo-benzol-imide,  phenyl-hydro-nitric  ester  C6H5N3,  b.p.  59°  (12 
mm.),  is  a  yellow  oil  with  stupefying  odour.  It  explodes  at  ordinary 
pressures  if  heated. 

o-,  m-,  and  p-Nitro-diazo-benzol-imide  NO2C6H4N3,  m.p.  52°,  55°, 
and  74°.  p-Bromo-diazo-benzol-imide,  m.p.  20°  (B.  33,  3409). 
p-Amido-diazo-benzol-imide  NH2C6H4N3,  m.p.  62°.  p-Bis-triazo-benzol, 
p-phenylene-bis-diazo-imide  N3C6H4N3,  light-yellow  plates,  m.p.  83°, 
formed  from  acetyl-p-phenylene-diamine  by  the  reactions  (C.  1906, 
I.  1338)  : 
CH3CONHC6H4NH2 >  CH3CONHC6H4N3 >  NH2CttH4N3 >  N3C6H4N3. 

Transformations  of   the  Diazo-benzol-imido-compounds. — (i)  On 

boiling  with  HC1  they  decompose  into  nitrogen  and  chloraniline 
(B.  19,  313).  (2)  On  boiling  with  H2SO4  they  split  into  nitrogen 
and  amido-phenols  (B.  27,  192).  (3)  On  boiling  with  alcoholic 
potash  the  diazo-benzol-imido-compounds  are  partly  split  into  nitro- 


AZOXY-COMPOUNDS  139 

phenols  and  hydro-nitric  acid  (B.  25,  3328).  (4)  Heated  by  them- 
selves, the  ortho-nitrogenated  diazo-imides  are  broken  up  into  nitro- 
gen and  o-dinitro-benzols.  (5)  With  methyl-magnesium  iodide,  and 
phenyl-magnesium  bromide,  diazo-benzol-imide  form  salts  of  diazo- 
amido-  compounds,  with  splitting  of  the  nitrogen  ring.  (6)  With 
KCN,  diazo-benzol-imide  combines  to  form  phenyl-cyano-triazene. 

(7)  It  combines   additively   with   acetylene-dicarboxylic  ester  ;  with 
j3-ketone-carboxylic   ester,  as  well  as  malonic  esters,  it  combines  to 
form   five-membered  heterocyclic  ring-systems,  of  the  triazol  group, 
water  or  alcohol  being  set  free  : 

CH2COOR  _  N/N  -  CCOOR    H  Q 
+COCH3  \N(C6H5)  .CCH3 

(8)  By   condensation  of  diazo-benzol-imide  with   benzaldehyde-aryl- 
hydrazones,  tetrazones  are  formed  (B.  40,  2402),  e.g.  : 


C6H6N<^||+C,H5NH.N:CHC8H5  = 


13.  Azoxy-compounds. 

Formation.  —  (i)  By  reduction  of  nitro-  and  nitroso-compounds 
with  methyl  or  ethyl  alcoholic  potash  solutions  (B.  26,  269)  : 

4C6H5N02+3HCH2ONa  ==  2(C6H5N)2O+3HCO2Na+3H2O. 

Sodium  amalgam  and  alcohol,  zinc  dust  in  alcoholic  ammonia,  and 
arsenious  acid  in  alkaline  solution  (B.  28,  R.  125)  reduce  nitro-bodies 
to  azoxy-compounds. 

(2)  By  the  oxidation  of  amido-  and  azo-derivatives  (Z.  f.  Ch.  1866, 
309  ;  B.  6,  557  ;  18,  1420  ;  36,  3805),  as  well  as  by  the  spontaneous 
oxidation  of  jS-phenyl-hydroxylamine  in  the  air.  Nitroso-benzol  is 
formed  intermediately,  and  combines  with  unchanged  /?-phenyl- 
hydroxylamine  to  form  azoxy-benzol  (see  Steric  hindrance)  . 

Behaviour.  —  (i)  When  reduced  by  heating  with  iron  filings  they 
yield  azo-compounds  ;  with  ammonium  sulphide,  hydrazo-derivatives  ; 
and  with  acid  reducing  agents,  amido-bodies,  resulting  from  the  de- 
composition and  rearrangement  of  the  hydrazo-compounds  first  pro- 
duced. (2)  Their  rearrangement  into  oxy-azo-compounds,  on  digest- 
ing them  with  concentrated  sulphuric  acid,  is  interesting  (Wallach  and 
Belli,  B.  13,  525). 

XX 

Azoxy-benzol,  azoxy-benzide  c,H5  —  N^-  —  -*N  —  C8H5,  m.p.  36°,  forms 
long  yellow  needles,  easily  soluble  in  alcohol  and  ether,  but  not  in 
water.  It  melts  at  36°,  and  decomposes  into  azo-benzol  and  aniline 
when  distilled.  It  is  converted  into  p-oxy-azo-benzol  by  digestion 
with  concentrated  sulphuric  acid,  besides  yielding  other  products 
(C.  1903,  I.  324,  1082). 

Concerning  an  isomeric  azoxy-benzol,  m.p.  84°,  formed  as  a 
by-product  of  the  reduction  of  nitroso-benzol  with  alcoholic  soda  solu- 
tion, see  B.  42,  1364. 

Benzene  and  H2C16,  acting  on  azoxy-benzol,  give  benzene-azo- 
diphenyl  C6H5N2C6H4.C6H5  and  diphenyl-azo-diphenyl  (C.  1904,  I. 
1491). 


140  ORGANIC   CHEMISTRY 

o-  and  p-Nitro-azoxy-benzol,  m.p.  49°  and  149°.  The  o-compound 
on  reduction  gives  phenyl-azo-nitroso-  and  phenyl-azo-amido-benzol  (B. 
32,  3262).  Sym.  o2-dinitro-azoxy-benzol,  m.p.  175°  (B.  36,  3813). 
Sym.  p2-dinitro-azoxy-benzol,  m.p.  192°,  by  oxidation  of  p2-dinitro- 
azo-benzol.  Sym.  m-dinitro-azoxy-benzol,  m.p.  141°,  from  m-di- 
nitro-benzol  (B.  25,  608  ;  38,  4013).  Sym.  m-diamido-azoxy-benzol, 
azoxy-aniline,  m.p.  147°  (B.  29,  R.  137).  p-Tetramethyl-diamido- 
azoxy-benzol,  m.p.  243°,  from  nitroso-dimethyl-aniline.  Trinitro- 
azoxy-benzols,  from  azoxy-benzol  (B.  23,  R.  104),  o-,  m-,and  p-Azoxy- 
toluol,  m.p.  59°,  38°,  and  70°. 

14.  Azo-compounds. 

Like  the  diazo-derivatives,  these  contain  a  group  consisting  of 
two  nitrogen  atoms  ;  in  the  former  the  N2  group  is  combined  with  only 
one  benzene  nucleus  and  an  inorganic  residue  ;  here  it  is  attached  on 
either  side  to  benzene  nuclei,  or  to  a  benzene  nucleus  and  an  aliphatic 
radicle  : 

C8H5— N = N— CeH5  C6H6— N  =N— CH3 

Azo-benzol  Benzol  azo-methane. 

In  consequence,  they  are  far  more  stable  than  the  former,  and  do 
not  react  with  the  elimination  of  nitrogen. 

Intermediate  links  between  diazo-  and  azo-compounds  are  re- 
presented by  the  diazo-benzol  cyanides,  the  benzol-azo-carboxylic 
derivatives,  etc. 

Classification  and  Nomenclature. — The  true  aromatic  azo-bodies 
are  distinguished  as  symmetrical,  those  in  which  the  two  residues  are 
the  same,  and  unsymmetrical,  those  in  which  the  two  residues  are  dis- 
similar. Mixed  azo-bodies  are  those  in  which  the  azo-group  joins  an 
aromatic  to  an  aliphatic  radicle. 

The  names  of  the  unsymmetrical  azo-bodies  are  derived  from  the 
names  of  the  two  bodies  in  which  the  azo-group  has  replaced  an  atom 
of  hydrogen  each,  separated  by  the  word  azo, — thus  :  C6H5 — N=N— 
C6H4N(CH3)2,  benzol-azo-dimethyl-aniline  ;  C6H6 — N=N — CH3,  ben- 
zol-azo-methane.  Should  the  benzene  residues  contain  substituents, 
the  positions  in  the  one  residue  are  indicated  by  numbers  i  to  6,  and 
in  the  second  residue  by  numbers  i'  to  6',  with  the  understanding 
that  the  azo-group  occupies  the  i,  I'-position.  Dis-azo-  and  tris-azo- 
compounds,  containing  two  or  three  azo-groups,  are  known  (B.  15, 
2812). 

Formation. — i.  By  the  moderated  reduction  of  nitro-bodies  in 
alkaline  solution,  because  in  acid  solution  the  final  reduction  products 
of  nitro-bodies,  the  amido-derivatives,  are  almost  invariably  produced. 
Azoxy-compounds  are  first  formed,  but  by  further  reduction  they 
pass  into  azo-derivatives.  The  reducing  agents  are  : 

(a)  Zinc  dust  in  alcoholic  potash  or  soda  (B.   21,  3139),   or  in 
ammonia. 

(b)  Sodium  or  magnesium  amalgam  and  alcohol  (C.  1904,  II.  1383). 

(c)  Stannous  chloride  in  sodium  hydroxide  (B.  18,  2912). 

Also  (d)  the  electrolytic  reduction  of  nitro-derivatives  to  azo-bodies 
(C.  1898,  II.  775  ;  1900,  I.  1175  ;  1901,  II.  153). 


AZO-COMPOUNDS  141 

By  more  complete  reduction  hydrazo-bodies  are  formed,  along  with 
the  azo-derivatives  ;  these  can  eventually  be  decomposed  into  amido- 
compounds.  Azo-benzol  is  the  middle  member  in  the  series  of  reduc- 
tion products  obtained  from  nitro-benzol,  if  j8-phenyl-hydroxylamine 
is  not  taken  into  consideration  : 


Nitro-benzol        Azoxy-benzol        Azo-benzol     Hydrazo  -benzol        Aniline. 

2.  By  reduction  of  azoxy-compounds  on  heating  them  with  iron 
filings. 

3.  By  the  oxidation  (a)  of   hydrazo-bodies,  and  (b)  of  primary 
amido-derivatives  in  alkaline  solution.     This  takes  place  in  air  alone 
(B.  42,  2938),  and  more  easily  by  means  of  potassium  permanganate 
(A.  142,  364),    potassium    ferricyanide    or    sodium   hypobromite    (B. 
39,  744). 

4.  By  the  action  of  nitroso-benzol  upon  aniline. 

5.  By  the  rearrangement  of  certain  diazo-amido-bodies  into  amido- 
azo-derivatives. 

6.  By  the  transposition  of    certain  diazo-amido-compounds  into 
azo-amido-compounds. 

7.  By  action  of  diazo-salts  (a)  upon  tertiary  anilines  ;    (b)  upon 
m-diamines  ;  and  (c)  upon  phenols. 

The  last  two  methods  lead  to  amido-derivatives  of  the  azo-hydro- 
carbons,  some  of  which  have  become  very  important  in  the  coal-tar 
colour  industry. 

Mixed  azo-derivatives  are  frequently  obtained  by  combining  diazo- 
salts  with  suitable  fatty  bodies,  i.e.  such  as  contain  easily  replace- 
able hydrogen  atoms  in  union  with  carbon,  or  with  heterocyclic  com- 
pounds like  pyrrol,  pyrazol,  etc. 

Properties.  —  The  azo-bodies  are  more  intensely  coloured  than  the 
pale-yellow  azoxy-derivatives.  They  unite  with  acids  with  great 
difficulty  unless  they  contain  an  additional  basic  amido-group.  They 
can  be  directly  chlorinated,  nitrated,  and  sulphonated.  Reducing 
agents  convert  them  into  hydrazo-compounds,  or  decompose  them  at 
the  point  of  double  union,  with  the  production  of  amido-compounds. 
The  latter  reaction  serves  to  determine  the  constitution  of  the  amido- 
azo-derivatives. 

INDIFFERENT,  SYMMETRICAL  AZO-COMPOUNDS.  —  Azo-benzol,  azo- 
benzide  C6H5N=NC6H5,  m.p.  68°  and  b.p.  293°,  was  discovered  by 
Mitscherlich  in  1834.  It  forms  orange-red,  rhombic  crystals,  readily 
soluble  in  alcohol  and  ether,  but  sparingly  soluble  in  water.  It  is 
produced  by  the  methods  outlined  above  from  nitro-benzol,  aniline, 
and  hydro-benzol.  Azoxy-benzol  yields  it  on  distillation  with  iron 
filings  (B.  207,  329).  It  has  also  been  obtained  from  potassium  aniline 
by  action  of  air,  and  from  aniline  and  sodium  (B.  10,  1802).  It  is 
converted  into  benzidin  by  tin  and  hydrochloric  acid  ;  this  is  due  to  a 
transposition  of  the  hydrazo-benzol  first  formed. 

HC1  in  methyl-alcohol  solution  produces  a  fundamental  change  in 
azo-benzol,  reduction  and  chlorination  taking  place  simultaneously 
(A.  367,  304).  With  benzol-sulphinic  acid  it  combines  to  form  phenyl- 


142  ORGANIC   CHEMISTRY 

sulphone-hydrazo-benzol.  On  heating  with  CS2  mercapto-thiazol  is 
produced  (B.  24, 1403). 

Nitration  of  azo-benzol  easily  produces  nitro-azoxy-benzols.  o-, 
m-,  and  p-Nitro-azo-benzol,  m.p.  71°,  96°,  and  135°,  are  obtained  by 
transformation  of  the  three  nitro-nitroso-benzols  with  aniline,  or  of 
the  three  nitranilines  with  nitroso-benzol  (B.  36,  3811,  3818).  2,  4- 
Dinitro-benzol-azo-benzol,  m.p.  117°,  by  oxidation  of  the  hydrazo- 
benzol.  m2-  and  p2-Dinitro-azo-benzol,  m.p.  153°  and  221°.  Trinitro- 
azo-benzols  (B.  32,  3256).  Sym.  hexa-nitro-azo-benzol,  m.p.  215° 
(B.  41,  1297). 

Reduction  of  o-nitro-azo-compounds  produces  phenyl-azimide 
oxides  and  phenyl-pseudo-azimides  (q.v.)  (B.  36,  3822). 

Azo-toluols. — o-Azo-toluol  melts  at  157°.  m-Azo-toluol  melts  at 
55°,  and  p-azo-toluol  at  143°  (B.  17,  463  ;  18,  2551).  Azoxylenes  and 
azo-trimethyl-benzols  are  known. 

MIXED  AZO-COMPOUNDS. — Benzol-azo-methane,  azo-phenyl-methane 
C6H5N=NCH3,  b.p.  about  150°,  andBenzol-azo-ethaneC6H5.N=NCH2. 
CH3,  b.p.  about  180°,  are  liquids  with  a  peculiar  odour.  They  are 
obtained  by  oxidising  the  corresponding  hydrazins  with  mercuric 
oxide.  Sulphuric  acid  transposes  benzol-azo-ethane  into  the  isomeric 
acetaldehyde-phenyl-hydrazone  C6HsNH.N  :  CH.CH3  (B.  29,  794 ; 
36,  56).  With  amyl  nitrite,  and  sodium  alcoholate,  both  benzol-azo- 
ethane  and  acetaldehyde-phenyl-hydrazone  give  benzol-azo-acet-ald- 
oxime  C6H5N  :  NC(NOH)CH3.  In  compounds  of  the  type  : 

ArN  :  NC(NOH)R     or    ArNH.N  :  C(NO)R 
ArN  :  NC(NOOH)R    or    ArNHN  :  C(NO2)R 

the  desmotropic  relations  between  azo-  and  hydrazone  forms  are  closer 
than  in  the  simple  mixed  azo-bodies.  These  classes  of  bodies,  desig- 
nated as  benzol-azo-aldoximes  or  nitroso-phenyl-hydrazones,  and  benzol- 
azo-nitronic  acids  or  nitro-phenyl-hydrazones,  respectively,  are  dealt 
with  below,  in  connection  with  the  related  amidrazones  and  formazyl 
compounds. 

Mixed  azo-compounds  are  also  produced  by  combination  of  diazo- 
salts  and  substances  with  a  reactive  CH2  group.  Thus  we  obtain 
benzol-azo-aceto-acetic  ester  with  desmotropic  hydrazone  forms  of 
the  type  C6H5.NHN  :  C(COCH3)(COOR).  Concerning  the  structure 
of  benzol-azo-amino-crotonic  ester,  see  B.  35,  1862. 

Certain  other  bodies  may  also  be  regarded  as  mixed  azo-com- 
pounds : — Benzol-diazo-carboxylic  acids  and  their  derivatives  the  diazo- 
cyanides,  diphenyl-sulpho-carbazone  and  carbo-diazone,  benzoyl-diazo- 
benzol  (q.v.),  and  numerous  azo-bodies  produced  by  combination  of 
diazo-salts  with  heterocyclic  compounds  like  pyrrol,  pyrazol,  etc. 

AMIDO-AZO-COMPOUNDS. — The  indifferent  azo-derivatives  are  all 
orange-yellow  to  orange-red  in  colour,  but  they  are  not  dyes.  By 
the  introduction  of  amino-  or  HO  groups  in  ortho-  or  para-position  to 
the  azo-group  the  resulting  bodies,  like  o-  and  p-amido-azo-com- 
pounds,  oxy-azo-compounds,  and  especially  amido-azo-benzol-sul- 
phonic  acids,  do  become  colours  applicable  in  the  dyeing  of  wool  and 
silk  (B.  35,  4225).  The  number  of  azo-dyes  is  very  great.  Some  of 
the  simplest  will  be  discussed  in  the  following  paragraphs,  while  the 
most  important  representatives  of  the  class,  technically  speaking, 


AZO-COMPOUNDS  143 

will  be  considered  in  other  portions  of  this  book,  particularly  in  con- 
nection with  the  naphthalene  group.  The  sulphonic  acids  of  the  amido- 
azo-bodies  are  of  greater  importance  than  the  parent  substances. 

Formation.  —  i.  From  diazo-amido  -  compounds  :  p-amido-azo- 
benzol  is  obtained  from  diazo-amido-benzol.  In  the  case  of  diazo- 
amido-benzol  this  transposition  occurs  on  standing  with  alcohol,  but 
more  readily  by  the  action  of  a  slight  quantity  of  aniline  chloro- 
hydrate. 

This  reaction  only  occurs  readily  if,  in  the  reacting  diazo-amido- 
compound,  the  position  hi  the  benzol  nucleus  adjacent  to  the  amido- 
group  in  the  para  place  be  unoccupied. 

However,  compounds,  like  diazo-amido-p-toluol  CH3[4]C6H4[i]N  : 
N  —  [i']NHC6H4[4']CH3,  in  which  the  p-position  with  reference  to  the 
imido-group  is  occupied  by  CH3,  also  suffer  this  transposition.  It 
occurs  on  heating  diazo-amido-p-toluol,  dissolved  in  fused  p-toluidin, 
to  65°  with  p-toluidin. 

The  amido-group  of  the  resulting  amido-azo-toluol  occupies  the 
o-position  with  reference  to  the  diazo-group.  It  is  o-amido-azo-toluol 
or  [$-methyl-benzol-azo-[^'}-methyl-[2r]-amido-benzol  CH3[4]C6H4[i]N  : 
N[i']C6H3[4']CH3[2']NH2  (B.  17,  77). 

2.  By  the  action  of  the  diazo-compounds  (a)  upon  the  tertiary 
aromatic  amines,  or  (b)  upon  m-diamines  in  neutral,  or  feebly  acid, 
solution  (B.  10,  389,  654)  : 

C6H6.NSN03+C6H5N(CH3)2    =  C,H6.N  :  N.[i]C,H4[4]N(CH3)2+NO3H 


The  first  products  with  primary  and  secondary  monamines,  especi- 
ally in  neutral  or  acetic  acid  solution  (B.  24,  2077),  are  diazo-amido- 
compounds,  which,  under  the  previously  mentioned  conditions,  are 
capable  of  rearranging  themselves  into  amido-azo-derivatives. 

But  in  the  formation  of  diazo-amido-compounds  from  diazonium 
salts  and  nucleus-substituted  anilines  the  isomeric  amido-azo-com- 
pounds  usually  occur  as  by-products,  and  only  become  chief  products 
in  meta-substitutions,  e.g.  m-toluidin  (/.  pr.  Ch.  2,  65,  401). 

The  phenols  act  like  the  tertiary  amines  upon  diazo-salts  with 
the  formation  of  oxy-azo-derivatives,  which  will  be  discussed  later 
after  the  amido-phenols. 

Properties  and  Behaviour.  —  The  amido-azo-compounds  are  usually 
crystalline,  and  generally  dissolve  readily  in  alcohol.  They  are  yellow, 
red,  or  brown  in  colour.  With  acids  they  form  two  isomeric  series  of 
salts  :  yellow  unstable,  and  violet  stable  salts.  The  former  are 
produced  by  the  action  of  a  defective  quantity  of  acid  upon  amido- 
compounds,  and  easily  pass  into  the  darker  isomeric  salts  by  excess 
of  acid,  pressure,  heat,  etc.  The  dark  salts  are  probably  salts  of 
the  quinone-imide-hydrazone  C6H5NHN  :  C6H4  :  NH.HC1,  and  form 
the  industrial  amido-azo-dyes  (B.  41,  1171). 

(i)  Their  decomposition  upon  reduction,  and  the  great  importance 
of  this  reaction,  have  been  previously  dwelt  upon  (B.  21,  3471  ; 
C.  1908,  1.  721).  Occasionally  decomposition,  such  as  this,  takes  place 
on  heating  the  bodies  with  hydrochloric  acid  (B.  17,  395).  If  titanium 
trichloride  is  employed,  the  reduction  splitting  can  be  used  for  the 


144  ORGANIC   CHEMISTRY 

volumetric  estimation  of  the  dyes  (B.  36,  1552).  (2)  Amido-azo- 
compounds  may  be  changed  to  diazo-azo-derivatives  with  nitrous  acid. 
Iso-dihydro-phene-tetrazins  may  be  obtained  by  reducing  the  diazo-salts 
of  o-amido-azo-derivatives.  (3)  Indulins  (q.v.)  are  produced  on  heat- 
ing p-amido-azo-compounds  with  aniline  hydrochloride,  and  eurhodins 
when  o-amido-azo-bodies  are  employed.  (4)  When  the  o-amido-azo- 
compounds  are  oxidised  they  become  pseudo-azimido-denva.tives.  (5) 
The  o-amido-azo-compounds  combine  with  aldehydes.  Condensation 
products  result,  which  are  derived  from  dihydro-pheno-triazin  (q.v.). 

p-Amido-azo-benzol  C6H5.N  :  N(i]C«H4i4]NH^  yellow  flakes  or 
needles,  m.p.  127°,  b.p.12.  225°,  boils  without  decomposition  even  at 
ordinary  pressures.  It  can  be  obtained  from  p-nitro-azo-benzol,  and  is 
prepared  industrially  by  transposition  of  diazo-amido-benzol  (B.  19, 
1953  ;  21,  1633).  MnO2  and  sulphuric  acid  oxidise  it  to  quinone  ; 
reduction  splits  it  into  aniline  and  p-phenylene-diamine.  With  HC1 
it  forms  a  bright-yellow  and  a  deep-violet  chlorohydrate.  The  latter 
was,  like  the  oxalate,  formerly  used  as  a  yellow  dye.  In  the  coal-tar 
industry  it  is  used  on  a  large  scale  as  a  fundamental  material  for  ob- 
taining diazo-dyes  and  indulins.  While  the  salts  of  amido-azo-benzol 
are  unimportant  as  dyes,  the  sulpho-acids,  "  acid  yellow  "  or  "  real 
yellow,"  have  valuable  properties. 

p-Aeetamido-azo-benzol,  m.p.  143°.  Benzol-azo-phenyl-cyanamide 
C6H5N  :  NC6H4NHCN,  m.p.  163°,  obtained  by  the  action  of  diazo- 
benzol  chloride  upon  sodium  cyano  -  aniline  (C.  1906,  II.  1054). 
Benzol-azo-phenyl-glyein  C6H5N  :  NC6H4NHCH2COOH,  m.p.  140°, 
obtained  from  phenyl  -  glycin  |and  benzol  -  diazonium  chloride  (B. 
35,  580).  For  further  acidyl  derivatives  of  p-amido-azo-benzol, 
see  B.  35,  1431 ;  C.  1902,  II.  360.  m-Amido-azo-benzol  C6H5N2[i] 
C6H4[3]NH2,  m.p.  57°;  its  aceto-compound,  m.p.  131°,  has  been  ob- 
tained from  nitroso-benzol  and  aceto-m-phenylene-diamine  (B.  28, 
R.  982).  Benzol-azo-p-dimethyl-aniline  C6H5N  :  N[i]C6H4[4]N(CH3)2, 
m.p.  116°.  p  -  Azo  -  benzol  -  trimethyl  -  ammonium  iodide  C6H5N  : 
NC6H4N(CH3)3I,  m.p.  185°,  obtained  from  benzol-azo-dimethyl-aniline 
with  methyl  iodide.  Unlike  the  corresponding  primary  and  tertiary 
amine  salts,  it  does  not  dye  wool  and  silk  (A.  345,  303).  Benzol-azo- 
diphenyl-amine,  p-anilido-azo-benzol,  m.p.  82°.  o-Amido-azo-toluol 
CH3[2]C6H4[i]N  :N[i']C6H3[3/,4'](CH3)NH2,  m.p.  100°,  from  o-tolui- 
din.  m-Amido-azo-toluol  CH3[3]C6H4[i]N  :  N[i']C6H3[2',4'](CH3)NH2, 
m.p.  80°.  m-Nitro-benzol-azo-p-amido-benzol,  m.p.  213°  (B.  29, 
R.  661). 

2, 4-Diamido-azo-benzol  C6H5N2C6H3(NH2)2,  m.p.  117°,  small 
yellow  needles,  obtained  from  diazo-benzol  nitrate  and  m-phenylene- 
diamine.  Its  HC1  salt  occurs  in  commerce  under  the  name  chryso'idin, 
and  dyes  orange-red.  On  reduction  it  splits  into  aniline  and  unsym. 
triamido-benzol  C6H3(NH2)3. 

Sym.  o2-Diamido-azo-benzol  H2N.C6H4.N2.C6H4NH2,  copper-red 
flakes,  m.p.  134°,  obtained  by  gentle  oxidation  of  o-phenylene-diamine, 
with  polymerisation  of  the  o-quinone-di-imine  first  formed  (B.  38,  2348). 
The  di-acetyl  compound,  m.p.  271°,  is  also  obtained  by  reduction  of 
o-nitro-acetanilide  (B.  39,  4062). 

The  sym.  p2-Diamido-azo-benzol  H2N.C6H4.N2.C6H4.NH2  has  been 
obtained  from  nitro-acetanilide  N02.C6H4.NH.C2H3O  by  reduction 


AZO-COMPOUNDS  145 

with  zinc  dust  and  alkali,  and  from  the  diazo-compound  of  mono-ace to- 
phenylene-diamine,  with  aniline  (B.  18,  1145)  ;  also  by  reduction  of 
p2-dinitro-azo-benzol  (B.  18,  R.  628).  It  crystallises  from  alcohol  in 
yellow  needles,  and  melts  at  241°. 

The  tetra-alkyl  derivatives  of  p2-diamido-azo-benzol  form  the  so- 
called  "  azylins,"  first  obtained  by  the  action  of  nitric  oxide  upon 
dialkyl-aniline  (B.  16,  2768)  : 

2C6H5.NR2.R2N.C6H4.N2.C6H4.NR2. 

Also  by  the  action  of  the  diazo-compounds  of  dimethyl-p-phenylene- 
diamine  upon  tertiary  anilines  (B.  18,  1143).  The  azylins  are  red, 
basic  dyes,  soluble  in  HC1  with  purple  coloration,  and  in  acetic  acid 
with  emerald-green  coloration.  By  reduction  with  stannous  chloride, 
or  with  tin  and  HC1,  they  are  split  into  two  molecules  of  dialkyl-p-pheny- 
lene-diamine.  By  heating  with  alkyl  iodides  (4  mol.)  to  100°  they  are 
also  split  up,  forming  tetra-alkylised  para-phenylene-diamine. 

mnii-Diamido-azo-benzol,  m.p.  155°,  and  Tetra-methyl-mnij-di- 
amido-azo-benzol,  m.p.  118°,  obtained  from  m-nitraniline  and  m- 
nitro-dimethyl-aniline  by  reduction  with  zinc  dust  and  alkali.  In 
contrast  with  the  o-  and  p-amido-azo-bodies,  they  are  very  feeble  dyes 
(B.  35,  4225). 

3, 2',  4'-Tri-amido-azo-benzol  c12H13N5=H2N.C8H4.N2.c,H3/^22'  m-P- 

\.N  Jcij 

144°,  is  best  obtained  from  m  -  amido  -  phenylene  -  oxaminic  acid 
NH2[i]C6H4[3]NH.CO.COOH  by  diazotising,  combining  with  m- 
phenylene-diamine,  and  saponincation.  The  action  of  nitrous  acid 
upon  m-phenylene-diamine  itself  produces  a  mixture  of  bases  contain- 
ing, besides  tri-amido-azo-benzol,  chiefly  Phenylene-disazo-m-pheny- 
lene-diamine  C6H4[N2C6H3(NH2)2]2,  m.p.  ii6°-ii8°.  The  chlorides 
of  this  mixture  of  bases  form  the  commercial  phenylene  brown,  Bis- 
marck brown,  Vesuvine,  or  Manchester  brown,  which  serves  for  dyeing 
cotton  and  leather  (cp.  B.  30,  2203  ;  31,  188). 

15.  Hydrazin  Compounds. 

The  simplest  aromatic  hydrazin  derivatives  are  :  Phenyl-hydrazin 
CeH5.NH.NH2 ;  unsym.  diphenyl-hydrazin  (C6H5)2N.NH2,  and  sym. 
diphenyl-hydrazin  C6H5NH.NH.C6H5,  or  hydrazo-benzol. 

Phenyl-hydrazin  and  unsym.  diphenyl-hydrazin  both  contain  an 
NH2  group.  They  show  similar  reactions  in  many  respects,  whereas 
the  symmetrical  diphenyl-hydrazin  deports  itself  rather  peculiarly.  In 
the  following  paragraphs  sym.  diphenyl-hydrazin  and  its  homologues, 
the  hydrazo-compounds,  the  hydrazin  derivatives  longest  known,  will  be 
placed  at  the  head  of  the  aromatic  hydrazins.  The  hydrazo-compounds 
arrange  themselves  with  the  previously  discussed  azo-bodies,  with  which 
they  possess  genetic  connections.  Then  will  follow  the  mono-phenyl- 
and  the  unsym.  diphenyl-hydrazin  group. 

Hydrazc-compounds. — Symmetrical  diphenyl-hydrazin  was  dis- 
covered in  1863  by  A.  W.  Hofmann  upon  reducing  azo-benzol  with  care, 
and,  inasmuch  as  it  differed  from  the  last  compound  in  containing  two 
hydrogen  atoms  more,  it  was  called  hydrazo-benzol,  a  name  which  has 
adhered  to  symmetrical  diphenyl-hydrazin. 

VOL.  II.  L 


146  ORGANIC  CHEMISTRY 

Formation. — Azo-benzol  and  allied  compounds  yield  hydrazo-benzo, 
upon  reducing  them  with  alcoholic  ammonium  sulphide,  with  zinc  dust, 
and  with  potassium  or  sodium  amalgam.  It  is  not  necessary  to  isolate 
the  azo-body  ;  the  proper  nitro-  and  azoxy-derivatives  can  be  treated 
with  zinc  dust  and  sodium  hydroxide.  Nitro-compounds  can  also  be 
converted  in  alkaline  solution  into  hydrazo-derivatives  by  electrolytic 
reduction  (Ch.  Ztg.  17,  129,  209 ;  C.  1898,  II.  775). 

Hydrazo-benzol,  sym.  diphenyl-hydrazin  C6H5NH.NHC6H5,  m.p. 
131°,  decomposes  at  higher  temperatures  ;  also  on  heating  with  alcohol 
to  120°— 130°  in  azo-benzol  and  aniline.  It  forms  colourless  flakes  or 
plates,  insoluble  in  water,  but  easily  soluble  in  alcohol  and  ether.  It 
smells  somewhat  like  camphor,  and  oxidises  spontaneously  in  moist 
air,  or  in  alcoholic  solution,  to  azo-benzol,  giving  off  H2O2,  especially 
in  the  presence  of  alkali  (B.  33,  476  ;  A.  316,  331).  Hydrazo-benzol 
is  an  indifferent  body,  forming  no  salts  with  mineral  acids,  but  under- 
going remarkable  intramolecular  atomic  displacements  (see  Benzidin 
and  semidin  transposition,  below).  Strong  reducing  agents  split  up 
hydrazo-benzol  into  2  mol.  aniline.  With  nitro-benzol  it  transposes 
itself  to  azo-benzol  and  j8-phenyl-hydroxylamine  (B.  33,  3508). 

With  phenyl  iso-cyanate  (B.  23,  490)  and  phenyl-mustard  oil  (B. 
25,  3115)  hydro-benzol  gives  urea  derivatives  ;  with  aldehydes  it  gives 
various  reactions  :  formaldehyde  gives  CH2(C6H5N.NHC6H5)2  and 


aldehyde  oxidises  hydrazo-benzol  to  azo-benzol  (/.  pr.  Ch.  2,  65,  97). 
On  heating  with  CS2  it  yields  sulpho-carbanilide  and  sulphur  (B.  36, 

3841). 

Mono-acetyl-hydrazo-benzol,  m.p.  159°,  decomposes  at  higher  tem- 
peratures into  azo-benzol  and  acetanilide.  Di-acetyl-hydrazo-benzol, 
m.p.  105°  (B.  17,  379;  A.  207,  327).  Further  acetyl  derivatives,  see 
B.  31,  3241  ;  C.  1903,  II.  359. 

o-,  m-,  p-Methyl-hydrazo-benzol  or  sym.  o-,  m-,  p-Tolyl-phenyl- 
hydrazin  melt  at  101°,  60°,  and  86°. 

Sym.  hydrazo-toluols  CH3C6H4NH.NHC6H4CH3 :  o-compound, 
m.p.  165° ;  m-compound,  liquid  (A.  207,  116)  ;  p-compound,  m.p.  128° 
(B.  9,  829).  Hydrazo-xylols  (B.  21,  3141). 

Sym.  di-halogen-substituted  hydrazo-benzols  are  obtained  from 
the  corresponding  azo-compounds.  p-Diamido-hydrazo-benzol,  di- 
phenin  NH2[4]C6H4[i]NH.NH[i']C6H4[4']NH2,  m.p.  145°,  from  p- 
dinitro-azo-benzol  with  AmS2  (B.  18, 1136). 

Unsym.  nitro-hydrazo-benzols  have  been  obtained  by  reduction 
of  nitro-azo-  and  nitro-azoxy-compounds,  and  also  from  chloro-dinitro- 
and  chloro-trinitro-benzol  with  phenyl-hydrazin  (A.  190,  132  ;  253,  2  ; 
/.  pr.  Ch.  2,  37,  345  ;  44,  67  ;  B.  32,  3280  ;  C.  1902,  II.  41).  Sym. 
hexanitro-hydrazo-benzol,  black  crystals  of  metallic  lustre,  m.p.  201°, 
from  picryl  chloride  and  hydrazin  (B.  41,  1295). 

THE  BENZIDIN  AND  SEMIDIN  TRANSPOSITION  OF  THE 
HYDRAZO-COMPOUNDS. 

Hydrazo-benzol  undergoes  a  very  remarkable  rearrangement  into 
an  isomeric  compound  when  it  is  treated  with  acids.  When  azo-benzol 


TRANSPOSITION   OF  THE   HYDRAZO-COMPOUNDS    147 

is  reduced  in  acid  solution,  the  hydrazo-benzol  which  is  produced  does 
not  form  salts,  but  even  in  the  cold  is  changed  by  mere  contact  with 
acids  into  a  diamine,  a  diacid  base  :  benzidin  (q.v.)  or  p-diamido-di- 
phenyl.  Benzidin,  a  fundamental  substance  for  the  preparation  of 
substantive  cotton  dyes,  is  prepared  technically  in  this  way.  Di- 
phenylin,  an  o-,  p-diamido-diphenyl,  occurs  in  small  quantities  besides 
benzidin  (B.  17,  1181)  : 

C8H4[4]NH,   _  C6H6NH  _   C,H4[4]NHt 

C8H4[4]NH,  C«H5ttH  CflH4[2]NH, 

Benzidin  Hydrazo-benzol         Diphenylin. 

The  chief  transposition,  in  which  the  two  amido-groups  take  up 
a  para-position  with  respect  to  the  junction  of  the  two  benzene  nuclei, 
is  called  the  benzidin  transposition  of  the  hydrazo-compounds. 

The  transposition  is  best  effected  by  means  of  mineral  acids,  but 
benzidin,  in  the  shape  of  its  acidyl  compounds,  is  also  obtained  from 
hydro-azo-benzol  by  boiling  with  formic,  or  acetic,  acids  (B.  35,  1433). 

Sym.  o-  and  m-ditolyl-hydrazin  or  o-  and  m-hydrazo-  toluol,  as  well 
as  other  hydrazo-compounds  in  which  the  p-hydrogen  atoms  of  the 
imido-groups  are  free  in  both  aromatic  residues,  yield  with  mineral 
acids  the  corresponding  p-diamido-ditolyls  or  tolidins,  etc. 

If,  however,  p-hydrazo-toluol  be  treated  with  aqueous  mineral  acids, 
it  changes  in  part  to  p-azo-toluol  and  p-toluidin,  and  partly  to  o-amido- 
ditolyl-amine  (B.  27,  2700).  The  latter  body  is  principally  formed  by 
the  action  of  stannous  chloride  and  hydrochloric  acid  upon  hydrazo- 
toluol  : 

CH3f«  HN-NH  ||  CH3  -   ->  CH3  |f  NH  |gj  H. 

p-Hydrazo-toluene  o-Amido-[4,  s'J-ditolyl-amine. 

This  is  the  semidin  transposition  ;  it  is  so  called  because  only  the 
one  NH  group  is  converted  into  an  NH2  group,  and  not  both  NH 
groups,  as  in  the  benzidin  transposition.  In  simple  p-substituted 
hydrazo-benzols  the  amido-group  can  enter  the  o-  or  p-position  with 
reference  to  the  imido-group.  Hence  it  is  necessary  to  distinguish 
between  an  o-  and  p-semidin  transposition. 

Often  these  transpositions  take  place  side  by  side,  so  that  the 
semidin  bases  are  obtained  together  with  the  diphenyl  bases.  Treated 
with  HC1  gas  in  benzene,  hydrazo-benzol  yields  also  small  quantities 
of  o-amido-diphenyl-amine  (Ch.  Ztg.  18,  1095)  : 


With    stannous    chloride    and    HC1,    p-acetamido-hydrazo-benzol 
passes  into  aceto-p-diamido-diphenyl-amine  : 

C,H3O.NH  £-2  NH.NH  g-g  H  -  >  CaH3O.NH  g-g  NH  S^  NHa. 


When  a  substituent  occupies  the  para-position  in  hydrazo-benzol, 
the  benzidin  transposition  takes  place  with  separation  of  this  sub- 
stituent. Thus,  benzidin  is  produced  by  p-chloro-hydrazo-benzol  and 
p-hydrazo-benzol-carboxylic  acid.  Concerning  the  influence  of  the 
substituents  upon  the  transposition,  see  A.  369,  i. 


148  ORGANIC   CHEMISTRY 

We  may  here  make  a  brief  survey  of  the  transposition  in  which 
anilines  substituted  for  the  nitrogen  become  nucleus-substituted  ani- 
lines, by  a  wandering  of  the  substituents  ;  this  generally  leads  to  a 
stronger  basicity.  These  transpositions  are  :  (i)  that  of  phenyl-nitros- 
amines  into  p-nitroso-anilines  (see  above)  ;  (2)  of  phenyl-nitramines 
(diazo-benzolic  acids)  into  p-nitraniline  ;  (3)  of  j3-phenyl-hydroxylamines 
into  p-amido-phenols  ;  (4)  of  phenyl-hydrazins  into  p-phenylene- 
diamines  ;  (5)  of  chloryl-anilines  into  p-chloranilines  ;  (6)  of  diazo- 
amides  into  p-amido-azo-bodies  ;  (7)  of  hydrazo-benzols  into  benzidins 
and  amido-diphenyl-amines,  the  formulae  being  : 

1.  C6H5N(CH3)NO  ->ONC6H4NHCH3  5.  C6H5NHC1  --  >C1C6H4NH2 

2.  C6H6NH.N02  -  >02NC6H4NH2  6.  C6H5NH(N2C6H5)  ->(C6H5N2).C6H4NH2 

3.  C6H5NH(OH)  -  ^HOC6H4NH2  xrTTNHr  w    |-*NH2C6H4.C6H4NH2 

4.  C6H5NH(NH2)  -  ^NH2C6H4NH2  7'  ^^        LC«n*- 


To  these  are  added  a  number  of  reactions  in  which  carbon  groups 
wander  from  nitrogen  to  the  nucleus.  Thus  we  have  the  transposition 
of  phenyl-alkylamines  into  homologous  anilines,  of  diacetanilide  into 
acetamino-aceto-phenone,  etc.  ;  also  the  transpositions  of  phenyl- 
sulphaminic  acid  into  o-  and  p-anilino-sulphonic  acid,  of  phenyl-sul- 
phuric  acid,  and  phenyl-carbonic  acid,  into  phenyl-sulphonic  acid, 
and  salicylic  acid,  respectively,  as  well  as  o-azo-compounds  into  oxy- 
azo-compounds  (q.v.). 

Phenyl-hydrazin  Group.  —  Phenyl-hydrazin  and  unsym.  di  phenyl- 
hydrazin  are  formed  in  the  reduction  of  diazo-benzol  salts  and  diphenyl- 
nitrosamine,  as  well  as  from  the  reaction  products  formed  when  nitrous 
acid  acts  upon  primary  and  secondary  anilines  : 

I  C6H5NH2HC1  --  >C6H5N  :  N.C1  --  >C6H5NHNH2HC1 
i  (C6H5)2NH     --  >(C6H5)2N.NO  --  >(C6H5)2N.NH2. 

Formation.  —  i.  By  the  reduction  of  diazo-salts  :  (a)  By  the  action 
of  acid  alkaline  sulphites  upon  the  diazo-derivatives.  On  allowing 
acid  potassium  sulphite  to  act  upon  the  yellow  potassium  salt  of  diazo- 
benzol-sulphonic  acid,  colourless  potassium  phenyl-hydrazin  sulphonate 
is  formed  : 

C6H5—  N=N—  SO3K+SO3HK+H2O  =  C6H5NH.NHSO3K  +  SO4KH. 

When  the  sulphonate  is  heated  with  concentrated  hydrochloric  acid, 
phenyl-hydrazin  chlorohydrate  is  produced,  together  with  primary 
potassium  sulphate  : 

C6H5.N2.H2.S03K+HC1+H20  =  =  C6H5.N2H3.HC1+SO4KH. 

The  sulphazides  —  e.g.  C6H5.NH.NH.SO2.C6H5,  phenyl-benzene  sulph- 
azide,  or  C6H5N  :NC6H4N2H2S03H,  azo-benzol-p-hydrazin-sulphonic 
acid  —  are  prepared  by  the  action  of  free  sulphurous  acid  upon  the  acid 
solution  of  diazo-benzene  salts. 

p-Nitro-diazo-benzol  nitrate  and  two  molecules  of  potassium  sul- 
phite yield  potassium  p-nitro-phenyl-hydrazin  disulphonate,  C6H4 
(NO2)N(SO3K)NH(SO3K),  which  hydrochloric  acid  decomposes  quanti- 
tatively into  p-nitro-phenyl-hydrazin. 

In  the  same  manner  dipotassium  sulphite  changes  potassium  ben- 


PHENYL-HYDRAZIN   GROUP  149 

zene-diazo-sulphonate  into  potassium  phenyl-hydrazin  disulphonate, 
C6H5N(SO3K)NH(SO3K),  which  can  be  more  easily  obtained  from 
nitroso-acetanilide  and  dipotassium  sulphite.  It  is  resolved  by  hydro- 
chloric acid  into  phenyl-hydrazin  and  sulphuric  acid,  and  decomposed 
by  alkali  into  potassium  benzene-diazo-sulphonate  (B.  30,  374). 

(b)  Potassium  diazo-benzene  sulphonate  can  be  reduced  with  acetic 
acid  and  zinc  dust. 

(c)  By  the  action  of  stannous  chloride  and  hydrochloric  acid  upon 
the  diazonium  chlorides  (B.  16,  2976  ;  17,  572)  : 

C6H5.N2Cl+2SnCl2+4HCl  =  C6H5.N2H3.HCl+2SnCl4. 

Diazo-  and  iso-diazo-benzol-alkali  salts,  when  reduced  with  sodium 
amalgam,  yield  phenyl-hydrazin  (B.  30,  339). 

2.  Diazo-amido-bodies  are  reduced  by  zinc  dust  and  acetic  acid  in 
alcoholic  solution,  and  split  into  anilines  and  hydrazins  : 

C6H5N2.NH.C6H5  +  2H2  ==  C6H5.N2H3  +  NH2.C6H5 

Diazo-amido-benzol        Phenyl-hydrazin      Aniline. 

3.  Nitrosamines,  reduced  by  zinc  dust  and  acetic  acid,  give  unsym. 
alkyl-phenyl-  or  diphenyl-hydrazins  ;    aliphatic  hydrazins   (Vol.    I.) 
have  been  similarly  obtained  : 


Diphenyl-nitroso-amine    a-Diphenyl-hydrazin  . 

Historical.  —  A.  Strecker  and  Romer  (1871),  on  treating  diazo-benzol 
nitrate  with  acid  potassium  sulphite,  obtained  potassium  phenyl- 
hydrazin  sulphonate  C6H5NH.NHSO3K,  and,  on  subjecting  the 
diazide  of  sulphanilic  acid  to  the  same  treatment,  a  soluble  potassium 
salt,  which,  on  boiling  with  HC1,  yielded  crystallising  phenyl-hydrazin- 


.  ,       .  •  ,      r>  TT  —  NH2       ,,         f. 

p-sulphonic     acid     C6H4^j  :  *      H       2,     the    first    pnmary    aromatic 

hydrazin  compound.  In  1875  Emil  Fischer  showed  how  to  convert 
this  body  into  phenyl-hydrazin  chlorohydrate  by  boiling  with  HC1, 
and  how  to  obtain,  by  means  of  alkaline  hydroxide,  the  free  phenyl- 
hydrazin,  a  body  exceedingly  capable  of  transposition  (B.  8,  589). 

Properties.  —  The  aromatic  hydrazins  are  mono-acid  bases,  almost 
insoluble  in  water,  but  easily  soluble  in  alcohol  and  ether.  They  boil 
at  ordinary  pressures  with  slight  decomposition,  and  under  low 
pressures  without  decomposition.  In  air  they  oxidise  easily,  assuming 
a  brown  coloration  (C.  1907,  II.  1067).  They  reduce  Fehling's 
solution. 

PHENYL-HYDRAZIN  C6H5NH  —  NH2,  flat  crystals,  m.p.  19-6°, 
b.p.  24i°-242°,  b.p.12  120°.  Density  at  21°,  1-091.  Obtained  by 
reduction  of  benzol-diazonium  chloride.  Also,  in  small  quantities,  on 
heating  hydrazin  hydrate  with  phenol  to  220°  (B.  31,  2909).  Its  trans- 
positions are  described  below.  As  one  of  the  generators  of  antipyrin 
it  has  attained  importance  in  industry,  and  it  also  serves  as  a  reagent 
for  aldehydes  and  ketones.  This  latter  use  is  of  special  importance  in 
the  chemistry  of  hydrocarbons. 

Phenyl-hydrazin  ehlorohydrate  C6H5NH.NH2HC1,  brilliant  white 
flakes,  slightly  soluble  in  concentrated  HC1,  yields  p-phenylene-diamine 


150  ORGANIC   CHEMISTRY 

on  heating  to  200°  with  HC1.  Carboxylates,  see  B.  27,  1521.  Sodium 
phenyl-hydrazin  C6H5NNa.NH2,  obtained  by  dissolving  sodium  in 
phenyl-hydrazin.  It  forms  a  reddish-yellow,  amorphous  mass,  which, 
with  halogen  alkyls  and  haloids,  forms  the  so-called  a-phenyl-hydrazin 
derivatives  (B.  19,  2448  ;  22,  R.  664). 

POTASSIUM  PHENYL-HYDRAZIN  (B.  20,  47). 

SUBSTITUTED  PHENYL-HYDRAZINS  (A.  248,  94  ;  B.  22, 2801, 2809).—- 
p-Chloro-phenyl-hydrazin,  m.p.  83°.  p-Bromo-phenyl-hydrazin,  m.p. 
106°.  p-Iodo-phenyl-hydrazin,  m.p.  103°.  o-Nitro-phenyl-hydrazin, 
m.p.  90°,  brick-red  needles  (B.  27,  2549).  o-Nitro-s-formyl-phenyl- 
hydrazid,  m.p.  177°  (B.  22,  2804). 

For  hetero-ring  formation  from  these  o-nitro-compounds,  see  below. 

p-Nitro-phenyl-hydrazin,  m.p.  157°,  is  often  useful  for  separating 
and  characterising  aldehydes  and  ketones  (B.  32,  1806).  2,  <\-Dinitro- 
phenyl-hydrazin,  yellow  prisms,  m.p.  197°,  from  dinitro-bromo-benzol 
and  hydrazin  hydrate  (C.  1908,  I.  125). 

HOMOLOGOUS  PHENYL-HYDRAZINS.- — o-Tolyl-hydrazin,  m.p.  59°. 
m-Tolyl-hydrazin,  liquid,  p  -  Tolyl  -  hydrazin,  m.p.  61°.  p-Xylyl- 
hydrazin,  m.p.  78°.  Pseudo-eumyl-hydrazin  (A.  212, 338  ;  B.  18, 3175  ; 
22,  834  ;  C.  1905,  II.  40). 

Unsym.  diphenyl-hydrazin  (C6H5)2N.NH2,  m.p.  34°,  b.p.50  220°, 
obtained  by  reduction  of  diphenyl-nitrosamine,  forms,  with  glucose, 
diphenyl-hydrazones,  soluble  with  difficulty.  By  oxidation  with 
ferric  chloride  it  passes  into  tetraphenyl-tetrazone. 

Triphenyl-hydrazin  (C6H5)2N.NHC6H5,  obtained  by  the  action  of 
phenyl  -  magnesium  bromide  upon  j8  -  phenyl  -  hydroxylamine.  By 
alcoholic  HC1  it  is  transposed  into  N-phenyl-benzidin  C6H5NH.C6H4. 
C6H4.NH2  (B.  40,  2099). 

Tetraphenyl-hydrazin  (C6H5)2N.N(C6H5)2,  m.p.  144°,  by  oxidation 
of  diphenyl-amine  with  MnO4K  or  PbO2  ;  also  from  sodium  diphenyl- 
amine  (C6H5)2N.Na  with  iodine  (B.  39,  1501).  It  dissolves  in  concen- 
trated H2SO4  with  a  deep-blue  colour,  being  partly  transposed  into 
NN'-diphenyl-benzidin  C6H5NH.C6H4.C6H4.NHC6H5  (cp.  C.  1907,  I. 
406).  HC1  splits  it  into  diphenyl-amine  and  p-chloraniline-triphenyi- 
amine,  a  reaction  in  which  diphenyl-chloramine  (C6H5)2NC1  must  be 
assumed  as  an  intermediate  product  (B.  41,  3508). 

Tetra-p-tolyl-hydrazin  (CH3.C6H4)2N.N(C6H4CH3)2,  m.p.  136°,  by 
oxidation  of  p-ditolyl-amine  with  MnO4K,  and  by  heating  tetra-p-tolyl- 
tetrazone.  It  combines  with  acids,  halogens,  metalloid  and  metallic 
chlorides  like  PC15,  SbCl3,  SnCl4,  etc.,  to  form  deep-violet  addition 
products,  resembling  salts,  from  which  water  regenerates  the  unchanged 
hydrazin.  In  neutral  solvents  these  partly  very  unstable  compounds 
soon  decompose  to  form  p-ditolyl-amine,  and  derivatives  of  ditolyl- 
hydroxylamine  (CH3C6H4)2NOH,  which,  however,  undergo  an  imme- 
diate further  change,  with  formation  of  derivatives  of  di-tertiary 
dihydro-phenazin  (B.  41,  3478). 

Behaviour  of  the  Phenyl-hydrazins. — (i)  While  the  phenyl-hydrazins 
are  pretty  stable  towards  reducing  agents,  they  may  be  readily  recon- 
verted into  diazo-compounds  by  moderate  oxidation  ;  this  is  effected 
by  the  action  of  mercuric  oxide  upon  their  sulphates  or  sulphonates. 

When  boiled  with  copper  sulphate,  ferric  chloride,  potassium 
chromate,  Caro's  acid,  or  sodium  hypochlorite  (C.  1909,  II.  596),  the 


BEHAVIOUR   OF  THE   PHENYL-HYDRAZINS         151 

phenyl-hydrazins  throw  off  nitrogen  and  become  benzols — this  reaction 
will  also  serve  for  the  replacement  of  the  diazo-group  by  hydrogen  and 
by  the  halogens  if  the  free  phenyl-hydrazin  be  replaced  by  chlorine, 
bromine,  or  iodine  (B.  18,  90,  786  ;  25, 1074 »  C.  1908,  II.  1022).  The 
liberated  nitrogen  also  answers  for  the  quantitative  estimation  of  the 
hydrazins. 

The  phenyl-hydrazins  also  reduce  Fehling's  solution  (B.  26,  R.  234). 
Consult  B.  28,  R.  996  ;  29,  R.  977,  for  additional  reduction  reactions 
with  phenyl-hydrazin. 

(2)  Sodium  liberates  hydrogen,  and   a-sodium    phenyl-hydrazins 
result. 

(3)  Nitrous   acid    converts    the   phenyl-hydrazins    into    nitroso- 
hydrazins. 

(4)  Halogen  alkyls  replace  the  imido-  and  amido-hydrogen  of  the 
phenyl-hydrazins,  and  eventually  form  phenyl-hydrazonium  compounds. 

(5)  Acid  radicles  may  also  thus  be  easily  introduced  into  phenyl- 
hydrazins. 

(6)  Chlorine  and  bromine,  at  low  temperatures,  convert  the  primary 
phenyl-hydrazins  into  the  corresponding  diazonium  salts.     At  higher 
temperatures,  and  in  the  presence  of  mineral  acids,  we  get  halogen 
phenyl-hydrazins  with  nuclear  substitution  (C.  1908,  I.  2149  ;    1909, 

II.  595). 

(7)  The  aldehydes  and  ketones  combine  with  the  phenyl-hydrazins, 
usually  with  the  immediate  separation  of  water  and  formation  of  phenyl- 
hydrazones.     This  reaction,  like  the  oxime  formation,  is  characteristic 
of  the  aldehydes  and  ketones. 

(8)  When  the  phenyl-hydrazins  are  heated  to  200°  with  fuming 
hydrochloric  acid,  they  are  transposed  into  para-phenylene-diamines 
(B.  28,  1538). 

PHENYL-ALKYL-HYDRAZINS. — The  unsymmetrical  compounds,  with 
an  alkyl  residue,  are  called  "  a  "-compounds,  and  the  symmetrical  ones 
"  j3  "-compounds. 

Modes  of  Formation. — (i)  Both  isomers  are  generated  by  the  action 
of  alkyl  bromides  upon  phenyl-hydrazin  (A.  199,  325  ;  B.  17,  2844). 
The  isolation  of  the  ^-compounds  is  based  upon  their  capacity  of  passing 
into  azo-compounds  by  oxidation  with  HgO.  These,  owing  to  their 
volatility,  and  their  indifference  towards  acids,  can  easily  be  separated 
from  the  other  products,  and  can  then  be  converted  by  reduction  back 
into  the  original  jS-alkyl-phenyl-hydrazins.  The  a-compounds  are 
formed  (2)  by  the  action  of  alkyl  bromides  upon  sodium-phenyl- 
hydrazin  (B.  19,  2450  ;  22,  R.  664)  ;  (3)  by  the  reduction  of  the  corre- 
sponding nitrosamines  with  zinc  dust  ;  (4)  by  treatment  of  /?-aceto- 
phenyl-hydrazin  C6H5NH.NHCOCH3  with  halogen  compounds,  and 
saponification  with  boiling  dilute  acids  (B.  26,  946). 

a-Methyl-phenyl-hydrazin  C6H5N(CH3)NH2,  b.p.35  131°,  by  trans- 
position gives  methyl-p-phenylene-diamine.  a-Ethyl-phenyl-hydrazin 
C6H5N(C2H5)NH2,  b.p.  237°.  Both  compounds  on  oxidation  give 
tetrazone  (qv.).  The  ethyl  compound  combines  with  ethyl  bromide 
to  form  Diethyl-phenyl-hydrazonium  bromide  C6H5N(C2H5)2BrNH2, 
which,  on  reduction,  gives  diethyl-aniline. 

a-Propyl-,  a-Isopropyl-,  a-Isobutyl-,  a-Isoamyl-phenyl-hydrazin 
boil  at  247°,  236°,  245°,  262°  (B.  30,  2809).  a-d-Amyl-phenyl-hydrazin 


152  ORGANIC  CHEMISTRY 

CH3  \CH.CH2N(C8H5).NH2,  b.p.50  I73°-I75°,  has  been  used  for  the  direct 

C2H5/ 

splitting  up  of  racemic  aldehydes  and  ketones  (B.  38,  868). 

Ethylene-phenyl-hydrazin  C6H5N(NH2)C2H4.N(NH2)C6H5,  m.p.  90° 
(B.  21,  3203 ;  A.  310,  156).  Unsym.  o-Amido-phenyl-methyl- 
hydrazin  NH2[2]C6H4[i]N(CH3)NH2,  an  easily  resinified  oil,  is  produced 
from  nitro-nitroso-methyl-aniline  by  reduction  with  alcoholic  Am2S. 

HETERO-RING  FORMATIONS  OF  O-SUBSTITUTED  PHENYL-HYDRAZINS. 
—On  boiling  with  an  alkaline  hydrate,  o-nitro-phenyl-hydrazin  passes 
into  azimidol  (q-v.).  The  formyl  compound  of  o-nitro-phenyl-hydrazin 
yields  a-pheno-triazin  on  reduction  with  sodium  amalgam  and  acetic 
acid.  The  unsym.  o-amido-phenyl-methyl-hydrazin,  when  treated 
with  HNO2,  passes  into  pheno-methyl-hydro-tetrazin  : 

Azimidol 
[2]N(OH) 

r  „  /[ijNH.NHCHO        H  /[i]N=N 

CeH4\  [2]N02  CeH4  \  [2]N=CH          a-Pheno-triazm 

c  H    f[i]N(CH3).NH2     NOQH     c  H    r[i]N(CH3).N     Pheno-methyl- 

4\[2]NH2  4\[2]NH N         dihydro-tetrazin. 

)8-Methyl-  and  j8-ethyl-phenyl-hydrazin  are  colourless  oils,  oxidising, 
in  air,  to  benzol-azo-methane  and  -ethane,  from  which  they  can  be 
recovered  by  reduction.  j3-Methyl-phenyl-hydrazin  is  also  obtained 
from  antipyrin  (q.v.)  by  boiling  with  alcoholic  potash  (B.  39,  3265). 
jS-Alkyl-phenyl-hydrazin,  b.p.110  177°  (B.  22,  2233). 

Di-  and  tri-alkylated  phenyl-hydrazins  are  prepared  from  the  sodium 
compound  of  a-methyl-phenyl-formyl-hydrazin  C6H5N(CH3)N.NaCHO 
with  alkylene  iodide,  the  formyl  group  being  detached  by  means  of 
fuming  hydrochloric  acid.  The  dialkylated  phenyl-hydrazins,  under 
the  action  of  alkylene  iodide, give  rise  to  quaternary  azonium  compounds, 
e.g.  C6H5N(CH3)2I.NH.CH3,  besides  trialkyl-phenyl-hydrazins.  a-j8- 
Dimethyl-phenyl-hydrazin  C6H5N(CH3).NH.CH3,  b.p.  93°;  a,  j8-Dl- 
ethyl-phenyl-hydrazin  C6H5N(C2H5)NHC2H5,  b.p.u  in0-ii5°,  are 
produced  by  the  action  of  zinc  methyl  and  zinc  ethyl  upon  benzol- 
diazonium  chloride  (B.  35, 4179).  Phenyl-trimethyl-hydrazin,  b.p.8  93° 
(B.  27,  696). 

PHENYL-HYDRAZONE  AND  OSAZONE. — As  the  aldehydes  and  ketones 
yield  oximes  with  hydroxylamines,  so  with  phenyl-hydrazin  they  pass 
into  phenyl-hydrazones.  The  compounds  derived  from  the  aldehydes 
are  also  called  "  aldehydrazones  "  (A.  247,  194,  footnote),  the  ketone 
derivatives  "  keto-hydrazones,"  and  the  dihydrazones  of  the  a-dicarbonyl 
compounds  "  osazones  "  (B.  21,  984  ;  41,  73)  : 

R'.CHO+NH2NHC6H5  =  R'.CH  :  N.NHC6H5+H2O 
(R')2CO+NH2NHC6H5  =  (R')2C  :  N.NHC6H5+H2O. 

The  osazones  are  also  formed  from  the  a-oxy-aldehydes  and  a-oxy- 
ketones,  hydrazones  being  formed  first,  in  which  the  alcohol  group, 
adjoining  the  aldehyde,  or  keto,  group,  is  oxidised  by  the  excess  of 
phenyl-hydrazin  to  a  CO  group  : 

RCHOH.CHO+3C6H5NH.NH2  =  RC(  :  N.NHC6H6)CH  :  N.NHC6H5 

+C6H5NH2+NH3. 


PHENYL-HYDRAZONE  153 

The  formation  of  osazones  has  acquired  a  special  importance  in 
the  chemistry  of  sugars  (Vol.  I.). 

Of  the  phenyl-hydrazones,  of  the  aldehydes  and  ketones,  numerous 
isomeric  forms  have  been  discovered,  and  their  occurrence  is,  as  in  the 
case  of  the  oximes,  attributed  to  a  cis-trans-isomerism.  The  first 
isomeric  osazones  were  found  in  1895,  through  the  action  of  phenyl- 
hydrazin  upon  dioxo-succinic  ester  (Vol.  I.),  three  forms  being  dis- 
covered (B.  28,  64).  But  no  definite  evidence  as  to  configuration 
resulted. 

The  monoximes  of  a-aldehyde-ketones  and  a-diketones,  treated 
with  phenyl-hydrazin,  yield  hydrazoximes.  Thus,  from  methyl- 
glyoxalic  oxime  we  obtain  methyl-glyoxal-oxime  :  Methyl-glyoxal- 
phenyl-hydrazoxime  CH3C(:  NNHC6H5)CH  :  NOH,  m.p.  134°  (A. 
262,  278). 

When  phenyl-hydrazones  are  formed,  an  addition  product  is  prob- 
ably first  generated,  corresponding,  in  its  constitution,  to  ammonia 
aldehyde.  In  a  few  cases,  e.g.  those  of  oxalic  acid  ester  and  dioxo- 
succinic  ester,  addition  products  have  been  identified,  which  easily 
pass  into  phenyl-hydrazones  with  elimination  of  water  : 

C02C2H5.CO  CO,C2H5C/^J  -NHC6H5 

I      +NH2NHCaH5  =  |XOH 

C02C2H6.CH2  C02C2H6CH2 

/NH— NHC6H5 

C02C2H6.CO  C02C2H6C<xoH 

C02C8H5.CO  ->  IC*H*  =  cOX,H5i/NH— NHCeH5- 

The  fact  that  dioxo-succinic  ester  gives  an  addition  compound  tells 
in  favour  of  the  ammonia-aldehyde  view,  and  against  the  ammonium- 
salt  view,  suggested  by  the  case  of  oxalic  ester  (A.  295,  339).  Phenyl- 
hydrazin-p-sulphonic  acid  seems  only  to  yield  addition  products  of 
the  formula  RCH(OH)NHNHC6H4SO3H  with  the  aldehydes  (B. 
35,  2000). 

Since  the  phenyl-hydrazones  are  characteristic  of  the  corresponding 
compounds  containing  aldehyde  and  ketone  groups,  they  had  to  be 
repeatedly  mentioned,  in  advance,  in  dealing  with  aliphatic  compounds, 
and  we  shall  deal  with  them  again  in  connection  with  the  aromatic 
compounds  in  which  aldehyde  and  ketone  groups  are  present.  It 
seems,  however,  advisable  to  refer  briefly  to  the  aliphatic  phenyl- 
hydrazone  derivatives.  The  following  have  received  mention  in  the 
first  volume  of  this  work : — Phenyl-hydrazones  of  the  simple  aldehydes  ; 
of  the  simple  ketones  ;  of  the  diketones  ;  of  glyoxylic  acid  ;  of  pyro- 
racemic  acid  ;  of  aceto-acetic  ester  ;  of  laevulinic  acid  ;  of  mesoxal- 
aldehyde  ;  of  acetone-oxalic  ester  ;  of  mesoxalic  acid  ;  of  oxal-acetic 
ester  ;  of  acetone-dicarboxylic  ester ;  of  acetone-diacetic  acid  ;  of 
tetroses ;  of  oxalyl-diacetone ;  of  dioxo-succinic  acid ;  of  oxalo- 
succinic  ester  ;  of  arabinose  ;  of  rhamnose  ;  of  the  glucoses  ;  of  milk 
sugar  ;  of  maltose  and  isomaltose. 

Formation  of  the  Phenyl-hydrazones. — (i)  By  the  action  of  phenyl- 
hydrazin  and  unsym.  alkyl-phenyl-  or  unsym.  diphenyl-hydrazin 
upon  aldehydes  and  ketones  (see  above).  (2)  By  the  addition  of  phenyl- 
hydrazin  to  trebly  linked  carbon  atoms  ;  the  phenyl-hydrazone  of 


154  ORGANIC   CHEMISTRY 

oxaloacetic  ester  is  also  produced  by  the  addition  of  phenyl-hydrazin 
to  acetylene-dicarboxylic  ester  : 

C02.C2H5.C  COa.C2H6.C=N.NH.C8H5 

|||+NH2NHC6H8  = 
CO2.C2H6.C  CO2.C2H6.CHa 


(3)  By  the  interaction  of  diazo-benzol  salts  and  many  aliphatic  bodies, 
containing  hydrogen  atoms  readily  replaceable  by  alkali  metals  —  e.g. 
malonic  ester  and  aceto-acetic  ester  : 

(C02C2H6)2CH2+C6H5—  N2OH  =  (CO2C2H6)2C=N—  NH.C8H5+H2O 

Phenyl-hydrazone-mesoxalo-ester 


Phenyl-hydrazone-aceto-glyoxylib  ester. 

The  examination  of  desmotropic  forms,  in  which  the  enol-  and  the 
keto-forms  can  be  isolated,  has  shown  that  only  the  former  reacts 
with  diazonium  salts.  We  must  therefore  assume  that,  in  all  cases, 
the  azo  group  tackles  the  enol  hydroxyl,  forming  0-azo-compounds, 
which  transpose  themselves  into  C-azo-compounds  and  then  into 
phenyl-hydrazones  (B.  41,  4012).  In  some  cases  (see  Tribenzoyl- 
methane)  the  isolation  of  the  various  intermediate  products  has  been 
accomplished. 

The  body  obtained  from  malonic  ester  with  diazo-benzol  hydrate  is 
identical  with  that  obtained  from  mesoxalic  ester  and  phenyl-hydrazin. 
For  the  compound  obtained  from  acetic  acid  ester,  and  diazo-benzol 
salts,  we  may  have  to  replace  the  hydrazone  formula  C6H5NHN  : 
C(COCH3)CO2C2H5  by  the  desmotropic  formula  of  a  benzol-azo-aceto- 
acetic  ester  C6H5N  :  N.CH(COCH3)CO2C2H5,  since  in  dilute  sodium 
hydrate  the  ester  dissolves  into  a  salt  from  which  CO2  precipitates  the 
ester  without  change  —  a  behaviour  which  is  best  explained  by  the 
presence  of  one  of  the  mobile  H  atoms  of  the  aceto-acetic  ester  (B.  32, 
197  ;  A.  312,  128).  On  the  other  hand,  benzol-azo-aceto-acetic  ester 
is  converted  into  the  hydrazone  of  pyro-racemic  aldehyde  by  saponin- 
cation  and  liberation  of  CO2.  This  involves  a  transposition,  for  the 
pyro-racemic  aldehydrazone,  treated  with  chloro-acetic  ester  and 
sodium  ethylate,  yields  an  ester  which,  on  reduction,  yields  anilido- 
acetic  acid.  The  latter  is  only  possible  if  the  residue  of  the  chloro- 
acetic  acid  was  connected  with  the  N  atom  to  which  the  phenyl  group 
had  been  attached  (A.  247,  190). 

The  product  of  the  combination  of  cyanacetic  ester  and  diazo- 
benzol  salts  occurs  in  two  forms  —  the  a-form,  m.p.  125°,  and  the  jS-form, 
m.p.  85°,  which  are  regarded  as  stereo-isomeric  hydrazone  forms 
C6H5NH.N  :  C(CN)COOR.  Alkali  easily  converts  the  £-form  into  the 
a-form  (B.  88,  2266).  Glutaconic  ester  (Vol.  I.)  reacts  with  2  mol. 
of  diazo-benzol  salts,  with  formation  of  compounds  containing  the 
phenyl  -hydrazone  group  as  well  as  the  azo  -group  CO2R.C  : 
(N.NHC6H5).CH  :  C.(N  :  NC6H5)CO2R  (B.  40,  4928).  Concerning  the 
constitution  of  the  reaction  products  of  diazo-benzol  salts  upon  amino- 
crotonic  ester,  etc.,  see  B.  36,  1449. 

The  tendency  towards  the  formation  of  phenyl-hydrazones  is  so 


TRANSFORMATIONS   OF  THE   PHENYL-HYDRAZONES     155 

great  that  CO2  is  split  off  from  alkyl-aceto-acetic  acids  by  diazo-benzol 
chloride,  with  formation  of  the  phenyl-hydrazone  of  an  a-diketone  ; 
and  from  alkyl  aceto-acetic  esters,  with  elimination  of  the  acetyl 
group,  phenyl-hydrazones  of  a-ketone-carboxylic  esters  are  formed  : 

CH3.CH.C02H  CH3.C  :  N.NHC6H6 

CH3.CO  -C«H5N2C1  =  CH3(,0  .02  + 

Diacetyl-phenyl-hydrazone  (Vol.  I.) 


CH3.CH.CO,C2H5  ri_i_TT  n        ^ 

CH3.CO  -C6H5N,C1     H20 

Phenyl-hy  drazone  -pyro-racemic  ester. 

From  malonic  acid  and  diazo-benzol  chloride,  also,  glyoxylic 
phenyl-hydrazone  is  formed  and  CO2  split  off  (C.  1905,  I.  1538).  On 
rales  of  rejection  of  acidyl  groups  from  di-acidyl-acetic  esters  by  diazo- 
benzol  salts,  see  B.  35,  915.  The  latter  act  like  HNO2,  which  produces 
oximes  under  similar  conditions  (Vol.  I.). 

Transformations  of  the  Phenyl-hydrazones.  —  On  heating  the 
phenyl-hydrazones  with  dilute  mineral  acids  they  break  up  into  their 
progenitors.  By  careful  reduction  many  phenyl-hydrazones  have  been 
converted  into  phenyl-hydrazido-compounds  (B.  28,  1223  ;  30,  736  ; 
C.  1899,  I-  S^o)-  The  phenyl-hydrazones  often  unite  with  HCN  even 
more  easily  than  do  aldehydes  and  ketones  to  form  cyano-hydrins,  or 
nitriles  of  a-phenyl-hydrazido-carboxylic  acids  (B.  33,  3550). 

Very  few  classes  of  organic  compounds  are  capable  of  entering  into 
the  formation  of  heterocyclic  bodies  to  the  extent  manifested  by  the 
hydrazin  derivatives,  whose  intramolecular  condensation  reactions 
are,  therefore,  of  the  utmost  importance  in  the  development  of  the 
chemistry  of  ring-systems  containing  nitrogen.  Some  of  the  most 
important  condensations  have  been  met  with  in  connection  with  the 
phenyl-hydrazones  of  the  fatty  compounds,  and  will  be  again  given  in 
condensed  form,  while  others  will  receive  mention  at  the  conclusion 
of  the  acid  hydrazides. 

1.  Indols  result  upon  heating  the  phenyl-hydrazones  of  aldehydes, 
ketones,  and  ketonic  acids  with  zinc  chloride,  stannous  chloride,  or 
mineral  acids. 

2.  Pyrazolins  result  from  the  transposition  of  the  phenyl-hydra- 
zones of  a-olefin  aldehydes  and  ketones. 

3.  Oso-tetrazones  are  produced  when  the  osazones  or  a-diphenyl- 
hydrazones  of  a-dialdhydes,  a-aldehyde-ketones,  and  a-diketones  are 
oxidised. 

4.  Boiling  acids  change  the  a-osazones  and  oso-tetrazones  to  oso- 
triazoles, 

5.  Dehydrating  agents  convert  a-hydrazoximes  into  oso-triazoles. 

6.  Pyrazoles  result  from   the   phenyl-hydrazones  of   the  i,  3-oxy- 
methylene  ketones,  and  j3-diketones,  by  the  exit  of  water  ;  they  are 
ring-shaped  nitrogen  derivatives  of  the  i,  3-olefin  ketones. 

7.  The  phenyl-hydrazones  of   i,  4-diketones  rearrange   themselves 
into  n-anilido-pyrrols. 

In  preparing  ring-shaped  condensation  products  of  the  hydrazones 
the  latter  have  frequently  not  been  isolated,  but  simply  worked 
over. 


156 


ORGANIC  CHEMISTRY 


The  following  scheme  represents  the  hetero-ring-formations  possible 
with  the  phenyl-hydrazones  : 


CH3.C=N— NHC6H6 

CH3 

CH=N— NHC6H5 

CH=N— NHC6H6 
CH3.C=N— NC8H5 

CH3.C=N— NC6H5 

CH3  .C=N— NH.C6H5     X  CH3 .( 

.C        -I 


CH3.C— NHV 

II  >C6H4 

CH_ 
CH=N— NCCH5 

CH=N— NC6H5 


NC6H5 


o-Methyl-indol,  or  methyl- 
ketol 


Glyoxal-osotetrazone 


Diaceto-ostriazone,  or 
n-phenyl-dimethyl- 
osotriazole 


CH 


-N— OH 


CH3.C N    N,  i-Phenyl-3-methyl-pyra- 

CH3.CO           +NHaNHC,H8         X       I         ru/NH6C5          Zole 
S  L/rl=UJrl 

CH=CHOH  \      CH=^NX 

)>N.C6H5     i  -Phenyl-5-methyl-pyra- 


CH3.CO 

CH2— CO 


+  NH2NHC,H5 


CH3 
CH3 


CH2     .     CO         +NH.NHC.H, 

CH2  .  CO 

CH3 


JH=:C/>N'C6H5          i-Phenyl-3,  5-dimethyl- 
x  pyrazole 

CH3 
CH3 
/ 
i  \-VT  -Mur^  TT    n-Anilido-a-dimethyl- 

CH^C/  p>rrro1- 


CH5 


PHENYL-HYDRAZIN  DERIVATIVES  OF  INORGANIC  ACIDS. — Thionyl- 
phenyl-hydrazone  C6H5NH.N=SO,  melting  at  105°,  consists  of 
sulphur-yellow  coloured  prisms.  It  is  obtained,  like  the  thionyl- 
alkylamines  and  thionyl-anilines,  by  the  interaction  of  thionyl  chloride 
and  phenyl-hydrazin.  All  phenyl-hydrazins  having  a  free  amido-group 
yield  thionyl-phenyl-hydrazones  when  acted  upon  with  thionyl  chloride 
(B.  27,  2549)  •  Thionyl-phenyl-hydrazone  is  more  easily  produced  when 
thionyl-aniline  acts  upon  phenyl-hydrazin.  Further,  it  results  upon 
gently  digesting  phenyl-hydrazin-sulphinic  acid  C6H5NH.NH.SOOH, 
obtained  from  sulphur  dioxide  and  phenyl-hydrazin  (B.  23,  474). 
Thionyl  chloride,  acetyl  chloride,  and  other  acid  chlorides  rearrange 
thionyl-phenyl-hydrazin  into  diazo-benzol  chloride,  in  that  it  reacts  as  if 
it  were  diazo-benzol  sulphoxide  C6H5N=N.S(OH)  (A.  270,  114). 

Phenyl-hydrazin-sulphonic  acid  C6H5NH.NH.SO3H.— The  potas- 
sium salt  is  formed  in  the  reduction  of  potassium  benzene-diazo-sul- 
phonate  with  sulphuric  acid  or  monalkaii  sulphites.  For  the  behaviour 
of  the  potassium  salt  towards  mineral  acids,  and  the  role  it  plays  in  the 
history  of  the  discovery  of  phenyl-hydrazin,  see  above. 

p  -  Nitro  -  phenyl  -  hydrazin  -  disulphonic  acid  C6H4(NO2)N (SO3H) 
NH(SO3H). — Its  dipotassium  salt  consists  of  sulphur-yellow  needles, 
formed  on  adding  an  excess  of  a  sulphite  solution  to  nitro-diazo-benzol 
ester,  nitrate,  or  potassium  iso-diazo-benzol.  Hydrochloric  acid 


DERIVATIVES   OF   PHENYL-HYDRAZIN  157 

resolves  it  into  p-nitro-phenyl-hydrazin,  and  it  dissolves  in  an  excess 
of  potash  to  a  red  tripotassium  salt  C6H4(NO2)N(SO3K)NK(SO3K) 
(B.  29,  1830). 

Azo- benzol- phenyl-hydrazin-sulphonic  acid  C6H5N  :  N.C6H4NH. 
NHSO3H,  in  purple  needles  decomposing  even  below  100°,  is  formed 
by  the  action  of  SO2  upon  a  concentrated  solution  of  diazo-benzol 
sulphate.  With  aldehydes  it  condenses  to  hydrazones,  splitting  off 
the  sulpho-group  (C.  1909,  I.  355). 

Phenyi-benzol-sulphazide  C6H5NH.NH.SO2C6H5,  m.p.  i48°-i5o°, 
formed  from  phenyl-hydrazin  and  benzol  sulpho-chloride  in  ether,  and 
from  a  diazo-benzo-salt  solution  with  SO2  or  Na  hydrosulphite  (B.  20, 
1238  ;  40,  422). 

For  the  action  of  PC13,  POC13,  PSC13,  AsCl3,  BC13,  SiCl4  upon 
phenyl-hydrazin,  see  A.  270,  123. 

CARBOXYLIC  ACID  DERIVATIVES  OF  PHENYL-HYDRAZIN. — Acid 
residues  of  the  most  varied  character  can  be  as  readily  introduced  into 
phenyl-hydrazin,  and  generally  by  the  same  methods,  as  into  aniline. 
The  domain  of  the  bodies  thus  won  from  phenyl-hydrazin  is  scarcely 
less  extensive  than  that  of  the  acid  derivatives  of  aniline,  and  in  the 
multiplicity  of  phenomena  really  surpasses  it. 

The  acid  hydrazides  and  the  hydrazido-acids  have  shown  themselves 
to  be  as  well  adapted  as  the  phenyl-hydrazones  for  the  formation 
of  heterocyclic  derivatives.  Each  group  of  carboxylic  derivatives  of 
phenyl-hydrazin  will  be  followed  by  the  most  important  hetero-ring 
formations,  arranged  in  tabular  form,  which  will  later  be  discussed 
in  a  different  connection  in  the  section  devoted  to  "  heterocyclic 
compounds." 

The  nitro-hydrazones,  amidrazones,  and  formazyl  derivatives  will  re- 
ceive attention  at  the  conclusion  of  the  simpler  carboxylic  derivatives 
of  phenyl-hydrazin. 

Fatty  Acid  Derivatives. — The  fatty  acid  residues  enter  the  amido- 
group  of  phenyl-hydrazin  very  readily  with  the  production  of  sym.  or 
J3-acidyl  compounds.  The  unsym.  or  a-acidyl  compounds  are  made 
(i)  by  the  action  of  acid  chlorides  or  anhydrides  upon  sodium  phenyl- 
hydrazin  (B.  22,  R.  664)  ;  (2)  by  action  of  suitable  haloid  derivatives 
upon  jS-acetyl-phenyl-hydrazin,  and  subsequent  splitting  off  of  the 
j8-aceto-group  on  boiling  with  dilute  sulphuric  acid,  when  the  group 
occupying  the  a-position  will  not  be  attacked  (B.  26,  945). 

The  sym.  phenyl-hydrazides,  treated  with  ferric  chloride  and  con- 
centrated sulphuric  acid,  yield  reddish  to  bluish  violet  colours,  whereas 
the  unsym.  bodies  are  not  coloured  (B.  27,  2965,  Billow's  reaction). 

Sym.  formyl-phenyl-hydrazide  C6H5NH.NH.CHO,  from  formic  acid 
and  phenyl-hydrazin,  melts  at  145°  (B.  27,  1522  ;  28,  B.  764). 

Unsym.  or  a-aeeto-phenyl-hydrazide  C6N5N(COCH3)NH2,  m.p. 
124°,  is  obtained  from  ajS-diaceto-phenyi-hydrazin,  by  heating  with 
dilute  sulphuric  acid  (B.  27,  2964).  Sym.  or  j8-aceto-phenyl-hydra- 
zide  C6H5NH.NHCOCH3,  m.p.  128°,  from  phenyl-hydrazin  with  acetic 
anhydride,  or  by  boiling  with  glacial  acetic  acid  (A.  100,  129).  aj8-Di- 
aceto-phenyl-hydrazide  C6H5N(CO.CH3)NHCOCH3,  m.p.  106°,  from 
potassium  phenyl  in  ether  with  acetyl  chloride  (B.  20, 47).  Propionyl- 
iso-butyryl-phenyl-hydrazide,  m.p.  158°  and  143°,  see  C.  1898,  II.  1051. 
Hetero-ring  Formations  of  the  Fatty  Acid  Phenyl-hydrazide  Deri- 


158  ORGANIC   CHEMISTRY 

vatives.  —  n-Phenyl-triazole  results  when  formyl-phenyl-hydrazide  is 
heated  with  formamide  (B.  27,  R.  801).  n-Diphenyl-iso-dihydro- 
tetrazin  is  also  a  formic-acid  derivative  of  phenyl-hydrazin.  It  re- 
sults from  the  action  of  chloroform  and  caustic  potash  upon  phenyl- 
hydrazin  (compare  action  of  chloroform  and  caustic  potash  upon 
primary  amines  :  I.  236,  and  II.  84,  isonitriles  or  carbylamines)  . 

The  sym.  or  ^-acidyl-phenyl-hydrazides,  treated  '  with  phosgene, 
thio-phosgene,  and  iso-cyan-phenyl  chloride,  yield  heterocyclic  com- 
pounds —  the  oxybiazolin  derivatives  (B.  26,  2870),  which  can  also  be 
regarded  as  derivatives  of  carbonic  acid  : 

C6H6NH.NHCHO         H:CONH?_>CflH6N_N\CH       n.phenyl.triazole 

HCCl,       C8H5N  -  N=CH       n-Diphenyl-iso-dihydro- 
CH=N—  ttCH         tetrazin 


C6H5NH.NH.COCH3 


cocit       C8H6N  -  N\  n-Phenyl-c-methyl- 

CO  —  O/          3       oxybiazolone 
CSC1L__>C6H5N  -  N\  n-Phenyl-c-methyl- 

CO  —  O/  '       3       thio-oxybiazolin 
C6H5N—  N\  n-Phenyl-c-methyl- 

/  '       3    phenyl-imido-oxybiazolin. 


ALCOHOLIC  ACID  DERIVATIVES  OF  PHENYL-HYDRAZIN.  —  Sym. 
Phenyl-hydrazido-aeetic  acid  C6H5NH.NH.CH2CO2H,  m.p.  158°,  is 
obtained  by  reduction  of  glyoxylic  phenyl-hydrazone,  a  process  which 
can  be  reversed  by  oxidation  with  ammoniacal  copper  solution.  Its 
ester  is  formed,  besides  the  unsym.  compound,  from  chloro-acetic  ester 
and  phenyl-hydrazin,  whereas  chloro-acetic  acid,  and  its  amides, 
yield  unsym.  Phenyl-hydrazido-aeetic  acid  C6H5N(NH2)CH2COOH, 
m.p.  167°,  or  its  derivatives  (B.  36,  3877  ;  cp.  also  the  behaviour  of 
chloracetyl  ureas  and  urethanes  with  phenyl-hydrazin  (C.  1899,  ^-  421)- 

The  ester  of  the  unsym.  acid  is  formed  by  reduction  of  nitroso- 
phenyl-glycin  ester  C6H5N(NO)CH2CO2C2H5  (B.  28,  1223)  ;  amide, 
m.p.  150°;  anilide,  m.p.  149°.  Unsym.  Phenyl-hydrazide  C6H5N(NH2) 
CH2CON(NH2)C6H5,  m.p.  155°  (A.  301,  55)  ;  sym.  Phenyl-hydrazide 
C6H5N(NH2)CH2.CONHNHC6H5,  m.p.  178°  (B.  29,  622). 

Unsym.  Phenyl-hydrazido-^-propionic  ester  C6H5N(NH2).CH2.CH2. 
CO2C2H5,  b.p.  175°,  from  nitroso-j8-anilido-propionic  ester  (B.  29, 
515). 

Unsym.  PhenyI-hydrazido-£-butyrie  acid  C6H5N(NH2).CH(CH3) 
CH2COOH,  m.p.  in0,  from  j8-chloro-butyric  acid  with  phenyl-hydra- 
zin (/.  pr.  Ch.  2,  45,  87). 

Hetero-ring  Formation  of  Phenyl-hydrazido-acids. — (i)  With  form- 
amide,  unsym.  phenyl-hydrazido-acetic  ester  condenses  to  phenyl- 
keto-hydro-j8-triazin. 

(2)  Similarly,     unsym.     anilido-acetic-a-phenyl-hydrazide     C6H5N 
(NH2)CO.CH2NHC6H5,  with  cryst.  formic  acid,  gives  n-diphenyl-keto- 
tetrahydro-a-triazin. 

(3)  The  i-phenyl-semicarbazide-i-acetic  ester  C6H5NH(CH2COOR) 
NHCONH2,  obtained  from  unsym.  phenyl-hydrazido-acetic  ester  with 
potassium  cyanate,  on  saponification,  yields  n-phenyl-diketo-hexahydro- 
a-triazin. 

The  phenyl-hydrazido-carboxylic  acids  4,  5,  and  6  (below),  corre- 


DERIVATIVES   OF   PHENYL-HYDRAZIN  159 

spending  to  the  j8-oxy-acids,  so  easily  develop  anhydrides  (pyrazoli- 
dones  and  lactames)  that  they  frequently  escape  isolation. 

C6H5N.NH2                     HCONH,  C6H6N  -  N=CH  n-Phenyl-keto-tetra- 

CH2COOC2H5  ~~  CH2—  CO  -  &H      hydro-a-triazin 

C6H5N.NH2                        HCOOH  C6H5.N  -  N=CH        n-Diphenyl-keto- 

5CO.CH2.NHC,H5-  CO-  CH2_*C8H5        *^™ 

C6H5NH-NH-CO      _  ^CflH5NH—  NH—  CO        n-Phenyl-diketo- 
CH2.CO2RtfH2  "  CH2—  CO—  ftH     hexahydro-a-triazin 

4.  C6H5NHNH2+C1CH2CH2C02H_C6H6.N-_NH>CO 

5.  C6H5NH.NH2+CH3CH  : 
. 


C6H5N  -  NH2  C6H6N  -  NH2\  i-Phenyl-5-methyl- 


CH3CH—  CH2—  COaH  CH3CH  —  CH  3-pyrazolidone. 

PHENYL-HYDRAZIN  DERIVATIVES  OF  THE  MONO-KETONIC  ACIDS.  — 
The  a-,  {3-,  and  y-ketone  carboxylic  esters  react  with  phenyl-hydrazin, 
forming  phenyl-hydrazones,  just  as  the  ketones  do.  The  phenyl-hydra- 
zones  of  a-  and  y-ketone  carboxylic  acids  are  known.  Zinc  chloride 
or  concentrated  sulphuric  acid  rearranges  the  phenyl-hydrazones  of  the 
a-,  ft-,  and  y-ketone  carboxylic  acids  into  indol  derivatives  (compare 
indol  formation  of  the  ketone  phenyl-hydrazones).  The  phenyl-hydra- 
zones of  the  ft-  and  y-ketone  carboxylic  esters  and  of  the  free  y-ketone 
carboxylic  esters  manifest  great  tendency  to  the  lactazame  formation. 
Laevulinic  phenyl-hydrazone  (i)  yields  i-phenyl-3-methyl-pyridazinone 
(q.v.),  and  under  other  conditions  a-methyl-indol-  ft-  acetic  acid.  Ace  to- 
acetic  ester  phenyl-hydrazone  C6H5NH.N=C(CH3).CH2.CO2C2H5,  melt- 
ing at  50°,  is  formed  on  adding  aceto-acetic  ester  to  phenyl-hydrazin 
(B.  27,  R.  793),  and  spontaneously  forms  i-phenyl-^-methyl-pyrazolone 
(q.v.)  ;  whereas  with  acetyl  chloride  or  excessive  hydrochloric  acid  it 
yields  i-phenyl-^-methyl-^-ethoxy-pyrazole. 

HETERO-RING  FORMATIONS  OF  THE  PHENYL-HYDRAZONE 
KETONE  ACIDS. 


i.  Indol  condensation  :   p.  155 
_=  IC6H5  _3_  —  \ 

CH2-CH2-COOH  COOH.CH2.C-  acetic  acid 


=      -NHC6H5  CH3C-NHX  a-Methyl-indol- 


2.  Lactazame  : 

C6H5.NH—  N  _      C6H5N  -  N  i-Phenyl-3-methyl- 

C02C2H5CH2.C.CH3  CO.CH2.C.CH3  5-pyrazolone 

C6H5.NH—  N  _  >  C6H5N  -  N  i-Phenyl-3-methyl- 

CO2H.CH2.CH2.C.CH3  CO.CH2.CH2C.CH3  pyridazinone 

3.  Pyrazole  : 

C6H5.NH—  N          _    C6H5N  -  N  i-Phenyl-3-methyl- 

C2H5OCO.CH2.C.CH3  *  C2H5OC=CH.C.CH3  ethoxy-pyrazole. 

PHENYL-HYDRAZIN  DERIVATIVES  OF  CARBONIC  ACID.  —  On  saturat- 
ing an  aqueous  solution  of  phenyl-hydrazin  with  CO2  we  obtain  Phenyl- 
hydrazin-phenyl-carbazinate  C6H5NHNHCOONH3NHC6H5,  a  white 


160  ORGANIC   CHEMISTRY 

crystalline  mass  (A.  190,  123  ;  C.  1901,  II.  1051).  Phenyl-earbazinie 
ethyl  ester  C6H5NHNHCOOC2H5,  m.p.  86°,  is  formed  when  C1.CO2C2H5 
acts  upon  an  etheric  solution  of  phenyl-hydrazin.  Heated  to  240°  it 
splits  off  alcohol,  and  passes  into  Diphenyl-urazin  (A.  263,  278 ;  B.  26, 
R.  20).  Unsym.  Phenyl-hydrazido-formie  ester  C6H5N(NH2)COOC2H5, 
an  oil,  is  formed  from  its  aceto-compound  obtained  from  aceto-phenyl- 
hydrazin,  and  chloro-formic  ester  (B.  29,  829;  32,  10).  On  further 
treatment  with  chloro-formic  ester  it  gives  Phenyl-hydrazido-a,j8-di- 
carboxylic  ester  C6H5N(CO2C2H5)NH.CO2C2H5,  m.p.  59°,  with  COC12  ; 
Diphenyl-carbazide-dicarboxylie  ester  CO[NH.N(C6H6)CO2C2H6]2,  m.p. 
159°.  a-  and  j3-Cyano-phenyl-hydrazin  C6H5(CN)N.NH2,  two  unstable 
oils,  formed  together  by  the  action  of  cyanogen  bromide  upon  phenyl- 
hydrazin  (C.  1907,  II.  802).  On  saponification,  the  a-compound  yields 
a-Phenyl-semicarbazide,  carbaminic  a-phenyl-hydrazide  NH2.N(C6H5). 
CO.NH2,  m.p.  120°. 

j8-Phenyl-semicarbazide,  carbaminic  f$-phenyl-hydrazide  C6H5NHNH 
CONH2,  m.p.  172°,  from  phenyl-hydrazin  salts,  and  potassium 
cyanate  (A.  190,  113),  or  by  heating  phenyl-hydrazin  with  urea  or 
urethane.  On  heating,  it  passes  into  phenyl-urazol,  and  diphenyl- 
urazin,  with  formation  of  CO,  CO2,  NH3,  and  benzene  (B.  21,  1224). 
With  potassium  hypochlorite  it  forms  diazo-benzolimide  (B.  40,  3033). 
Phenyl-semicarbazide  changes  into  oxy-biazolone  compounds  with 
COC12,  CSC12,  and  C6H5NCC12  (B.  26,  2870),  like  sym.  aceto-phenyl- 
hydrazin.  For  homologous  aryl  semicarbazides,  see  C.  1898,  II.  199. 

m-Tolyl-semicarbazide  CH3C6H4NH.NH.CONH2,  m.p.  184°,  from 
m-tolyl-hydrazin  and  urea.  It  possesses  antipyretic  properties  (C. 
1905,  I.  196  ;  II.  1299). 

2,  4-Diphenyl-semicarbazide,  phenyl-carbaminic  a-phenyl-hydrazide 
C?H5NH.CO.N(C6H5)NH2,  m.p.  165°,  is  best  obtained  from  phenyl- 
dithio-carbazinic  ester  C6H5NHNHCSSCH3,  by  combining  it  with 
phenyl  cyanate  to  C6H5NHCON(C6H5).NHCSSCH3,  converting  the 
latter,  with  methyl  iodide  and  alkali,  into  the  dimethyl  ester  C6H5 
NHCON(C6H5)N  :C(SCH3)2  and  then  breaking  up  with  dilute  sul- 
phuric acid.  The  2,  4-diphenyl-semicarbazide  is  heated  above  its  m.p. 
and  converted  into  the  isomeric  1,  4-Diphenyl-semicarbazide,  phenyl- 
carbaminic  fi-phenyl-hydrazide  C6H5NH.CO.NHNHC6Hg,  m.p.  176°, 
which  is  distinguished  from  its  isomers  by  its  reaction  with  FeCl3,  and 
the  resulting  formation  of  an  azo-body  (B.  36, 1362).  Triphenyl-semi- 
carbazide  (C6H5)2NCO.N(C6H5)NH2,  m.p.  128°,  formed  as  an  aceto- 
compound,  from  diphenyl-urea  chloride  and  j3-aceto-phenyl-hydrazin 
(B.  33,  246). 

Diphenyl-carbazide,  phenyl-hydrazin-urea  (C6H5NH.NH)2CO,  m.p. 
170°,  obtained  by  heating  urethane  or  phenyl  carbonate  with  phenyl- 
hydrazin  (B.  20, 3372  ;  C.  1900, 1.  290) ;  by  boiling  with  alcoholic  potash, 
or  bv  the  action  of  copper  or  mercury  salts,  it  loses  two  H  atoms  and  is 
transformed  into  salts  of  Diphenyl-earbazone  C6H5N  :  NCONHNHC6H5, 
orange-red  needles  of  m.p.  157°  with  decomposition  (A.  263,  274). 
With  metals  this  diphenyl-carbazone  forms  red  or  blue  and  partly 
explosive  salts  of  the  type  C6H5N2CONMeNHC6H5,  and  it  dyes  silk  or 
wool  in  a  neutral  bath..  Like  the  diphenyl-carbazide,  it  is  converted 
by  oxidation,  with  silver  and  acetate,  into  diphenyl-carbo-diazone 
(C6H6N  :  N)2CO,  colourless  needles,  decomposing  on  heating,  and  re- 


PHENYL-HYDRAZIN   DERIVATIVES  161 

generating  the  K  salt  'of  diphenyl-carbazone  on  boiling  with  alcoholic 
potash  (C.  1900,  II.  n'o8  ;  1901,  I.  703  ;  II.  682). 

Cyclic  Urea  and  Carbamic  Acid  Derivatives.  —  Phenyl-urazol  is  pro- 
duced on  heating  phenyl-semicarbazide,  or  phenyl-hydrazin  chloro- 
hydrate  with  urea,  or  biuret  with  phenyl-hydrazin.  Diphenyl-urazin 
results  upon  heating  ethyl-phenyl-carbazinate  and  phenyl-semicarbazide 
(A.  263,  582). 

i-Phenyl-3-methyl-5-triazolone  is  obtained  from  acetyl-ur  ethane  and 
phenyl-hydrazin  (B.  22,  R.  737)  : 

C6H5NH.NH2+2NH2CONH2  --  »  C«H5N~"S^NH  Phenyl-urazol 

2C6H5NH.NHCOOC2H5  -  ->  C6H5N  ---  NH-CO  Diphenyl.urazin 

2C6H5NH.NHCONH2  -      -  >          CO  —  NH—  NC6H5 


C6H5NH.NH2  +NH25  -_>     65—      \  NR  i-Phenyl-3-methyl- 

-H3  \CH  5-triazolone. 

PHENYL-HYDRAZIN  DERIVATIVES  OF  CARBONIC  ACID.  —  On  passing 
CS2  through  an  etheric  solution  of  phenyl-hydrazin  we  obtain  Phenyl- 
dithio-carbazimie  phenyl-hydrazin  C6H5NH.NH.CSSNH3NHC6H5,  m.p. 
96  °  .  From  solutions  of  th  e  salts  of  phenyl-dithio-earbazimie  acid,  mineral 
acids  precipitate  the  free  acid  in  fine  shiny  flakes,  easily  oxidised  to  the 
corresponding  bisulphide  (A.  190,  114).  The  mono-  and  dialkyl  esters 
obtained  from  the  acid  with  alkali  and  halogen  alkyls  are  partly 
derivable  [from  the  desmotropic  form  of  phenyl-sulpho-carbazinic  acid 
C6H5NHN  :  C(SH)2,  corresponding  to  the  formula 

C6H5NHN  :  C(SCH3)SH,    C6H3NHN  :  C(SCH3)2,    C6H5NHN  : 
On  introducing  two  different  radicles,  the  resulting  compounds 

<"OTQ 
\  occur  in  stereo-isomeric  forms.     Dilute  acids  break 
oK. 

up  the  dialkyl  esters  of  phenyl-dithio-carbazinic  acid  into  phenyl- 
hydrazin  and  dithio-carbonic  ester  (see  Vol.  I.  and  B.  34,  1119  ;  /.  pr. 
Ch.  2,  65,  473).  On  treating  the  potassium  salt  of  phenyl-sulpho- 
carbonic  acid  with  COC12  or  CS2  we  obtain  n-phenyl-thio-biazolone- 
sulphohydrate  and  also  the  dithio-sulphohydrate. 

a-Phenyl-sulpho-semicarbazide,  thio-carbaminic  a-phenyl-hydrazide 
NH2.N(C6H5)CS.NH2,  m.p.  153°,  from  the  action  of  NH4SH  upon 
a-cyano-phenyl-hydrazin. 

jg-Phenyl-sulpho-semicarbazide  C6H5NH.NH.CSNH2,  m.p.  200°, 
isomeric  with  phenyl-thio-semicarbazide,  is  obtained  from  phenyl- 
hydrazin  sulphocyanate  at  i6o°-i70°  ;  on  heating  with  HC1  it 
passes  into  sulpho-earbizin  and  benzo-diazo-thin  (B.  27,  861). 

2,  4  -  Diphenyl  -  sulpho  -  semicarbazide,  phenyl  -  thio  -  carbaminic  a- 
phenyl-hydrazide  C6H5NHCSN(C6H5)NH2,  m.p.  139°,  is  obtained  from 
phenyl-dithio-carbaminic  acid  with  aniline,  as  well  as  the  combination 
of  phenyl-mustard  oil  with  phenyl-hydrazin.  It  is  transposed  like  the 
2,  4-diphenyl-semicarbazide,  but  much  more  easily,  into  2,  4-Di- 
phenyl-sulpho-semiearbazide,  or  phenyl  -  thio  -  carbaminic  p-phenyl- 
hydrazide  C6H5NHCSNHNHC6H5,  m.p.  176°.  Both  isomeric  com- 
pounds give,  with  methyl  iodide  and  alkali,  the  isomeric  methyl 
ethers  C6H5N  :  C(SCH3)N(C6H5)NH2  and  C6H5N.C(SCH3).NHNHC6H5. 

VOL.  II.  M 


162  ORGANIC  CHEMISTRY 

With  benzaldehyde,  the  2,4-  diphenyl  -  thio  -  semicarbazide  reacts 
smoothly  with  formation  of  a  benzylidene  derivative,  while  the 
i,  4-compound  does  not  react  in  this  manner.  For  other  isomeric 
transpositions,  see  B.  34,  320. 

Diphenyl-sulpho-earbazide  (C6H5NH.NH)2CS,  m.p.  150°,  is  formed 
by  heating  phenyl-hydrazin-phenyl-sulpho-carbazinate  to  ioo°-iio°. 

Diphenyl  -  sulpho-carbazone  C6H5N = N.CSNH.NHC6H5,  bluish- 
black  crystals  formed  by  short  boiling  of  diphenyl-sulpho-carbazide 
with  moderately  concentrated  alcoholic  potash. 

Diphenyl-sulpho-earbo-diazone  (C6H5N=N)2CS,  from  diphenyl- 
sulpho-carbazone  by  oxidation  with  manganese  peroxide  hydrate, 
forms  small  red  needles  (A.  212,  316). 

HETERORING  FORMATION  OF  PHENYL-HYDRAZIN  DI-THIO- 
CARBONIC  ACID  DERIVATIVES. 

COCl.       C6H5N — N\p  CTJ  n-Phenyl-thio-biazolon- 

CHNHNHCSSK    / >  CO-S/*  sulphohydrate 

C6H5JNH.JN±i.C.  c^          c6H5N— N\r  <m  n-Phenyl-dithio-biazolin- 

CS— S/  sulphohydrate 

CeH6NH.NH.CSNH2         ~NH'-»  C.H4/*  Phenyl.-sulpho-carbizin 

4\g £H  Benzo-diazo-thin. 

PHENYL-HYDRAZIN  DERIVATIVES  OF  GUANIDIN. — Anilino-guanidin 
NH  :  C(NH2).NHNHC6H5,  and  Amido-phenyl-guanidin  NH  :  C(NH2). 
N(C6H5JNH2,  are  produced  together  from  cyanamide  and  phenyl- 
hydrazin  (B.  29,  R.  1109  ;  cp.  /.  pr.  Ch.  2,  61,  440 ;  C.  1901,  II.  591)  ; 
under  different  conditions  a  phenyl-hydrazin  derivative  of  biguanide 
is  formed,  the  unstable  Anilo-biguanide  C6H5NH.NH.C  :  (NH).NH.C  : 
(NH)NH2.  On  heating  with  cyanamide  the  anilo-biguanide  (I.)  passes 
into  n-phenyl-guanazol  (II.),  which  is  also  formed  from  diazano- 
diamide  (III.)  with  phenyl-hydrazin  (B.  24,  R.  649) : 

I.  C6H6NH.NH.C:NH        II.  C6H5N.NH.C :  NH       III.  C6H5NH.NH2+CN 
NH.\C NH  HN:C— NH  ™«>C ^ 

DianUino-guanidin  NH  :  C(NH.NHC6H?)2,  bromo-hydrate,  m.p. 
180°,  is  formed  as  a  by-product  in  the  action  of  BrCN  upon  phenyl- 
hydrazin. 

PHENYL-HYDRAZIN  DERIVATIVES  OF  DICARBOXYLIC  ACIDS. — 
Corresponding  to  oxanilic  acid  and  oxanilide  we  have  Oxal-phenyl- 
hydrazilie  acid  C6H5NH.NH.CO.CO2H,  m.p.  110°  (A.  236,  197),  and 
Oxal-phenyl-hydrazide  (C6H5NH.NH.CO)2,  m.p.  278°. 

From  malonic  acid  we  have  the  following  phenyl-hydrazin  deriva- 
tives : — Malonic  ester  phenyl-hydrazide,  malono-phenyl-hydrazilic  ester 
C6H5.NH.NH.CO.CH2.COOC2H5,  m.p.  90°,  from  malonic  ester  chloride 
with  phenyl-hydrazin.  The  compound  easily  dissolves  in  KHO,  and, 
from  the  solution,  HC1  precipitates  Malonyl-phenyl-hydrazide,  or 
i-phenyl-3,  ^-pyrazolidone.  Malonyl  -  diphenyl  -  hydrazide  (C6H5NH. 
NH.CO)2CH2,  m.p.  187°,  from  malonic  acid  amide  and  phenyl-hydrazin 
at  200°  (B.  25,  1550). 

Compounds  of  ethylene-succinic  acid  are  known  corresponding  to 


PHENYL-HYDRAZIN   DERIVATIVES  163 

those  of  malonic  acid  : — Succinic  phenyl-hydrazilic  ester,  m.p.  107°  ; 
Sueeinyl-phenyl-hydrazin  (see  below),  from  phenyl-hydrazin  chloro- 
hydrate  and  succinyl  chloride  (B.  26,  2181)  ;  Succinyl-diphenyl- 
hydrazide,  m.p.  209°  (B.  21,  2462),  and  also  Anilo  -  succimide, 
(CH2CO)2NNHC6H5. 

PHENYL-HYDRAZIN  DERIVATIVES  OF  OLEFIN-  AND  OXY-DICAR- 
BOXYLIC  ACIDS. — Maleinic  anhydride  yields,  with  phenyl-hydrazin, 
Maleino-phenyl-hydrazil.  On  boiling  maleiinic  or  fumaric  acid  in 
water  with  excess  of  phenyl-hydrazin,  it  adds  itself  as  it  does  to 
acrylic  or  crotonic  acid,  and  lactazame  is  formed  subsequently  (B. 
26,  117).  l-Phenyl-5-pyrazolidone-3-carboxylie  acid  is  formed. 

HETERO-RING  FORMATION  OF  PHENYL-HYDRAZIN  DERIVATIVES 
OF  DlCARBOXYLIC  ACIDS. 

CONH.NHC6H5 CH  /CO— NH  Malonyl-phenyl-hydrazin, 

CO— ttC6H5  i  -Phenyl-3,5-pyrazolidone 


CH— COOH          NH,NHCtHt       CO2H.CHNH\  NC  H     i-Phenyl-5-pyrazolidone- 
CH— COOH    "  CH2CO/  3-carboxylic  acid. 


16.  Hydrazidins  or  Amidrazones.  Nitrazones.  Phenyl-hydrazo-aldoximes. 
Phenyl-azo-aldoximes  (Nitrosazones).    Formazyl  Compounds. 

In  connection  with  the  phenyl-hydrazin  derivatives  of  the  carboxylic 
acids,  some  classes  of  compounds  must  be  dealt  with  which  are  com- 
posed according  to  the  amidine  type.  The  hydrazidins  are  amidins 
in  which  the  imido-group  is  replaced  by  the  phenyl-hydrazone  group. 
In  the  nitrazones  there  is  also  a  replacement  of  the  amido-group  by 
the  nitro-group,  and,  in  the  formazyl  compounds,  by  the  azo-phenyl 
group: 

/NH2 


3H3C\N^HC6H5 

Ethenyl-phenyl- 
hydrazidin 

3   \NNHC6H5 
Nitro-acetaldehy- 
drazone 

HC/N=NC6H5 
\N—  NHC6H5 
Fonnazyl 
hydride. 

Acetamidin 

To  these  must  be  added  the  phenyl-azo-aldoximes,  the  stable  trans- 
position products  of  the  very  unstable  nitroso-phenyl-hydrazones  : 

rM  r/NO  rrr  r//NOH 

'HsC\NNHC6H5  HaC\N  :  NC6H5 

Nitroso-aceto-phenyl-hydrazone  Phenyl-azo-acetaldoxime. 

HYDRAZIDINS      OR      AMIDRAZONES.  —  Ethenyl  -  phenyl  -  hydrazin 

CH3C^KNHC6H5.     The  chlorohydrate  of  this  base  is   formed  by  the 
\NH2 

action  of  phenyl-hydrazin  upon  hydrochloric  acetimido-ether  (B.  17, 
2002)  .  Cyan-amidrazone  or  dieyano-phenyl-hydrazinNC—  c^^HC«H5  1 
m.p.  160°,  with  decomposition,  and  diamidrazone  or  cyano-phenyl- 


164  ORGANIC  CHEMISTRY 

hvdrazin  fC^"N5"?\P^  ,   m.p.   225°,   are  formed  by  the  action  of 
y  V  NH2/    /•' 

cyanogen  upon  phenyl-hydrazin.  Dicyano-phenyl-hydrazin  is  also 
formed  by  reduction  of  the  prussic  acid  addition  product  of  diazo-benzol 
cyanide,  to  which,  therefore,  probably  the  following  formula  must  be 

ascribed :  CCH5N :  NC^H  (B.  28,  2082  ;  A.  287,  300).  The  constitution 
of  cyan-amidrazone  follows  from  its  formation  by  the  action  of  phenyl- 
hydrazin  upon  Flaveanic  hydride  NC— C\^H  >  and  tne  constitution  of 
diamidrazone  from  its  formation  by  the  action  of  phenyl-hydrazin 
upon  Rubeanie  hydride  NHS/C-C\NH  'see  VoL  L)  and  upon  Oxal°" 

diamido-oxime  ^H^/C— c/*     H  (B.  26,  2385).    Diamidrazone  is  also 

jSfHjj/  r^2 

formed  by  the  reduction  splitting  of  diformazyl. 

Acetyl-amidrazone,  pyro-racemic   acid  phenyl - hydrazidine 

CH3CO.C<f  N>NHCeH5,  melting  at  182°,  is  produced  by  reducing  formazyl 
\NH2 

methyl-ketone  with  ammonium  sulphide  (B.  26,  2783). 

HETERO-RING  FORMATIONS  WITH  THE  AMIDRAZONES. — The  ami- 
drazones condense  with  carboxylic  acids,  their  anhydrides  or  chlorides, 
to  heterocyclic  derivatives  of  the  triazol  group  (q.v.).  Nitrous  acid 
converts  the  amidrazones  into  tetrazol  derivatives  (q.v.).  Cyan-ami- 
drazone is  changed  by  acetic  anhydride  to  n-phenyl-3-cyano-5-methyl- 
triazol ;  by  nitrous  acid  to  n-phenyl-3-cyan-tetrazol  : 

C6H5NH.N\r  rM     CH3COQH      C6H5N— N\r  rM     n-Phenyl-3-cyan- 
NH2/  CH3C=N/  5-methyl-triazol 

C6HSNH.N\C  CN          N203          C6H5N— N\CCN     n-Phenyl-3-cyan- 
NH2/  S=N/  tetrazol. 

NITRO  -  HYDRAZONES  or  NiTRAZONES  are  the  nitro  -  compounds 
coi  responding  to  the  amidrazones  ;  they  are  formed  from  the  alkali 
salts  of  primary  nitro-paraffins  (Vol.  I.)  with  diazonium  salts,  and 
were  formerly  regarded  as  nitro-azo-paraffins  ;  but  the  free  compounds 
must  probably  be  regarded  as  nitrogenated  hydrazones,  while  their 
metallic  salts  are  derivable  from  the  tautomeric  form  of  Phenyl-azo- 


nitro-aeid    RC\NNC  H  '    They  are  easily  split  up  by  alkalies  into 
nitrites,  and  jS-Acidyl-phenyl-hydrazides  (B.  31,  2626)  : 

CH3C(NO2)  :  NNHC6H5+KOH  =  CH3CONHNHC6H5+NO2K. 

Certain  poly-halogenated  diazo-compounds  also  unite  with  primary 
nitro-paramns  in  the  molecular  ratio  2:1,  mixed  azo-compounds 
being  obtained  (B.  36,  3833)- 

Nitro-formaldehydrazone  CH(NO2)  :  N.NHC6H5,  occurs  in  two 
forms  :  a-form,  m.p.  75°  ;  j8-form,  m.p.  85°  (B.  34,  2002).  With 
diazo-methane  it  yields  an  unstable  O-methyl  ether  HC(:  NOOCH3)N  : 
NC6H5,  m.p.  54°,  but  with  methyl  iodide,  and  sodium  methylate,  it 
gives  an  N-methyl  derivative  HC(NO2)  :  NN(CH3)C6H5,  m.p.  92°, 
which,  on  reduction,  yields  Phenyl-methyl-formhydrazin  CH(NH2)  : 
NN(CH3)C6H5,  m.p.  101°,  and  then  methyl-amine  and  unsym.  phenyl- 
methyl-hydrazin  (B.  34f,  574). 


PHENYL-HYDRAZO-ALDOXIMES  165 

Nitro-acetaldehydrazone  CH3C(NO2)  :  NNHC6H5,  yellow  flakes,  m.p. 
142°,  gives,  with  diazo-methane,  O-methyl  ether  CH3C(:  NOOCH3). 
N  :  NC6H5,  m.p.  68°. 

PHENYL  -  HYDRAZO  -  ALDOXIMES  AND  PHENYL  -  AZO  -  ALDOXIMES 
(NITROSAZONES). — Formation  : — (i)  On  reducing  nitrazones  with  Am2S 
we  obtain  phenyl-hydrazo-aldoximes,  which  are  easily  oxidised,  by 
ferric  chloride,  to  phenyl-azo-aldoximes  : 

RC(NO2) :  NNHC6H5      H   >  RC( :  NOH)NHNHC6H5 °_>  RC( :  NOH)N :  NC6H5. 

(2)  The  O-methyl  ethers  of  the  nitrazones,  boiled  in  water,  easily  decom- 
pose into  formaldehyde  and  phenyl-azo-aldoximes  : 


(3)  Aldehyde-phenyl-hydrazones,  treated  with  amyl  nitrite  and 
sodium  alcoholate,  or  pyridin,  probably  first  give  the  very  unstable 
nitroso-hydrazones  (nitrosazones),  which  easily  transpose  into  azo- 
aldoximes  (B.  35,  54,  108  ;  36,  53,  86,  347)  : 

RCH  :  NNHC6H5 >  RC(NO) :  NNHC6H5 >  RC( :  NOH)N  :  NC6H5. 

The  aryl  hydrazones  of  glyoxylic  acid,  treated  with  HNO2,  split 
off  CO2  and  pass  into  phenyl-azo-aldoximes  (C.  1905,  I.  1538). 

Phenyl  -  hydrazo  -  formaldoxime  HC(:  NOH)NH.NHC6H5,  white 
needles,  m.p.  113°,  from  nitro-formaldehydrazone,  with  alcoholic 
Am2S,  gives,  by  oxidation  with  ferric  chloride,  Phenyl-azo-formal- 
doxime,  golden-yellow  needles,  m.p.  94°  with  decomposition. 

Phenyl-hydrazo-acetaldoxime  CH3C(:  NOH)NHNHC6H5,  m.p.  128°, 
from  nitro-acetaldehydrazone,  gives  by  oxidation  Phenyl-azo- 
acetaldoxime  CH3C(:NOH)N  :NC6H5,  m.p.  118°.  This  is  obtained 
from  the  O-methyl  ether  of  nitro-acetaldehydrazone  on  boiling  with 
water,  also  from  acetaldehyde-phenyl-hydrazone,  or  benzol-azo-ethane 
with  amyl  nitrite  and  sodium  ethylate,  or  pyridin,  and  also  from 
acetaldehyde-ammonia  with  nitroso-phenyl-hydrazin  (B.  35,  1009). 
Its  Ag  salt,  with  methyl  iodide,  gives  the  O-methyl  ether  CH3C 
(:  NOCH3)N  :  NC6H5,  an  oil  of  b.p.12  134°  ;  whereas  the  Na  salt 
gives,  with  methyl  iodide,  an  N-methyl  ether,  m.p.  96°.  This  latter, 
under  the  influence  of  sodium  alcoholate,  easily  undergoes  cyclic 
condensations  into  Phenyl-methyl-triazol : — 

— H2O 

:  NC6H5  ' 

HC1  converts  the  phenyl-azo-aldoximes,  with  primary  addition, 
and  wandering  of  the  chlorine  atom  into  the  benzene  nucleus,  into 
Chloro-phenyl-hydrazo-aldoximes  : 

T-TC1 

RC(:  NOH)N  :  NC0H5  -  -»  RC(:  NOH)NH.NC1.C6H5— >  RC(:  NOH)NH.NHG6H4C1. 

FORMAZYL  COMPOUNDS  are  strongly  coloured,  usually  red,  easily 
crystallised  substances.  Their  sulpho-acids  are  dyes  (B.  33,  747). 
They  are  obtained  (i)  from  phenyl-hydrazones  and  normal  diazo-benzol, 
usually  in  alkaline  solution ;  (2)  from  phenyl-hydrazin  and  phenyl- 
hydrazides  ;  the  hydrazone-hydrazide  produced  at  first  oxidises,  under 
the  influence  of  phenyl-hydrazin,  with  the  loss  of  two  hydrogen  atoms  ; 


166  ORGANIC  CHEMISTRY 

(3)  from  the  phenyl-hydrazone  chlorides,  corresponding  to  the  imide 
chlorides,  by  action  of  phenyl-hydrazin  (B.  27,  320  ;  29,  1386). 

Formazyl  hydride  H0^^^.  m'p'  Il6°  (L  233''  has  been 
obtained  from  formazyl-carboxylic  acid  by  fusion,  or  by  the  action 
of  diazo-benzol  acetate  upon  malonic  acid,  or  from  acetyl-formazyl 
hydride  CH(N2C6H5)  :  NN(COCH3)C6H5,  generated  on  acetyling  form- 
azyl-carboxylic acid  with  methylated  potash  (/.  pr.  Ch.  2,  65,  131). 

Methyl-formazyl  CH3C(N2C6H5)  :  NNHC6H5,  m.p.  121°,  see  /.  pr. 
Ch.  2,  64,  213  ;  B.  36,  87. 

Formazyl-methyl  ketone  CB»-CO-C\N  N^H  '  m'p'  I34°'  results 
from  the  action  of  diazo-benzol  upon  acetone,  aceto-acetic  ester,  pyro- 
racemic  aldehyde  hydrazone,  and  benzol-azo-acetyl  acetone  (B. 
25,  3211). 

Formazyl-carboxylic  acid  CO2H.C/^  -**'1**  TT  ,  m.p.   162°  with  de- 

NxN.JNri.C6H5 

composition,  is  made  by  saponifying  the  ethyl-f  ormazyl-carboxylic  ester, 
m.p.  117°.  The  latter  is  produced  when  diazo-benzol  chloride  acts 
upon  aceto-acetic  ester,  oxalo-acetic  ester  (B.  25,  3456),  or  upon  phenyl- 

hydrazone-mesoxalic-ester  acid.  Diformazyl  c^  .^^N.NHW 
greenish-brown,  brilliant  flakes,  m.p.  226°.  It  results  from  the  action 
of  diazo-benzol  chloride  upon  laevulinic  acid,  hydro-chelidonic  acid,  or 
acetone-diacetic  acid,  and  from  dioxy-tartrosazone. 

Formazyl-acrylic  acid  co2H.CH  :  CH.C/^  ;  ^3?*   ,  m.p.   129°  with 

v-JN  !  ^1  JtdLC-'girj.e 

decomposition,  formed  by  the  action  of  diazo-benzol  acetate  upon 
glutaconic  acid  (B.  40,  4927). 

Formazyl-azo-benzol,  Phenyl-azo-f  ormazyl  (C6H5N  =  N)  2C  =  N  . 
NHC6H5,  m.p.  162°,  from  formazyl-carboxylic  acid,  glyoxalic  phenyl 
hydrazone  or  acetaldehyde,  with  diazo-benzol  in  alkaline  solution 
(/.  pr.  Ch.  2,  64,  199).  In  the  action  of  diazo-benzol  alkali  upon  pyro- 
racemic  acid,  the  first  product  is  Formazyl-glyoxalic  acid,  m.p.  166°, 
which,  on  further  action,  is  decomposed  into  oxalic  acid  and  phenyl- 
azo-f  ormazyl  (/.  pr.  Ch.  2,  64,  204). 

Nitro-formazyl  NO2.C(N2C6H5)  :  NNHC6H5,  m.p.  153°,  from  sodium 
nitro-methane,  with  diazo-benzol  nitrate,  is  both  a  formazyl  and  a 
nitrazone  compound  (B.  27,  156  ;  cp.  B.  33,  2043). 

Hetero-ring  Formations  in  Formazyl  Compounds.  —  Under  the  in- 
fluence of  strong  mineral  acids  the  formazyl  compounds  split  off 
aniline  and  give  pheno-triazin  derivatives  :  formazyl-carboxylic  ester 
gives  a-pheno-triazin.  On  oxidation,  the  formazyl  compounds  give 
tetrazolium  compounds  ;  thus,  from  formazyl  hydride  n-Diphenyl- 
tetrazolium  hydroxide  is  obtained  : 


C6H5N=N\CH  O  C6H5N(OH)  :  N\rTT      n-Diphenyl-tetrazolium- 

C6H5NH—  N/  >  C6H5tt—     —  N/"  hydroxide. 


Phenyl  -  nitroso  -  hydrazin   C6H5N          or  C6H5NHNHNO,  yellowish- 

\NH2 
brown  crystalline  flakes  easily  passing  into  diazo-benzol-imide  (A.  190, 


TETRAZONES  167 

89).  Obtained  from  phenyl-hydrazin  and  HNO2;  an  excess  of  acid 
oxidises  phenyl-hydrazin  to  diazo-benzol  nitrate  (C.  1897,  I-  3&1  •  B.  33, 
1718).  Heating  in  indifferent  solvents  decomposes  the  phenyl-nitroso- 
hydrazin  with  nitrous  oxide  and  aniline  (B.  41,  2809).  By  reduction 
it  is  split  up  with  recovery  of  phenyl-hydrazin.  A  similar  behaviour 
is  shown  by  the  nitroso-derivatives  of  alkylated  phenyl-hydrazins. 

Nitroso  -  a,  £  -  diethyl  -  phenyl  -  hydrazin  C6H5N(C2H5)N(C2H5)NO 
yields  ethyl-aniline  and  ethyl-hydrazin  (B.  36,  202).  But  in  the  re- 
duction of  Nitroso-formyl-phenyl-hydrazin  C6H5N(NO)NHCHO,  m.p. 
85°,  and  Nitroso-acetyl-phenyl-hydrazin  C6H5N(NO)NHCOCH3,  m.p. 
63°  with  decomposition,  with  Na  amalgam  and  alcohol,  derivatives 
of  an  hypothetical  phenyl-triazane  C6H5N(NH2)2  are  obtained,  and 
these  have  been  isolated  in  the  form  of  their  benzylidene  compounds. 

Benzylidene-formyl-phenyl-triazane  C6H5N(N  :  CHC6H5)NHCHO, 
m.p.  183°,  and  Benzylidene-acetyl-phenyl-triazane  C6H5N(N  :  CHC6H5) 
NHCOCH3,  m.p.  163°  (B.  35,  1900).  Nitroso-phenyl-semicarbazide 
C6H5N(NO)NHCONH2,  m.p.  127°  with  decomposition,  from  phenyl- 
semicarbazide  \vith  NO2Na  and  acetic  acid,  decomposes  gradually  even 
at  ordinary  temperatures,  and  more  rapidly  on  heating,  with  formation 
of  phenyl-azo-carbamide  ;  boiling  with  potassium  hydroxide  yields 
diazo-benzol-imide  (B.  28,  1925). 

Tetrazones,  or  tetrazenes,  derived  from  the  hypothetical  nitro- 
gen hydride  NH2  —  N=N  —  NH2,  are  formed  from  the  unsym.  alkyl- 
phenyl-  or  diphenyl-hydrazins  by  oxidation  with  HgO  in  alcoholic  or 
etheric  solution,  or  with  dilute  ferric  chloride  solution  : 

2C6H5N(CH3).NH2+2O-C6H5.N(CH3).N  :  N.N(CH3).C6H5+2H2O. 

They  are  solid  bodies,  decomposed  on  melting  or  boiling  with  dilute 
acids.  Dimethyl-diphenyl-tetrazone  C6H5.N(CH3)N2.N(CH3)C6H5,  m.p. 
133°.  Diethyl-diphenyl-tetrazone,  m.p.  108°  (A.  252,  281).  Tetra- 
phenyl-tetrazone  (C6H5)2N.N2.N(C6H5)2,  m.p.  123°,  from  as-Diphenyl- 
hydrazin.  p  -  Tetratolyl  -  tetrazone  (CH3C6H4)  2N.N2.N(C6H4CH3)  2, 
fiery-yellow  needles,  m.p.  134°  with  decomposition,  from  unsym. 
p-ditolyl-hydrazin  with  MnO4K  in  acetone  solution.  On  heating  in 
indifferent  solvents  the  quaternary  tetrazones  decompose  into  nitrogen 
and  tetra-aryl-  hydrazin.  In  concentrated  acids  they  dissolve  with 
liberation  of  N,  forming  intensely  blue  solutions,  the  transformation 
products  being  the  same  as  those  obtained  with  the  corresponding  tetra- 
aryl-hydrazins  (B.  41,  3502). 

Hydro-tetrazones,  tetrazanes,  derived  from  the  hypothetical  nitro- 
gen hydride  NH2.NH.NH.NH2,  have  been  obtained  by  the  oxida- 
tion of  aldehyde-phenyl-hydrazones  with  HgO  or  amyl  nitrite  (B.  26, 
R.  55  ;  27,  2920).  Thus,  from  benzal-phenyl-hydrazone  the  compound 

5  Benzal-diphenyl-dihydro-tetrazone  is  obtained,  m.p. 


g.5.          . 

190°.  Under  the  influence  of  other  oxidisers,  e.g.  aerial  oxygen  in 
alkaline  solution,  the  aldehydrazones  are  oxidised  to  osazones  of  di- 
ketones.  Thus,  benzal-hydrazone  is  oxidised  to  benzile-osazone  (A. 
305,  165).  Concerning  a  third  type  of  oxidation,  producing  the  so- 

called  dehydro-benzal-phenyl-hydrazone  ^S^:  ^S^S*,  m.p.  207°,  see 
C.  1897,  II.  899  ;  B.  34,  528,  etc. 


168  ORGANIC  CHEMISTRY 

1 8.  Buzylene  or  Diazo-hydrazo-compounds. — In  Hippuryl-phenyl- 
buzylene  C6H5N=N— NH— NHCO.CH2NHCOC6H5,  m.p.  84°,  we  have 
a  hippuric  acid  derivative  of  the  unknown  nitrogen  hydride  "  buzylene  " 
NH=N— NH— NH2  (B.  26,  1268).     It  is  formed  from  hippuryl-hydra- 
zin  and  diazo-benzol  sulphate.     From  the  same  buzylene  the  Diazo- 
benzol-phenyl-hydrazide  C6H5N  :  N.N(C6H5).NH2,  m.p.  71°  with  decom- 
position, is  derived.     It  has  been  prepared  (i)  from  diazo-benzol  and 
phenyl-hydrazin  ;    (2)  from  phenyl-hydrazin  by  oxidation  with  iodine 
solution  (/.  pr.  Ch.  2,  66,  336).      By  the  first  method  a  number  of 
nucleus-substituted   derivatives   have   also   been   prepared.      As   the 
unsym.  hydrazins  are  converted  into  tetrazones,  so  these  diazo-phenyl- 
hydrazides  are  converted,  by  oxidation  with  MnO4K,  into  bodies  con- 
taining a  chain  of  eight  N  atoms. 

19.  Octazones. — Bis-diazo-benzol-  diphenyl  -  tetrazone,    tetraphenyl- 
octazone  C6H5N  :  N.N(C6H5)N  :  N.N(C6H5)N  :  NC6H5,  m.p.  51°  ;    bis- 
bromo-diazo-benzol-diphenyl-tetrazone,  m.p.  60°.     These  substances 
decompose,  and  explode  very  easily  (B.  33,  2741). 


4.  Aromatic  Compounds  of  Phosphorus,  Arsenic,  Antimony, 
Bismuth,  Boron,  Silicon,  and  Tin. 

The  phenyl  derivatives  of  phosphorus,  arsenic,  antimony,  bismuth, 
boron,  silicon,  and  tin  are  correlated  to  the  aromatic  nitrogen  com- 
pounds. Their  chlorides  are  most  suitable  for  the  preparation  of  these 
bodies,  (i)  They  react  with  benzene  at  a  red  heat,  hydrochloric  acid 
being  eliminated ;  (2)  with  benzene  and  aluminium  chloride ;  (3) 
with  mercury-diphenyl ;  (4)  with  phenyl-magnesium  bromide  (B.  37, 
4620)  ;  (5)  with  sodium  and  benzene  chloride,  or  benzene  bromide. 
This  class  of  derivatives  is  produced  also  (6)  from  alloys  of  the  elements 
with  alkali  metals  and  benzene  haloids. 

Special  importance  is  attached,  on  account  of  their  destructive 
action  upon  trypanosomes,  to  a  series  of  aromatic  compounds  of  arsenic 
which,  being  relatively  but  slightly  poisonous,  were  found  useful  as 
medicines  in  protozoic  diseases.  It  was  found  that  compounds  con- 
taining trivalent  arsenic  were  much  more  effective  than  those  con- 
taining quinquivalent  arsenic  (like  those  of  cacodylic  acid,  Vol.  I.). 
The  monosodium  salt  of  p-amido-phenyl-arsinic  acid,  known  as  "atoxyl," 
is  used  therapeutically  for  fighting  "  sleeping  sickness "  and  the 
diamido-dioxy-arseno- benzol,  in  the  form  of  its  bichlorohydrate 
"  salvarsan  "  (P.  Ehrlich-Hata  666)  for  fighting  syphilis. 

PHENYL-PHOSPHORUS  COMPOUNDS. — Michaelis  in  1876  succeeded, 
by  the  preparation  of  phosphenyl  chloride,  the  substance  for  obtaining 
phosphenyl  derivatives,  in  overcoming  the  experimental  difficulties 
which  opposed  the  union  of  the  phenyl  residue  with  phosphorus  (A.  181, 
265  ;  293,  193,  325  ;  294,  i).  Some  phosphenyl  compounds  in  com- 
position correspond  to  known  aromatic  nitrogen-containing  substances  ; 
the  names  of  the  respective  phosphenyl  bodies  recall  these  : 

Aniline,  C6H5NH2  C6H5PH2,  Phenyl-phosphine 

Nitro-benzol,  C6H5NO2  C6H5PO2,  Phosphino-benzol 

Azo-benzol,     C6H5N  :  NC6H5      C6H5P  :  PC6H5,   Phospho-benzol. 


PHENYL-PHOSPHORUS   COMPOUNDS  169 

Phenyl-phosphine  C6H5.PH2,  phosphaniline,  boiling  at  160°,  is  ob- 
tained by  the  action  of  hydriodic  acid  and  then  alcohol  upon  phosphenyl 
chloride  C6H5.PC12.  It  is  a  liquid  possessing  an  extremely  disagreeable 
odour.  When  exposed  to  the  air,  it  oxidises  to  phosphenyl  oxide 
C6H5.PH2O,  a  crystalline  mass  easily  soluble  in  water.  Phenyl- 
phosphine  combines  with  HI  to  the  iodide  C6H5.PH3I,  out  of  which 
water  again  separates  phenyl-phosphine. 

Phosphenyl  chloride  C6H5.PC12,  boiling  at  225°,  with  sp.  gr.  1-319 
(29°) ,  is  a  strongly  refracting  liquid  which  fumes  in  the  air.  It  is  formed 
(i)  by  conducting  a  mixture  of  benzene  and  PC13  vapours  through  tubes 
heated  to  redness  (A.  181,  280)  ;  (2)  by  heating  mercury-diphenyl  with 
PC13 ;  and  (3)  by  the  action  of  A1C13  upon  benzene  and  PC13.  Aided  by 
this  last  reaction,  the  chloro-phosphine  residue  has  also  been  introduced 
into  dimethyl-aniline  (6.21,1497), and  into  phenol-alkyl  ether  (B.  27,2559). 
It  forms  the  tetrachloride  C6H5.PC14  with  chlorine  ;  this  melts  at  73°. 
With  oxygen  it  yields  the  oxychloride  C6H5.PC12O,  boiling  at  250°,  and 
with  sulphur  phosphenyl  sulpho-chloride,  boiling  at  205°  (130  mm.). 
When  the  dichloride  is  heated  with  water,  we  obtain  phenyl-hypophos- 
phorous  acid  C6H5.PHO.OH,  melting  at  70°,  while  the  tetrachloride 
forms  phenyl-phosphinic  acid  C6H5.PO.(OH)2,  which  melts  at  150°. 

p-Tolyl-phosphoro-chloride  CH3[4]C6H4PC12,  forms  a  tetrachloride, 
which  forms  with  aniline  tolyl-trianilido-phosphonium  chloride  CH3[4] 
C6H4P(NHC6H5)3C1,  melting  at  245°.  Sodium  hydroxide  converts  the 
latter  into  the  hydroxide  CH3C6H4P(NHC6H5)3OH,  melting  at  240° 
(B.  28,  2214). 

Phosphino-benzene  C6H5PO2,  melting  at  100°,  is  obtained  from 
phosphenyl  oxychloride  and  phenyl-hypophosphorous  acid  (B.  25, 1747). 

Phosphenyl  chloride  converts  phenyl-phosphine  into  phospho- 
benzol  C6H5.P  :  P.C6H5,  melting  at  150°  (B.  10,  812). 

Diphenyl-phosphine  chloride  (C6H5)2PC1,  boiling  at  320°,  is  ob- 
tained from  phosphenyl  chloride  alone  at  280°,  or  with  mercury-di- 
phenyl at  220°  (B.  21, 1505).  Writh  phenol  it  yields  phenoxyl-diphenyl- 
phosphine  (C6H5)  2POC6H5,  boiling  at  265°-270°  (62  mm.)  (B.  18,  2118)  ; 
and  with  dilute  sodium  hydroxide  :  diphenyl-phosphine  (C6H5)2PH, 
boiling  at  280°,  and  diphenyl-phosphinic  acid  (C6H6)2PO.OH,  melting 
at  190°  (B.  15,  801). 

Triphenyl-phosphine  (C6H5)3P,  melting  at  75°  and  boiling  about 
360°,  is  produced  from  C6H5.PC12,  and  bromo-benzol,  or  from 
PC13  and  bromo-benzol  by  the  action  of  sodium  (B.  18,  R.  562).  It 
combines  with  halogen  alkyls  to  quaternary  phosphonium  salts; 
with  a-halogen  ketones,  such  as  chloracetone  CH3COCH2C1,  compounds 
are  formed,  which  easily  pass  into  so-called  phospho-keto-betai'ns 

(C^kP/^V/O**  (B.  32,  1566).     It  forms,  with  bromine,  the  di- 

\L/JH.3 

bromide  (C6H5)3PBr2,  which  is  converted  by  water  or  alkalies  into 
the  dihydroxide  (C6H5)3P(OH)2.  At  100°  this  passes  into  the  oxide 
(C6H5)3PO.  The  latter  melts  at  143°  and  boils  above  360°.  It  is  also 
obtained  from  C6H5MgBr  and  POC13  (C.  1904,  II.  1638).  Triphenyl- 
phosphine  oxide  (C6H5)3PO,  is  isomeric  with  phenoxyl-diphenyl-phosphine 
(C6H5)2POC6H5.  Both  compounds,  in  vapour  density  determina- 
tions made  with  reduced  pressure,  yield  values  according  with  the 
simple  molecular  formulas.  Phosphorus,  therefore,  in  the  first  body 


170  ORGANIC  CHEMISTRY 

is  quinquivalent,  and  in  the  second  it  is  trivalent  (Michaelis  and 
La  Coste,  B.  18,  2118). 

PHENYL-ARSENIC  COMPOUNDS. — Reactions,  similar  to  those  used 
in  obtaining  the  phenyl  substitution  products  of  phosphorus  chloride, 
have  been  used  with  arsenic,  and  the  following  bodies  have  been  ob- 
tained : — Phenyl-arsenious  chloride  C6H6AsCl2 ;  Diphenyl-arsenious 
chloride  (C6H5)  2 AsCl ;  Triphenyl  -  arsin  (C6Hg)  3 As  ;  Phenyl  -  arsinic 
acid  C6H5AsO(OH)2 ;  Diphenyl-arsinic  acid  (C6H5)2AsOOH. 

Arseno-benzol  C6H5As  :  AsC6H5  (A.  201,  191  ;  207,  195 ;  270,  139 ; 
321,  141 ;  B.  19,  1031  ;  25,  1521  ;  27,  263).  p-Amido-phenyl-arsinic 
acid,  arsanilic  acid  NH2C6H4AsO(OH)2,  brilliant  white  needles,  m.p. 
above  200°,  is  formed  besides  p2-diamido-diphenyl-arsinie  acid 
(NH2C6H4)2AsOOH,  m.p.  232°,  by  heating  aniline  arsenate  to  190°- 
200°  (B.  41,  2367).  By  reduction  with  HI  and  SO2  the  amido-phenyl- 
arsinic  acid  passes  into  p-amido-phenyl-arsinic  oxide  NH2C6H4AsO. 
2H2O,  whereas  with  tin,  and  HC1,  it  passes  into  the  yellow  p2-diamido- 
arseno-benzol  NH2C6H4As  :  AsC6H4NH2,  m.p.  140°  (C.  1909, 1.  963). 

From  arsanilic  acid,  through  the  diazo-compound,  p-oxyphenyl- 
arsinie  acid  HOC6H4As(OH)2,  m.p.  174°  is  formed.  This  can  also  be 
obtained  direct  by  heating  phenol  with  arsenic  acid  (C.  1909,  I,  807). 
On  nitrifying  and  reducing  this  to  m-amido-p-oxy-phenyl-arsinic  acid 
HO(NH2)C6H3AsO(OH2),  the  m,  m-diamido-p,  p-dioxy-arseno-benzol 
HO(NH2)C6H3As  :  AsC6H3(NH2)OH  is  obtained,  the  dichlorohydrate 
of  which  is  the  before-mentioned  salvarsan.  For  homologous  amido- 
phenyl-arsinic  acids  and  their  transformation  products,  see  B.  41,  3859. 

Triphenyl-stibin  (C6H5)3Sb,  m.p.  48°,  is  produced  on  introducing 
sodium  into  a  solution  of  chloro-benzol  and  of  antimonious  chloride  in 
benzene  (A.  233,  43).  Also  from  C6H5MgBr  and  SbCl2  (B.  37,  4621). 
On  heating  with  antimonious  chloride  in  xylol,  it  yields  phenyl-stibinous 
chloride,  m.p.  58°,  b.p.  290°,  starting  from  which,  the  oxide,  sulphide, 
tetrachloride,  and  phenyl-stibinic  acid  have  been  prepared  (B.  31, 
2910).  Triphenyl-stibin  sulphide  (C6H5)3SbS,  m.p.  120°,  from  triphenyl- 
stibin  bromide  with  Am2S  (B.  41,  2762). 

Bismuth-triphenyl  (C6H5)3Bi,  m.p.  78°,  is  prepared  by  heating 
bromo-benzol  and  bismuth  sodium  (A.  251,  324).  Diphenyl-bismuth 
iodide  (C6H5)2BI,  m.p.  133°  (B.  30,  2843). 

PHENYL-BORON  COMPOUNDS. — Phenyl-boron  chloride  C6H5BC12,  m.p. 
o°,  and  b.p.  175°,  and  diphenyl-boron  chloride  (C6H5)2BC1,  b.p.  271°, 
result  from  the  interaction  of  mercury-diphenyl  and  boron  chloride. 
Phenyl-boron  bromide  C6H5BBr,  m.p.  330°,  b.p.20  100°.  Diphenyl- 
boron  bromide  (C6H5)2BBr,  m.p.  25°  (B.  27,  244  ;  A.  315,  29). 

PHENYL-SILICON  COMPOUNDS.  —  Phenyl-silico-chloride  C6H5.SiCl3 
is  prepared  by  heating  mercury-diphenyl  and  SiCl4  to  300°.  It  boils 
at  197°  (Ladenburg,  A.  173,  151).  Water  decomposes  it  into  silico- 
benzoic  acid  C6H5.SiO.OH,  m.p.  92°.  Alcohol  forms  ortho-silico- 
benzoic  acid  ester  C6H5.Si(O.C2H5)3,  b.p.  137°.  Zinc  ethyl  converts 
the  chloride  into  triethyl-phenyl  silicide  C6H5.Si.(C2H5)3,  b.p.  230°. 
Triphenyl-methyl  silicide  (C6H5)3SiCH3,  m.p.  67°,  and  triphenyl-ethyl 
silicide  (C6H5)3SiC2H5,  m.p.  76°,  are  obtained  from  triphenyl-silico- 
chloride  (C6H5)3SiCl  with  methyl-  and  ethyl-magnesium  iodide  respect- 
ively (C.  1908,  I.  1266).  Mixed  alkyl-silicon  compounds  with  four 
different  radicles,  like  phenyl-methyl-ethyl-propyl-silicon  C6H5SiCH3 


PHENYL  METAL  DERIVATIVES  171 

(C2H5)(C3H7),  a  liquid  of  b.p.  231°,  are  formed  by  treating  silicon 
chloride  successively  with  phenyl,  methyl,  ethyl,  and  propyl  magnesium 
bromides  (C.  1907/1.  1192).  Concerning  optically  active  silicon  com- 
pounds, see  C.  1908, 1. 1688  ;  1909, 1.  360  ;  1910, 1.  2083. 

Triphenyl-silicane  (C6H5)3SiH,  m.p.  203°  (B.  40,  2278). 

Tetraphenyl-silicon  Si(C6H5)  is  produced  by  the  action  of  sodium 
upon  a  mixture  of  SiQ4,  chloro-benzol,  and  ether  (B.  19,  1012).  It 
melts  at  228°  and  boils  above  300°.  On  heating  with  bromine  it  yields 
triphenyl-silicon  bromide  (C6H5)3SiBr,  m.p.  120°,  which  on  boiling 
with  potash  solution  becomes  triphenyl-silicol  (C6H5)3SiOH,  m.p.  155° 
(C.  1899,  II.  57;  1901,  I.  999  ;  B.  40,  2275).  Diphenyl-silieol  (C6H5)2 
Si(OH)2,  m.p.  139°,  on  melting,  passes  into  trimolecular  diphenyl-silieon 
[(C6H5)2SiO]3,  m.p.  110°  (C.  1904,  I.  1257). 

PHENYL-TIN  COMPOUNDS. — Mercury  diphenyl  and  stannic  chloride 
interact  to  form  tin-diphenyl  chloride  (C6H5)2SnCl2,  m.p.  42°  (A.  194, 
145  ;  282,  328). 

Tin-tetraphenyl  Sn(C6H5)4  is  produced  by  the  action  of  tin-sodium 
upon  bromo-benzol,  m.p.  226°  and  b.p.  above  420°  (B.  22,  2917). 
Also  by  the  action  of  tin  tetrachloride  upon  phenyl-magnesium  bromide. 

5.  Phenyl  Metal  Derivatives. 

The  phenyl  group  has  been  combined  with  magnesium,  mercury, 
and  lead. 

Magnesium-diphenyl  (C6H5)2Mg,  is  a  light,  yellowish-white  powder, 
dissolving  readily  in  a  mixture  of  benzene  and  ether.  It  is  produced 
on  heating  mercury-diphenyl  with  magnesium  powder  and  some  acetic 
ester  to  i8o°-i85°  (A.  282,  320).  In  air  it  undergoes  spontaneous  com- 
bustion ;  water  decomposes  it  violently  with  formation  of  Mg(OH)2 
and  benzene. 

ARYL-MAGNESIUM  HALOIDS. — Phenyl-magnesium  bromide  C6H5 
MgBr,  and  phenyl-magnesium  iodide  CgHgMgl,  as  well  as  homo- 
logous aryl-magnesium  haloids,  are  formed  in  a  manner  analogous  to 
the  alkyl-magnesium  haloids,  by  the  action  of  magnesium  upon  the 
etheric  solutions  of  bromine  and  iodine  benzols.  They  are  as  suitable 
for  synthetic  reactions  as  are  the  alkyl-magnesium  haloids  : 

(i)  With  CO 2  they  unite  to  form  salts  of  aromatic  carboxylic  acids, 
e.g.  C6H5COOH.  (2)  With 'COS  they  form  thiol-carboxylic  acids 
C6H5COSH,  besides  triphenyl-carbinols  (C6H5)3COH.  (3)  With  CS2, 
carbo-thio-acids  are  formed,  e.g.  C6H5CSSH.  (4)  Triphenyl-carbinol 
is  formed  from  C6H5MgBr  with  phosgene  and  benzoic  ester.  (5)  With 
mustard  oils,  thio-anilides  are  formed,  CH3CSNHC6H5.  (6)  With  iso- 
nitriles,  alkylated  aldehydimines  C6H5CH=NCH3.  (7)  With  diazo- 
benzol-imide  C6H5N3,  diazo-amido-benzol  C6H5N2NHC6H5.  (8)  The 
action  of  nitroxyl  chloride  upon  phenyl-magnesium  bromide  produces 
nitroso-benzol.  (9)  With  S  and  Se,  thio-phenols  and  seleno-phenols 
are  formed,  C6H5SH,  and  C6H5SeH.  (10)  With  iodine,  iodo-benzol 
and  MgBrl,  etc.  (C.  1901,  I.  1357  ;  1903,  I.  568,  1403  ;  1909,  II.  1349  '> 
B.  35,  2692  ;  36,  587,  910, 1007, 1588,  2116  ;  37,  875  ;  39,  3219). 

Mercury-diphenyl  (C6H5)2Hg,  m.p.  120°,  is  formed  by  treating 
bromo-benzol  in  benzene  solution  for  some  time  with  liquid  sodium 
amalgam  (Otto  and  Dreher,  A.  154,  93)  ;  the  addition  of  some  acetic 


172  ORGANIC  CHEMISTRY 

ether  facilitates  the  reaction.  It  is  also  obtained  by  the  action  of 
HgCl2  or  HgCl  upon  phenyl-magnesium  bromide  (B.  37,  1127).  It 
crystallises  in  colourless,  rhombic  prisms,  and  can  be  sublimed.  It 
assumes  a  yellow  colour  in  sunlight.  It  dissolves  readily  in  benzene 
and  carbon  disulphide,  but  with  more  difficulty  in  ether  and  alcohol ; 
in  water  it  is  insoluble.  When  distilled,  it  decomposes  for  the  most  part 
into  diphenyl,  benzene,  and  mercury.  The  action  of  sodium  upon 
mercury-diphenyl  in  benzene  solution,  produces  sodium  amalgam  and 
sodium-phenyl  C6H5Na,  a  body  capable  of  many  reactions  (C.  1903, 
II.  195).  Acids  decompose  it,  with  formation  of  benzene  and  mercury 
salts.  Haloid  compounds  are  produced  by  the  action  of  the  halogens— 
e.g.  mereury-phenyl  chloride  C6H5HgCl,  m.p.  250° ;  mercury-phenyl 
bromide  C6H5HgBr,  m.p.  275° ;  mercury-phenyl  iodide  C6H5HgI, 
m.p.  265°.  Mercury-phenyl  hydroxide  C6H5HgOH  is  produced  when 
silver  oxide  and  alcohol  act  upon  the  chloride  (/.  pr.  Ch.  I.  186). 

Mercury-phenyl  acetate  C6H5Hg.O.COCH3  is  also  formed  direct 
by  heating  benzene  with  mercury  acetate  to  iio°-i2O°.  Similarly, 
the  mercury  atom  is  easily  introduced  in  the  place  of  the  nuclear  H 
atom  in  other  aromatic  compounds,  such  as  nitro-benzols,  anilines, 
phenols,  benzoic  acid,  etc.,  so  that  we  may  speak,  not  only  of  chlorina- 
tion,  nitrogenation,  and  sulphuration,  but  also  of  a  "  mercuration  " 
of  aromatic  substances,  as  a  general  reaction.  In  these  combinations 
the  mercury  is  rather  firmly  attached  to  the  nucleus.  When  the  action 
is  strong,  several  H  atoms  are  replaced,  and  we  may  obtain  compounds 
like  C6H4(Hg.OCOCH3)2,  C6H3(HgO.COCH3)3,  and  C6H2(HgO.COCH3)4 
(B.  35,  2032,  2853  ;  C.  1899, 1-  734  ;  1900,  I.  1097). 

Mercury-dialphyls.  See  A.  173,  162  ;  B.  14,  2112  ;  17,  2374  ;  20, 
1719  ;  22,  1220,  etc. 

Lead-tetraphenyl  (C6H5)4Pb  is  formed  by  heating  bromo-benzol 
with  lead-sodium  and  acetic  ester.  It  melts  at  224°  (B.  20,  3331). 
Also  from  lead  chloride,  and  phenyl-magnesium  bromide  (B.  37, 1126). 

6.  Sulphonic  Acids. 

The  ease  with  which  sulphonic  or  sulpho-acids  are  produced  dis- 
tinguishes the  aromatic  hydrocarbons  from  the  aliphatic  compounds 
in  the  same  manner  as  does  the  easy  formation  of  nitro-compounds. 
The  introduction  of  sulpho-groups,  in  the  place  of  aromatic  H  atoms, 
is  called  "  sulphonation." 

Formation. — (i)  The  sulpho-acids  of  benzene  hydrocarbons,  and 
other  benzene  derivatives,  are  easily  produced  by  mixing  or  heating 
them  with  concentrated  or  fuming  sulphuric  acid.  In  this  manner  it 
is  possible  to  combine  three  sulpho-groups  with  one  benzene  nucleus  : 

C6H6+HO.S03H  *=  C6H5.SO3H+H20. 

(2)  In  the  action  of  an  excess  of  chloro-sulphonic  acid  C1.SO2OH 
the  principal  products,  with  careful  cooling,  are  the  chlorides  of  the 
sulpho-acids  (B.  12,  1848  ;  28,  2172).  The  reaction  then  proceeds  in 
the  following  way  (B.  22,  R.  739)  : 

C6H6+C1S02OH  =  HC1     +C6H5.S02OH 
C6H5S02OH+C1S02OH  =  H2SO4+C6H6SO2C1. 

Sulphones  are  secondary  products  (p.  182). 


SULPHONIC  ACIDS  173 

(3)  Further,  sulphonic  acids  can  be  obtained  from  the  diazo-amido- 
derivatives  by  boiling  with  sulphurous  acid. 

(4)  By  the  oxidation  of  thio-phenols.     This  reaction  proves  that  the 
sulphur  atom  of  the  sulpho-group  is  in  union  with  the  aromatic  nucleus 
(compare  mercaptans). 

(5)  By  the  oxidation  of  sulphinic  acids. 

Properties  and  Transformations. — Many  aromatic  sulpho-acids  are 
very  soluble  in  water  and  crystalhse  with  difficulty.  They  can  be  sepa- 
rated from  aqueous  solution  in  the  form  of  their  sodium  salts  by  means 
of  sodium  chloride  :  salting  out  (B.  28,  91).  In  a  cathode-ray  vacuum 
many  sulpho-acids  can  be  distilled  without  decomposition  (B.  33, 
3207).  The  ready  solubility  of  the  sulpho-acids,  in  conjunction  with 
their  easy  production,  meets  with  an  important  technical  application 
in  the  conversion  of  aromatic  dyes  insoluble  in  water  into  their 
sulpho-acids,  which  dissolve  in  water  with  ease. 

(1)  The  chlorides  of  the  acids  are  made  by  acting  upon  the  alkali 
salts  with  POC13  and  PC15,  and  from  the  acids  themselves  by  the  action 
of  PC15.     The  chlorides  are  converted  into  amides,  esters,  etc.,  as  in- 
dicated under  the  alkyl-sulphonic  acids  (Vol.  I.).     The  esters  of  the 
sulpho-acids  are  transposed  by  alcohol  at  I40°-I50°,  with  the  pro- 
duction of  ethers  (Vol.  I.).     Heating  with  phenols  and  with  amines 
also  makes  the  benzol-sulphonic  esters  transfer  their  alkyl  groups  to 
the  former,  so  that  they  are  generally  useful  as  means  of  alkylation 
(A.  327, 120).     The  sulphonamides  are  stable  and  crystallise  well ;  they 
are  frequently  prepared  for  the  characterisation  of  a  sulpho-acid. 

(2)  Hydrocarbons   (together  with  phenyl  sulphones)   are  formed 
when  the  free  acids  are  subjected  to  distillation  : 

C6H5.S03H  =  C6H6+S03. 

This  rupture  is  more  easily  accomplished  by  heating  the  acids  with 
concentrated  HC1  to  150°,  or  by  distilling  the  ammonium  salt  of  the 
sulphonic  acid,  or  a  mixture  of  the  lead  salt  with  ammonium  chloride 
(B.  16,  1468).  The  decomposition  results  with  least  difficulty  by  con- 
ducting steam  into  the  dry  sulpho-acid,  or  its  solution  in  concentrated 
sulphuric  acid  ;  superheated  steam  is  most  effective  (B.  19,  92). 

(3)  The  SO2C1  group  in  the  sulpho-chlorides  can  be  replaced  by 
chlorine  through  the  action  of  PC15.     In  some  sulphonic  acids  free 
chlorine  and  bromine  are  capable  of  eliminating  the  sulpho-group  and 
introducing  the  halogens  (B.  16,  617). 

(4)  The  sulpho-group  in  many  sulphonic  acids  is  often  replaced  by 
NO  2  upon  treating  them  with  concentrated  nitric  acid. 

(5)  The  sulphonic  acids  of  the  alkyl-benzols,  more  frequently  applied 
in  the  form  of  their  sulphamides,  yield  sulpho-carboxylic  acids  upon 
oxidation.     The  oxidation  of  o-toluol-sulphamide  to  the  sulphimide 
of    o-sulpho-benzoic    acid    (q.v.),  called  saccharin,   is  technically  im- 
portant. 

(6)  The  chlorides  of  the  aromatic  sulpho-acids  become  thio-phenols 
upon  reduction  (cp.  C.  1900,  I.  252  ;  107,  II.  397)  : 

C6H5S02C1+6H  =  C6H5SH+2H20+HC1. 
This  reaction,  like  that  of  the  oxidation  of  thio-phenols  to  sulphonic 


174  ORGANIC  CHEMISTRY 

acids,  demonstrates  that  in  the  sulphoacids  the  sulphur  is  in  immediate 
union  with  the  benzene  nucleus. 

(7)  The  sulphonic  acids  are  not  decomposed  upon  boiling  them  with 
aqueous  alkalies.     Phenols  are  formed  when  they  are  fused  with  alkalies. 
This  reaction  serves  for  the  technical  preparation  of  resorcin  and  other 
phenols  : 

C6H6.S03K+KOH  ==  C6H5.OH+S03K2. 

(8)  When  distilled  with  potassium  cyanide  (or  dry  yellow  prussiate 
of  potash)  nitriles  result  : 

C6H5.S03K+CNK  =  C6H5.CN+S03K2, 

and  these  may  be  readily  saponified  to  carboxylic  acids. 

(9)  Carboxylates  are  also  obtained  on  fusing  the  alkali  -sulphonates 
with  sodium  formate. 

(10)  Melting  sulpho-acids  with  Na  amide  yields  anilines  (B.  19,  903  ; 
39,  3014)  : 

C6H5S03Na+NaNH2  -  C6H5NH2+SO3Na2. 

MONOSULPHONIC  ACIDS. — Benzol-sulphonie  acid  C6H5.SO3H,  m.p. 
66°,  b.p.  I35°-I37°,  crystallises  from  water,  in  which  it  is  exceedingly 
soluble,  in  plates  containing  water  of  crystallisation. 

The  barium  salt  (C6H5.SO3)2Ba+H2O  forms  pearly  flakes,  and  is 
sparingly  soluble  in  alcohol. 

The  chloride  C6H5.SO2C1,  m.p.  14-5°,  b.p.  116°  (B.  25,  2257; 
C.  1900,  I.  252),  has  a  specific  gravity  of  1*378  at  23°.  It  slowly 
reverts  to  the  acid  upon  boiling  with  water. 

Methyl  ester,  b.p.20 154°  (C.  1903,  I.  396). 

The  ethyl  ester,  b.p.15  156°,  obtained  by  the  action  of  ethyl  alcohol 
on  the  chloride,  is  decomposed  into  benzol-sulphonic  acid  and  ethyl 
ether  (Vol.  I.)  when  it  is  heated  to  150°  with  ethyl  alcohol. 

Benzol-sulphamide  C6H5.SO2.NH2,  m.p.  150°. 

Benzol-sulphone-anilide  C6H5SO2NHC6H5,  m.p.  110°.  The  benzol- 
sulphamides  of  the  primary  bases  are  mostly  soluble  in  alkali ;  their 
behaviour  towards  benzol  sulpho-chloride  may  therefore  be  used  for 
determining  whether  an  amine  base  is  primary  or  secondary  (cp.  B.  33, 
477  ;  38,  906).  Concentrated  sulphuric  acid  splits  up  the  benzol- 
sulphonamides  into  their  components  (A.  367,  157). 

Dibenzol-sulphimide  (C6H5SO2)2NH,  from  sodium-benzol-sulphimide 
with  benzol  sulpho-chloride  (C.  1901,  II.  1185).  Benzol-sulpho-dichlor- 
amide  C6H5SO2NC12,  m.p.  76°,  is  formed  by  the  action  of  sodium  hypo- 
chlorite  upon  benzol-sulphamide.  The  latter  is  regenerated  by  HC1 
and  HI,  with  liberation  of  chlorine  and  iodine.  With  alkalies  in  the 
cold,  salts  of  benzol-sulpho-monochloramide  are  formed  in  which 
the  alkali  is  probably  linked  to  oxygen  :  C6H5SO(OK)  :  NCI  (C.  1905, 
I.  1010). 

Benzol-sulpho-nitramide  C6H5SO2NHNO2  consists  of  colourless 
plates,  readily  soluble  in  water.  It  decomposes  at  100°  into  benzol- 
sulphonic  acid  and  nitrous  oxide.  It  is  formed  when  a  mixture  of 
nitric  and  sulphuric  acids  acts  upon  benzol-sulphamide.  Its  potassium 
salt  C6H5SO2NK.NO2,  m.p.  275°,  when  reduced  by  glacial  acetic  acid 
and  zinc  dust  becomes  benzol-sulphono-hydrazide  C6H6SO2NH.NH2, 


SULPHONIC   ACIDS  175 

m.p.  105°  with  decomposition,  which  also  form  benzol  sulpho-chloride 
with  hydrazin  hydrate. 

Benzol-sulphone-phenyl-hydrazide,  phenyl-benzol-sulphazide  (see 
above).  Dibenzol  -  sulphone  -  hydrazin  (C6H5S02.NH)2,  m.p.  228°. 
Benzol-sulphone-azode  C6H5SO2.N3,  an  oil,  is,  in  contrast  with  car- 
boxylic  azides,  not  attacked  by  hot  water  or  alcohol  (/.  pr.  Ch. 
2,  58,  160). 

The  sulphamide  and  nitrous  acid  yield  dibenzol-sulphon-hydroxyl- 
amine  (C6H5SO2)2NOH,  which  can  also  be  made  by  the  interaction  of 
benzol-sulphinic  acid  and  sodium  nitrite  ;  with  diazo-benzol  chloride 
the  product  is  benzol-sulpho-diazo-benzol-amide  C6H5SO2NH — N  = 
N.C6H5,  m.p.  101°  (B.  27,  598). 

Benzo  -  sulpho  -  hydroxamic  acid  C6H5SO2.NHOH,  m.p.  126°,  is 
obtained  from  benzol-sulpho-chloride  and  hydroxylamine.  Alkalies 
decompose  it  into  benzol-sulphinic  acid  and  hyponitrous  acid  (B.  29, 
1559,  2324)  : 

2C6H5SO2NHOH+4KOH  =  2C6H5SO2K-f  (NOK)2+4H2O. 

With  aldehydes,  benzo-sulpho-hydroxamic  acid  passes  into  benzol- 
sulphinic  acid  and  carbo-hydroxamic  acids  (C.  1901,  II.  99). 

Benzol-sulpho-isoeyanate  C6H5SO2NCO,  b.p.9  130°,  from  benzol- 
sulpho-chloride  and  silver  cyanate.  An  oil  of  feeble  odour,  exhibiting 
all  the  properties  and  transformations  of  the  isocyanates  (B.  37,  690). 

TOLUOL-SULPHONIC  ACIDS. — In  sulphonating,  toluol-o-  and  p-acids 
are  the  chief  products.  The  o-acid  can  be  obtained  from  p-tolyl- 
hydrazin-o-sulphonic  acid  free  from  the  p-acid.  The  m-acid  is  obtained 
from  p-toluidin-m-sulphonic  acid.  o-Toluol-sulpho-chloride  is  a 
liquid,  formed  from  o-toluol-sulphinic  acid  and  Cl  (C.  1901,  II.  961  ; 
B.  38,  730).  o-Toluol-sulphamide  melts  at  155°  (see  o-Sulpho-benzoic 
acid),  m- Toluol -sulphonic  acid  CH3[i]C6H4[3]SO3H+H2O  ;  its 
chloride  is  a  liquid  ;  its  amide  melts  at  107°.  p-Toluol-sulphonic  acid 
CH3[i]C6H4[4]SO3H+4H2O  ;  melts  at  35°,  b.p.  147° ;  its  chloride  melts 
at  69°,  and  boils  at  145°  (15  mm.)  ;  its  bromide  melts  at  96°,  its 
iodide  at  84°,  and  its  amide  at  137°.  Methyl  ester,  m.p.  28°;  ethyl 
ester,  m.p.  33°  (A.  327,  121). 

Ditoluol-sulpho-hydroxamic  acid  (C7H7.SO2)2NOH  melts  with 
decomposition  at  148°.  It  results  from  the  action  of  sodium  nitrite 
upon  toluol-sulphinic  acid.  It  combines  with  an  additional  molecule 
of  the  sulphinic  acid  to  tritoluol-sulphonamide  (C7H7.SO2)3N,  melting  at 
I9°°  (/•  Pr-  Ch.  2.  54,  95 ;  C.  1901,  I.  455).  Further  derivatives  of 
p-toluol-sulphonic  acid,  see  B.  34,  2996.  v 

XYLOL-SULPHONIC  ACIDS. — 1, 2-Xylol-4-sulphonie  acid :  its  chloride 
melts  at  51°,  its  amide  at  144°.  1,  3-Xylol-4-sulphonic  acid :  its  chloride 
melts  at  34°,  and  its  amide  at  137°.  1,  3-Xylol-2-sulphonic  acid  :  its 
amide  melts  at  95°.  1,  4>-Xylol-3-sulphonic  acid  :  its  chloride  melts  at 
25°,  and  its  amide  at  247°.  They  result  upon  sulphonating  the  various 
xylols. 

[1,  2,  4]-Pseudo-eumol-5-sulphonie  acid  (CH3)3C6H2SO3H+2H2O 
melts  at  111°.  Its  chloride  melts  at  61°,  and  the  amide  at  181°.  Mesity- 
lene-sulphonic  acid  C9H12SO3+2H2O  melts  at  77°,  its  chloride  at  57°, 
and  its  amide  at  141°. 


176  ORGANIC   CHEMISTRY 

POLY-SULPHONIC   ACIDS.  —  Benzol  -  disulphonic    acids   C6H4/S°3H. 

\SO3H 

On  heating  benzene  with  fuming  sulphuric  acid  to  200°  C.,  we  get  meta- 
and  ^>flra-benzol-disulphonic  acids,  with  the  former  in  predominating 
quantity,  but  by  prolonged  heating  it  passes  into  the  para-variety 
(B.  9,  550).  Meta-disulphonic  acid  is  produced  from  disulphanilic  acid 
by  means  of  the  diazo-compound. 

Ortho-benzol-disulphonic  acid  is  formed  from  meta-amido-benzol- 
sulphonic  acid  by  further  introduction  of  the  sulpho-group,  and  replace- 
ment of  NH2  by  hydrogen.  The  melting-points  of  the  sulpho-chlorides 
and  sulphamides  of  the  three  isomeric  disulphonic  acids  are  : 

Ortho.          Meta.  Para. 

CaH4(S02Cl)2  105°  63°  132° 

C6H4(S02NH2)2  233°  228°  288°. 

The  corresponding  dicyanides,  CeH4(CN)2,  the  nitriles  of  the  three 
phthalic  acids,  are  obtained  by  distillation  with  potassium  cyanide  or 
potassium  ferrocyanide.  When  fused  with  potassium  hydroxide,  both 
meta  and  para  acids  yield  resorcin  (meta-dioxy-benzol)  ;  at  lower  tem- 
peratures meta-phenol-sulphonic  acid  C6H4(OH)SO3H  results  at  first 
from  both  acids. 

Benzol- trisulphonic  acid  C6H3(SO3H)3  (i,  3,  6)  is  easily  made 
by  heating  potassium  m-benzol  disulphonate  with  common  sulphuric 
acid  (B.  21,  R.  49).  The  free  acid  (from  the  lead  salt)  crystallises  in 
long  needles  with  3H2O  ;  its  chloride  melts  at  184°,  its  amide  at  306°. 
Fused  with  caustic  potash,  it  yields  phloroglucin  C6H3(OH)3,  or  i,  3,  5- 
trioxy-benzol ;  and  upon  heating  with  potassium  cyanide  it  forms 
the  trinitrile,  which  upon  saponification  becomes  trimesinic  acid 
C6H3(C02H)3. 

Toluol-disulphonie  acids.  The  six  possible  isomerides  are  known 
(B.  20,  350  ;  29,  R.  868). 

Xylol-disulphonie  acids  (B.  25,  R.  700). 

Benzol-seleno-aeid  C6H5SeO2OH,  hygroscopic  needles,  m.p.  142°, 
is  formed  by  heating  benzene  with  selenic  acid  to  ioo°-no°,  as  well  as 
by  oxidation  of  phenyl-diselenide  with  chlorine  water.  It  detonates 
on  heating  to  180°,  yielding  oxygen,  phenyl-selenide,  and  phenyl- 
diselenide.  Reduction  with  SH2  or  SO2  converts  it  into  seleno-phenol. 
With  concentrated  HC1  it  develops  Cl,  even  in  the  cold,  being  reduced 
to  benzol-seleninic  acid  (C.  1909,  II.  20). 

CHLORO-,  BROMO-,  IODO-,  IODOSO-,  NITRO,  NITROSO-  and  AMIDO 
BENZOL-SULPHONIC  ACIDS. — The  chloro-,  bromo-  and  iodo-benzol- 
sulphonic  acids  are  prepared  from  the  three  amido-benzol-sulphonic 
acids  by  means  of  the  diazo-reactions  (B.  28,  90).  p-Compounds  are 
the  principal  products  in  the  sulphonation  of  chloro-  and  bromo- 
benzols.  In  nitrating  benzol-sulphonic  acid  and  sulphonating  nitro- 
benzol  the  three  isomeric  nitro-benzol-sulphonic  acids  are  produced 
with  the  m-derivatives  in  predominating  quantity  (A.  177,  60). 

o-  and  p-Nitro-benzol-sulphonic  acids  are  best  prepared  by  oxida- 
tion of  the  corresponding  nitro-benzol-disulphides  (NO2C6H4S)2, 
obtained  from  the  nitro-chloro-benzols,  with  fuming  sulphuric  acid 
(B.  35,  651  ;  C.  1903,  I.  508). 


SULPHONIC  ACIDS 


177 


The  following  table  contains  the  melting-points  of  the  chlorides  and 
amides  of  the  acids  : — 


ORTHO. 

META. 

PARA. 

Chloride. 

Amide. 

Chloride. 

Amide. 

Chloride. 

Amide. 

Chloro-sulpho-  . 
Bromo-sulpho-  . 
lodo-sulpho- 
Nitro-sulpho-    . 

28° 

g 

67° 

188° 
186° 
170° 
1  86° 

Oil 
Oil 

23° 
60° 

148° 

154° 
152° 
161° 

53° 
75° 
84° 
Oil 

143° 
166° 
183° 
181° 

o-Iodo-chloride-benzol  sulpho-chloride  ICl2[2]C6H4[i]SO2Cl,  m.p. 
60°,  is  converted  by  sodium  hydroxide  into  iodoso-benzol-sulphonic 
acid  (B.  28,  95). 

m-Nitroso-benzol-sulphonic  acid  (B.  25,  75). 

Amido-benzol-sulphonie  acids. — (i)  On  sulphonating  aniline  at 
180°  with  fuming  sulphuric  acid  (8-10  per  cent.  SO3),  the  p-derivative 
constitutes  the  chief  product.  It  is  sulphanilic  acid,  important  in  the 
technology  of  dyes,  and  was  discovered  in  1845  by  Gerhardt.  The 
second  sulpho-group  enters  the  o-position  with  the  formation  of 
l-aniline-2, 4-disulphonic  acid  or  disulphanilic  acid  ;  a  trisulphonic 
acid  is  not  produced  (B.  23,  2143). 

Amido-benzol-sulphonic  acids  are  also  produced  (2)  by  reduction 
of  nitro-benzol-sulphonic  acids  ;  (3)  by  heating  chloro-benzol-sulphonic 
acids  with  ammonia  in  the  presence  of  copper  salts  (C.  1909,  I.  477). 
(4)  The  sodium  salts  of  phenyl-sulphaminic  acids,  on  being  heated  to 
i7O°-i8o°,  transpose  themselves  into  amido-benzol-sulphonates  (C. 
1907,1.1792). 

The  amido-benzol-sulphonic  acids,  like  glycocoll  and  taurine,  can  be 

/-SO2O 
regarded  as  cyclic  ammonium  salts,  C6H4<'        I 

\NH3' 

The  three  amido-benzol-sulphonic  acids  dissolve  with  difficulty  in 
water,  alcohol,  and  ether.  The  (ortho)-a.cid  either  crystallises  in  an- 
hydrous rhombohedra  or  in  four-sided  prisms  containing  JH2O  ;  these 
do  not  effloresce.  It  is  best  prepared  by  the  reduction  of  p-bromo- 
aniline-o-sulphonic  acid  (B.  28,  R.  751  ;  29,  1075  ;  C.  1903,  I.  508). 

The  (w£ta)-acid,  called  metanilic  acid,  and  also  important  in  the 
technology  of  dyes,  crystallises  in  delicate  needles  or  in  prisms  with 
i|H2O,  which  effloresce. 

p-Sulphanilic  acid  crystallises  from  hot  water  in  rhombic  plates 
with  i  molecule  H2O  ;  these  effloresce  in  air.  They  are  soluble  in 
112  parts  H2O  at  15°  (B.  14,  1933).  It  yields  a  considerable  quantity 
of  quinone  when  oxidised  with  MnO2  and  H2SO4  or  chromic  acid.  It 
yields  aniline  and  not  amido-phenol  when  fused  with  caustic  potash  ; 
unlike  its  isomerides,  it  is  readily  converted  by  bromine  water  into 
tribromo-aniline  (B.  29,  R.  309). 

The  sodium-amido-benzol-sulphonates  yield  acetyl  derivatives  with 
acetic  anhydride  (B.  17,  708  ;  39,  1561),  whereas  the  free  acids  are 

VOL.  II.  N 


178  ORGANIC  CHEMISTRY 

not  in  condition  to  do  this.  This  fact  argues  for  the  ammonium-salt 
formula  of  the  free  acids. 

In  the  o-  and  p-amido-benzol-sulphonic  acids  the  sulpho-group  is 
replaced  by  the  nitro-group  under  the  action  of  nitric  acid,  nitranilines 
being  produced  (A.  339,  202). 

p-Phenylene-diamido-monosulphonic  acid  C6H3(SO3H)(NH2)2  is 
produced  by  heating  p-dichloro-benzol-sulphonic  acid  with  ammonia 
in  the  presence  of  copper  bronze  (C.  1908,  II.  1307). 

Toluylene-diamido-sulphonic  acids,  see  C.  1904,  I.  1410. 

Diazo-benzol-sulphonic-acid  anhydrides,  cyclic  diazides.  —  Nitrous 
acid  transforms  the  three  amido-benzol-sulphonic  acids  into  the  an- 
hydrides of  the  diazo-benzol-sulphonic  acids  (cp.  C.  1898,  I.  293)  : 


20 
2OH  C°H4\N2/C 

Diazo-benzol-sulphonic  acid  Anhydride. 

The  hydrated  sulpho-acids  are  not  known  ;  they  pass  at  once  into 
anhydrides.  The  dipotassium  and  the  disodium  salts  of  the  o-  and 
p-diazo-benzol-sulphonic  acids,  C6H4(S03Me)(N2OMe),  exist  each  in 
two  forms,  one  of  which  belongs  to  the  normal  and  the  other  to  the 
iso-diazo-series.  The  iso-salts  are  produced  on  digesting  the  normal 
salts  ;  they  give  up  nitrogen  less  readily,  and  do  not  combine,  or  at 
least  with  difficulty,  with  aromatic  amines  or  phenols,  to  yield  azo- 
dyes  (B.  29,  1059,  1388).  Primary  potassium-iso-diazo-sulphonate 
C6H4(SO3K)N2OH-|-H2O  results  on  treating  the  corresponding 
dipotassium  salt  with  acetic  acid  (B.  28,  1386). 

It  is  rather  remarkable  that,  while  otherwise  it  is  only  the  ortho- 
compounds  of  the  benzene  di-derivatives  which  form  inner  anhydrides, 
all  three  of  the  diazo-benzol-sulpho-acids  are  capable  of  anhydride  forma- 
tion. They  exhibit  all  of  the  reactions-  of  the  diazo-compounds. 

The  diazide  of  sulphanilic  acid,  p-diazo-benzol-sulphonic  acid,  con- 
sists of  sparingly  soluble  white  needles  ;  although  relatively  stable  for 
a  diazo-body,  it  sometimes  explodes  spontaneously  (B.  34,  n).  Heated 
with  absolute  alcohol,  it  forms  benzol-  sulphonic  acid  ;  with  water  the 
diazo-acid  becomes  p-phenol-sulphonic  acid  ;  while  with  potassium 
sulphide  the  dipotassium  salt  of  p-thio-phenol-sulphonic  acid  results. 
Concerning  the  effect  of  bleaching-lime  upon  diazo-benzol-sulphonic 
acids,  see  A.  330,  I. 

Amido-azo-benzol-sulphonic  acids.  —  The  diazides  of  sulphanilic 
acid  and  metanilic  acid  are  used  in  the  manufacture  of  sulphurised 
azo-dyes.  The  first  group  of  this  great  class  of  dyes  has  received 
mention  ;  it  comprises  the  amido-azo-compounds,  which  are  insoluble 
or  dissolve  with  difficulty  in  water.  Upon  introducing  the  sulpho- 
group  into  the  amido-azo-derivatives  it  will  be  discovered  that  the 
solubility  in  general  increases  with  the  number  of  sulpho-groups.  The 
alkali  salts  of  the  amido-azo-benzol-sulphonic  acids  constitute  the 
dyes  soluble  in  water.  We  shall  meet  with  other  groups  of  azo-dyes 
when  we  study  the  phenols  :  oxyazo-compounds.  The  naphthalin-azo- 
compounds  and  the  benzidin  dyes,  containing  the  diphenyl  residue, 
are  especially  important. 

Arbitrary  names  are  assigned  these  dyes,  with  the  addition  of  the 
letters  Y  (yellow),  O  (orange),  and  R  (red),  whose  number  approxi- 


SULPHONIC  ACIDS  179 

mately  expresses  the  intensity  of  the  colour.  They  colour  wool  and 
silk  directly,  cotton  after  it  has  been  mordanted. 

Formation. — (i)  The  amido-azo-bodies  are  sulphurised.  (2)  The 
diazides  of  sulphonic  acids  are  combined  with  bases. 

Upon  sulphonating  amido-azo-benzol  there  results  a  mixture  of 
amido-azo-benzol-mono-  and  disulphonic  acids,  known  in  commerce 
under  the  names  acid  yellow  or  pure  yellow  :  SO3H[4]C6H4(i)N= 
N[i']C6H4[4']NH2  and  SO3H[4]C6H4[i]N=:N[i']C6H3[4']NH2[3']SO3H 
(B.  22,  847).  Being  amido-bodies,  the  sulpho-acids  are  themselves 
capable  again  of  diazotising  and  combination,  whereby  very  valuable 
dyes  have  been  obtained  (compare  Biebrich  scarlet).  Amido-azo- 
benzol-trisulphonic  acid,  see  B.  33,  1366. 

The  following  azo-dyes  have  been  made  by  combining  the  diazide 
of  sulphanilic  acid  with  dimetnyl-aniline  and  diphenyl-amine,  and  the 
diazide  of  metanilic  acid  with  diphenyl-amine  : 

[4'>Dimethyl-amido-azo-benzol-  [4]  -sulphonic  acid  SO3H[4]C6H4 
[i]N=N[i]C6H4[4']N(CH3)2,  melting  at  115°,  consists  of  golden-yellow 
flakes  (B.  10,  528  ;  12,  1490  ;  41,  1187).  Its  sodium  salt,  as  a  dye, 
bears  the  names  tropceolin  O,  orange  III,  and  helianthin.  It  serves  as 
a  delicate  indicator  in  alkalimetry  ;  mineral  acids  convert  the  alkaline 
orange-coloured  solution  into  pink.  CO2,  H2S,  and  acetic  acid  do  not 
act  on  it  in  the  cold  (Ch.  Z.,  VI.  1249  '•  B-  18,  3290).  By  reduction 
helianthin  yields  sulphanilic  acid  and  para-amido-dimethyl-aniline. 
Fuming  nitric  acid  splits  it  up  into  diazo-benzol-sulphonic  acid  and 
2,  4-dinitro-dimethyl-aniline  (B.  38,  3206  ;  41,  1989). 

[4']-Phenyl-amido-azo-benzol-[4]-sulphonie  acid  SO3H[4]C6H4[i]N= 
N[i]C6H4[4']NHC6H5.  Its  sodium  salt  dyes  wool  and  silk  a  beautiful 
orange,  and  as  a  dye  is  known  by  the  names  tropceolin  OO,  orange  IV. 
It  is  used  as  an  indicator  in  alkalimetry  (B.  16, 1989).  By  reduction  it 
yields  sulphanilic  acid  and  p-amido-diphenyl-amine. 

[4'] -Phenyl-amido-azo-benzol- [3] -sulphonic  acid  is  formed  from 
metanilic  acid,  and  bears  the  name  metanil  yellow. 

Phenyl-hydrazin-sulphonie  acids  are  produced  upon  reducing  the 
diazides  of  aniline-sulphonic  acids  with  sodium  sulphite  or  stannous 
chloride  (B.  22,  R.  216),  and  by  the  direct  action  of  concentrated 
sulphuric  acid  upon  phenyl-hydrazins  (B.  18,  3172). 

Phenyl-hydrazin-p-sulphonie  acid  C6H4.(NH.NH2)SO3H  is  not 
readily  soluble  in  water.  It  is  used  in  the  preparation  of  tartrazin 
(Vol.  I.),  having  the  following  constitution  : 

N— NHC6H4SO3Na 
II 
COoNaC— C— CO 

II  I 

N NC6H4SO3Na. 

Hydrazo-benzol-m-disulphonic  acid  SO3H[3]C6H4[i]NH— NH[i] 
C6H4[3']SO3H  has  been  prepared  by  the  reduction  of  m-nitro-benzol- 
sulphonic  acid,  and  is  converted  into  benzidin-disulphonic  acid  by 
hydrochloric  acid  (B.  21,  R.  323  ;  23,  1053). 

Sulphinic  Acids. — Formation  : — (i)  By  the  action  of  zinc  dust  upon 
the  ethereal  solution  of  the  sulphonic-acid  chlorides.  (2)  From  the 
latter  and  thio-phenol  salts : 

C6H5S02Cl+2C6H5SNa^C6H5S02Na+NaCl+(C6H6S)2. 


i8o  ORGANIC  CHEMISTRY 

(3)  By  a  straightforward  reaction,  sulphinic  acids  are  produced  by  the 
action  of  Cu  powder  upon  diazonium-salt  solutions  saturated  with  SO2 
(B.  32,  1136) : 

C6H5N2.SO4H+SO2+Cu=C6H5.SO2H+N2+SO4Cu. 

(4)  Sulphinic  acids  are  also  produced  from  SO2  and  benzene  in  the 
presence  of  Al  chloride,  a  reaction  in  which  the  compound  C1SO2A1C12 
is  formed  as  an  intermediate  product.    The  reaction  is  an  extremely 
smooth  one  (B.  41,  3315).     In  this  case  the  phenol  ethers  yield  also 
sulphoxides  and   sulphonium  bases  (C.  1908,   II.   237).     (5)   By  the 
action  of  SO2,  or  SO2C12,  upon  phenyl-magnesium  bromide  (B.  37, 
2153  ;    C.  1905,  I.  1145).     (6)  From  sulphones  with  sodium  (B.  26, 
2813).     (7)  By  the  action  of  KCN  or  sodium  arsenate  upon  benzol 
thio-sulphonates    (B.    41,   3351).     (8)   By   decomposition    of   benzol- 
sulphydroxamic  acids. 

Behaviour. — The  sulphinic  acids  are  not  very  stable,  and  when 
heated  with  water  split  up  into  sulphonic  acids  and  disulphoxides. 

The  air  and  oxidising  agents  (especially  MnO4K  or  BaO2)  convert 
them  into  sulphonic  acids.  By  reduction,  zinc  dust,  and  sulphuric  acid, 
the  sulphinic  acids  are  converted  into  thio-phenols. 

Their  salts  unite  with  sulphur,  forming  thio-sulphonates.  When 
fused  with  alkalies  they  decompose  into  benzenes  and  alkaline  sulphites. 
By  the  action  of  thionyl  chloride  they  yield  sulphinic  chlorides  (B.  41, 
4114),  and  with  acetic  anhydride,  sulphinic  anhydride  (B.  41,  3323). 
With  aldehydes  the  sulphinic  acids  combine  to  form  oxy-sulphones 
CH3CH(OH)S02C6H5 ;  to  ajS-unsaturated  aldehydes,  ketones,  and 
carboxylic  acids  they  add  themselves  like  sulphurous  acid  with  forma- 
tion of  sulphones,  like  C6H5CH(SO2C6H5)CH2COOH  (C.  1904,  I.  874). 

Benzol-sulphinic  acid  and  quinone  unite  to  unsym.  p-dioxy-diphenyl- 
sulphone  (H0)2[2,  5]C6H3[i]SO2C6H5  (B.  27,  3259) ;  this  also  reacts  with 
a  number  of  other  substances  containing  quinoid  linkages  (cp.  B.  29, 
2019).  Benzol-sulphinic  acid  also  reacts  with  o-  and  p-dioxy-benzols, 
forming  dioxy-diphenyl-sulphones,  while  phenol  gives  compounds  like 
oxy-diphenyl  sulphide  HOC6H4SC6H5,  and  aniline  chlorohydrate  yields 
amido-diphenyl  sulphide  H2NC6H4SC6H5  (B.  36,  107). 

The  alkaline  sulphinates  form,  with  iodo-alkylene,  mixed  sulphones, 
and  with  chloro-carbonic  esters  they  form  the  real  sulphinic  esters 
(B.  26,  308,  430)  : 

C6H5SO2Na+ClCO2C2H5  ==  C6H5SOO.C2H5+NaCl+CO2. 

With  ferric  chloride  the  sulphinic  acids,  in  acid  solution,  form 
slightly  soluble  ferric  salts,  well  adapted  to  the  isolation  of  the  sulphinic 
acids  (C.  1909,  I.  1649). 

Benzol-sulphinic  acid  C6H5.SO.OH,  m.p.  83°.  Zinc  salt  (C6H5SO2)2 
Zn+2H2O.  Ethyl  ester,  sp.  gr.  1-141  (20°),  decomposes  when  it  is 
heated. 

Benzol-sulphinic  anhydride  (C6H5SO2)2O,  m.p.  67°,  deliquesces 
rapidly  with  formation  of  benzol-sulphonic  acid  and  benzol-thio- 
sulphonic  phenyl  ester  C6H5SO2SC6H5. 

Benzol-sulphinic  chloride  C6H3SOC1,  colourless  plates,  m.p.  38°, 
fumes  in  air,  and  is  rapidly  decomposed  by  water,  with  regeneration 
of  benzol-sulphinic  acid. 


ESTERS  OF  THE  THIO-SULPHONIC  ACIDS  181 

o-  and  p-Toluol-sulphinie  acid  C6H4[i](CH3)[2]SOOH,  m.p.  80° 
and  85°  (/.  pr.  Ch.  54,  517  ;  56,  213).  For  further  homologues,  see 
B.  32,  1140.  Dimethyl-  and  diethyl-aniline-sulphinic  acid  R2NC6H4 
SO2H  is  formed  by  the  action  of  thionyl  chloride  upon  dimethyl-  and 
diethyl-aniline  (A.  310,  137).  Benzol-disulphinic  acid  C6H4(SO2H)2, 
see  B.  35,  2168  ;  36,  189. 

Benzol-seleninie  acid  C?H5SeOOH,  m.p.  124°,  by  oxidation  of 
phenyl  diselenide  with  nitric  acid,  and  by  the  action  of  HC1  upon 
benzol-seleno-acid.  On  heating  to  130°  it  passes  into  benzol-seleninic 
anhydride  (C6H5SeO)2O,  m.p.  164°  (C.  1909,  II.  21). 

Benzol- thio-sulphonic  acid. — Its  salts  result  from  the  chloride  of 
benzol-sulphonic  acid,  and  alkali  sulphides,  as  well  as  from  the  inter- 
action of  benzol  sulphinates  and  sulphur  (B.  25,  1477).  With  organic 
bases  the  thio-sulphonic  acids  often  form  easily  crystallised  salts 
(C.  1900,  I.  611). 

DlSULPHOXIDES  OR  ESTERS  OF  THE  THIO-SULPHONIC  ACIDS. — Alkyl 

esters  and  alkylene  esters  of  benzol-thio-sulphonic  acid  result  from  the 
interaction  of  the  potassium  salt  with  the  corresponding  bromides 
(B.  25,  1477).  Phenyl-thio-sulphonic  aceto-acetic  ester  C6H5SO2S. 
CH(COCH3)COOC2H5,  m.p.  56°,  from  chloraceto-acetic  ester  and 
potassium-benzol  thio-sulphonate  (C.  1900,  II.  178). 

Phenyl  esters — e.g.  C6H5.SO2.S.CgH5 — are  obtained  (i)  by  oxi- 
dising the  thio-phenols  with  nitric  acid  ;  (2)  by  heating  the  sulphinic 
acids  with  water  to  130°  ;  (3)  by  oxidation  of  disulphides  with  hydrogen 
peroxide  (B.  41,  2838). 

Benzol  disulphoxide  C6H5.SO2.S.C6H5,  m.p.  45°,  is  insoluble  in 
water,  but  dissolves  readily  in  alcohol  and  ether  (B.  20,  2090). 

Sulpho-benzol  sulphide  (C6H5SO2)2S,  m.p.  133°,  and  sulpho-benzol 
disulphide  (C6H5SO2)2S2,  m.p.  76°,  trisulphide,  m.p.  103°,  result  from 
the  action  of  iodine  and  of  chlorine  upon  potassium-benzol  thio- 
sulphonate  ;  also  from  benzol  sulphinates  and  benzol  thio-sulphinates 
with  sulphur  chlorides  (B.  24,  1141  ;  /.  pr.  Ch.  2,  60,  113). 

Disulphones,  like  diphenyl-sulphone  C6H5SO2.SO2C6H5,  m.p.  194°, 
phenyl-tolyl-disulphone  C6H5SO2.SO2C6H4.CH3,  m.p.  166°,  Ditolyl-di- 
sulphone  CH3C6H4SO2.SO2C6H4CH3,  m.p.  212°  with  decomposition,  are 
formed  by  transposition  of  sulphinates  with  sulpho-chlorides  (C.  1899, 
II.  719).  Also  in  small  quantities,  besides  sulpho-acids,  during  the 
oxidation  of  benzol-sulphinic  acids  with  MnO4K  (C.  1908,  II.  1427). 
On  heating  with  alkalies  they  decompose  into  a  mixture  of  sulphinates 
and  sulphonates. 

Sulphoxides. — Mixed  aromatic-aliphatic  sulphoxides  are  formed  from 
the  aryl-alkyl  sulphides  by  oxidation  with  H2O2  (B.  41,  2836  ;  C.  1909, 
I-  35°) >  or  from  their  dibromo  addition  products  by  the  action  of  water. 

Phenyl-sulphoxy-acetie  acid  C6H5SOCH2COOH,  m.p.  116°,  is  split 
up  by  heating  with  mineral  acids  into  thio-phenol  and  glycolic  acid. 

Diphenyl-sulphoxide,  thionyl-benzol  (C6H5)2SO,  m.p.  70°,  is  pro- 
duced (i)  by  the  action  of  SO2  or  SOC12  upon  benzenes  in  the  presence 
of  A12C13  (B.  20,  195  ;  27,  2547)  '>  (2)  ^Y  oxidation  of  diphenyl  sulphide 
with  H2O2  (B.  43,  289)  ;  (3)  by  the  action  of  thionyl  chloride  or 
diethyl  sulphite  upon  phenyl-magnesium  bromide  (B.  43,  1135). 
Potassium  permanganate  oxidises  it  to  diphenyl-sulphone. 

Diphenyl-selenium  oxide  (C6H5)2SeO  has  been  prepared  by  oxi- 


182  ORGANIC  CHEMISTRY 

dising  diphenyl  selenide  (q.v.),  or  from  the  dibromide  of  the  latter 
(B.  29,  424). 

SULPHONES.  —  The  alkyl-aryl  sulphones  are  isomeric  with  the  esters 
of  the  alkyl-sulphonic  acids.  They  result  from  the  sodium  sulphinates 
and  the  alkylogens.  The  purely  aromatic  sulphones  are  obtained  (i) 
by  the  action  of  SO3  or  chloro-sulphonic  acid  upon  benzenes  (together 
with  sulphonic  acids),  2C6H6+SO3=(C6H5)2SO2+H2O  ;  (2)  by  the 
distillation  of  sulphonic  acids  (together  with  hydrocarbons);  (3)  by 
the  oxidation  of  the  phenyl  sulphide  ;  (4)  on  heating  benzol-sulphonic 
acids  with  benzenes  and  P2O5  ;  (5)  by  the  action  of  zinc  dust,  or 
aluminium  chloride,  upon  a  mixture  of  a  sulphonic  chloride  and  a 
benzene  hydrocarbon  : 


C6H5S02C1+C6H6CH3  -  >  S°2  "  -  C6H6+CH3[i]CeH4[4]SO2Cl. 


The  same  phenyl-p-tolyl-sulphone  results  from  benzol-sulphonic  acid 
and  toluol,  as  from  p-toluol-sulphonic  acid  chloride  and  benzene,  which 
would  prove  that  both  groups  are  in  union  with  siilphur,  and  that  the  latter 
is  sexivalent  (B.  11,  2181).  (6)  Nitro-substituted  sulphones  are  readily 
formed  from  o-  and  p-chloro-nitro-benzols  with  sulphinates  (B.  34, 
1150).  (7)  Oxy-  and  amido-substituted  sulphones  result  from  the  union 
of  sulphinic  acids  with  quinone-  and  quinone-imine  derivatives. 

Phenyl-ethyl-sulphone  C6H5SO2C2H5,  m.p.  42°  and  b.p.  above  300°. 
Phenyl-ethyl-sulphone  alcohol  C6H5.SO2.CH2.CH2OH,  is  a  syrup 
formed  from  ethylene  chloro-hydrin  and  sodium-benzene  sulphinate, 
as  well  as  by  the  action  of  concentrated  sodium  hydroxide  upon 
ethylene-diphenyl-disulphone  C6H5SO2.CH2.CH2.SO2.C6H5,  m.p.  180°. 
Phenyl-sulphone-ethyl  alcohol  upon  oxidation  yields  phenyl-sulphone- 
acetic  acid  C6H5SO2CH2.CO2H,  m.p.  112°  ;  caustic  potash  resolves  this 
into  CO2  and  phenyl-methyl-sulphone  C6H5.SO2.CH3,  m.p.  88°.  Phenyl- 
sulphone  acetamide  C6H5SO2CH2CONH2,  m.p.  156°,  from  sodium- 
benzol  sulphinate  and  chloro-acetamide  (C.  1905,  I.  1134).  Phenyl- 
sulpho-aceto-nitrile  C6H5SO2CH2CN,  m.p.  114°. 

The  hydrogen  of  the  CH2  group  in  the  esters  of  phenyl-sulphone- 
acetic  acid  is  replaceable  by  sodium,  but  not  by  alkyls  (B.  22,  1447  ; 
23,  1647  ;  /.  pr.  Ch.  2,  60,  96  ;  C.  1905,  II.  1784). 

Phenyl-allyl-sulphone  C6H5SO2.C3Hs  is  an  oil  (A.  283,  185). 

The  a-  and  j3-phenyl-sulphone-propionic  acids,  melting  at  115°  and 
123°  (B.  21,  89),  as  well  as  numerous  other  mixed  fatty-aromatic 
sulphones  of  the  greatest  variety,  have  also  been  prepared. 

Diphenyl-sulphone  (C6H5)2SO2,  benzol-sulphone,  sulpho-benzide,  melt- 
ing at  128°  and  boiling  at  276°,  is  formed  by  the  distillation  of 
benzol-sulphonic  acid,  and  by  the  oxidation  of  the  phenyl  sulphide 
(C6H5)2S  and  diphenyl  sulphoxide  (see  above)  ;  further,  from  benzol- 
sulphonic  chloride  C6H5.SO2C1  and  mercury-diphenyl,  as  well  as  from 
benzol  and  benzol-sulphonic  chloride  or  sulphuryl  chloride  with 
aluminium  chloride  (B.  26,  2940).  It  is  also  obtained  by  the  action 
of  fuming  sulphuric  acid  or  SO3  upon  benzene.  It  is  converted  into 
benzol-sulphonic  acid  when  digested  with  concentrated  sulphuric  acid. 
When  heated  with  PC15,  or  in  a  current  of  chlorine  gas,  it  is  decomposed 
into  chloro-benzol  and  the  chloride  of  benzol-sulphonic  acid. 

With  sulphur  or  selenium  it  forms  the  diphenyl-sulphone  :  diphenyl 


PHENOLS  183 

sulphide  or  diphenyl  selenide  (B.  27,  1761).  Sodium  converts  it  into 
sodium-benzol  sulphinate  and  diphenyl  (B.  26,  2813).  0-  and  p-nitro- 
diphenyl-sulphone  NO2C6H4SO2C6H5  m.p.  147°  and  143°  ;  and  2,  4,  6- 
trinitro-diphenyl-sulphone  (NO2)3C6H2SO2C6H5,  m.p.  233°,  are  formed 
from  o-  and  p-nitro-chloro-benzol  or  picryl  chloride  with  sodium-benzol 
sulphinate.  Diphenyl-selenone  (C6H5)2SeO2,  melting  at  155°  and 
boiling  at  271°,  results  on  oxidising  diphenyl-selenium  oxide  with 
potassium  permanganate  (B.  29,  424).  On  heating  alone  it  deflagrates, 
giving  off  its  oxygen  and  forming  a  stable  diphenyl  selenide. 

7.  Phenols. 

The  phenols  are  derived  from  the  aromatic  hydrocarbons  by  the 
replacement  of  hydrogen  of  the  benzene  residue  by  hydroxyl.  The 
phenols,  like  the  alcohols,  are  distinguished  as  mono-,  di-,  and  tri- 
hydric,  according  to  the  number  of  hydroxyl  groups  which  have  entered. 
All  of  the  six  hydrogen  atoms  in  benzene  can  be  replaced  by  hydroxyl 
groups.  The  phenols  correspond  to  the  tertiary  alcohols,  as  they  yield 
neither  acids  nor  ketones  upon  oxidation.  Their  acid  nature,  dis- 
tinguishing them  from  alcohols,  is  governed  by  the  more  negative 
nature  of  the  phenyl  group,  and  is  enhanced  by  the  entrance  of  more 
negative  groups  (see  Picric  acid ;  C.  1903,  1. 326 ;  II.  717).  In  contrast 
to  the  phenols,  the  aromatic  alcohols,  which  are  their  isomerides,  and 
have  the  hydrogen  of  the  side-chains  replaced  by  hydroxyl,  approach 
the  aliphatic  alcohols  in  their  behaviour. 

Various  representatives  of  the  phenols  have  been  found  in  the 
vegetable  kingdom. 

Some  of  them  occur  already  formed  as  phenol-sulphonic  acids  in 
the  urine  of  mammalia.  In  the  organism  of  the  latter  many  organic 
bodies  are  oxidised  to  phenols  :  benzene  to  phenol,  bromo-benzol  to 
bromo-phenol,  aniline  to  amido-phenol,  phenol  to  hydroquinone.  In  the 
decay  of  albumin  the  presence  of  phenols  has  also  been  established. 

Phenols  are  produced  in  the  dry  distillation  of  wood,  particularly 
beech-wood,  turf,  bituminous  coal  (B.  26,  R.  151),  and  anthracite  coal. 
To  isolate  the  phenols  from  coal-tar,  shake  the  latter  with  caustic  alkali, 
in  which  they  are  soluble.  Acids  liberate  them  from  this  solution,  and 
then  they  can  be  purified  by  fractional  distillation. 

MONOHYDRIC  PHENOLS. — In  addition  to  the  methods  of  formation 
just  given,  the  following  are  worthy  of  note  : 

(1)  The  decomposition  of  the  diazo-derivatives,   especially  their 
sulphates,  with  boiling  water  or  copper  sulphate  solution. 

(2)  Fusion  of  the  sulphonic  acids  with  potassium  or  sodium  hydrox- 
ide.    This  reaction  was  discovered  in  1867  by  Kekule,  Wiirtz,  and 
Dusart,  independently  of  each  other  : 

C6H5.S03K+KOH  ----  C6H5.OH+S03K2. 

In  practice  this  method  is  used  to  obtain  phenols  from  sulpho-acids, 
the  operation  being  carried  out  in  iron  vessels. 

The  experiment  in  the  laboratory  is  executed  in  a  silver  or  nickel 
dish,  the  fusion  supersaturated  with  sulphuric  acid,  and  the  phenol 
extracted  by  shaking  with  ether. 

In  fusing  sulphonic  acids  or  phenols  containing  halogens,  the  latter 


184  ORGANIC  CHEMISTRY 

are  also  replaced  with  formation  of  polyhydric  phenols.  Occasionally 
the  sulpho-group  splits  off  as  sulphate  and  is  replaced  by  hydrogen  ; 
thus,  cresol-sulphonic  acid  yields  cresol. 

(3)  The  halogen  benzene  substitution  products  do  not  react  with 
alkalies  ;  but  if  nitro-groups  are  present  at  the  same  time,  the  halogens 
are  replaced  even  by  digesting  with  aqueous  alkalies — this  will  occur 
the  more  readily  if  the  nitro-groups  be  multiplied.     In  this  respect 
they  approach  the  acid  chlorides  : 

C6H2(N02)3C1+H20  =  C6H2(N02)3OH+HC1 

Picryl  chloride  Picric  acid. 

(4)  The  amido-group  in  the  nitro-amido-derivatives  can  also  be 
replaced  by  hydroxyl  on  boiling  with  aqueous  alkalies  ;    ortho-  and 
para-nitranilines  C6H4(NO2).NH2  (not  meta-),  yield  their  corresponding 
nitro-phenols.     The  ortho-dinitro-products  react  similarly. 

(5)  Small  quantities  of  phenol  can  be  obtained  from  benzene  by  the 
action  of  ozone,  hydrogen  peroxide  (palladium  hydride  and  water),  and 
by  shaking  with  sodium  hydroxide  and  air  (B.  14,  1144).     By  the 
addition  of  oxygen  to  benzene  through  the  instrumentality  of  alu- 
minium chloride. 

(6)  By  the  breaking  down  of  phenol-carboxylic  acids,  when  their 
salts  are  subjected  to  dry  distillation  with  lime. 

(7)  The  synthesis  of  the  higher  phenols  by  introduction  of  alkyls  into 
the  benzene  nucleus  takes  place  readily  on  heating  the  phenols  with 
alcohols  and  ZnCl2  to  200°  (B.  14, 1842  ;  17,  669  ;  27, 1614  ;  28,  407)  : 

C6H5.OH+(CH3)2CH.CH2.OH  ==  (CH3)3CH[4]C6H4[i]OH. 

Alkyl  ethers  of  the  phenols  are  simultaneously  produced  ;  methyl 
alcohol  yields  only  phenyl-methyl  ether  C6H5.O.CH3.  Magnesium 
chloride  (B.  16,  792)  and  primary  alkali  sulphates  (B.  16,  2541)  possess 
the  same  condensing  power  as  ZnCl2. 

(8)  Phenols,  under  the  influence  of  concentrated  sulphuric  acid, 
take  up  unsaturated  hydrocarbons — e.g.  iso-amylene — and  form  alkyl 
phenols  (B.  25,  2649). 

(9)  The  introduction  of  alkyl  groups  into  the  phenol  nucleus  by 
means  of  the  aluminium  or  ferric  chloride  reaction  is  not  simple  (cp. 
B.  32,  2424)  ;   the  phenol  ethers  are  more  suitable.     On  ethylation  of 
phenol  by  means  of  ether  and  aluminium  chloride,  see  B.  32,  2391. 

Behaviour  :  Replacement  of  the  Hydrogen  Atoms. — (i)  The  character 
of  the  phenols,  recalling  the  acids,  expresses  itself  in  the  ease  with  which 
they  form  salts,  particularly  with  the  alkalies.  The  hydrogen  of  the 
hydroxyl  group  is  also  readily  replaced  (2)  by  alcohol  radicles  and 
(3)  by  acid  radicles. 

(4)  The  presence  of  an  hydroxyl  group  in  the  place  of  an  aromatic 
hydrogen  atom  renders  more  easy  the  substitution  of  other  hydrogen 
atoms  by  chlorine,  bromine,  and  the  nitro-group. 

(5)  The  phenols  unite  with  the  diazo-compounds,  forming  azo-  and 
diazo-dyes  :    oxy-azo-derivatives. 

(6)  Colour  Reactions  of  the  Phenols. — On  adding  phenols  (mono-  or 
polyhydric)  to  a  solution  of  KNO2  (6  per  cent.)  in  concentrated  sulphuric 
acid,  intense  colorations  arise ;    with  common  phenol  we  get  first  a 


PHENOLS  185 

brown,  then  green,  and  finally  a  royal-blue  colour  (reaction  of  Lieber- 
mann)  (see  B.  17,  1875).  Dyes  are  produced  in  this  manner  ;  their 
character  is  as  yet  unexplained.  They  have  been  called  dichrolns 
(B.  21,  249).  The  phenols  afford  similar  colours  in  the  presence  of 
sulphuric  acid,  with  diazo-compounds  and  nitroso-derivatives.  Ferric 
chloride  imparts  colour  to  the  solutions  of  most  phenols.  Mercury 
nitrate,  containing  nitrous  acid,  colours  nearly  all  the  phenols  red 
(reaction  of  Plugge)  (B.  23,  R.  202). 

Replacement  of  the  Hydroxyl  Group. — (7)  When  heated  with  zinc  dust 
the  phenols  are  reduced  to  hydrocarbons. 

(8)  The  oxygen  of  the  simple  phenols  is  not  very  easily  replaced 
by  chlorine  when  phosphorus  pentachloride  acts  upon  them.     Phenol 
itself  has  given  the  body  C6H5OPC14.     The  pentachloride  acts  with 
greater  ease  upon  the  nitro-phenols,  forming  nitro-chloro-benzols. 

(9)  Phosphorus  sulphide  converts  the  phenols  into  thio-phenols. 
(loa)  The  anilines  result  on  heating  with  zinc  ammonium  chloride. 
(io&)  In  the  alkyl  ethers  of  the  nitro-phenols  (as  with  the  acid 

esters)  we  can  replace  the  OH  by  NH2,  on  heating  with  alcoholic 
ammonia. 

(n)  For  the  oxidation  of  the  alkyl  residues  of  homologous  phenols, 
see  below. 

Nuclear  Syntheses. — (i)  Compare  methods  7,  8,  and  9,  upon  the 
replacement  of  the  aromatic  hydrogen  atoms  of  the  phenols  by  alkyl 
groups. 

(2)  The  alkali  salts  of  the  phenols  are  converted  by  carbon  dioxide, 
at   higher  temperatures,  into  the  alkali  salts  of    oxy-acids — phenol- 
carboxylic  acids  (compare  salicylic  acid). 

(3)  The  phenols  also  yield  phenol-carboxylic  acids  with  carbon  tetra- 
chloride  and  sodium  hydroxide. 

(4)  Oxy-aldehydes  or  phenol-aldehydes   (see  salicyl-aldehyde)  are 
produced  from  phenols,  chloroform,  and  caustic  soda. 

(5)  The  phenols  condense  with  formaldehyde  to  phenol  alcohols  (see 
Saligenin) . 

(6)  Cumarins  (q.v.)  are  formed  on  heating  phenols  with  malic  acid 
and  sulphuric  acid. 

(7)  Dye-stuffs  belonging  to  the  aurin  series,  and  derived  from  tri- 
phenyl-methane  CH(C6H5)3  (q.v.),  are  obtained  from  the  phenols  by 
their  action  upon  benzo-trichloride  C6H5.CC13. 

(8)  The   so-called   phthalelns  are   combinations   of   phthalic   acid 
and  o-sulpho-benzoic  anhydride  with  the  phenols.     Similar  reactions 
occur  with  naphthalic  anhydride  (q.v.),  succinic  anhydride,  and  other 
anhydrides  of  dibasic  carboxylic  acids. 

Reduction  of  the  Phenols. — On  conducting  phenyl  vapours  mixed  with 
excess  of  hydrogen  over  finely  divided  nickel  at  2i5°-230°,  the  phenols 
are  reduced  to  hexahydro-phenols  (C.  1904,  I.  279  ;  see  also  B.  40, 
1286). 

By  reduction  of  phenol  with  alternating  currents,  cyclo-hexanone  is 
produced  (/.  pr.  Ch.  2,  38,  65). 

Breaking  down  of  the  Benzene  Nucleus  of  the  Phenols. — (i)  By  oxida- 
tion of  phenol  (q.v.).  (2)  By  treating  the  phenols  with  chlorine,  and 
then  decomposing  the  chlorine  addition  products  with  alkalies. 

BENZO-PHENOL,  Phenol,  carbolic  acid,  C6H5.OH,  m.p.  43°  anol  b.p. 


i86  ORGANIC  CHEMISTRY 

183°;  its  specific  gravity  is  1-084  (°°)-  It  is  obtained  from  amido- 
benzol,  from  benzol-sulphonic  acid,  from  the  three  oxy-benzoic  acids, 
etc.,  by  the  methods  previously  described.  It  occurs  already  formed 
in  Castoreum  and  in  the  urine  of  the  herbivorae. 

Commercial  phenol  is  a  colourless,  crystalline  mass,  which  gradually 
acquires  a  reddish  colour  on  exposure  to  the  air  (B.  27,  R.  790  ;  C. 
1909,  II.  597).  Pure  phenol  crystallises  in  long,  colourless  prisms.  It 
possesses  a  characteristic  odour,  burning  taste,  and  poisonous  and 
antiseptic  properties.  It  dissolves  in  15  parts  at  20°,  and  very  readily 
in  alcohol,  ether,  and  glacial  acetic  acid.  It  is  volatile  with  steam. 
Ferric  salts  impart  a  violet  colour  to  its  neutral  solutions.  Bromine 
water  precipitates  [2, 4, 6]-tribromo-phenol  from  even  very  dilute 
solutions.  On  introducing  phenol  into  the  organism,  it  occurs  in 
the  urine  as  phenol-glucuronic  acid  (Vol.  I.)  and  as  phenyl-sulphuric 
acid. 

Diphenols  C12H8(OH)2,  derivatives  of  diphenyl  (q.v.),  are  produced 
on  fusing  phenol  with  caustic  potash. 

Diphenylene  oxide  is  produced  when  phenol  is  distilled  over  lead 
oxide.  Aurin  results  when  it  is  heated  with  oxalic  or  formic  acid  and 
dehydrating  agents  (q.v.).  Potassium  permanganate  oxidises  phenol 
to  inactive  or  meso-tartaric  acid  (Vol.  I.).  Mono-persulphonic  acid 
oxidises  it  to  pyrocatechin  and  hydroquinone  (/.  pr.  Ch.  2,  68,  486). 
Chlorine  finally  changes  phenol  to  keto-chlorides,  which  are  derived 
from  di-  and  tetrahydro-benzol  (B.  27,  537).  Chlorine  and  caustic  soda 
convert  phenol  into  trichloro-R-pentene-dioxy-carboxylic  acid.  The 
most  important  reactions  of  phenol  have  been  previously  described. 

History. — -Runge  discovered (1834)  phenol  in  coal-tar  and  called  it 
carbon-oil  acid,  or  carbolic  acid.  He  also  observed  the  physiological 
properties  it  possessed  in  common  with  creosote.  Laurent,  in  1841, 
first  obtained  it  pure  and  gave  it  the  names  hydrate  de  phenyle  or  acide 
phenigue,  from  (fraivew,  to  illuminate,  probably  because  it  occurs  in  the 
tar  produced  in  the  manufacture  of  illuminating  gas.  Gerhardt,  who 
prepared  it  from  salicylic  acid,  introduced  the  name  phenol,  indicating 
thereby  that  it  was  an  alcohol.  In  1867  Lister,  of  Glasgow,  showed  its 
great  importance  in  surgery  as  a  disinfectant. 

Phenolates. — Phenates,  potassium  phenate  C6H6OK,  and  sodium 
phenate  C6H5ONa,  are  obtained  by  dissolving  phenol  in  caustic  potash 
or  soda,  evaporating  the  solution,  and  sharply  drying  the  residue.  Both 
salts  dissolve  readily  in  water  (B.  26,  R.  150).  Carbon  dioxide  sets 
phenol  free  from  them  ;  it  is,  therefore,  not  soluble  in  the  alkali 
carbonates. 

Calcium  phenate  (C6H5O)2Ca,  and  mercury  phenate  (C6H5O)2Hg. 
(See  B.  29,  R.  178,  for  the  compounds  of  the  phenols  with  aluminium 
chloride ;  and  see  Salicylic  acid  for  the  action  of  CO2  upon  dry  phenates.) 
Aluminium  phenate  (C6H5O)3A1,  by  heating  phenol  with  Al.  It  is  a 
glassy  mass,  melting  about  265°  (C.  1906,  II.  114).  On  combinations 
of  phenols  with  Al  chloride,  see  B.  29,  R.  178  ;  with  nitrogen  bases, 
B.  35,  1207). 

HOMOLOGOUS  PHENOLS. — It  is  strange  that  the  cresols,  as  well  as 
other  higher  phenols,  cannot  be  oxidised  by  the  chromic  acid  mixture  : 
the  OH-group  prevents  the  oxidation  of  the  alkyl  groups  by  chromic 
acid.  If,  however,  the  phenol-hydrogen  is  replaced  by  alkyls,  or  acid 


PHENOLS  187 

radicles  (in  the  phenol  ethers  and  esters),  then  the  oxidation  of  the 
alkyl  does  take  place  with  the  production  of  ether  acids  or  ester 
acids. 

The  readily  prepared  sulphuric,  or  phosphoric,  acid  esters  of  the 
homologous  phenols  are  best  adapted  for  oxidation  with  an  alkaline 
permanganate  solution  (B.  19,  3304),  whereas  the  free  phenols  are 
completely  destroyed  by  this  reagent  (compare  oxidation  of  phenol, 
above) . 

The  oxidation  of  the  alkyls  in  the  sulpho-acids  of  the  homologous 
phenols  is  similarly  influenced  by  the  sulpho-group.  In  general,  nega- 
tive atoms,  or  groups,  prevent  the  oxidation  of  alkyls  in  the  ortho-position 
by  acid  oxidants,  whereas  alkaline  oxidants — e.g.  KMnO4 — do  precisely 
the  reverse,  in  that  they  first  oxidise  the  alkyl  group  holding  the  ortho- 
position  (A.  220,  16).  The  methyl  groups  of  the  methyl-phenols,  such 
as  the  cresols  and  xylenols,  are  converted  by  molten  alkalies,  with 
the  addition  of  PbO  or  PbO2  (B.  39,  794),  into  carboxyl  groups, 
and  there  result  oxy-benzoic  acids,  oxy-toluic  acids,  oxy-phthalic 
acids,  etc.  (compare  the  like  behaviour  of  the  homologous  pyrrols  and 
indols). 

p-Alkylated  halogen  phenols  are  oxidised  by  nitric  acid  to  so-called 
quinitrols  and  quinols,  which  substances  are  dealt  with  in  connection 
with  pseudo-phenol  bromides  and  methylene-quinones  in  the  chapter 
on  "  Phenol  Alcohols." 

Other  transposition  reactions  are  given  above.  The  liquid  homo- 
logous phenols  are  particularly  characterised  by  the  melting-points  of 
their  benzoyl  esters  ;  therefore  these  will  be  given  in  connection  with 
the  various  members. 

1.  Cresols,  oxy-toluols,  CH3.C6H4OH. — The  three  isomerides  occur 
in  coal-tar  and  beechwood  tar. 

They  are  obtained  from  the  toluidins  by  method  I.,  and  from  the 
toluol-sulphonic  acids  by  method  II.  They  have  a  similar  odour,  but 
it  is  more  disagreeable  than  that  of  phenol.  They  are  less  poisonous, 
and  are  disinfectants.  They  are  changed  to  toluol  when  heated  with 
zinc  dust.  Sodium  and  carbon  dioxide  produce  the  corresponding 
cresotinic  acids. 

See  above  for  their  behaviour  towards  molten  caustic  potash  and 
other  oxidising  agents.  o-Cresol  is  obtained  from  carvacrol,  and  the 
m-body  from  thymol  (see  below) .  The  latter  is  also  prepared  from  the 
dibromide  of  synthetic  j8-methyl-keto-R-hexene  (q.v.)  by  the  elimina- 
tion of  hydrogen  bromide  (A.  281,  98). 

o-Cresol,  [i,  2\-oxy-toluol,  m.p.  31°,  b.p.  188° 
m-Cresol,  [i,  3}-oxy-toluol,  ,,  4°,  „  201° 
p-Cresol,  [i,  ^-oxy-toluol,  „  36°,  „  198°. 

Ferric  chloride  colours  o-cresol  blue.  The  crude  cresols  are  used 
as  disinfectants  :  creolin  is  a  solution  of  the  crude  cresols  in  alkalies  ; 
cresolin  is  a  solution  of  the  same  in  resin  soaps ;  while  lysol  is  a  solution 
of  crude  cresols  in  oline  soaps.  See  B.  14,  687,  for  the  behaviour  of  the 
cresols  in  the  animal  organism. 

2.  Phenols  CSH9OH. — Oxy-dimethyl-benzols  and  oxy-ethyl-benzol. 
The  six  possible  xylenols  C6H3(CH3)2.OH  have  been  prepared. 


i88  ORGANIC  CHEMISTRY 

Ethyl-phenols  C6H4(C2H5).OH.— From  the  ethyl-benzol-sulphonic 
acids  (B.  27,  R.  189). 

o-Ethyl-phenol,  liquid,    b.p.  203°  ;  benzoyl  compound,  m.p.  39° 
m-Ethyl-phenol,      „  „    214°;         „  „  „     52° 

p-Ethyl-phenol,  m.p.  45°,  „    215° ;         „  „  „    59°. 

3.  Phenols    C9Hn.OH.— Mesitol     C6H2(CH3)3.OH,    from     amido- 
mesitylene   and   mesitylene-sulphonic   acid,  m.p.   68°  and  b.p.   220°. 
[i]OH[2,4,5]-Pseudo-cumenol    C6H2(CH3)3.OH,   from   pseudo-cumene- 
sulphonic  acid,  m.p.  73°  and  b.p.  232°  (B.  17,  2976).     On  the  bromina- 
tion  products  of  pseudo-cumenol,  and  the  formation  of  pseudo-phenol 
bromides,  insoluble  in  alkalies,  see  "  Phenol  Alcohols." 

m-n-Propyl-phenol,  from  iso-safrol,  m.p.  26°  and  b.p.  228°  (B.  23, 
1162).  p-n-Propyl-phenol  boils  at  232°.  p-Iso-propyl-phenol  melts  at 
61°,  and  boils  at  229°.  It  is  also  produced  along  with  hydroquinone 
on  decomposing  diphenol-/?-propane  (CH3)2C(C6H4OH)2  (from  the 
action  of  fuming  hydrochloric  acid  on  acetone  and  phenol),  with 
molten  caustic  potash  (B.  25,  R.  334). 

4.  Phenols   C10H13.OH. — There   are    twenty    possible   isomerides. 
Thymol  and  carvacrol  merit  notice.     They  occur  in  vegetable  oils. 
Both  are  derivatives  of  ordinary  p-cymol,  and  contain  the  iso-propyl 
group. 

Thymol,  when  heated  with  P2O5,  breaks  down  into  propylene  and 
m-cresol;  while  carvacrol,  under  similar  treatment,  yields  propylene 
and  o-cresol. 

Thymol     =  [3]-Methyl-[6]-iso-propyl-phenol  C3H7[6]C6H3  •£  f^ 

Carvacrol  =  [2] -Methyl- [5] -iso-propyl -phenol  C3H7[5]C6H3  <  p 

U[2]CH3 

Thymol,  melting  at  44°  and  boiling  at  230°,  crystallises  in  large, 
colourless  plates.  It  exists  with  cymol  C10Hj4,  and  thymol  C10H1?, 
in  oil  of  thyme  (from  Thymus  vulgaris),  and  in  the  oils  of  Ptychotis 
ajowan  and  Monarda  punctata.  To  obtain  the  thymol,  shake  these  oils 
with  potassium  hydroxide,  and  from  the  filtered  solution  precipitate 
thymol  with  hydrochloric  acid.  It  is  artificially  prepared  from  nitro- 
cumin-aldehyde  (q.v.),  as  well  as  from  dibromo-menthone,  by  the  split- 
ting-off  of  hydrogen  bromide  (B.  29,  420).  It  has  a  thyme-like  odour 
and  answers  as  an  antiseptic. 

Ordinary  cymol  is  obtained  by  distilling  it  with  P2S5.  Thymo- 
quinone  (q.v.)  is  produced  in  its  oxidation. 

Iodine  and  caustic  potash  convert  thymol  into  di-iodo-di-thymol, 
a  diphenyl  derivative  which  has  been  substituted  for  iodoform  under 
the  names  aristol  and  annidalin. 

On  the  processes  of  iodination  and  bromination  of  thymol,  see 
C.  1903,  I.  766. 

Carvacrol,  cymo-phenol,  melting  at  o°  and  boiling  at  236°,  isomeric 
with  thymol,  occurs  already  formed  in  the  oil  of  certain  varieties  of 
satureja,  also  in  Briganum  hirtum,  and  is  obtained  from  an  isomeric 
carvol,  a  dihydro-cymol  derivative  (q.v.)  contained  in  the  oil  of  Carvum 
carvi,  and  certain  other  oils,  when  it  is  heated  with  glacial  phosphoric 
acid  (B.  19,  12).  It  is  further  prepared  by  heating  camphor  with 


PHENOLS  189 

iodine  (i  part),  using  a  return  condenser.  It  is  made  artificially  from 
cymol-sulphonic  acid  (B.  11,  1060). 

Distillation  with  P2S5  converts  carvacrol  into  cymol  and  thio- 
carvacrol  C10H13.SH. 

s-Carvaerol  (CH3)[3](CH3)2CH[5]C6H3[i]OH  melts  at  54°  and  boils 
at  241°  (B.  27,  2347).  Methyl-p-norm.-propyl-phenol  (CH3)[2]C3H7 
[5]C6H3OH,  from  the  corresponding  sulpho-acid,  boils  at  240°  (B.  29, 
R.  417). 

p-Tertiary  butyl-phenol  (CH3)3C[4]C6H4[i]OH,  melting  at  98°  and 
boiling  at  237°,  is  obtained  from  isobutyl  alcohol,  phenol,  and  zinc 
chloride  (B.  24,  2974).  Oxidised  with  MnO4K,  it  gives  trimethyl-pyro- 
racemic  acid  and  trimethyl-acetic  acid  (A.  327,  201). 

p-Tertiary  amyl  -  phenol  (CH3)2(C2H5)C[4]C6H4[i]OH,  melting  at 
93°  and  boiling  at  266°,  results  from  the  action  of  ZnCl2  upon  iso-amyl 
alcohol  or  tertiary  amyl  alcohol,  and  from  iso-amylene,  phenol,  acetic 
acid,  and  sulphuric  acid  (B.  28,  407).  Oxidised  with  MnO4K,  it  gives 
dimethyl-ethyl-pyro-racemic  acid  and  dimethyl-ethyl-acetic  acid 
(A.  327,  201). 

Diethyl-phenols,  tetra-ethyl-phenol  (B.  22, 317 ;  32,  2392). 

Tetramethyl-phenols  (B.  15,  1852  ;  17,  1916 ;  18,  2842  ;  21,  645, 
907). 

Pentamethyl-phenol,  m.p.  125°,  b.p.  267°  (B.  18, 1826). 

DERIVATIVES  OF  THE  MONOHYDRIC  PHENOLS. 

The  behaviour  of  the  phenols  was  given  under  the  example  selected- 
ordinary  phenol.  Because  this  can  be  obtained  with  comparative  ease, 
more  derivatives  of  it,  than  of  its  homologues,  have  been  prepared. 
In  the  following  pages  the  derivatives  of  the  homologues  will  only  be 
brought  forward  and  discussed  in  case  they  possess  theoretical  or 
practical  value,  and  then  in  connection  with  the  compounds  of  the 
corresponding  phenol. 

Phenol-alcohol  Ethers. — (i)  Like  the  ethers  of  the  aliphatic  alcohols, 
they  result  from  the  interaction  of  alkyl  iodides  and  phenates.  The 
phenol  is  digested  with  caustic  potash,  and  the  alkyl  iodide,  or  methyl 
chloride,  is  conducted  over  sodium  phenate  heated  to  200°  (B.  16, 

2513). 

(2)  By  heating  a  mixture  of  the  alkali  salts  of  the  phenols  with  an 
excess  of  alkyl  sulphates,  in  aqueous  or  alcoholic  solution  (B.  19,  R.  139). 

(3)  Together   with    hydrocarbons    on    decomposing   benzol-diazo- 
compounds  with  alcohols  (B.  25,  1973). 

(4)  By  heating  phenyl-carbonic  alkyl  ester  with  elimination  of  CO2: 

C6H5OCOOCH3  =  C6H5OCH3+CO2 
(B.  42,  2237). 

(5)  The  phenols  are  converted  at  ordinary  temperatures  by  diazo- 
methane,  with  evolution  of  nitrogen,  into  their  methyl  ethers  (B.  28, 

857)  : 

C6H5OH+CH2N2  =  C6H5OCH3+N2. 

Dimethyl  sulphate  (CH3)2SO4,  p-toluol-sulphonic  ester,  and  other 
bodies  have  been  recommended  as  practical  alkylators  for  phenols 
(A.  327,  120  ;  B.  27,  R.  955). 


igo  ORGANIC  CHEMISTRY 

(6)  By  heating  the  phenol  ethers  of  phenol-carboxylic  acids  with 
lime  or  baryta : 

C02H[i]C6H4[4]OCH3  — ^~>  C6H6OCH3 
Anisic  acid  Anisol. 

Boiling  with  alkalies  does  not  change  the  phenol  ethers.  Only 
after  long  heating  with  alcoholic  potash  to  a  high  temperature  does 
phenol  form  by  disintegration  (B.  34,  1812).  The  ethers  of  multi- 
valent  phenols  are  partly  saponified  ;  veratrol  produces  guajacol  (C. 
1898,  I.  456).  Heating  with  HI,  HBr,  or  HC1  breaks  up  most  phenyl- 
alkyl  ethers  into  their  generators  : 

C6H5OCH3-fHI  =  C6H5OH+CH3I. 

This  easy  detachment  of  CH3I  and  C2H5I,  on  heating  phenol  ethers 
with  concentrated  HI,  may  be  used  for  the  quantitative  determination 
of  the  number  of  methoxyl  or  ethoxyl  groups  in  a  compound,  the  iodine 
compounds  being  converted  into  silver  iodide  in  an  alcoholic  silver 
nitrate  solution,  and  weighed  (Zeisel,  M.  6,  989  ;  7,  406).  The  phenol 
ethers  are  also  decomposed  by  A12C16  (B.  25,  3531)  ;  PC15  only  chlorinates 
the  nucleus  (B.  28,  R.  612).  With  Cl,  Br,  I,  HNO3,  and  H2SO4  the 
phenol  ethers  behave  like  aromatic  hydrocarbons. 

Anisol,  methyl-phenyl  ether  C6H5.O.CH3,  is  produced  by  distilling 
anisic  or  p-methyl-salicylic  acid.  It  boils  at  152°  ;  its  specific  gravity 
at  15°  is  0-991.  It  is  not  reduced  by  zinc  dust  (C.  1904, 1. 1005). 

Phenetol,  ethyl-phenyl  ether  (C6H5).O.C2H5,  b.p.  172°,  has  the 
specific  gravity  0-9822(0°).  The  iso-amyl  ether  boils  at  225°. 

Bromethyl-phenyl  ether  BrCH2.CH2.O.C6H5  melts  at  39°  (/.  pr.  Ch. 
2,  24,  242). 

Bromethenyl-pheny*  ether  BrCH  :  CHOC6H5,  b.p.16  166°,  from 
acetylene  dibromide  with  potassium  phenol ;  when  treated  with  alcoholic 
potash  it  gives  phenoxy-aeetylene  C6H5.OC=CH,  b.p.35  75°,  an  easily 
decomposed  oil,  which  readily  forms  normal  acetylene  salts  C6H5OC ; 
CAg,  (C6H5OCC)2Cu2,  C6H5OCCNa. 

Phenol-methylene  ether  CH2(OC6H5)2,  m.p.  81°,  b.p.  165°  (B.  46, 
2789).  Phenol-ethylene  ether,  glyeol-diphenyl  ether  C6H5OCH2CH2 
OC6H5,  m.p.  95°,  is  isomeric  with  phenol-acetol  (C6H5O)2CHCH3,  m.p. 
10°,  b.p.  175°,  obtained  from  potassium  phenol,  with  aldehyde  chloride 
(C.  1900, 1.  813).  Glycol-monophenyl  ether,  b.p.80 165°  (B.  29,  R.  289). 
Glycerine-monophenyl  ether  C6H5OCH2.CHOH.CH29H,  m.p.  70°, 
is  formed  by  heating  phenol  with  glycerine  and  sodium  acetate  (M. 

/°\ 
29,  951),  or  by  adding  water  to  phenyl-glyeidie  ether  C6H5OCH2CH— CH2, 

b.p.  242°,  obtained  besides  glycerine-diphenyl  ether,  m.p.  82°,  by  trans- 
formation of  sodium  phenyl  with  epichloro-hydrin  (C.  1908,  I.  2032 ; 
1910,  I.  1134). 

Phenoxalkylamines . — ^-Phenoxethylamines  NH2.CH2.CH2.O. C6H5, 
b.p.  228°  (B.  24,  189).  y-Phenoxy-propylamine  NH2.CH2.CH2. 
CH2.O.C6H5,  b.p.  241°  (B.  24,  2637).  S-Phenoxy-butylamine  NH2CH2 
CH2CH2CH2OC6H5,  b.p.  255°  (B.  24,  3232). 

Phenol  ethers  of  aldehyde  alcohols,  ketone  alcohols,  and  alcohol 
acids  have  been  obtained  from  the  corresponding  chlorinated  alde- 
hydes, ketones,  and  carboxylic  acids,  by  the  action  of  sodium  phenate : 


PHENOLS  191 

Phenoxy-acetaldehyde  C6H6O.CH2.CHO,  b.p.  119°  (30  mm.)  (B. 
28,  R.  295). 

Phenoxy-aeetone,  phenacetol  C6H5O.CH2.CO.CH3,  b.p.  230°,  is  con- 
densed by  concentrated  sulphuric  acid  to  methyl  cumarone  (q.v.)  (B.  28, 
1253  ;  35,  3553). 

Phenoxy-aeetie  acid  C6H5O.CH2.COOH,  m.p.  96°,  is  isomeric  with 
almond  acid  C6H5CH(OH).COOH.  It  results  from  monochloracetic 
acid  and  potassium  phenate  at  150°,  as  well  as  from  the  oxidation  of 
phenoxy-acetaldehyde.  It  is  a  strong  antiseptic  (B.  19,  1296  ;  27, 
2796). 

Phenoxy-acetyl  chloride  C6H5OCH2COC1,  b.p.^  169°  (see  B.  35, 
356o). 

Diphenoxy-aeetic  acid  (C6H5O)2CHCO2H,  m.p.  91°  (B.  27,  2796). 
a-  and  y-Phenoxy-butyrie  acid  melt  at  99°  and  60°  (B.  29,  1421).  For 
homologous  a-phenoxy-aliphatic  acids,  see  B.  33,  924,  1249. 

a-Phenoxy-aceto-acetic  ester  CH3.CO.CH(OC6H5)CO2C2H5,  from 
sodium  phenate  and  a-chloraceto-acetic  ester,  is  a  thick  oil.  Con- 
centrated sulphuric  acid  condenses  it  to  methyl-cumarilic  ester. 
Phenoxy-fumarie  ester  C6H5OC(COOR)  :  CHCO2R,  from  sodium 
phenol  and  acetylene-dicarboxylic  ester  (C.  1900,  II.  1210). 

Phenol  Ethers. — Phenyl  ether  (C6H5)2O,  diphenyl  oxide,  melting 
at  28°  and  boiling  at  252°,  is  produced  by  distilling  copper  benzoate 
(together  with  benzoic  phenyl  ether)  and  digesting  diazo-benzol  sul- 
phate with  phenol  (B.  25,  1973)  ;  also  by  heating  phenol  with  zinc 
chloride  to  350°,  or,  better,  with  aluminium  chloride  (B.  14,  189).  It 
crystallises  in  long  needles,  and  possesses  an  odour  resembling  that  of 
geraniums.  It  dissolves  readily  in'alcohol  and  ether.  It  is  not  reduced 
on  heating  with  zinc  dust  or  hydriodic  acid. 

Nitrated  phenyl  ethers  have  been  obtained  by  the  interaction  of  the 
corresponding  nitro-haloid  benzols  and  the  potassium  salts  of  phenols  : 
o-Nitro-phenyl  ether  C6H5O.C6H4NO2  boils  at  235°  (60  mm.),  o,  o'-Di- 
nitro-phenol  ether  (NO2.C6H4)2O  melts  at  114°  (B.  29,  1880,  2084; 
C.  1903,  I.  634). 

Acid  Esters  of  Phenol. — The  acid  esters  are  obtained  by  acting  with 
acid  chlorides  or  anhydrides  upon  the  phenols  or  their  salts  ;  also  by 
digesting  the  phenols  with  acids  and  POC13.  To  effect  the  substitu- 
tion of  all  the  hydroxyl-hydrogen  atoms  in  the  polyhydric  phenols  by 
acetyl  groups,  it  is  recommended  to  heat  them  with  acetic  anhydride 
and  sodium  acetate.  On  boiling  with  alkalies,  or  even  with  water,  they, 
like  all  esters,  break  down  into  their  components. 

Esters  of  Inorganic  Acids. — Phenyl-sulphonic  ester  is  not  known  in 
a  free  state.  Its  sodium  salt  NaSO2OC6H5  results  from  the  action  of 
SO 2  upon  sodium  phenate.  Methyl  iodide  converts  it  into  methyl-sul- 
phonic  phenyl  ester  CH3SO2OC6H5  (cp.  B.  25,  1875).  Sulphonic  aryl 
ester  salts  are  also  formed  from  phenols  with  sodium  disulphite  ;  they 
are  distinguished  for  their  reacting  power  ;  in  some,  the  OSO2Na 
group  is  replaced  by  NH2  on  heating  with  ammonia  (C.  1901,  II.  1136). 

Phenyl-sulphurie  acid  C6H5.O.SO3H  is  not  known  in  a  free  state  ; 
when  liberated  from  its  salts  by  concentrated  hydrochloric  acid,  it  im- 
mediately breaks  down  into  phenol  and  sulphuric  acid.  Its  potassium 
salt  C6H5.O.SO3K  forms  flakes,  not  very  soluble  in  cold  water,  and 
occurs  in  the  urine  of  herbivorous  animals,  and  also  in  that  of  man  and 


I92  ORGANIC  CHEMISTRY 

the  dog  after  the  ingestion  of  phenol.  It  is  synthetically  prepared,  like 
other  phenols,  on  heating  potassium  phenoxide  with  an  aqueous  solu- 
tion of  potassium  pyro-surphate  (B.  9,  1715) ;  also  from  phenol  and 
chloro-sulphonic  acid  by  means  of  pyridin  in  CS2  solution,  and  subse- 
quent treatment  with  KOH  (C.  1901,  I.  313). 

The  phenyl-sulphuric  acids  are  very  stable  in  aqueous  and  alkaline 
solution  ;  upon  digesting  with  mineral  acids,  however,  they  are  very 
rapidly  decomposed.  When  potassium-phenyl  sulphate  is  heated  in 
a  tube,  it  passes  quietly  into  potassium-p-phenol  sulphonate. 

Phenyl  Esters  of  the  Phosphoric  Acids. — These  arise  in  the  action 
of  PC13  and  POC13  (A.  239,  310  ;  253, 120  ;  B.  30,  2369)  : 

Phenyl-phosphorous  chloride         .          .  C6H6O.PC12,       boils  at    90°  (n  mm.) 

Diphenyl-phosphorous  chloride     .          .  (C6H5O)2PC1,  „        172° 

Triphenyl  phosphite    ....  (C6H5O)3P,  „        220° 

Phenyl-phosphoric  chloride  .  (CCH5O)POC12,        „        121° 

Diphenyl-phosphoric  chloride        .          .  (C6H5O)2POC1,        „        195°  (14  mm.) 

Triphenyl  phosphate,  m. p.  45°      .          .  (C6H5O)3PO,  „        245°  (n  mm.) 

The  last  of  these  is  best  obtained  by  shaking  up  an  alkaline  phenol 
solution  with  phosphorus  oxy-chloride. 

The  two  phenyl-phosphorous  chlorides  take  up  chlorine  : 

Phenyl-phosphoric  tetrachloride       .          .     C6H5OPC14 
Diphenyl-phosphoric  trichloride        .          .      (C6H6O)2PC13 

On  phenol  sulpho-phosphates,  e.g.  triphenyl  sulpho-phosphate 
(C6H5O)3PS,  m.p.  53°,  see  B.  31, 1094. 

Phenyl  Silicates  (B.  18,  1679). 

Phenyl  Esters  of  Monocarboxylic  Acids. — Phenyl  formate  (/.  pr. 
Ch.  2,  31,  467).  Phenyl-ortho-formic  ester  CH(O.C6H5)3  is  formed  by 
boiling  phenol  with  sodium  hydroxide  and  chloroform.  It  melts  at  71° 
and  distils  at  265°,  under  50  mm.  pressure  (B.  18,  2656). 

Phenyl  acetate  CH3.COOC6H5  boils  at  195°  (B.  18,  1716).  Ortho- 
acetic  phenyl  ester  CH3C(OC6H5)3  melts  at  98°  (B.  24,  3678). 

Phenyl  Carbonates. — The  free  phenyl-carbonic  acid  is  not  known. 
The  opposite  is  true  of  sodium-phenyl  carbonate  C6H5OCO2Na.  It 
is  produced  when  CO2  acts  upon  sodium  phenoxide  (under  pressure). 
It  is  a  white  hygroscopic  powder,  decomposed  again  by  water.  When 
heated  under  pressure  to  I2o°-i3o°,  sodium  salicylate  HOC6H4CO2Na 
results,  just  as  phenol-sulphonic  acid  is  obtained  from  phenyl-sulphuric 
acid  (see  above).  Heated  to  I2O°-I3O°  under  pressure,  it  transposes 
to  sodium-phenol-o-carboxylie  acid  NaOC6H4COOH.  When  heated 
to  190°  with  sodium  phenate,  sodium-phenyl  carbonate  yields  disodium 
salicylate  and  phenol  (B.  38,  1375). 

Phenyl  Carbonate. — The  carbonic  acid  ester  CO(O.C6H5)2  is  pro- 
duced on  heating  phenol  and  phosgene  gas  COC12  to  150°.  It  is 
readily  obtained  by  leading  phosgene  gas  into  the  aqueous  solution  of 
sodium  phenylate  (/.  pr.  Ch.  17, 139  ;  B.  17,  287).  It  crystallises  from 
alcohol  in  shining  needles,  and  melts  at  78°.  It  yields  sodium  salicylate 
when  heated  to  200°  with  sodium  hydroxide.  Urea  results  if  it  be 
heated  with  ammonia  (B.  23,  694). 

Mixed  carbonates  containing  phenol  and  alkyls — e.g.  phenyl-ethyl 
carbonate  CO3(C2H5)(C6H5) — are  produced  by  the  action  of  chloro- 


PHENOLS  193 

formic  esters  upon  the  sodium  salts  of  the  phenols,  or  of  alcohols  upon 
chloro-formic  phenyl  ester,  obtained  from  phosgene  with  phenols  (C. 
1899,  II.  825) ;  they  also  form  on  heating  phenyl  carbonate  with  the 
alcohols  in  the  presence  of  urea  (C.  1898,  II.  476).  On  heating,  they 
split  off  CO 2  and  pass  into  phenol-alkyl  ether  (B.  42,  2237). 

Diphenyl-thio-carbonic  ester  C6H5OCSOC6H5  (B.  27,  3410  ;  C.  1906, 
II.  1760).  Phenyl-earbaminate,  phenyl-urethane,  NH2COOC6H5,  melts 
at  141°  (B.  33,  51  ;  A.  244,  43).  Phenyl-earbamic  phenyl  ester  C6H5 
NHCO2C6H5,  from  carbanile  and  phenol,  m.p.  124°  (B.  18,  875  ;  27, 
1370).  Diphenyl-thio-earbamic  phenyl  ester  (C6H5)2NCOOC6H5,  m.p. 
105°,  from  diphenyl-urea  chloride  and  phenol.  Phenyl-carbaminic 
phenyl  ester  C6H5O.CSNHC6H5,  m.p.  148°,  is  produced  on  heating 
phenyl-mustard  oil  with  phenol  to  280°  (B.  29,  R.  177). 

Phenyl-imido-carbonic  phenyl  ester  C6H5N  :  C(OC6H5)2,  m.p.  136°, 
is  obtained  from  iso-cyano-phenyl  chloride  and  sodium  phenate 
(B.  28,  977). 

Phenyl-allophanic  ester  cov^2Vr        T  is  produced  by  conducting 

\JN11. LxUo-^ails 

cyanic  acid  vapours  into  anhydrous  phenol.     A  crystalline  mass. 

Phenyl  Esters  of  Dicarboxylic  Acids.  —  Phenyl  -  oxalic  ester 
(COOC6H5)2,  m.p.  136°,  b.p.15  191°  (B.  35,  3437).  Malonic  diphenyl 
ester,  m.p.  50°  (B.  35,  3455). 

Ethyl-phenyl-oxalic  ester  COOC2H5.COOC6H5,  b.p.  236°,  is  obtained 
from  ethyl-oxalic  chloride  (Vol.  I.).  The  succinic  ester  melts  at  118° 
and  boils  at  330°.  Phenyl-fumaric  ester,  m.p.  161°,  decomposes  when 
distilled  slowly  into  CO2,  phenyl-cinnamic  ester  (q.v.),  and  stilbene  (q.v.) 
(B.  18,  1948). 

PHENOL  SUBSTITUTION  PRODUCTS. 

Phenol  Haloids. — Formation: — (i)  Chlorine  and  bromine  react 
readily  with  phenols ;  this  is  exemplified  in  bromine  precipitating  phenol 
quantitatively  from  its  aqueous  solutions  as  [i  OH,2,  4,  6]-tribromo- 
phenol.  Chlorine  and  bromine  enter  the  ortho-  and  para-positions  ; 
there  result  at  first  the  [i,  2]-  and  [i,  4] -mono-,  then  the  [i,  2,  4-] 
di-,  and  finally  the  [i,  2,  4,  6]-tri-substitution  products.  At  I5o°-i8o°, 
by  action  of  chlorine  or  bromine  vapours,  abundant  quantities  of 
o-chloro-  and  o-bromo-phenol  (B.  27,  R.  957)  are  produced.  Sulphuryl 
chloride,  which  easily  chlorinates  the  free  phenols  (but  not  their 
ethers),  yields  p-chloro-phenol  (C.  1898,  I.  1051). 

The  iodo-derivatives  are  formed  by  adding  iodine  and  iodic  acid  to 
a  dilute  potassium  hydroxide  solution  of  phenol  (Kekule,  A.  137,  161)  : 

5C6H5OH+2l2+I03H  ----  5C6H4I.OH+3H20, 

or  by  the  action  of  iodine  and  mercuric  oxide.  Di-iodo-phenol  is  the 
chief  product  in  the  latter  case. 

(2)  In  the  phenol-sulphonic  and  phenol-carboxylic  acids  the  action 
of  chlorine  and  bromine  leads  to  the  replacement  of  the  sulpho-  and 
carboxyl  groups  in  the  o-  and  p-positions  as  phenyl  hydroxyl  by  halogens 
(B.  42,  4361). 

(3)  From  substituted  anilines,  by  the  replacement  of  NH2  by  OH, 
which  may  be  brought  about  by  the  diazo-compounds  ;   this  reaction 
leads  to  pure  mono-haloid  phenols.     (4)  From  the  nitro-phenols  by 

VOL.  II.  O 


194   '  ORGANIC  CHEMISTRY 

replacing  the  nitro-group  with  halogens  (effected  through  the  amido- 
and  diazo-derivatives) .  (5)  By  distilling  substituted  oxy-acids  with 
lime  or  baryta. 

Behaviour. — (i)  The  introduction  of  halogen  atoms  considerably 
increases  the  acid  character  of  phenol  ;  thus,  trichloro-phenol  readily 
decomposes  the  alkaline  carbonates. 

(2)  When  fused  with  potassium  hydroxide,  the  halogen  is  replaced 
by   the  hydroxyl  group.     In    this   reaction   it   frequently   happens, 
especially  at  high  temperatures,  that  not  the  corresponding  isomerides, 
but  rather  the  more  stable  derivative,  results  ;   for  example,  all  the 
bromo-phenols  yield  resorcin.     The  caustic  potash  fusion  is,  therefore, 
not  applicable  in  determining  constitution. 

(3)  Sodium  amalgam  causes  the  replacement  of  the  halogen  atoms 
by  hydrogen. 

(4)  By  the  action  of  HNO2  upon  bromine-substituted  phenols  the 
Br  atoms,  in  o-  or  p-position  to  the  hydroxyl,  are  easily  replaced  by 
nitroyl  (/.  pr.  Ch.  2,  61,  561  ;  A.  333,  346). 

Monohaloid  Phenols. — The  monochloro-phenols  in  particular  are 
characterised  by  a  disagreeable,  very  adherent  odour.  The  bromo- 
and  iodo-phenols,  being  attacked  at  a  lower  temperature  than  the 
chloro-derivatives,  are  changed,  on  fusing  with  potash,  into  the  corre- 
sponding dioxy-benzols.  The  higher  the  temperature  rises  in  the 
fusion  of  the  o-  and  p-compounds,  the  greater  will  be  the  yield  of 
resorcin  or  m-dioxy-benzol ;  the  three  isomeric  monochloro-phenols 
yield  resorcin  : 

Ortho-  Meta-  Para- 

M.p.         B.p.         M.p.          B.p.        M.p.        B.p. 
Chloro-phenol  7°          176°  28°  212°          41°         217° 

Bromo-phenol       liquid        195°  32°  236°          66°         238° 

lodo-phenol  43°  ..  40°  ..  94°  ..       (6.20,3019). 

See  B.  29,  997,  1409,  2595,  for  the  iodo-anisols  and  phenetols. 

Poly  haloid  Phenols. — In  the  direct  substitution  the  [2,  4]-di-  and 
[2,  4,  6]-trihaloids  are  produced  quite  readily.  On  prolonged  chlorina- 
tion  of  the  phenols  a  tetrachloro-phenol  is  finally  obtained  (C.  1903, 
I.  232).  As  to  the  iodination  of  phenol,  see  C.  1901,  I.  1004  ;  1902,  I. 
638,  668. 

[2,  4]-Dichloro-phenol,  m.p.  43°,  b.p.  210°     [2,  4,  6]-Trichloro  phenol,  m.p.  68°,  b.p.  244° 

[2,  5] -Dichloro -phenol,     ,,     58°,    ,,    211°     [2   4,  6]-Tribromo-phenol,     ,,       92° 

[2,  4]-Dibromo-phenol      ,,     40°,     ,,      ..        [2, 3,  5] -Tribromo -phenol,      ,        92°,  (B.  39,  4251) 


[2,  4]-Di-iodo-phenol,       ,,     72°,     ,,      ..        [2,  4,  6] -Tri-iodo -phenol, 

[3,  5,  6]-Tri-iodo  phenol, 

[2,  3,  4,  6]-Tetrachloro-ph.,  m.p.    70°  (B.  37,  4013).   Pentachloro-ph., 
[2,  3,  4,  6]-Tetrabromo-ph.,    „     120°  (A.  137,  209).   Pentabromo-ph. 


156° 

114°  (C.  1904,  I.  266) 

186°  (B.  28,  R.  150) 

225°. 


The  silver  salts  of  tribromo-phenol,  as  well  as  of  some  other  poly- 
brominated  phenols,  exist  in  an  unstable  orange-red,  and  a  stable 
white,  modification.  The  cause  of  this  allotropy  is  still  unexplained 
(B.  40,  4875). 

The  tri-,  tetra-,  and  pentachloro-  and  bromo-phenols  take  up 
chlorine  and  bromine,  becoming  chlorinated  and  brominated  oxodi- 
and  oxotetra-hydra-benzols,  from  which  the  halogen  phenols  are  regen- 
erated by  reduction  (B.  37,  4010).  On  further  bromination  tribromo- 
phenol  gives  bromine  tribromo-phenol  C6H2Br4O,  m.p.  148°  (A.  302, 


NITRO-PHENOLS  195 

133  ;  C.  1902,  II.  358),  which  is  easily  reconverted  into  tribromo- 
phenol,  but  is  transposed  into  tetrabromo-phenol  C6Br4H(OH)  by 
concentrated  SO4H2,  and  yields  dibromo-quinone  on  digesting  with 
lead  acetate  ;  it  must  therefore  be  regarded  as  p-keto-dihydro-tetra- 
bromo-benzol  (B.  33,  675  ;  C.  1902,  I.  469)  : 

Br  H         Br  H          Br  H 

°B7HBr >°BTHBr2-         "0BFHa 

HNO3  oxidises  trichloro-phenol  into  dichloro-quinone  (C.  1908, 
I.  1776). 

NITRO-PHENOLS. 

The  phenols,  like  the  anilines,  are  very  readily  nitrated.  The 
entrance  of  the  nitro-groups  increases  their  acid  character  very  con- 
siderably. All  nitro-phenols  decompose  alkaline  carbonates  (but  see 
C.  1898,  II.  596). 

Trinitro-phenol  is  a  perfect  acid  in  its  behaviour  ;  its  chloro- 
anhydride  C6H2(NO2)3C1  reacts  quite  readily  with  water,  re-forming 
trinitro-phenol.  The  benzene  nucleus  of  the  nitro-phenols  is  capable 
of  ready  substitution  with  the  halogens  ;  whereas  the  nitro-hydro- 
carbons  are  chlorinated  with  difficulty. 

The  nitro-groups  replace  the  o-  and  p-hydrogen  atoms  referred  to 
hydroxyl,  and  with  reference  to  one  another,  in  the  m-position  : 


C,H5OH 


f[i]OH 

r       )[2]N02 

2   |[4]N02 
l[6]N02 


While  the  colourless  or  faint-yellow  free  nitro-phenols  are  un- 
doubtedly true  phenols,  the  intensely  red  or  yellow  salts  of  the  nitro- 
phenols,  as  in  the  aliphatic  nitro-compounds,  are  probably  derivable 
from  a  hypothetical  nitrous  acid  of  the  structure  O=C6H4=N^° 

which  is  designated  as  an  aci-nitro-phenol  form  (B.  39,  1084).  Con- 
siderable support  is  given  to  this  view  by  the  observation  that  the 
ethers  of  the  nitro-phenols  exist  in  two  isomeric  series  (B.  39,  1073). 
Besides  the  colourless  normal  nitro-phenol  ethers,  the  halogen  alkyls, 
acting  upon  the  silver  salts  of  the  nitro-phenols,  produce  very  unstable 
ethers  of  a  deep-red  colour.  These  pass  spontaneously  into  the 
colourless  isomeric  ethers,  and  are  quickly  saponified  with  water  alone, 
with  regeneration  of  the  nitro-phenols.  These  unstable  ethers  corre- 
spond to  the  strongly  coloured  nitro-phenol  salts,  and  probably  also 

possess    a   quinoid   structure:    O=C6H4=N^    __ .     Of    the    m-nitro- 

\UCJti3 

phenols  only  the  normal,  colourless  ethers  have  hitherto  been  obtained, 
and  this  corresponds  to  the  absence  of  m-quinones. 

Mononitro-phenols  NO2.C6H4.OH. — Dilute  nitric  acid  converts 
phenol  into  o-  and  p-  mononitro-phenol  (in  the  cold  it  is  chiefly  the 
p-compound  which  is  formed).  At  —67°,  with  the  use  of  the  electric 
spark,  there  is  five  times  as  much  of  the  p-body  as  at  —40°  (B.  26, 
R.  362). 


196  ORGANIC  CHEMISTRY 

The  o  and  p-compounds  are  separated  by  distillation  with  steam, 
in  which  the  p-compound  is  not  volatile.  Phenol  in  presence  of 
sulphuric  acid  is  also  nitrated  by  nitrogen  dioxide  (B.  24,  R.  722). 
o-Nitro-phenol  is  also  obtained,  together  with  a  little  of  the  para- 
body,  from  nitro-benzol  on  heating  with  dry  potash  ;  or  from  the 
product  of  metallic  sodium  and  nitro-benzol  under  a  current  of  air. 

o-  and  p-Nitro-phenols  are  also  obtained  by  heating  the  correspond- 
ing chloro-  and  bromo-nitro-benzols  with  caustic  potash  to  120°, 
whereas  m-bromo-nitro-benzol  does  not  react  under  similar  circum- 
stances. Ortho-  and  para-nitro-phenols  are  likewise  produced  from 
the  corresponding  nitranilines  by  heating  with  alkalies.  m-Nitro- 
phenol  is  formed  from  m-nitraniline  (from  ordinary  dinitro-benzol)  by 
boiling  the  diazo-compound  with  dilute  sulphuric  acid.  p-Nitro-phenol 
has  also  been  obtained  synthetically  from  nitro-malonic  aldehyde  with 
acetone. 

It  is  obtained  from  p-nitroso-phenol  by  oxidation  with  nitric  acid 
(C.  1903,  I.  144).  o-Nitro-phenol  is  formed,  besides  polynitro-phenols, 
on  the  nitrogenation  of  benzene  in  the  presence  of  mercury  nitrate  : 

o-Nitro-phenol,  m.p.  45°,  b.p.  214°;  methyl  ether,  m.p.-f  9°,  b.p.  265° 
m-Nitro-phenol,  „  96°,  .'.  methyl  ether,  „  38°,  „  254° 
p-Nitro-phenol,  ,,  114°,  . .  methyl  ether,  ,,  48°,  „  260°. 

o-  and  m-Nitro-phenols  form  yellow  crystals  ;  the  latter  is  rather 
soluble  in  water.  The  o-body  has  a  peculiar  odour  and  sweet  taste. 
Its  sodium  salt  forms  dark-red  prisms. 

p-Nitro-phenol  crystallises  from  hot  water  in  long,  colourless  needles. 
The  potassium  salt  crystallises  in  yellow  needles  with  two  molecules 
of  water. 

With  HgO  or  mercuric  nitrate  the  nitre-phenols  yield,  in  the  first 
instance,  the  mercury  salts  of  the  phenols,  (NO2C6H4O)2Hg,  which 
pass  into  mercuri-nitro-phenols,  the  Hg  wandering  to  the  nucleus. 
These  easily  form  the  intensely  coloured  mercuric  anhydrides,  probably 

derivable  from  the  formula  O  :  C6H3^°^>o    (B.  39,  1105).     By  bromi- 

nation,  the  p-nitro-phenol  passes  into  [i,  OH,  2,  6,  4]-dibromo-p-nitro- 
phenol,  m.p.  141° ;  [4,  6]-dibromo-2-nitro-phenol,  m.p.  117°,  is  formed 
from  2,  4,  6-tribromo-phenol  with  ethyl  nitrite  in  alcoholic  solution. 

Dinitro-phenols  (NO2)2C6H3OH.— a-  or  [i  OH,  2,  4]-Dinitro-phenol, 
melting  at  114°,  and  jS-  or  [i  OH,  2,  6]-dinitro-phenol,  melting  at  64°, 
are  produced  in  the  nitration  of  phenol  and  of  o-nitro-phenol.  The 
a-compound  can  also  be  obtained  from  p-nitro-phenol,  as  well  as 
from  m-dinitro-benzol,  by  means  of  alkaline  potassium  ferricyanide. 
The  a-methyl  ether  melts  at  86°.  It  is  transformed  into  [i  NH2,  2,  4]- 
dinitraniline  by  heating  with  ammonia. 

The  nitration  of  [i,  3]-nitro-phenol  produces  three  isomeric  dinitro- 
phenols,  melting  at  104°,  134°,  and  141°.  Further  nitration  produces 
trinitro-phenols  and  trinitro-resorcin, 

Sym.  dinitro-phenelol  C6H5O[i]C6H4[3, 5](NO2)2,  m.p.  96°,  is 
obtained  by  the  action  of  sodium  ethylate  upon  trinifro-benzol  (C.  1906, 
I-  833). 

Trinitro-phenols.— Picric  acid  C6H2(NO2)3.OH,  melting  at  122°, 
is  obtained  by  the  nitration  of  phenol,  of  [i,  2]-  and  [i,  4]-nitro-phenol, 


NITRO- PHENOLS  197 

and  of  the  two  dinitro-phenols ;  also,  by  the  oxidation  of  sym- 
metrical trinitro-benzol  with  potassium  ferricyanide.  It  is  therefore 
[i  OH,  2,  4,  6]-trinitro-phenol. 

Picric  acid  is  produced  in  the  action  of  concentrated  nitric  acid 
upon  various  organic  substances,  like  indigo,  aniline,  resins,  silk, 
leather,  and  wool. 

History. — Woulfe  found,  in  1711,  that  nitric  acid  acting  on  indigo 
produced  a  liquid  which  coloured  silk  yellow.  Welter,  in  1799,  first 
prepared  pure  picric  acid  by  nitrating  silk.  It  was  called  Welter's 
bitter.  Liebig  called  it  carbon-nitric  acid,  carbazotic  acid.  Dumas 
analysed  it  and  called  it  picric  acid,  from  TTIK/OO'S,  bitter.  Laurent,  in 
1842,  discovered  it  to  be  a  derivative  of  phenol. 

Properties. — Picric  acid  crystallises  from  hot  water  and  alcohol,  in 
yellow  flakes  or  prisms  which  possess  a  very  bitter  taste.  It  dissolves 
in  160  parts  of  cold  water,  and  rather  readily  in  hot  water.  Its  solution 
imparts  a  beautiful  yellow  colour  to  silk  and  wool.  It  sublimes  un- 
decomposed  when  carefully  heated. 

Behaviour. — With  many  hydrocarbons,  like  benzene,  naphthalene, 
and  anthracene,  picric  acid  forms  beautiful  crystalline  derivatives,  well 
adapted  for  the  recognition  and  separation  of  the  higher  aromatic 
hydrocarbons. 

The  action  of  PC15  upon  picric  acid  produces  picryl  chloride.  On 
heating  barium  picrate  in  an  aqueous  solution  of  bleaching  lime,  chloro- 
picrin  is  formed  (Vol.  I.). 

Prussic  acid  is  produced  on  boiling  a  solution  of  barium  picrate  with 
baryta  water.  Picric  acid  is  converted  by  potassium  cyanide  into  the 
potassium  salt  of  isopurpuric  or  picro-cyaminic  acid  C8H4N5O6K.  It 
crystallises  in  brown  flakes  with  green-gold  lustre,  and  formerly  appeared 
in  commerce  under  the  name  Grenat  soluble.  It  is  no  longer  used. 
Isopurpuric  acid,  liberated  from  its  potassium  salt  by  phosphoric  acid, 
and  of  a  deep-violet  colour,  possesses,  according  to  its  decomposition 
products,  the  constitution  C6[2,  6](CN)2[i,  3](NO2)2[4,  5](OH)(NHOH). 
A  behaviour  towards  KCN  resembling  that  of  picric  acid  is  also  shown 
by  o,  p-  and  o,  o-dinitro-phenols  and  other  polynitro-phenol  derivatives 
(B.  37,  1843,  4388  ;  38,  3538,  3938)- 

Salts  and  Ethers.— The  potassium  salt,  C6H2(NO2)3.OK,  crystallises 
in  yellow  needles,  soluble  in  260  parts  of  water  at  15°.  The  sodium 
salt  is  soluble  in  10  parts  water  at  15°,  and  is  separated  from  its  solution 
by  sodium  carbonate.  The  ammonium  salt  consists  of  beautiful  large 
needles,  and  is  applied  in  explosive  mixtures.  All  the  picrates 
explode  very  violently  when  heated  or  struck. 

The  methyl  ether  of  picric  acid  is  produced  in  the  nitration  of  anisol. 
It  melts  at  65°.  The  ethyl  ether  melts  at  78°. 

jS-Trinitro-phenol,  melting  at  96°,  and  y-trinitro-phenol,  m.p.  117°, 
have  been  obtained  from  the  dinitro-phenols  resulting  from  the  nitra- 
tion of  m-nitro-phenol. 

Tetranitro-phenol,  m.p.  130°,  consists  of  golden-yellow  needles.  It 
is  produced  in  the  oxidation  of  diquinoyl-trioxime  (q.v.).  It  is  very 
explosive  (B.  30,  184). 

Tetranitro-anisol,  m.p.  154°  (C.  1904,  II.  205). 

Nitro-cresols.— o-Nitro-p-eresol  NO2[2]CH3[4]C6H3OH,  m.p.  77°, 
and  p-nitro-o-cresol,  m.p.  118°,  are  prepared  pure  from  the  corre- 


ig8  ORGANIC   CHEMISTRY 

spending  nitro-toluidins.  The  former  is  also  easily  obtained  by  nitro- 
genation  of  p-cresol  carbonate,  and  saponification  of  the  resultant 
compound  (C.  1909,  I.  965).  By  the  action  of  fuming  sulphuric  acid  it 
is  split  up  with  formation  of  acetyl-acrylic  acid  (B.  42,  577).  By 
further  nitrogenation  of  the  methyl  ethers  of  o-nitro-p-cresol  and 
p-nitro-o-cresol  we  obtain  o-dinitro-compounds  (B.  34,  2238).  Nitro- 
genation of  o-  and  p-cresol  easily  yields  dinitro-derivatives  (B.  15, 1858). 
Of  these,  the  [2, 6]-dinitro-p-eresol,  m.p.  84°,  has  been  used  as  an  orange 
dye  in  the  form  of  its  sodium  salt,  called  Victoria  orange,  or  saffron 
substitute.  Dinitro-o-cresol  is  used  as  an  insecticide  in  the  form  of 
salt-solutions,  more  especially  against  caterpillars,  under  the  name  of 
Antinonnin  (B.  27,  R.  316).  Nitrogenation  of  m-cresol  yields  a 
trinitro-cresol  (NO2)3C6H(CH3)OH,  m.p.  106°,  also  formed  from  nitro- 
coccus  acid,  and  by  nitrating  thymol  (C.  1901,  II.  411).  Tetranitro-m- 
cresol,  m.p.  175°  (C.  1908,  I.  724).  Nitro-xylenols,  see  B.  42,  2917  ; 
C.  1904,  II.  1213. 

Haloid  Nitro-phenols. — Numerous  representatives  of  this  class  have 
been  obtained  by  the  action  of  the  halogens  upon  the  nitro-phenols, 
or  by  the  nitration  of  the  haloid  phenols. 

It  is  interesting  to  note  that  p-nitro-o-iodanisol  C6H3[4]NO2[2]I 
[i]OCH3  has  been  prepared  both  in  the  nitration  of  o-  as  well  as  in 
that  of  p-iodanisol.  In  the  latter  case,  therefore,  a  migration,  or 
wandering,  of  the  iodine  atom  in  the  nucleus  has  occurred  (B.  29,  997) 

NlTROSO-COMPOUNDS   OF  THE   PHENOLS. 

The  nitroso-phenols  are  made  :  (i)  by  the  action  of  nitrous  acid 
upon  phenols  (Baeyer,  B.  7,  964),  when  the  monohydric  phenols  yield 
only  mononitroso-compounds ;  whereas  dinitroso-derivatives  are 
obtained  from  the  dihydric  meta-dioxy-benzols,  like  resorcin. 

(a)  Nitrous  acid,  from  alkali  nitrite  and  dilute  sulphuric  acid  or 
acetic  acid,  is  allowed  to  act  upon  the  phenols  (B.  7,  967  ;  8,  614)  ; 
(b)  by  means  of  the  nitrites  of  heavy  metals,  which  are  decomposed 
by  the  phenols  themselves  (B.  16,  3080)  ;  (c)  from  nitrosyl-sulphuric 
acid  HO.SO2.NO  and  phenols  (A.  188,  353  ;  B.  21,  429)  ;  (d)  from 
amyl  nitrite  and  sodium  phenolates  (B.  17,  803). 

(2)  Upon    boiling    p-nitroso-alkylamines,    like    nitroso-dimethyl- 
aniline  (I.  163  ;  II.  94)  with  alkalies  : 

NO[4]C6H4[i]N(CH3)2+NaOH  =  NO[4]C6H4[i]OK+HN(CH3)2. 

(3)  By  the  action  of  HC1  hydroxylamine  upon  quinones  in  aqueous 
or  alcoholic  solution.     Free  hydroxylamine  reduces  the  quinones  to 
hydroquinones  (B.  17,  2061).     This  method  favours  the  idea  that  the 
nitroso-phenols  are  quinone-monoximes   (Goldschmidt,   B.    17,  801). 
Hence,  three  constitutional  formulas  have  been  brought  forward  for 
p-nitroso-phenol  or  quinone-monoxime  (Quinones,  q.v .)  : 

C6H4/OH  and  C6H4/°          or  C6H4/° 

\NO  \N.OH  \N.OH 

p-Nitroso-phenol  Quinoxime. 

o-Nitroso-phenol  HO.C6H4[2]NO :  as  aniline  is  oxidised  to  nitroso- 
benzol,  so  o-anisidin  is  oxidised  by  Caro's  acid  to  o-nitroso-anisol 


NITROSO-COMPOUNDS   OF  THE   PHENOLS  199 

CH3OC6H4[2]MO,  m.p.  103° ;  on  saponification  with  bisulphate, 
this  yields  the  o-nitroso-phenol,  the  Na  salt  of  which  forms  deep-red 
flakes  (B.  35,  3036). 

p-Nitroso-phenol,  quinone-monoxime,  crystallises  from  hot  water  in 
colourless,  delicate  needles,  which  readily  brown  on  exposure,  and  from 
ether  it  separates  in  large  greenish-brown  flakes  ;  also  by  the  action  of 
nitroso-benzol  and  NaHO  (B.  33,  1954).  It  is  soluble  in  water,  alcohol, 
and  ether,  and  imparts  to  them  a  bright-green  colour.  When  heated,  it 
melts  with  decomposition,  and  deflagrates  at  no°-i2o°.  The  sodium 
salt  crystallises  in  red  needles,  containing  two  molecules  of  water  of 
crystallisation. 

The  methods  of  producing  nitroso-phenol  from  phenol  with  nitrous 
acid,  and  from  nitroso-dialkyl-anilines,  argue  for  the  nitroso-formula 
of  the  nitroso-phenols  ;  as  does  their  oxidation  to  p-nitro-phenol  with 
nitric  acid  or  with  an  alkaline  potassium  ferricyanide  solution. 

The  quinoxime  formula  is  supported  by  their  formation  from  quinone 
with  hydroxylamine  hydrochloride,  and  the  conversion  into  quino- 
dioxime,  as  well  as  by  the  formation  of  hypochlorous  esters 
C6H4(O).NOC1  when  acted  upon  by  bleaching  -  lime  (B.  19,  280). 
Further,  by  the  behaviour  of  the  related  nitroso-naphthols  (q.v.),  and 
finally  the  feeble  basic  character  of  the  nitroso-phenols  (B.  18,  3198  ; 
19,  280).  Methylation  of  nitroso-phenol  yields,  not  nitroso-anisol, 
but  quinone-methoxime  O  :  C6H4 :  NOCH3,  m.p.  83° ;  p-nitroso-anisol 
CH3OC6H4[4]NO,  m.p.  23°,  from  p-anisidin,  by  oxidation  with  mono- 
persulphonic  acid  (Caro's  acid),  or  from  p-anisol-hydroxylamine  with 
ferric  chloride  (B.  37,  44).  By  dilute  H2SO4  it  is  easily  saponified 
into  p-nitroso-phenol  (B.  35,  3034). 

Possibly  the  free  nitroso-phenols  have  a  quinone-oxime  formula, 
while  the  salts  are  derivable  from  the  nitroso-phenol  formula  (cp. 
B.  32,  3101). 

The  nitroso-phenols  can  be  changed  to  nitroso-anilines.  Hydro- 
chloric acid  converts  nitroso-phenol  into  dichloramido-phenol.  With 
nitrous  acid  and  with  hydroxylamine  it  yields  p-diazo-phenol  : 

HOC6H4NO  ^?2»  (HOC6H4N2OH)  -     --»  O  :  C6H4 :  N2. 

In  a  similar  manner  it  forms  azo-compounds  with  the  amines. 
Phenyl-hydrazin  reduces  it  very  readily  to  amido-phenol  (B.  29,  R.  294). 
On  adding  a  little  concentrated  sulphuric  acid  to  a  mixture  of  nitroso- 
phenol  and  phenol,  we  obtain  a  dark-red  coloration,  which  changes 
to  dark  blue  upon  adding  caustic  potash. 

Nitroso-m-cresol,  m.p.  155°  (B.  21,  729  ;  C.  1900,  I.  120). 

Nitroso-o-eresol,  from  o-cresol  and  toluquinone  (q.v.)  (B.  21,  729), 
m.p.  134°. 

Nitroso-thymol  melts  at  160°  (B.  17,  2061 ;  A.  310,  89). 

AMIDO-PHENOLS. 

These  result  from  the  reduction  of  nitro-  and  nitroso-phenols,  or 
the  oxy-azo-compounds  (B.  38,  2752).  In  the  case  of  poly-nitrated 
phenols,  ammonium  sulphide  occasions  but  a  partial  reduction  ;  tin 
and  hydrochloric  acid,  however,  effect  a  complete  reduction  of  the 


200  ORGANIC   CHEMISTRY 

nitro-groups.  For  special  methods  of  formation,  see  m-  and  p-amido- 
phenol. 

Behaviour.  —  The  free  amido-phenols  decompose  quite  easily,  especi- 
ally in  moist  air  on  exposure  to  light. 

The  amido-group  considerably  diminishes  the  acid  character  of  the 
phenols.  This  class  of  derivatives  no  longer  forms  salts  with  alkalies, 
and  only  yields  such  compounds  with  the  acids. 

Like  the  o-phenylene-diamines,  the  o-amido-phenols  form  hetero- 
cyclic  derivatives  with  ease.  These  are  anhydro-bases  ;  the  benzox- 
azoles,  corresponding  to  the  benzimide-azoles,  are  similar  bodies  obtained 
from  the  o-amido-thio-phenols. 

o-Amido-phenol  NH2[2]C6H4[i]OH,  m.p.  170°,  dissolves  with  diffi- 
culty in  water.  o-Anisidin  NH2[2]C6H4[i]OCH3,  b.p.  218°. 

o-Imido-diphenyl    oxide,   phenoxazin    o/^4^>NH    wil1   be    de- 


H 
6H4  6 


scribed  together  with  thio-diphenyl-amine,  hydro-phenazin,  and  phena- 
zin  under  the  heterocyclic  compounds  (cp.  also  pyro-catechol) . 

Methylation  of  the  Amido-group  of  o-Amido-phenol  (B.  23,  246).— 
When  o-amido-phenol  in  methyl  alcohol  is  treated  with  methyl  iodide 
and  caustic  potash,  and  later  with  hydrogen  iodide,  there  results  the 
iodide  of  an  ammonium  base,  which  moist  silver  oxide  changes  to  the 
ammonium  hydroxide.  The  latter  loses  water  at  105°,  and  changes 
to  a  cyclic  ammonium  derivative  similar  to  betai'n  :  o-trimethyl- 
ammonium-phenol,  which,  heated  to  higher  temperatures,  rearranges 
itself  into  o-dimethyl-anisidine.  The  hydrochloride  of  the  ammonium 
base  breaks  down  upon  distillation  into  methyl  chloride  and  o-di- 
methyl-amido-phenol,  m.p.  45° : 

/[i]N(CH3)3Cl  /  [i]N(CH3)3OH  _  /[i]N(CH3)3 

4\[2]OH  4\[2]OH  6    4\[2]6 

o-Trimethyl-ammonium-       o-Trimethyl-ammonium-       |  o-Trimethyl-ammo- 
chlorodi-phenol  oxyd-hydrat-phenol  |        mum-phenol 

[i]N(CH3)2 
[2]OCH3 
o-Dimethyl-amido-phenol  o-Dimethyl-anisidin. 

o-Methyl-amido-phenol  CH3NH[2]C6H4[i]OH,  from  o-methyl-anisi- 
din  C6H4(NHCH3)OCH3,  with  HC1.  Its  sulphate,  mixed  with  hydro- 
quinone,  is  sold  as  a  photographic  developer  under  the  name  "  ortol  " 
(B.  32,  3514) ;  see  also  Metol  (C.  1903,  I.  1129). 

o-Oxethyl-anisidin  HO.CH2CH2.NH[2]C6H4[i]OCH3,  from  o-anisi- 
din  and  ethylene-chloro-hydrin,  b.p.  305°. 

o-Formyl-amido-phenol  CHO.NHC6H4OH,  m.p.  129°,  from  o-amido- 
phenol  with  formic  acid.  Also,  besides  anthr  anile,  from  o-amido- 
benzaldehyde  by  oxidation  with  Caro's  acid,  probably  by  transposition 
of  o-hydroxylamine-benzaldehyde  CHO.C6H4.NHOH.  On  heating 
to  i6o°-i70°  it  passes  into  benzoxazol  (B.  36,  2042).  For  acylated 
o-amido-phenols,  see  C.  1907,  I.  806. 

o-Oxy-phenyl-urethane  COOC2H5.NH[2]C6H4[i]OH,  m.p.  86°,  is 
formed  by  the  reduction  of  o-nitro-phenyl-ethyl  carbonate  by  trans- 
position of  the  first  product,  viz.  o-amido-phenyl-ethyl  carbonate 
NH2[2]C6H4[iJO.COOC2H5.  Chlorohydrate,  m.p.  151°  (C.  1900,  I.  413  ; 
1904,  II.  94,  695).  This  transformation  of  the  O-acyl  compounds  of 


AMIDO-PHENOLS  201 

the  o-amido-phenols  into  the  isomeric  N-acyl  compounds  is  quite  a 
general  reaction.  It  is  so  straightforward  that  the  O-acyl-o-amido- 
•phenols  can  usually  not  be  obtained  (cp.  the  similar  transformations  in 
the  o-oxy-benzylamines  and  o-amido-benzyl  alcohols,  A.  332,  159  ; 
364,  147). 

o-Oxy-phenyl-urea  NH2CONH[2]C6H4[i]OH,  m.p.  154°.  o-Oxy- 
phenyl-thiurea  NH2CSNH[2]C6H4[i]OH,  m.p.  161°. 

o-Oxy-diphenyl-amine  OH[2]C6H4[i]NHC6H5,  m.p.  70°,  produced 
by  the  action  of  acetyl  and  benzoyl  peroxide  upon  diphenyl-amine 
(B.  42,  4003). 

The  Condensations  of  the  o-Amido-phenols.  —  (i)  Benzoxazoles  result 
by  the  union  of  o-amido-phenol  with  carboxylic  acids  ;  thus,  with 
acetic  acid  the  product  is  ^-methyl-benzoxazole.  (2)  With  phosgene  it 
is  p,-oxy-benzoxazole,  or  carbonyl-amidc-phenol.  The  latter  body  is  also 
produced  upon  heating  o-oxy-phenyl-urea  (see  above).  (3)  On  heating, 
o-oxy-phenyl-thiurea  yields  o-oxy-phenyl-mustard  oil.  (4)  o-Oxy-ethyl- 
anisidine,  when  heated  with  hydrochloric  acid,  becomes  pheno-mor- 
pholine  (q.v.).  (5)  Oxidants  convert  o-amido-phenol  into  oxy-phenoxaziri 
(q.v.).  o-Amido-phenol  and  pyro-catechol  condense  to  phenoxazin 
(?.«.). 

CH,COSH  /[i]O\rriT  /i-Methyl-benzoxazol  or 

f[i]OH  _  f  ~  •    H[2]N^          3      Ethenyl-amido-phenol 

4\[2]NH2  COC12  /[i]0\r  nM  /t-Oxy-benzoxazol-  or 

\  [2]N/  Carbonyl-amido-phenol 


r  W  /W°H  —  NF,   ,  ,,  „    f[i]O\rCTT  w-Sulpho-hydro-benzo-thiazol 

4\[2]NHCSNH2  *    4\[2]N/  or  Oxy-phenyl-mustard  oil 


,  pheno.morpholin 


m-Amido-phenol,  m.p.  122°,  is  obtained  from  m-nitro-phenol  (B.  11, 
2101),  from  theoxamic  acid  derivative  of  m-phenylene-diamine  (B.  28, 
R.  30)  ;  by  melting  up  metalinic  acid  with  caustic  soda  (B.  32,  2112), 
and  by  heating  resorcin  to  200°  with  ammonium  chloride  and  aqueous 
ammonia. 

Monoalkyl-m-amido-phenols  (B.  27,  R.  953  ;  22,  R.  622).  —  Dimethyl- 
m-amido-phenol  melts  at  87°  ;  diethyl-m-amido-phenol  boils  about  280°. 
m-Amido-phenol  and  its  alkyl  derivatives  are  employed  in  the  prepara- 
tion of  rhodamine  dyes. 

Consult  B.  29,  501,  for  the  action  of  phosgene  upon  the  alkyl  m- 
amido-phenols.  Trimethyl-m-amido-phenol  C6H4[i]OH[3]N(CH3)3OH, 
see  B.  29,  1533. 

p-Amido-pnenol  melts  at  184°  with  decomposition,  and  sublimes. 
It  results  (i)  from  p-nitro-phenol  ;  (2)  from  j3-phenyl-hydroxylamine  ; 
(3)  by  the  action  of  the  electric  current  upon  nitro-benzol  in  strong 
sulphuric  acid  solution  ;  its  formation  here  is  due  to  the  rearrangement 
of  the  j3-phenyl-hydroxylamine  produced  at  first  ;  (4)  from  [5]-amido- 
salicylic  acid  by  elimination  of  CO2  ;  (5)  by  heating  p-chloro-phenol 
with  ammonia  in  the  presence  of  copper  (C.  1909,  I.  600).  By 
oxidation  with  silver  oxide  it  yields  quinone  mono-imine. 

It  is  oxidised  to  quinone  by  chromic  acid,  or  by  PbO.j  and  sulphuric 


202  ORGANIC   CHEMISTRY 

acid.  Bleaching-lime  converts  it,  as  well  as  its  substitution  products, 
into  quinone  chlorimides.  p-Amido-phenol  acts  the  same,  and  just  as 
readily,  as  phenyl-hydrazin  upon  aldehydes  and  ketones  in  dilute  acetic 
acid  (B.  27,  3005).  Ethers  of  p-amido-phenetol  are  produced  by  re- 
duction of  p-nitro-phenol  ether  (B.  34,  1935),  as  well  as  by  the  trans- 
position of  /S-phenyl-hydroxylamine  with  alcoholic  H2SO4  (B.  33, 
3602).  Methyl  ether,  p-anisidin,  m.p.  56°,  b.p.  246°. 

p-Amido-phenetol,  p-phenetidine  NH2[4]C6H4[i]OC2H5  is  the  ethyl 
ether.  It  boils  at  242°.  Boiling  glacial  acetic  acid  converts  it  into 

p-acetamido-phenetol  c.H4/NH.co.CH^  phenacetin,  melting  at  135°, 

\{j.(szt±& 
which  has  been  applied  as  an  antipyretic. 

The  splitting  up  of  phenacetin  by  80  to  90  per  cent,  sulphuric  acid 
into  acetic  ether  and  p-amido-phenol  is  worthy  of  note  (A.  309,  233). 
On  prolonged  boiling  with  excess  of  acetic  anhydride  (B.  31,  2788), 
phenacetin  is  converted  into  diacetyl-phenetidin  (CH3CO)2NC6H4OC2H5, 
m.p.  54°,  b.p.12  182°,  which  has  an  action  similar  to  phenacetin,  as 
has  also  p-ethoxy-phenyl-succinimide,  pyrantin  (CH2CO)2NC6H4OC2H5, 
melting  at  155°,  which,  it  is  claimed,  does  not  have  the  unpleasant  action 
or  after-effects  peculiar  to  phenacetin  (B.  29,  84).  p-Phenetol-earba- 
mide,  "  dulcin,"  NH2CO.NH[4]C6H4[i]OC2H5  (B.  28,  R.  78,  83),  has  a 
very  sweet  taste. 

m-Oxy-diphenyl-amine  C6H5NH[3]C6H4[i]OH,  melting  at  82°  and 
boiling  at  340°,  and  p-oxy-diphenyl-amine,  melting  at  70°  and  boiling  at 
330°,  are  formed  on  heating  resorcin  and  hydroquinone  with  aniline 
and  zinc  chloride  (B.  22,  2909).  For  homologues,  see  C.  1902,  I.  578. 
p2-Dioxy-diphenyl-amine  NH(C6H4[4]OH)  2,  m.p.  174°,  is  obtained  from 
hydroquinone  by  heating  with  ammonia  or  with  p-amido-phenol  (B.  32, 
689).  The  oxy-diphenyl-amines  are  closely  related  to  the  indo-phenol 
dyes  (see  Quinones).  p2-Amido-oxy-diphenyl-amine  NH2C6H4NHC6H4 
OH,  m.p.  166°,  is  formed  by  the  reduction  of  the  corresponding  nitro- 
compound  (B.  42,  1080)  or  by  oxidation  of  a  mixture  of  p-phenylene- 
diamine  and  phenol  with  hypochlorite  in  the  presence  of  copper  salts 
(C.  1909,  I.  115).  The  solution  of  p-amido-p-oxy-diphenyl-amine  in 
alkalies  soon  acquires  a  blue  colour  with  the  formation  of  indamine. 
p2-dimethyl-amido-oxy-diphenyl-amine  N(CH3)2C6H4NHC6H4OH,  m.p. 
161°,  see  B.  35,  3085. 

Diamido-phenols.  —  [2 ,4]-Diamido-phenol  (NH2) 2[2,  4]C6H3[i]OH 
is  obtained  from  [2,  4]-dinitro-phenol,  and  by  the  electrolytic  reduction 
of  m-dinitro-benzol  or  m-nitro-aniline  in  sulphuric  acid  (B.  26,  1848). 
The  free  base  is  very  unstable,  and  its  salts  have  been  used  as  developers 
in  photography  under  the  name  amidol.  4,  5-  and  2,  5-Diamido-phenols 
are  formed  from  the  nitro-amido-phenols  obtained  by  the  action  of 
H2SO4  upon  the  o-  and  p-nitro-diazo-imides  (B.  30,  2096  ;  31,  2403). 

m-Anilido-p-phenitidin  C6H5NH[3]C6H3/W^H5;  see  Hydrazin  phenols 

WL4J-iN±i2 

for  its  formation. 

Pieramic  acid,  [2]-amido-[3, 4]-dinitro-phenol  C6H2(NH2).(NO2)2. 
OH,  is  obtained  by  the  reduction  of  picric  acid  with  alcoholic  Am4SH 
or  with  sodium  hydrosulphite.  (For  further  dinitro-p-amido-phenols, 
see  B.  38, 1593.)  It  forms  red  needles,  which  melt  at  165°. 

[2,  4,  6]-Triamido-phenol  C6H2(NH2)3.OH  is  obtained  from  picric 


DIAZO-PHENOLS  203 

acid  by  the  action  of  phosphorus  iodide,  or  by  tin  and  hydrochloric  acid 
(B.  16,  2400).  When  set  free  from  its  salts,  it  decomposes  very  quickly. 
Its  salts,  with  three  equivalents  of  acids,  crystallise  well.  The  Hi-salt, 
C6H3O(NH2)3.3HI,  crystallises  in  colourless  needles.  These  salts  colour 
water  which  is  faintly  alkaline,  and  even  spring  water,  a  beautiful  blue. 
If  ferric  chloride  be  added  to  the  solution  of  the  hydrochloride,  it  will 
become  deep  blue  in  colour,  and  brown-blue  needles  with  metallic 
lustre  will  separate  ;  they  are  HCl-amido-di-imido-phenol,  or  diamido- 
quinone-imine,  which  dissolves  in  water  with  a  beautiful  blue  colour. 

An  isomeric  triamido-phenol  has  been  prepared  by  reducing  di- 
quinoyl-trioxime  (B.  30,  183). 

[2,  3,  4,  5]-Tetramido-anisol  (NH2)4C6HOCH3  (B.  25,  282). 

Diazo-phenols.  —  Phenol-diazo-chlorides  HO.C6H4N2C1  result  from 
the  action  of  nitrous  acid  upon  the  hydrochlorides  of  the  amido-phenols. 

The  diazonium  polyhaloids,  nitrates,  and  sulphonates,  with  weak 
acids,  like  acetic  acid  and  carbonic  acid,  form,  by  the  replacement  of 
a  halogen  atom,  a  nitroyl  or  a  sulphoxyl  in  the  o-  or  p-position  by 
hydroxyl-substituted  diazo-phenols  (B.  36,  2069  ;  39,  79  ;  C.  1903,  I. 
393  ;  1907,  II.  1785).  The  free  diazo-hydrates  of  the  o-  and  p-amido- 
phenols  anhydrate  themselves,  the  yellow,  so-called  quinone  diazides 
being  generated,  probably  by  a  transposition  into  the  quinoid  form 
(cp.  Vol.  L,  Diazo-methane,  and  B.  35,  888)  : 


p-Diazo-phenol  cyanide  HO[4]C6H4N2.CN,  from  the  action  of 
potassium  cyanide  on  the  chloride,  consists  of  yellow  needles.  Caustic 
potash  saponifies  it  to  the  potassium  salt  of  diazo-phenol-carboxylie 
acid  HO.C6H4N2COOH. 

Dibromo-diazo-phenol  Br2[4,  6]C6H2(:  O)(:  Na)[i,  2],  orange  prisms, 
m.p.  130°  with  decomposition  (B.  39,  4248). 

Dibromo-phenol-diazo-sulphonie  acid  C6H2Br2(OH)N2SO3H+2H2O 
can  be  isolated  from  its  potassium  salt  produced  from  the  interaction 
of  potassium  sulphite  and  dibromo-phenol-diazo-chloride. 

p  -  Phenol  -  diazo  -  mereaptan  hydrosulphide  C6H4(OH).N2SH.SH2, 
from  the  action  of  hydrogen  sulphide  upon  diazo-phenol  solutions,  con- 
sists of  red  needles  melting  at  75°  with  decomposition  (B.  28,  3250). 

p-Oxy-diazo-benzol-imideOH[i]C6H4[4]N3,  m.p.  about  20°,  explodes 
at  150°.  From  p-amido-phenol  with  nitrous  acid.  The  potassium  com- 
pound exists  in  two  forms,  one  colourless,  the  other  blue,  easily  con- 
vertible into  each  other.  Both  yield  the  same  benzoyl  compound,  of 
m.p.  81°,  which  is  also  obtained  from  benzoyl-p-amido-phenol  with 
nitrous  acid  (C.  1907,  II.  247). 

Azoxy-phenols.  —  p-Oxy-azoxy-benzol  C6H5(N2O)C6H4[4]OH,  m.p. 
156°,  is  obtained  by  the  combination  of  p-nitroso-phenol  with  j8-phenyl- 
hydroxylamine  and  elimination  of  water  ;  it  also  forms  on  the  action 
of  sodium  hydroxide  upon  nitroso-benzol  at  100°,  which  also  produces 
two  isomeric  o-oxy-azoxy-benzols,  m.p.  76°  and  108°  respectively. 
Oxidation  with  permanganate  disintegrates  the  oxy-azoxy-benzols  to 
potassium  iso-diazo-benzol  : 

C6H5(N2O)C6H4OH  --  >  C6H5N2OK 
(B.  35,  1614). 


204  ORGANIC   CHEMISTRY 

Azo-phenols,  Oxy-azo-benzols.  —  Formation:  —  (i)  From  diazo-salts 
and  monohydric  phenols,  m-dioxy-benzols,  m-amido-phenols,  and 
m-phenol-sulphonic  acids  : 

C6H5Na.N03+C6H5OH  ==  C6H5N  :  N[i]C6H4[4]OH. 

The  solution  of  the  diazo-salt  is  allowed  to  run  into  the  alkaline 
phenol  solution  while  cooling  and  stirring.  Phenol-diazo-benzol  is 
produced,  together  with  phenol-azo-benzol. 

As  with  the  amido-azc-compounds,  the  entering  diazo-group  ar- 
ranges itself  in  the  phenols  in  the  p-position,  and  when  this  is  already 
occupied  it  takes  the  o-position  with  reference  to  the  hydroxyl  group 
(B.  17,  1876  ;  21,  R.  814). 

Intermediate  products  have  been  sometimes  isolated  in  this  reaction 
in  the  form  of  the  so-called  o-azo-compounds  (diazo-oxy-benzols), 
corresponding  to  the  diazo-amido-compounds,  which,  however,  trans- 
pose themselves  with  even  greater  ease  into  the  isomeric  oxy-azo-com- 
pounds  (B.  41,  4016,  4304)  : 

C6H5O.N  :  N.C6H5  ---  >  C6H5N  :  N.C6H4OH. 

(2)  By  heating  the  diazo-amido-benzols  with  monohydric  phenols, 
and  also  with  resorcin  (B.  20,  372,  904,  1577)  : 

C6HB.N2.NH.C6HB+C6H6.OH  ==  C6H5.N2.C6H4.OH+C6H5.NH2. 

(3)  By  the  molecular  rearrangement  induced  by  heating  azoxy- 
benzols  with  sulphuric  acid  (B.  14,  2617)  : 


--  >  C6H5N2.C6H4.OH 
Azoxy-benzol  Oxy-azo-benzol. 

(4)  By  reduction  of  the  nitro-phenols  in  alcoholic  potassium  hydrox- 
ide solution. 

(5)  By  the  action  of  anilines  upon  nitroso-phenols. 

(6)  From  amido-azo-benzols  and  from  azo-benzol-sulphonic  acids. 
Constitution,  —  The  oxy-azo-compounds,  containing  hydroxyl  in  the 

ortho-position  to  the  azo-group,  are  probably  quinone-hydrazones  : 

r  H  I  OH  r  TT  /  :  °  r  w  <f° 

CeJ:l4\N:NC6H5        CeH4l  :NNHC6H6    l       ^^  \  ftNHC6H5 

Oxy-azo-benzol  Quinone-phenyl-hydrazone. 

Quinone-phenyl-hydrazone  itself  is  not  obtained  by  condensation 
of  benzo-quinone,  since  the  quinone  is  reduced  by  phenyl-hydrazin, 
but  the  monophenyl-hydrazins  of  quinone  have  been  obtained  with 
o-nitro-  and  o-,  p-dinitro-phenyl-hydrazin.  The  latter  have  proved 
themselves  to  be  identical  with  the  nitro-oxy-azo-compounds  obtained 
by  coupling  diazotated  o-nitro-  and  o-,  p-dinitro-aniline  with  phenol 
(A.  357,  171  ;  see  also  Naphtho-quinone-hydrazones)  : 

f[l]0     H1N.NHCSH4N02  /  [l]N  :  NC6H4NO,          ClN:NC6H4NOa 

C«H*  \  [4]0  ~  C«H4  \  [4]OH  C6H5OH. 

Unsym.  acetyl-  and  benzoyl-phenyl-hydrazin  also  yield  n-acylated 
quinone-phenyl-hydrazones  with  quinone,  and  these,  on  saponification, 
pass  into  p-oxy-azo-benzol.  They  are  isomeric  with  the  o-acyl-oxy- 


/ 
6    4  L 


AZO-PHENOLS  205 

azo-benzols  obtained  by  acetylation  or  benzoylation  of  oxy-azo-benzol 
(C.  1900,  I.  30). 

Of  special  importance  for  deciding  the  question  of  the  constitution 
of  the  oxy-azo-compounds  is  the  observation  that  the  N-acylated  p- 
quinone-phenyl-hydrazones  are  transposed  with  great  facility  into  the 
isomeric  O-acylated  oxy-azo-benzols  (B.  40,  1432)  : 

[i]  :  N.N(COCH3)C6H5  _  /[i]N  :  NC.H6 

O  ^M  [4]0(COCH3)- 

The  tendency  to  pass  into  true  azo-compounds  is  so  great  among 
the  o-quinones  that  the  isomeric  N-acylated  o-quinone-phenyl-hydra- 
zones  have  not  been  obtained  at  all  up  to  the  present  time  (B.  40, 
2154  ;  A.  359,353  ;  but  cp.  C.  1909,  1.  1093).  On  account  of  this  easy 
conversion  of  derivatives  of  quinone-phenyl-hydrazone  into  those  of 
oxy-azo-benzol,  we  are  justified  in  regarding  the  free  o-  and  p-oxy-azo- 
compounds  as  true  azo-compounds.  This  is  in  agreement  with  the 
fact  that  the  m-oxy-azo-benzol  (see  below),  which,  on  account  of  the 
non-existence  of  m-quinones,  cannot  be  formulated  as  a  quinone-phenyl- 
hydrazone,  closely  corresponds  in  its  behaviour  to  o-  and  p-oxy-azo- 
benzol  (B.  36,  4118).  With  phenyl  cyanate,  o-  and  p-oxy-azo-benzol 

combine  to  O-carbanilido-derivatives,  QH^OCON^H  'B'  38'  I098)' 
The  total  or  partial  insolubility  of  oxy-azo-compounds  in  alkalies, 
which  was  regarded  as  a  special  argument  in  favour  of  their 
quinone  structure,  finds  its  analogy  in  the  similar  behaviour  of  the 
phenyl-hydrazones  of  the  o-phenol-aldehydes  and  ketones  (B.  35,  4100  ; 
C.  108,  II.  306). 

p-Oxy-azo-benzol,  benzol-p-azo-phenol  C6H5N=N[i]C6H4[4]OH, 
m.p.  148°,  crystallises  in  orange-yellow  needles.  It  is  produced  by  the 
methods  mentioned  in  connection  with  oxy-azo-derivatives  ;  treated 
with  phosphorus  pentachloride,  and  then  with  water,  it  is  converted 
into  the  phosphoric  ester  PO(OC6H4N2C6H5)3,  m.p.  148°  (B.  24,  365  ; 
cp.  35,  1622).  Benzol-p-azo-phenetol,  m.p.  77°  (B.  25,  994).  p-Azo- 
phenol  HO[4]C6H4[i]N2[i]C6H4[4]OH,  m.p.  204°,  consists  of  light- 
brown  crystals.  It  is  produced  : 

(1)  By  fusing  p-nitro-  and  nitroso-phenol  with  caustic  alkali. 

(2)  By  the  pairing  of  diazo-benzol  nitrate  with  phenol. 

(3)  From  p-oxy-azo-benzol-sulphonic  acid  (B.  15,  3037). 
o-Oxy-azo-benzol,  m.p.  83°,  is  volatile  with  water  vapour,  therein 

contrasting  with  the  p-derivative  ;  it  is  formed  beside  the  p-oxy-azo- 
benzol  in  small  quantities  from  benzol-diazonium  salts  with  phenol 
(B.  33,  3189)  ;  also  by  transposition  of  azoxy-benzol  (C.  1903,  I.  324, 
1082)  ;  and  partly  by  the  action  of  NaHO  upon  nitroso-benzol  (B.  33, 
1939).  Its  methyl  ether,  benzol-azo-o-anisol,  m.p.  41°,  obtained 
synthetically  from  o-anisidin  and  nitroso-benzol,  also  yields  with 
A12C16  the  o-oxy-azo-benzol  (B.  33,  3190). 

m-Oxy-azo-benzol,  m.p.  114°-!  17°,  canary-yellow  crystals,  is 
formed  by  the  coupling  of  o-amido-phenetol  with  diazo-benzol  chloride, 
with  splitting  off  of  the  amido-group,  and  saponification  of  the  resulting 
benzol-azo-m-phenetol,  m.p.  64°,  with  A12C16  (B.  36,  4102)  : 

f[i]OC,H5 

C.I-1  .  f  [I]OC*H>  —  >  C6Ht     [2]NH2  _  >  c.H,  (  ™OC*U*         —*  C,H<  )  ™OH 

I  [a]NH.  I  [5N  .  2NCHs  'H'  \  [5]N  :  NC.H.  "'  (  [5JN  :  NC.HS 


206  ORGANIC  CHEMISTRY 

mm'-Dioxy-azo-benzol,  m-azo-phenol,  m.p.  205°,  is  formed  by 
fusing  m-nitro-phenol  with  caustic  potash  (B.  39,  303).  It  has  also 
been  prepared  from  m-azo-aniline,  by  means  of  diazo-compounds, 
and  from  m-nitro-phenol  by  electrol3'tic  reduction  (C.  1902,  II.  1182  ; 
1903,  I.  1221). 

Concerning  azo-  and  diazo-compounds  of  cresol,  see  B.  17,  351. 

The  sulpho-acids  of  the  oxy-azo-benzols  are  dyes— e.g.  p-sulpho- 
benzol-p-azo-phenol  SO3H[4]C6H4[i]N=N[2]C6H4[4]OH,  from  p-oxy- 
azo-benzol  and  sulphuric  acid,  and  from  p-diazo-benzol-sulphonic 
acid  by  means  of  sodium  phenate,  is  the  tropaoline  yellow  of  commerce 
(B.  11,  2192).  Also  compare  resorcin. 

Phenol-2,  4-dis-azo-benzol  OH[i]C6H3[2,  4](N  :  NC8H5)2,  m.p.  123° 
(C.  1904,  II.  96),  and  phenol-2,  4,  6-tris-azo-benzol  OH[iJC6H2[2,  4,  6] 
(N  :  NC6H5)3,  m.p.  215°,  are  formed  by  coupling  phenol  with  2,  or  3, 
molecules  of  diazo-benzol  chloride  in  alkaline  solution.  Tin  and  HC1 
reduce  phenol-tris-azo-benzol  to  2,  4,  6-tri-amido-phenol  (/.  pr.  Ch.  2, 
78,  384). 

HYDRAZO-PHENOLS. 

m  -  Oxy  -  hydrazo  -  benzol  OH[i]C6H4[3]NH.NHC6H5,  colourless 
needles,  m.p.  126°,  is  obtained  by  reduction  of  m-oxy-azo-benzol 
with  zinc  dust  and  glacial  acetic  acid  (B.  36,  4112).  Mineral  acids 
transpose  it  into  m-oxy-benzidin.  m-Oxy-hydrazo-benzol  is  the  only 
known  free  oxy-hydrazo-compound,  since  o-  and  p-oxy-azo-benzol, 
on  reduction,  decompose  at  once  into  aniline  and  o-  or  p-amido- 
phenol  respectively.  But  the  alkyl  ethers  of  the  oxy-azo-benzols 
may  be  reduced  to  the  benzol-o-  and  p-hydrazo-phenol  ethers.  Benzol 
p-hydrazo-phenol  ethers  undergo,  with  stannous  chloride  and  HC1, 
the  semidin  transposition.  Thus,  benzol-p-hydrazo-phenetol  passes 
into  m-ethoxy-o-amido-diphenyl-amine  (B.  27,  2700  ;  28,  R.  753  ; 
29,  2680)  : 

C,H6NHNH[i]C6H4[4]OC2H5 

The  free  hydrazin-phenols  are  very  unstable.  o-Hydrazin-anisol 
NH2NH[2]C6H4[i]OCH3,  m.p.  43°,  b.p.  240°,  see  A.  221,  314. 

Sulphonic  Acids  of  Phenol.— The  sulphonation  of  phenol  proceeds 
with  the  replacement  of  the  o-  and  p-hydrogen  atoms,  just  as  in  the 
nitration  process  (the  sulpho-groups  enter  the  meta-position  with 
reference  to  one  another)  : 

~TT  f[i]OH 

-       -ceH4l[2]SOH_  , 

C8H5OH  I  (  '  £?      •  c  H  ) 

I 

l[6]S03H 

o-  and  p-Phenol-sulphonic  acids  are  formed  when  phenol  dissolves 
in  concentrated  sulphuric  acid  ;  at  medium  temperatures  the  former 
is  the  more  abundant,  but  readily  passes  into  the  para-  on  the  applica- 
tion of  heat,  or  even  upon  boiling  with  water.  This  change  is  due  to 
the  fact  that  o-phenol-sulphonic  acid  easily  sheds  its  sulpho-group 
with  regeneration  of  phenol,  which  then  forms  p-phenol-sulphonic  acid 
under  the  influence  of  sulphuric  acid.  o-Phenetol-sulphonic  acid  is 


SULPHONIC  ACIDS   OF  PHENOL  207 

just  as  easily  changed  to  the  p-acid  by  heating  it  to  100°   (B.   27, 

R.  591)- 

The  separation  of  o-  and  p-phenol-sulphonic  acid  succeeds  through 
the  crystallisation  of  its  mono-barium  salts,  the  barium  ortho- 
salt  (C6H4)OH(SO3)2B  +  H2O  crystallising  first  in  coarse  needles  of 
the  rhombic  system.  The  p-acid  is  best  obtained  from  the  mother- 
liquor,  as  in  the  magnesium  salt  (C6H4)OH(SO3)2Mg+8H2O,  large 
rhombic  columns  (B.  40,  3637).  The  p-acid  is  also  formed  by  trans- 
position of  phenyl-sulphuric  acid. 

The  free  acids  can  be  obtained  in  crystalline  form  by  the  slow 
evaporation  of  their  aqueous  solution.  The  aqueous  solution  of  the 
ortho-acid  is  applied  as  an  antiseptic  under  the  name  of  aseptol  (B.  18, 
R.  506).  The  para-acid  yields  quinone  if  its  sodium  salts  be  oxidised 
with  MnO2  and  sulphuric  acid.  When  the  ortho-acid  is  fused  with 
KOH  at  310°  it  yields  pyrocatechin  or  o-dioxy-benzol  ;  the  para-acid 
does  not  react  at  320°,  and  at  higher  temperatures  yields  diphenols 
(see  Diphenyl). 

The  action  of  nitric  acid  leads  easily  to  the  replacement  of  the 
sulpho-group  by  the  nitro-group. 

With  PC15  the  phenol-sulphonic  acids  give,  in  the  first  place,  the 
phosphor-oxy-chloride  derivative  of  the  phenol-sulphonyl  chlorides, 
which,  on  heating  to  180°  with  PC15,  are  converted  into  those  of  the 
chloro-phenols.  On  further  heating  of  the  latter  with  PC15,  we  get 
chloro-benzols  : 


r  w  /M011  .  r  M  /[i]OPOCl2       ^  r  „  /[i]OPOQ2  ~  „  J[i]Cl 

c«M[4]so3K  -     c<M[4]so2ci          C6M[4]ci  c'M[4]cr 

These  reactions  may  be  used  to  determine  the  location  of  the 
sulphoxyl  (B.  6,  943  ;  A.  358,  92).  If  phenyl-sulphonyl  chlorides  are 
required  for  reactions,  it  is  best  to  acetylate  the  potassium-phenol 
sulphonates,  then  to  prepare  the  acetyl-phenol-sulphonyl  chlorides, 
and  finally  to  remove  the  acetyl  (Anschiitz). 

From  acetyl-phenol-o-sulphonile  chloride  we  obtain,  by  the  action 
of  ammonia,  or,  better,  of  diethyl-amine  in  etheric  solution,  and  with 
shedding  of  the  acetyl-chloride  constituents,  phenylene-sulphonylide 

CeH4([2]SO^O[i]}C6H4'  m'p-  237°'  corresP°ndinS  to  salicylide,  as 
suggested  by  the  name. 

lodination  of  para-sulphonic  acid  yields  [2,  6]-di-iodo-p-phenol- 
sulphonic  acid  C6H2I2(OH).SO3H,  which  is  used  as  an  antiseptic  under 
the  name  sozo-jodol  (B.  21,  R.  250). 

Meta-phenol-sulphonic  acid  [1,  3]  is  produced  when  meta-benzol- 
disulphonic  acid  is  heated  to  I70°-i8o°  with  aqueous  potassium 
hydroxide  (B.  9,  969).  The  free  acid  contains  two  molecules  of  H2O. 
Fusion  with  potassium  hydroxide  at  250°  converts  it  into  resorcin  [i,  3]. 
When  para-benzol-disulphonic  acid  is  heated  with  caustic  alkali, 
meta-phenol-sulphonic  acid  is  also  produced  at  first,  but  it  yields 
resorcin  later. 

Phenol-  [2,  4]-disulphonic  acid  results  from  the  action  of  an  excess 
of  sulphuric  acid  upon  phenol,  also  upon  [i,  2]-  and  [i,  ^-phenol- 
sulphonic  acid.  The  solutions  of  the  acid  and  its  salts  are  coloured  a 
dark  red  by  ferric  chloride. 


208  ORGANIC   CHEMISTRY 

Phenol- [2,  4,  6]-trisulphonie  acid  is  obtained  when  concentrated 
sulphuric  acid  and  P2O5  act  upon  phenol.  It  crystallises  in  thick 
prisms  with  3jH2O. 

Nitro-phenol-sulphonic  acids,  see  /.  pr.  Ch.  2,  73,  519. 

p-Amido- phenol -sulphonic  acid  NH2[4]C6H3(OH)[i]SO3H[2]  is 
formed  in  small  quantity  by  the  action  of  concentrated  H2SO4  upon 
nitro-benzol.  There  is  probably  a  reduction  to  /3-phenyl-hydroxyl- 
amine,  followed  by  formation  of  p-amido-phenol  and  then  amido- 
phenol-sulphuric  acid  (C.  1908,  II.  587).  For  other  amido-phenol- 
sulphonic  acids,  see  B.  28,  R.  378,  399  ;  39,  3345  ;  C.  1904,  I.  1235). 

THIO-DERIVATIVES  OF  PHENOL. 

Mercaptans. — Thio-phenol,  phenyl-mercaptan  [pheno-thiol]  C6H5SH, 
boiling  at  168°,  with  specific  gravity  1-078  (14°),  is  a  mobile,  ill-smelling 
liquid.  It  is  made  (i)  by  letting  P2S5  act  upon  phenol  (Z.  f.  Ch.  1867, 
193)  ;  (2)  by  distilling  sodium  benzol-sulphonate  with  potassium 
sulphydrate  (B.  17,  2080)  ;  (3)  by  reduction  of  benzol-sulpho-chloride, 
or  benzol-sulphinic  acid,  with  zinc  and  sulphuric  acid,  or  stannous 
chloride  (C.  1900, 1.  252  ;  B.  32, 1147  ;  C.  1904,  II.  98)  ;  (4)  from  pheriyl- 
dithio-carbonic  ester ;  (5)  from  phenyl-magnesium  bromide,  with 
sulphur,  the  compound  C6H53MgBr  being  formed  first,  and  then 
decomposed  by  acids  with  rejection  of  thio-phenol  (C.  1908,  II.  1349  '• 
1909,  II.  193).  It  manifests  great  tendency  to  throw  off  hydrogen  and 
become  phenyl  disulphide  ;  hence  it  often  acts  as  a  reducing  agent  (cp. 
B.  29,  R.  979) .  Mercury  thio-phenate  (C6H5S)  2Hg.  Thio-phenyl-acetal 
C6H5.S.CH2.CH(OC2H5)2,  b.p.  273°  (B.  24, 160).  Thio-phenyl-acetone, 
m.p.  34°,  and  b.p.  266°  (B.  24,  163).  Consult  B.  24,  234;  28,  1120  ; 
A.  253,  161,  for  mercaptal  (Vol.  I.)  and  mercaptal  derivatives  of  thio- 
phenol.  Phenyl-ortho-thio-formic  ester  C6H5S.CO2.C2H5,  m.p.  39° 
(B.  25,  347,  252).  Phenyl-dithio-carbonic  ester  C6H5S.CSOR  is  formed 
from  diazo-benzol  chloride  and  potassium  xanthogenate  ;  it  represents 
a  common  reaction  (C.  1900, 1.  252).  It  yields  thio-phenol  when  saponi- 
fied. This  is  the  most  convenient  way  of  preparing  thio-phenols  (B.  21, 
R.  915),  next  to  the  reduction  of  the  sulphinic  acids.  Phenyl-thio- 
carbonic  chloride  C6H5S.COC1,  b.p.13  104°,  and  phenyl-dithio-carbonic 
chloride  C6H5S.CSC1,  b.p.15  135°,  are  formed  by  the  action  of  phosgene 
and  thio-phosgene  upon  sodium  thio-phenate.  Both  compounds, 
treated  with  alcohol,  phenol,  thio-phenol,  aniline,  etc.,  have  given  rise 
to  many  thio-phenol  derivatives  (C.  1907,  II.  1159). 

Diazo-benzol- thio-phenyl  ether  C6H5N2.SC6H5,  an  oil,  is  produced 
from  diazo-benzol  chloride  and  phenyl-mercaptan  (B.  28,  3237). 

o-Thio-cresol,m.p.  15°  and  b.p.  188° ;  them-body  is  a  liquid,  boiling 
at  I95°-202°,  while  the  p-compound  melts  at  43°  and  boils  at  194°. 
Thio-carvacrol  (CH3)(C3H7)(C6H3SH),  b.p.  235°,  see  Carvacrol.  For 
further  thio-phenols,  see  B.  32,  1147  ;  C.  1908,  II.  1349. 

o-Nitro-thio-phenol  NO2[2]C6H4SH,  m.p.  45°,  easily  obtained  from 
o-nitro-chloro-benzol  with  sodium  sulphide  ;  it  easily  oxidises  to  the 
disulphide  (NO2[2]C6H4)2S2,  m.p.  198°,  which  is  also  easily  obtained 
from  o2-dinitro-benzol  with  sodium  sulphide,  and  from  o-nitro-chloro- 
benzol  with  alkaline  poly-sulphides  ;  p-nitro-chloro-benzol  is  similarly 
transformed  into  p  -  nitro  -  phenyl  -  disulphide  (NO2[4]C6H4)2S2.  By 


THIO-DERIVATIVES   OF   PHENOL  209 

oxidation  of  these  disulphides  with  HNO3  we  obtain  the  corresponding 
nitro-benzol-sulphonic  acids  (/.  pr.  Ch.  2,  66,  551). 

Of  the  substitution  products  of  thio-phenol,  the  o-amido-thio-phenol 
should  be  noted  on  account  of  its  heterocyclic  condensation  products. 

o-Amido-thio-phenol  NH2[2]C6H4[i]SH  is  obtained  from  ortho- 
nitro-benzol-sulphonic  chloride  by  reduction  with  tin  and  hydrochloric 
acid.  A  better  method  to  pursue  is  to  fuse  benzenyl-o-amido-thio- 
phenol  with  caustic  potash  (B.  20,  2259).  It  melts  at  26°  and  boils 
at  234°. 

m-Amido-thio-phenol  (B.  27,  2816).  p-Amido-thio-phenol,  m.p. 
46°,  by  reduction  of  aceto-sulphanilic  chloride  (B.  42,  3362). 

The  Condensations  of  the  o-Amido-thio-phenols  (compare  o-diamines 
and  o-amido-phenols). — (i)  Benzo-thiazols  are  formed  on  heating 
o-amido-thio-phenol  with  carboxylic  acids,  acid  chlorides,  or  acid 
anhydrides.  (2)  o-Amido-thio-phenol,  by  the  action  of  chloro-carbonic 
esters,  forms  ^-oxy-benzo-thiazol  or  carbonyl-amido-thio-phenol.  (3) 
With  chloro-  or  bromo-acetic  acid  it  yields  keto-dihydro-benzo- 
thiazin  (q.v.).  (4)  Carbon  disulphide  produces  /x-sulphydro-benzo- 
thiazol  (q.v.).  (5)  Nitrous  acid  converts  o-amido-thio-phenol  into 
o-phenylene-diazo-sulphide  (q.v.) ;  at  200°-22O°  this  becomes  dipheny- 
lene  disulphide  : 

CHjCOj  H  f  [j]s  \^  /i-Methyl-benzo-thiazol 

«n*|  [2]N^  Ethenyl-amido-thio-phenol 

C1CO,C,HS  fms\  frT-K  fi-Oxy-benzo-thiazolor 

>      C.H4  -[  JIJ^  \C.OH  or  C.H,  j  L  J  ~>CO      Carbonyl-o-amido- 

v.  L^j^'y  v  L^JWrl  thio~phcDol 

CHtCl.COOH  f  [I]S CH, 

*-•"*  "»  f2lNH CO      Keto-dihydro-benzo-thiazin 


o-Amido-thio- 
phenol 


CS 


NOOH 
> 


C.H4     [I]S      C.SH     M-Sulphydro-benzo-thiazol 
C.H«  |  [I]S  \N     o-Phenylene-diazo-sulphide. 


See  below  for  the  condensation  of  o-amido-thio-phenol  with  pyro- 
catechol  to  thio-diphenyl-amine. 

Sulphides. — Phenyl  disulphide  (C6H5)2S2,  m.p.  61°  and  b.p.  310°, 
results  from  the  oxidation  of  thio  phenol  with  a  chromic  acid  mixture, 
or  in  ammoniacal  solution,  by  the  oxygen  of  the  air  ;  by  the  action  of 
iodine  upon  aqueous  potassium  thio-phenate  ;  by  heating  thio-phenol 
with  benzol-sulphinic  acid  ;  by  heating  thio-phenol  or  phenyl  sulphide 
with  sulphur,  etc.  Reducing  agents  decompose  it  into  two  molecules 
of  thio-phenol,  and  alcoholic  potash  breaks  it  down  into  potassium 
thio-phenate  and  potassium-benzol  sulphinate  (B.  41,  3403). 

p2-Diamido-diphenyl  disulphide,  dithio-aniline  S2[C6H4NH2]2,  m.p. 
77°,  is  produced  besides  thio-aniline  on  melting  up  sulphur  with  aniline 
and  aniline  chlorohydrate.  On  reduction,  or  on  boiling  with  alcoholic 
KHO,  it  is  converted  into  p-amido-thio-phenol  (B.  39,  2427).  The 
diacetyl  compound  exists  in  three  isomeric  forms  of  m.p.  215°,  182°, 
and  122°  respectively.  This  isomerism  is  not  as  yet  explained  (B.  41, 
626).  Dithio-m-toluylene-diamine,  see  B.  42,  743. 

Phenyl  sulphide  (C6H5)  2S,  benzol  sulphide,  a  colourless  liquid,  with 

an  odour  resembling  that  of  leeks,  b.p.  292°,  has  a  specific  gravity 

of  i -12.     It  is  formed  (i)  by  distilling  phenol  with  P2S5  (along  with 

thio-phenol)  ;    (2)  from  sodium-benzol  sulphonate  with  P2S5  ;    (3)  by 

VOL.  II.  P 


2io  ORGANIC  CHEMISTRY 

heating  mercury-diphenyl  with  sulphur  (B.  27,  1171)  ;  (4)  on  heating 
sulphur  with  diphenyl  sulphone  (method  of  preparation),  into  which 
it  is  also  converted  by  oxidants  (B.  26,  2816)  ;  (5)  by  the  action  of 
sulphur  hypochloride  or  finely  divided  sulphur  and  Al  chloride  upon 
benzene  (C.  1905,  II.  228).  The  two  last  methods  are  specially  suitable 
for  preparing  phenyl  sulphides.  (6)  Phenyl  sulphide  and  its  homologues 
are  also  readily  prepared  by  heating  aromatic  lead  mercaptides  with 
haloid  benzols  (the  bromides  are  the  best  adapted  for  this  purpose) 
(B.  28,  2322),  or  sodium  mercaptides  with  iodo-benzols  in  the  presence 
of  powdered  copper  (B.  39,  3593). 

Diphenylene  sulphide  or  dibenzo-thio-phene  (q.v.)  is  produced  on 
conducting  the  vapours  of  phenyl  sulphide  through  a  tube  heated  to 
redness. 

Fatty  aromatic  sulphides,  which  may  also  be  regarded  as  alcohol 
ethers  of  thio-phenols,  are  produced  (i)  by  the  action  of  iodo-alkylene 
or  dimethyl  sulphate  upon  the  sodium  salts  of  the  thio-phenols ;  (2)  by 
heating  phenyl-dithio-carbonic  ester  alone : 

C6H5S.CSOC2H5  =  =  C,H5SCaH5+COS  ; 

(3)  by  successive  action  of  sulphur  and  iodo-alkylene  upon  phenyl- 
magnesium  bromide  (C.  1905,  I.  80)  : 

C6H5MgBr  — ->  C6H5SMgBr  — '->  C6H5SCH3. 

Phenyl-methyl  sulphide  C6H5SCH3,  b.p.  i87°-i90° ;  phenyl-ethyl 
sulphide  C6H5SC2H5,  b.p.  200°-2o6°.  The  fatty  aromatic  sulphides 
easily  add  two  atoms  of  bromine  or  iodine,  with  formation  of  dibromides 
or  di-iodides,  usually  crystallising  easily,  which,  under  the  action  of 
water,  exchange  the  halogen  for  oxygen,  and  form  mixed  sulph-oxides. 

Phenyl-thio-glycolic  acid  C6H5SCH2COOH,  m.p.  43-5°,  is  formed 

(1)  from  sodium  thio-phenate  and  monochloracetic  acid  ;    (2)  by  the 
action  of  thio-glycolic   acid  upon   diazo-benzol   chloride  in   aqueous 
solution.     In  this  action  the  compound  C6H5N2S.CH2COOH  is  formed 
first,   and  passes,   on  warming,   into  phenyl-thio-glycolic  acid,  with 
rejection  of  nitrogen  (M.  28,  247  ;   C.  1908,  I.  1221). 

With  dimethyl  sulphate  the  aromatic  and  fatty  aromatic  sulphides 
combine  to  mixed  sulphinic  or  sulphonium  compounds,  which  change 
in  stability  with  the  number  of  aromatic  radicles.  Thus,  diphenyl- 
methyl-sulphonium  chloride  decomposes  on  boiling  with  water,  and 
rapidly  on  adding  alkali,  into  methyl  alcohol  and  diphenyl  sulphide 
(B.  39,  3559). 

Amido-phenyl  Sulphides  or  Thio-anilines. — Formation  : — (i)  These 
compounds  result  when  nitro-thio-phenyls  are  reduced  (cp.  B.  29,  2362)  ; 

(2)  from  anilines  by  boiling  the  latter  with  sulphur  and  lead  oxide 
(B.  4,  384).     Sulphur  chloride  converts  the  dialkyl-anilines  into  sym. 
p-tetra-alkyl-diamido-phenyl  sulphides.     Silver  nitrate  and  ammonia 
desulphurise  the  tetra-alkyl  compounds,  with  the  formation  of  sym. 
p  -  tetra  -  alkyl  -  diamido  -  diphenyl    oxides — e.g.     O[C6H4[4]  .N(CH3)  2]  2 
(B.  21,  2056).     Upon  heating  methyl-thio-anilines — e.g.  thio-p-toluidin 
—with    sulphur    to    higher    temperatures,    thiazol    derivatives,    like 
dehydro-thio-toluidin  (see  Benzo-thiazol),  are  produced. 

p-Diamido-diphenyl  sulphide  s<««,  thio-aniline,  melts  at  105°. 


THIO-DERIVATIVES   OF  PHENOL  211 

o-Diamido-diphenyl  sulphide  melts  at  93°  (B.  27,  2807).  See  B.  38, 
1130  for  isomeric  thio-anilines,  melting  at  80°  and  86°. 

Thio-p-toluidin  K^(CI£)NH!'  diamido-ditolyl  sulphide,  melts 
at  103°.  The  sodium  salts  of  thio-  and  dithio-toluidin-sulphonic  acids 
dye  unmordanted  cotton  a  greenish  yellow  (B.  21,  R.  877).  They  are, 
therefore,  so-called  substantive  cotton  dyes. 

The  bis-diazo-salts  of  thio-p-toluidin,  which  may  be  produced  in 
the  fibre  itself,  combine  with  naphthyl-amine-sulphonic  acids,  and 
yield  diazo-dyes  of  a  brown-red  colour  (B.  20,  664). 

Thio-diphenyl  -  imides.—  Thio-diphenyl-amine   S { ^'^  }NH,  js 

W[IJ^6i:14L2J  J 

the  simplest  of  these  heterocyclic  bodies.  Methylene  blue,  a  most 
valuable  dye,  is  derived  from  it.  The  thio-phenyl-amine  group  will  be 
discussed  later  with  the  hetero  six-ring  compounds. 

Thio-anisol  S(C6H4OCH3)2,  melting  at  46°,  and  allied  bodies,  are 
formed  when  thionyl  chloride  or  sulphur  chloride  with  aluminium 
chloride  acts  upon  the  phenol  ethers  (A.  27,  2540). 

Seleno-phenols. — Like  sulphur,  selenium  also  attaches  itself  to 
phenyl-magnesium  bromide,  forming  C6H5SeMgBr,  from  which  seleno- 
phenol  is  produced  with  dilute  acids. 

Seleno-phenol  C6H5SeH,  b.p.  182°,  is  also  formed  by  reduction  of 
benzol-seleninic  acid  and  diphenyl  diselenide,  into  which  it  easily 
passes  by  oxidation  in  air.  p-Seleno-cresol,  white  flakes,  m.p.  47° 
(C.  1906,  II.  1119). 

Phenyl  selenides  and  tellurides  are  quite  readily  obtained  from  the 
mercury-diphenyl  compounds  by  the  action  of  selenium  and  tellurium. 

Diphenyl  selenide  (C6H5)2Se  also  results  upon  heating  selenium 
with  diphenyl  sulphone.  Sulphur  dioxide  escapes  at  the  same  time. 
It  boils  at  163°  (14  mm.).  Further  action  of  selenium  produces  diphenyl 
diselenide  (C6H5)2Se2,  melting  at  63°  and  boiling  at  203°  (n  mm.). 
Reduction  changes  it  to  two  molecules  of  phenyl-selenium  hydrate 
C6H5SeH,  melting  at  183°.  Diphenyl  telluride  (C6H5)2Te  boils  at  174° 
(10  mm.) ;  see  B.  28,  1670  ;  29,  428.  Further  aromatic  Se  and  Te 
compounds,  see  B.  30,  2821. 

DIHYDRIC  PHENOLS. 

Several  representatives  of  this  family  occur  in  plants,  or  have  been 
obtained  as  decomposition  products  of  plant  substances.  Resorcin  or 
m-dioxy-benzol  is  especially  important  from  a  technical  standpoint. 

The  general  methods  of  formation  are  like  those  of  the  corresponding 
monohydric  phenols — (i)  by  fusing  monohalogen  phenols,  halogen 
benzol-sulphonic  acids,  phenol-sulphonic  acids,  and  benzol-disulphonic 
acids  with  potassium  hydroxide  ;  (2)  by  diazotising  the  amido-phenols  ; 
and  (3)  by  aromatic  dioxy-acids  alone  or  with  lime  or  baryta. 

(4)  o-  and  p-Dioxy-benzols  also  result  from  the  careful  reduction 
of  their  corresponding  quinones.  (5)  o-  and  p-Dioxy-benzols  are 
obtained  in  a  straightforward  reaction  by  the  oxidation  of  o-  and  p-oxy- 
benzaldehydes  and  o-  and  p-oxy-aceto-phenones  with  H2O2  in  feeble 
alkaline  solution  ;  m-oxy-benzaldehyde  gives  no  resorcin  when  treated 
similarly  (C.  1910,  I.  634). 

Behaviour. — Their  behaviour  is  largely  dependent  upon  the  position 


212  ORGANIC  CHEMISTRY 

of  the  two  hydroxyl  groups  with  reference  to  one  another.  The  three 
simplest  dioxy-benzols,  pyrocatechol  [i,  2],  resorcin  [i,  3],  hydroquinone 
[1,4],  are,  therefore,  typical  representatives  of  the  three  groups  of 
dihydric  phenols.  The  behaviour  of  such  bodies  can  be  fully  illus- 
trated through  them.  The  dihydric  phenols  can  be  changed  by 
chlorine  to  hydro-aromatic  keto-chlorides,  whose  carbon  ring  may  be 
readily  ruptured.  Chloroform  and  caustic  potash  convert  them  into 
dioxy-aldehydes,  while  they  yield  dioxy-carboxylic  acids  with  carbon 
tetrachloride  and  caustic  potash,  as  well  as  alkaline  carbonate  solutions. 

Pyrocatechin  Group. — All  o-dioxy-benzols  are  coloured  green  by 
ferric  chloride.  They  are  further  distinguished  from  the  m-  and 
p-compounds  by  their  ability  to  exchange  their  hydroxyl  hydrogen 
atoms  and  thus  form  cyclic  esters  readily. 

Pyrocatechin,  pyrocatechol,  o-dioxy-benzol  [i,  2-pheno-diol]  C6H4 
[1,2] (OH) 2,  melting  at  104°  and  boiling  at  245°,  was  first  (Reinsch, 
1839)  obtained  in  the  distillation  of  catechine  (the  juice  of  Mimosa 
catechu),  and  also  from  Moringa  tannic  acid. 

It  is  produced  in  fusing  many  resins  with  caustic  potash.  It  occurs 
in  kino,  the  dried  juice  of  different  kinds  of  Pterocarpus,  Butea,  and 
Eucalyptus,  in  beechwood  tar,  and  has  been  obtained  as  a  by-product 
in  the  manufacture  of  paraffin  from  bituminous  shales  at  the  Messel 
mine,  near  Darmstadt,  etc.  Pyrocatechol-sulphuric  acid  occurs  in  the 
urine  of  the  horse  and  in  that  of  man.  It  is  artificially  made  (i)  by 
oxidising  phenol  with  hydrogen  peroxide  or  with  Caro's  acid  ;  (2)  by 
the  distillation  of  pyrocatechuic  acid,  or  [i  CO2H,  3,  4]-dioxy-benzoic 
acid  ;  (3)  by  fusing  [i,  2]-chloro-phenol,  [i,  2]-bromo-phenol  (B.  27, 
R.  957),  [i,  2]-benzol-disulphonic  acid,  and  [i,  2]-phenol-sulphonic  acid 
with  caustic  potash  ;  (4)  by  heating  guaiacol-pyrocatechol-monomethyl 
ether  to  200°  with  hydriodic  acid. 

On  exposure  to  the  air  its  alkaline  solutions  assume  a  green,  then 
brown,  and  finally  a  black  colour.  Lead  acetate  throws  out  a  white 
precipitate,  PbC6H4O2,  from  its  aqueous  solution.  Neither  resorcin 
nor  hydroquinone  shows  this  reaction.  Similarly,  the  formation  of 
antimonyl  compounds  is  characteristic  of  o-dioxy-benzols,  e.g.  C6H4O2. 
SCOH  (C.  1898,  II.  598).  Pyrocatechin  reduces  cold  silver  solutions  and 
alkaline  copper  solutions.  The  application  of  heat  is  required  in  the 
latter  case.  Silver  oxide  oxidises  it  in  etheric  solution  to  o-benzo- 
quinone.  Pyrocatechin  in  glacial  acetic  acid  solution  is  converted  by 
chlorine  into  tetrachloro-pyrocatechin,  tetrachloro-o-quinone,  and  hexa- 
chloro-o-diketo-R-hexene ;  in  nitrous  acid,  to  dioxy-tartaric  acid.  Con- 
sult p.  214  for  the  heterocyclic  formations  obtainable  from  pyrocatechol. 
Heated  with  phthalic  anhydride  and  sulphuric  acid,  it  yields  alizarine 
and  hystazarine.  Compare  protocatechuic  aldehyde  and  protocatechuic 
acid.  It  is  used  in  photography  as  a  developer. 

Ethers. — Some  ethers  of  pyrocatechin,  such  as  the  mono-  and 
dimethyl  ether,  as  well  as  the  methylene  ether,  are  of  special  import- 
ance, as  being  closely  connected  with  numerous  vegetable  substances, 
such  as  eugenol,  safrol,  apiol,  vanillin,  piperonal,  papaverin,  etc. 

Pyroeateehin-methyl  ether,  guaiacol,  occurs  in  the  creosote  from 
beechwood  tar  (B.  28,  R.  156).  It  is  produced  on  heating  pyrocatechin 
with  potassium  hydroxide  and  potassium-methyl  sulphate  to  180°,  as 
well  as  by  heating  calcium  vanillate,  and  from  veratrol  (B.  28,  R.  362). 


PYROCATECHIN   GROUP  .  213 

Ferric  chloride  gives  its  alcoholic  solution  an  emerald-green  colour  (see 
Vanillin). 

p-Nitroso-guaiaeol  C6H3[2,  i](OCH3)(OH)[4]NO,  from  guaiacol  with 
sodium  alcoholate  and  ethyl  nitrite,  gives  on  oxidation  nitro-,  and 
on  reduction  amido-guaiacol  C6H3(OCH3)(OH)NH2  (B.  30,  2444). 

Guaiacol-sulphonic  acids,  see  B.  39,  3685  ;  C.  1907,  II.  1467. 
Numerous  guaiacol  derivatives  are  extensively  employed  in  the  treat- 
ment of  pulmonary  tuberculosis. 

Dimethyl  ether,  veratrol  C6H4[i,  2](OCH3)2,  melting  at  15°  and 
boiling  at  205°,  is  prepared  by  treating  the  potassium  salt  of  the  mono- 
methyl  ether  with  CH3I,  and  by  distilling  vetraric  acid  with  lime. 

Pyroeateehin-methylene  and  ethylene  ether,  b.p.  173°  and  216° 
respectively. 

Glyoxal-dipyrocateehin  (C6H4O2)CH.CH(O2C6H4),  m.p.  89°,  from 
acetylene  tetrabromide  and  sodium  pyrocatechin,  on  hydrolysis,  gives 
o-oxy-phenoxy-acetie  acid  OHC6H4O.CH2COOH,  m.p.  131°,  which 
also  forms  direct  from  monosodium  pyrocatechin  and  chloracetic  acid 
(/.  pr.  Ch.  2,  61,  345 ;  C.  1900,  II.  327),  and  easily  passes  into  its 

lactone  C6H4<£^2>  m.p.  55°,  b.p.  243°  (B.  40,  2779). 

<s~\         /"*  TT 
„      and    propene-pyrocatechin    are 

formed  from  o-oxy-phenoxy-acetaldehyde  and  o-oxy-phenoxy-acetone 
with  acetyl  chloride  or  P2O5  (C.  1899,  II.  620). 

Pyrocatechin-diphenyl  ether  C6H4[i,  2](OC6H5)2,  m.p.  93°,  is  formed 
by  heating  o-dibromo-benzol  with  potassium  phenate  in  the  presence 
of  copper  powder.  Similarly,  we  obtain  pyrocatechin-monophenyl  ether 
OH[i]C6H4[2]OC6H5,m.p.  107°,  and  o2-dioxy-phenyl  ether  [C6H4OH]2O, 
m.p.  121°,  by  melting  o-bromanisol  \vith  potassium-phenol  or  guaiacol, 
from  the  mono-  or  dimethyl  ether  formed  at  first.  Heating  with  con- 
centrated HBr  transforms  o2-dioxy-phenyl  ether  into  diphenylene 

dioxide  c«H«{^o[2]}C6H4)  m'p-  II9°  (B'  39'  622)' 

Mono-  and"  dibenzoyl  ester,  m.p.  130°  and  84°  (B.  26,  1076  ;  A. 
210,  261). 

Pyrocatechin  sulphite  boils  at  2io°-2ii°  (B.  27,  2752)  ;  pyrocatechin 
chloro-phosphine  melts  at  130° ;  pyrocatechin  oxy-ehloro-phosphine 
melts  at  35°  (B.  27,  2569)  (see  below). 

The  carbonic  ester  C6H4-[^   \CO  results  from  the  action  of  chloro- 

U.  L2jU/ 

carbonic  ester  upon  pyrocatechin,  melts  at  118°  and  boils  at  227°. 
Also  from  the  action  of  PC15  upon  pyrocatechin-methylene  ether,  and 
decomposition  of  the  resulting  dichloro-pyrocatechin-methylene  ether 

C8H4{°\CC12  with   water    (C.  1908,   I.    1689).      This  reaction  is  of 

importance,  inasmuch  as  by  its  means  the  numerous  derivatives  of 
pyrocatechin-methylene  ether  occurring  in  nature  may  be  transformed 
into  pyrocatechin  derivatives  otherwise  difficult  to  obtain  ;  cp.  Pyro- 
catechin-aldehyde. 

By  heating  with  alcohols  or  amine  bases  the  pyrocatechin  carboxy- 
late  is  easily  broken  up  into  o-oxy-phenol-carbonic  esters,  or  carba- 
minic  o-oxy-phenol  esters  ;  with  hydrazin  hydrate  it  yields  pyro- 
cateehin-carbonic  hydrazide  HOC6H4OCONHNH2,  which,  in  alcoholic 


214 


ORGANIC   CHEMISTRY 


solution,  reacts  easily  with  aldehydes,  but  not  with  ketones  (B.  13, 
697  ;  A.  226,  84  ;  300,  135  ;  317,  190).  Oxalic  ester,  m.p.  185°,  from 
sodium-pyrocatechin  and  oxal-ethyl-ester  chloride  (B.  35,  3452). 

HETERO-RING  FORMATIONS  FROM  PYROCATECHOL. — By  the  replace- 
ment of  both  hydroxyl  hydrogen  atoms  of  pyrocatechol,  cyclic  esters 
are  formed  with  SOC12,  PC13,  POC13,  COC12,  and  ethylene  bromide. 
o-Phenylene-diamine,  o-amido-phenol,  and  o-amido-thio-phenol  con- 
dense with  pyrocatechin,  forming  phenazin,  phenoxazin,  and  thio- 
diphenyl-amine  : 


f[i]OH 
C«M[2]OH~ 

SOC12 

\[i  O/^0        Pyrocatechin  sulphite 

r[i]O\PCl       Pyrocatechin  chloro- 
\[2]O/                      phosphine 
{[i]O\_._  „.    Pyrocatechin  oxychloro- 
[2]0/                     phosphine 

s  r^Q/^0       Pyrocatechin  carbonate 

{[i]O  —  CH2     Pyrocatechin-ethylene- 
[2]O—  CH2             ether 

<  ?  J~                [  J  )  C6H4  Phenoxazin 

\[2]—  NH—  [2]J 

<                            rC6H4  Thio-diphenyl-an 
U  [2]  —  NH  —  [2]  ^ 

PCJ3                      >r    n 

->C6hL4 

15008       >c  n 

COC1, 

->^6n4 
BrCHsCH2Br          ^  „ 

—  >Lx6xl4 
C,H4[i>2](NHs)z  _^c  H 

NH,[2]C,H4[i]OH      c  n 

NH2[2]C,H4[i]SH   ^  H 

6      4 

Homologous  Pyrocatechols. — Iso-homo-pyrocatechol  CH3  [i]  C6H3  [2,3] 
(OH)2,  m.p.  47°  (B.  24,  4137).  Homo-pyrocatechol  CH3[i]C6H3[3,  4] 
(OH)  2,  m.p.  51°  and  b.p.  251°,  occurs  in  the  form  of  its  3-methyl  ether 
as  ereosol  CH3[i]C6H3[3](OCH3)[4]OH,  b.p.  221°,  in  beechwood  tar, 
together  with  phloral  (B.  14,  2005). 

Creosol  is  also  formed  together  with  guaiacol  (see  above)  in  the  dis- 
tillation of  guaiacol  resin.  Higher  homologues  of  pyrocatechol  have 
been  obtained  by  treating  pyrocatechol  with  aliphatic  alcohols  and 
zinc  chloride  (B.  28,  R.  312). 

Ethyl-,  propyl-  and  iso-propyl-pyroeateehin,  m.p.  39°,  60°,  and  78°, 
are  obtained  from  the  corresponding  methylene  ethers  (C.  1904,  I.  797  ; 
II.  436). 

Mono-thio-pyrocateehol  C?H4[i,  2](SH)(OH),  m.p.  +5°  and  b.p. 
217°,  results  from  the  reduction  of  diphenol  disulphide  [C6H4OH]2S2, 
produced  on  heating  sodium  phenoxide  with  sulphur.  o2-Dioxy- 
diphenyl  sulphide  [C6H4OH]2S,  m.p.  142°,  see  B.  39,  1350. 

Diphenylene    disulphide,    or    thianthrene  c6H4/fI^fIHc6H4,  m.p. 

L|_2jb[2J  J 

158°  and  b.p.  360°,  should  be  regarded  as  a  derivative  of  dithio-pyro- 
catechol  C6H4(SH)2.  It  is  made  by  boiling  phenyl  sulphide  with 
sulphur,  also  from  benzene,  SC12,  and  aluminium  chloride,  as  well  as 
by  heating  phenylene  diazo-sulphide  (C.  1899,  II.  648  ;  1905,  II.  228). 
Also  by  the  action  of  A12C13  upon  thio-phenol  or  phenyl  disulphide 
(C.  1909,  I.  1652).  HNO3  oxidises  it  to  thianthrene  dioxide  C6H4(SO)2 
C6H4,  m.p.  230°,  which  is  transposed  by  heating  to  270°  into  thianthrene 

monosulphone  C.HXH*  m.p.  279°. 


RESORCIN   GROUP  215 

Oxidation  converts  thianthrene  into  a  disulphone,  C6H4(SO2)2C6H4. 
When  the  latter  is  heated  with  selenium,  diphenylene  diselenide,  selen- 
anthrene  C6H4  :  (Se2)  :  C6H4,  m.p.  181°  and  b.p.  223°  (n  mm.),  results 
(B.  29,  435,  443). 

RESORCIN  GROUP. 

Resorcin,  and  many  of  its  homologues,  combine  with  phthalic  anhy- 
dride, the  products  being  the  fluoresceins  (q.v.).  The  aqueous  solutions 
of  the  m-dioxy-benzols  are  coloured  dark  violet  by  ferric  chloride. 

Resorcin  C6H4[i,  3](OH)2,  m.p.  118°  and  b.p.  276°,  is  produced 
from  galbanum,  asafcetida,  and  other  resins  upon  heating  them  with 
potash,  as  well  as  by  distilling  the  extract  of  Brazil-wood.  It  can  also 
be  obtained  from  many  m-disubstitution  products  of  benzene,  such  as 
[i,3]-chloro-andiodo-phenol,  [i,  3]-phenol-sulphonic  acid,  [i,3]-benzol- 
disulphonic  acid,  etc.,  on  fusing  them  with  potash  or  soda  at  23O°-28o°  ; 
by  the  same  method  from  umbelliferone. 

Even  o-  and  p-compounds  (B.  7,  1175  ;  8,  365),  especially  when 
fused  at  high  temperatures  with  caustic  alkali,  yield  resorcin  ;  hence 
the  potash  fusion  is  not  available  in  the  determination  of  position. 
Resorcin  is  made  on  a  technical  scale  from  m-benzol-disulphonic  acid 
(/.  pr.  Ch.  2,  20,  319)- 

Properties  and  Behaviour. — Resorcin  crystallises  in  rhombic  prisms 
or  plates.  It  dissolves  readily  in  water,  alcohol,  and  ether,  but  not  in 
chloroform  or  carbon  disulphide.  It  possesses  a  sweet  taste.  Lead 
acetate  does  not  precipitate  its  aqueous  solution  (distinction  from 
pyrocatechin) . 

Sodium  amalgam  reduces  resorcin  to  dihydro-resorcin  (A.  278,  20), 
or  m-diketo-hexamethylene  (B.  27,  2129).  Bromine  precipitates  it  from 
aqueous  solution  as  tribromo-resorcin,  m.p.  111°,  while  chlorine  con- 
verts it  in  glacial  acetic  acid  solution  finally  into  heptachloro-resorcin 
(B.  26,  498),  which  can  be  easily  decomposed.  Fusion  with  caustic 
soda  produces  phloroglucin,  pyrocatechol,  and  diresorcin  (HO)2C6H3 — 
C6H3(OH)2  (B.  26,  R.  233).  The  chlorohydrate  of  a  triresorcin 
C18Hj4O4  (A.  289,  61)  is  formed  when  resorcin  is  heated  with  hydro- 
chloric acid. 

Ethers  and  Esters. — The  monomethyl  ether  boils  at  243°  (B.  16, 151). 
The  dimethyl  ether  boils  at  214°  (B.  10,  868).  The  diacetyl  ester  boils 
at  278°  (B.  16,  552).  The  diearbonie  ester  C6H4(OCO2C2H5)2  boils  at 
300°  (B.  13, 697).  The  dibenzoate  melts  at  117°  (A.  210, 256).  Resorcin 
combines  with  the  various  sugars  under  the  influence  of  hydrochloric 
acid  (B.  27,  1356). 

Fluorescei'n  is  produced  when  resorcin  is  heated  with  phthalic 
anhydride. 

If  resorcin  be  heated  with  sodium  nitrite,  it  forms  a  deep-blue  dye, 
soluble  in  water.  Acids  turn  this  red  (B.  17,  2617).  It  is  used  as  an 
indicator  under  the  name  of  lacmoid  (B.  18,  R.  126).  Nitric  acid, 
containing  nitrous  acid,  converts  resorcin  into  two  dyes — resorufin  and 
resazurin — derivatives  of  phenoxazin  (q.v.)  (B.  23,  718). 

When  diazo-salts  act  upon  aqueous  or  alkaline  resorcin  solutions, 
azo-dyes  and  dis-azo-dyes  are  produced ;  thus,  with  diazo-benzol 
nitrate  or  chloride  the  products  are  :  benzol-azo-resorcin  (C6H5N2) 
C6H3(OH)2,  a-  and  jS-diazo-benzol-dis-azo-resorcin  (C6H5N2)2C0H2(OH)2 


216  ORGANIC  CHEMISTRY 

(B.  15,  2816  ;  16,  2858  ;  17,  880)  ;  while  with  the  diazo-chloride  of 
amido-azo-benzol  there  results  azo-benzol-azo-resorcin  C6H5N2.C6H4 
N2.CeH3(OH)2  (B.  15,  2817).  The  action  of  amyl  nitrite  upon  an 
alkaline  solution  of  resorcin  produces  4-nitroso-resorein  NO[4]C?H3JX  3] 
(OH)  2  (B.  35,  4191).  On  the  other  hand,  dinitroso-resorein,  diquinoyl- 
dioxime  C6H2[i,3](OH)2[4,6](NO)2  or  C6H2(O)2(N.OH)2[i,  3,  2, 4] 
crystallises  in  yellow-brown  flakes,  which  detonate  on  heating  to 
115°  C.  (B.  20,  3133).  It  occurs  in  commerce  under  the  names  solid 
green  or  chlorin  (B.  20,  3133). 

Nitroso-resorcin-monomethyl  and  -ethyl  ether  NO[4]C6H3[3]OH[i] 
OCH3  and  -OC2H5  respectively,  exist  each  in  two  isomeric  modifica- 
tions, one  of  them  being  green  and  unstable,  the  other  yellowish 
brown  and  stable.  On  heating  to  130°  the  former  passes  into  the 
latter.  Both  modifications  yield  the  same  alkali  salt,  from  solutions 
of  which  the  yellowish-brown  modification  is  precipitated  by  acids. 
This  isomerism  is  perhaps  to  be  interpreted  in  the  sense  of  the  following 
formulae  :  (RO)C6H3(OH)NO  and  (RO)C6H3  :  O  :  (NOH),  according 
to  which  the  green  form  is  to  be  regarded  as  a  true  nitroso-phenol, 
and  the  yellow  as  o-quinone-monoxime  (/.  pr.  Ch.  2,  70,  332). 

v-Nitro-resorcin  (NO2)[2]C6H3[i,  3](OH)2,  m.p.  85°,  orange  needles, 
volatile  with  water  vapour,  is  produced  by  nitrating  resorcin-disulphonic 
acid  and  splitting  of  the  sulpho-groups  with  superheated  steam  (B. 
37,  726). 

v-Dinitro-resorein  (NO2)[2, 4]C6H2[i,  3](OH)2,  m.p.  148°,  by  the 
action  of  HNO3  fumes  upon  resorcin.  Iso-dinitro-resorcin  (NO2)2 
[4,  6]C6H2[i,  3]OH2,  m.p.  212°. 

When  cold  nitric  acid  acts  on  resorcin  and  various  gum  resins 
(galbanum,  etc.),  or  by  nitrating  meta-nitro-phenol  and  various 
dinitro-phenols,  we  get  trinitro-resorcin  (NO2)3[2,  4,  6]C6H[i,  3](OH)2. 
It  melts  at  175°.  Ferrous  sulphate  and  lime  water  colour  it  green 
(picric  acid  colours  it  blood-red).  The  diethyl  ester  melts  at  120° 
(C.  1903,  II.  829).  It  is  reduced  by  tin  and  HC1  to  triamino-resorcin 
ethers.  Stryphinic  acid,  like  picfic  acid,  gives,  with  hydrocarbons  like 
naphthalin,  phenanthrene,  etc.,  and  with  amines,  readily  crystallising 
molecular  combinations  (C.  1909,  I.  526). 

Tetranitro-resorcin  (NO2)4C6(OH)2,  m.p.  152°,  on  boiling  with  water, 
yields  trinitro-phloroglucin  (C.  1908,  I.  724). 

Thio-resorcin  C6H4[i,  3](SH)2,  m.p.  27°  and  b.p.  243°.  It  results 
from  the  reduction  of  benzol-m-disulphonic  chloride,  and,  when 
heated  with  phenyl  iso-cyanate,  becomes  bis-phenyl  carbamate,  C6H4 
(SCONHC6H5)2,  m.p.  179°  (B.  29,  R.  177  ;  C.  1900,  I.  252). 

HOMOLOGOUS  RESORCINS.  —  Orcin  is  by  far  the  most  important 
body  among  those  which  follow  : 

M.p.  B.p. 

Orcin      ....    CH3[i]C6H3[3,  5](OH)2  107°  290° 

Cresorcin         .         .         .   CH3[i]C6H8[2,  4](OH)2  io4°  269°    (6.19,136) 
2, 6-Dioxy-toluol    .          .          .    CH3[i]C6H3[2,  6](OH)2     64°     ..       (B.  17, 1963) 
3, 5-Dioxy-o-xylol  .     (CH3)2[i,  2]C6H2[3,  5](OH)2  137°     ..       (A.  329, 305) 

2, 4-Dioxy-m-xylol  .  (CH3)2[i,  3]C6H2[2,  4](OH)2  147°  149°  (B.  23,  3114) 
m-Xylorcin  .  .  (CH3)2[i,  3]C6H2[4,  6](OH)2  125°  277°\m  1Q  _T^ 
/9-Orcin  .  .  .  (CH3)2[i,  4]C6H2[3,  5] (OH),  163°  279°  f(*' LV>23 

Mesorcin          .          .(CH3)3[i,  3,  5]C6H[2,  4](OH)2    i49°  275°     (A.215,ioo) 

Di-tertiary-amyl-resorcin    (C5H11)2C6H2[i,  3](OH  2     89°    ..       (B.  25,2653). 


HOMOLOGOUS   RESORCINS  217 

Orcin  CH3[i]C6H3[3,  5](OH)2,(B.  15,  2995).  It  is  found  in  many 
lichens  of  the  varieties  Roccella  and  Lecanora,  partly  free  and  partly  as 
orsellic  acid,  or  partly  as  erythrine  or  diorsellic  erythric  ester.  It  is 
obtained  from  orsellic  acid  either  by  dry  distillation  or  by  boiling 
with  lime. 

It  is  obtained  by  fusing  the  extract  of  aloes  with  caustic  potash. 
It  can  be  prepared  synthetically  from  3,  5-dinitro-p-toluidin  and  various 
other  toluol  derivatives  by  the  replacement  of  their  side  groups  by 
hydroxyl  groups  (B.  15,  2990). 

Orcin  is  produced  in  the  distillation  of  o-dioxy-phenyl  acetate  of 
silver  (HO)2[3,  5]C6H3[i]CH2.CO2Ag  (B.  19,  1451),  and  upon  heating 
dehydracetic  acid  (see  Vol.  I.)  with  concentrated  caustic  potash  (B.  26, 
R.  316).  Orcin  crystallises  in  colourless,  six-sided  prisms  containing 
one  molecule  of  water.  It  dissolves  easily  in  water,  alcohol,  and  ether, 
and  has  a  sweet  taste.  It  melts  at  56°,  when  it  contains  water,  but 
gradually  loses  this,  and  melts  (dried  in  the  desiccator)  at  107°.  It  boils 
at  290°.  Lead  acetate  precipitates  its  aqueous  solution ;  ferric 
chloride  colours  it  a  blue-violet.  Bleaching  lime  causes  a  rapidly 
disappearing  dark- violet  coloration.  It  yields  azo-colouring  sub- 
stances with  diazo-compounds,  and  therefore  has  the  2OH-groups  in 
the  meta-position.  It  does  not  form  a  fluorescei'n  with  phthalic 
anhydride.  Chlorine  changes  it,  when  dissolved  in  glacial  acetic  acid, 
into  trichlororcin,  melting  at  127°.  Dissolved  in  chloroform  it  is  con- 
verted by  the  same  reagent  into  pentachlororein,  or  [1,  3,  5]-diketo- 
methyl-pentachloro-R-hexene  (B.  26,  317). 

Nitroso-orein  CH3.C6H2(OH)2(NO)  consists  of  two  modifications — 
dark-red  crystals  and  bright-yellow  needles  ;  the  first  change  to  the 
second  when  heated  to  ioo°-no°  (B.  29,  989). 

On  allowing  its  ammoniacal  solution  to  stand  exposed  to  the  air, 
orcin  changes  to  orcein  C2,H24N2O7  (B.  23,  R.  647),  which  separates 
out  in  the  form  of  a  reddish-brown  amorphous  powder.  It  dissolves 
in  alcohol  and  alkalies  with  a  dark-red  colour,  and  is  reprecipitated  by 
acids.  Orcein  forms  red  lac-dyes  with  metallic  oxides.  It  is  the  chief 
constituent  of  the  colouring  matter  archil  (called  also  persio,  cudbear, 
and  purpur — French),  which  originates  from  the  same  lichens  as  orcin 
through  the  action  of  ammonia  and  air.  Litmus  is  produced  from  the 
lichens  Roccella  and  Lecanora  by  the  action  of  ammonia  and  potassium 
carbonate.  The  concentrated  blue  solution  of  the  potassium  salt, 
when  mixed  with  chalk  or  gypsum,  constitutes  the  commercial 
litmus. 

Iso-orcin  (cresorcin,  y-orcin)  is  obtained  by  fusing  2, 4-toluol- 
disulphonic  acid  with  KOH.  Also  from  amido-o-cresol,  etc.  Also 
from  methylene-bis-resorcin  (q.v.),  resulting  from  the  action  of  formalde- 
hyde upon  resorcin,  by  reduction  with  zinc  dust  and  NaOH.  By 
repeating  the  formaldehyde  condensation  and  by  reduction  of  the 
resulting  methylene  bis-cresorcin  we  obtain  m-xylorcin  (C.  1907,  I.  547). 
Similarly,  3,  5-dioxy-o-xylol  and  1,  2,  6-trimethyl-3,  5-dioxy-benzol 
have  been  obtained  from  orcin  (A.  329,  305). 

p-Xylorcin,  or  fi-orcin,  from  m-dinitro-p-xylol,  rapidly  acquires  a  red 
colour  on  exposure  to  air  containing  ammonia.  It  has  been  obtained 
by  distillation  from  various  lichen  acids — e.g.  usnic  acid.  Mesorcin,  or 
dioxy-mesitylene,  is  made  from  dinitro-mesitylene. 


2i8  ORGANIC   CHEMISTRY 


HYDROQUINONE  GROUP. 

The  p-dioxy-benzenes  are  usually  called  hydroquinones,  because 
they  are  easily  obtained  by  the  reduction  of  the  p-quinones,  and 
just  as  readily  reconverted  into  the  latter  by  ferric  chloride. 

Hydroquinone,  p-dioxy-benzene  C6H4[i,  4](OH)2,  melting  at  169°, 
was  first  obtained  by  the  dry  distillation  of  quinic  acid  and  by  digesting 
its  aqueous  solution  with  lead  dioxide  (Wohler,  A.  65,  349)  : 

C6H7(OH)4COOH+0  =  C6H4(OH)2+ C02+3H20. 

It  results  also,  together  with  glucose,  on  boiling  the  glucoside 
arbutin  with  dilute  sulphuric  acid,  and  occurs  in  Protect  mellifera 
(B.  29,  R.  416). 

It  is  further  formed  by  the  electrolytic  oxidation  of  an  alcoholic 
benzene  solution  acidulated  with  sulphuric  acid  (B.  27,  1942),  and  by 
fusing  [i,  4]-iodo-phenol  with  potassium  hydroxide  at  180°  ;  or  from 
[2,  5]-oxy-salicyclic  acid,  and  from  para-amido-phenol ;  also  in  small 
quantities  in  the  distillation  of  succinates.  The  most  convenient 
method  of  preparing  it  consists  in  reducing  quinone  with  sulphurous 
acid  : 

Extract  the  hydroquinone  from  the  aqueous  solution  by  shaking 
with  ether,  and  purify  the  product  by  recrystallisation  from  hot  water 
that  has  passed  through  animal  charcoal  (B.  19,  1467)  and  contains 
sulphur  dioxide. 

Hydroquinone  is  dimorphous  and  crystallises  in  monoclinic  flakes 
and  hexagonal  prisms.  It  decomposes  when  quickly  heated.  It  dis- 
solves readily  in  water  (in  17  parts  at  15°),  alcohol,  and  ether.  It  forms 
crystalline  compounds  with  H2S  and  SO2;  these  are  decomposed  by 
water.  Ammonia  colours  the  aqueous  solution  reddish  brown.  It  is 
only  in  the  presence  of  ammonia  that  lead  acetate  produces  a  precipitate 
in  the  solution  of  hydroquinone.  Oxidising  agents  (like  ferric  chloride 
and  chromic  acid)  convert  hydroquinone  into  quinone  ;  quinhydrone 
is  an  intermediate  product. 

Hydroquinone,  like  quinone,  forms  quinone-dioxime  (B.  22,  1283) 
with  hydroxylamine.  It  does  not  combine  with  diazonium  salts  to 
form  azo-compounds,  but  it  is  oxidised  by  them  to  quinone  (C.  1908, 
II.  409). 

Hydroquinone  is  used  as  a  "  developer  "  in  photography,  and  in 
therapeutics  as  an  antifermentative  and  antipyretic  agent. 

Ethers.— Hydroquinone-monomethyl  ether  CH3.O[4]C6H4[i]OH  is 
formed  from  methyl-arbutin  ;  and  from  hydroquinone  by  heating  it 
with  caustic  potash,  and  methyl  iodide  or  potassium-methyl  sulphate 
(B.  14,  1989).  It  melts  at  53°  and  boils  at  247°.  The  dimethyl  ether 
melts  at  56°  and  boils  at  205°.  The  ethyl  ether  melts  at  66°  and  boils 
at  246°.  The  diethyl  ether  melts  at  71°.  Diphenyl  ether,  m.p.  77° 
(A.  350,  97). 

Hydroquinone  bis-chloro-phosphin  C6H4(OPC12)2  melts  at  65°  and 
boils  at  200°  (65  mm.),  while  hydroquinone  bis-oxy-chloro-phosphin 
C6H4(OPOC12)2  melts  at  123°  and  boils  at  270°  (70  mm.)  (B.  27, 
2568). 

Hydroquinone  diacetate  C6H4(O.COCH3)2  melts  at  123°, 


HYDROQUINONE  GROUP  219 

Hydroquinone  dibenzoate  C6H4(O.COC6H5)2  melts  at  199°. 

Homologous  hydroquinones  are  usually  prepared  by  action  of  sul- 
phur dioxide  upon  the  homologous  quinones.  Tolu-hydroquinone  re- 
sults from  the  action  of  hot  dilute  sulphuric  acid  upon  p-tolyl-hydroxyl- 
amine  and  other  p-alkyl  phenyl-hydroxylamines,  by  atomic  displace- 
ment in  the  quinols  first  formed.  The  intermediate  formation  of  tolu- 
quinols  is  also  the  cause  of  the  peculiar  formation  of  tolu-hydroquinone 
during  the  oxidation  of  p-cresol  with  potassium  persulphate  (B.  41, 
299). 

Hydro-p-xylo-quinone  bears  the  name  hydrophlorone.  Dimethyl- 
hydro-thymo-quinone,  boiling  at  249°,  occurs  in  the  ethereal  oil  of  Arnica 
montana,  also  in  "  ayapana  oil  "  of  Eupatorium  ayapana  (B.  41,  509  ; 
A.  170,  363).  Ditertiary  amyl-hydroqiiinone  results  from  hydroquinone 
and  iso-amylene  with  glacial  acetic  acid  and  sulphuric  acid  (B.  25, 2650). 

M.p. 

Hydro-tolu-quinone  (B.  15,  2981)  (CHt)[i]CtUt[2, 5](OH),  124°  (A.  215,  159) 

Hydro-o-xylo-quinone      .          .  (CH,),[i,  2]C,H,[3, 6](OH)t  121°  (B.  18,  2673) 

Hydro-m-xylo-quinone     .          .  (CH,),[i,  3]C,H,[2,  s])OH)t  150°  (B.  18,  1151) 

Hydro-p-xylo-quinone      .          .  (CH,),[i,  4]C.H,[2, 5](OH)t  212°  (A  215,  169) 

Hydro-cumo -quinone        .          .  (CH,),[i,  2, 4JC.H[3, 6](OH),  169°  (B.  18,  1152) 

Hydro-thymo-quinone     .          .  (CH,)(C,H,)[i,  4]C.H1[2,  5] (OH)  ,  139°,  b.p.  290° 

Ditert.  amylhydro-quinone       .  (CsHu),C,Hj[i,  4](OH),  185° 

Substituted  Hydroquinones. — Monochloro-  and  monobromo-hydro- 
quinones  have  been  obtained  by  the  action  of  concentrated  hydro- 
chloric or  hydrobromic  acid  upon  p-quinone  (B.  12,  1504).  Mono- 
chloro-quinone  gave  dichloro-quinone,  etc.  (A.  210,  153).  Di-,  tri-,  and 
tetrachloro-hydroquinones  result  from  the  corresponding  chlorinated 
quinone  by  the  action  of  SO2. 

Monochloro-quinone  melts  at  104°  ;  Monobromo-quinone  melts  at  110° 
[2, 5]-Dichloro-quinone  „  166°  ;  [2, 5]-Dibromo-quinone  „  186° 
[2, 6] -Dichloro-quinone  „  158°;  [2, 6]-Dibromo-quinone  „  163° 
Trichloro-quinone  ,,  134° ;  Tribromo-quinone  ,.  136° 

Tetrachloro-quinone  ,,         232° ;   Tetrabromo-quinone  „         244° 

Nitro-hydroquinone,  m.p.  133°,  is  formed  in  the  action  of  ammonium 
persulphate  upon  nitro-phenol  (/.  pr.  Ch.  2,  48,  179). 

[1, 3]-Dinitro-  and  [2, 6]-dinitro-diethyl-hydroquinone,  m.p.  233° 
and  176°  (A.  215,  149),  result  from  the  nitration  of  hydroquinone  di- 
ethylate  and  diacetate.  They  change  into  the  same  trinitro-diethyl- 
hydroquinone,  m.p.  130°,  and  [2, 5]-dinitro-hydroquinone  diacetate, 
m.p.  96°.  The  latter  compound  exchanges  an  NO2  group  very  readily 
for  NH.C6H5  (B.  24,  3824). 

Dinitro-hydroquinone  results  from  dinitro-arbutin  and  dinitro-hydro- 
quinone  diacetate.  Reduction  changes  these  compounds  to  amido- 
hydroquinones  (B.  22,  1656  ;  23,  1211).  1,  4-Diamido-hydroquinone 
is  obtained  from  the  dioxime  of  2,  5-dioxy-quinone. 

When  tetrachloro-quinone  is  digested  with  a  diluted  solution  of 
primary  sodium  sulphite  (A.  114,  324),  we  get  dichloro-hydroquinone- 
disulphonic  acid  C6C18  \  (°u^  jts  aqueous  solution  is  coloured 

( (SO3H)2 

indigo-blue  by  ferric  chloride.     When  its  alkaline  solution  is  boiled  it 
oxidises  to  potassium  euthio-chronate. 


220  ORGANIC  CHEMISTRY 

Monothio-hydroquinone  C6H4[i,  4](OH)(SH),  m.p.  30°  and  b.p. 
167°  (45  mm.),  results  from  p-diazo-phenol  chloride  and  potassium 
xanthogenate.  p-Oxy-diphenyl  sulphide  C6H5S[i]C6H4[4]OH  results 
from  heating  benzol-sulphinic  acid  with  phenol  to  150°  (C.  1904, 
I.  130). 

Dithio-hydroquinone  CgH4[i,  4](SH)2,  m.p.  98°,  is  obtained  from 
p-benzol-disulphonic  chloride  or  diazo-phenyl  disulphide.  In  the  air 
it  gradually  oxidises  to  p-phenylene  disulphide  [C6H4S2]*.  Methyla- 
tion  converts  it  into  p-phenylene-dimethyl  sulphide  C6H4(SOCH3)2, 
m.p.  188°,  which,  on  oxidation  with  HNO3,  yields  a  disulphoxide 
C6H4(SOCH3)2,  m.p.  188°,  and  a  disulphone  C6H4(SO2CH3)2,  m.p.  260° 
(B.  42,  2721). 

TRIHYDRIC  PHENOLS. 

The  three  isomeric  trioxy-benzols  are  known  in  the  compounds 
pyrogallol,  phloroglucin,  and  oxy-hydroquinone. 

Among  the  methods  of  forming  polyoxy-benzols  we  must  mention 
the  hydrolysis  of  polyamido-benzols,  which  is  useful  for  preparing 
phloroglucins  or  sym.  trioxy-benzols. 

Pyrogallol,  pyrogallic  acid  C6H3[i,2,3](OH)3,  'm.p.  132°,  is  pro- 
duced by  the  elimination  of  CO2  from  gallic  acid  or  pyrogallo-carbo- 
xylic  acid  CO2H[i]C6H2[3,4,5](OH)3,  when  heated  alone,  as  was  first 
observed  by  Scheele  (1786),  or,  better,  with  water  to  210°  ;  also  by 
fusing  the  two  p-chloro-phenol-disulphonic  acids  and  haematoxylin  with 
potassium  hydroxide.  It  forms  white  flakes  or  needles.  It  dissolves 
readily  in  water,  with  more  difficulty  in  alcohol  and  ether.  Its  alka- 
line solution  absorbs  oxygen  very  energetically  (B.  14,  2666),  turns 
brown,  and  decomposes  into  carbon  dioxide,  acetic  acid,  and  brown 
substances.  It  is  used  in '  gas  analysis  for  the  determination  of 
oxygen.  Pyrogallol  quickly  reduces  salts  of  mercury,  silver,  and 
gold,  with  precipitation  of  the  metals,  while  it  is  oxidised  to  acetic 
and  oxalic  acids. 

Ferrous  sulphate  containing  ferric  oxide  colours  its  solution  blue, 
ferric  chloride  red.  Lead  acetate  precipitates  white  C6H6O3.PbO. 
An  iodine  solution  imparts  a  purple-red  colour  to  an  aqueous  or  alco- 
holic pyrogallol  solution.  Gallic  and  tannic  acids  react  similarly. 
Electrolytic  dissociation  produces  purpuro-gallin  (C.  1903, 1.  927  ;  1904, 
I.  798,  1005). 

1-Monomethyl  ether,  m.p.  40°,  b.p.16 147°.  2-Monomethyl  ether, 
m.p.  87°,  b.p.24  155°. 

1,  3-Dimethyl  ether  is  found  in  beechwood  creosote.  It  melts  at 
5i°-52°  and  boils  at  252°  (B.  11,  333  ;  M.  19,  557).  Also  by  partial 
saponification  of  pyrogallol-trimethyl  ether.  It  is  notable  that  the 
methoxyl,  although  occupying  the  middle  position,  is  most  easily 
saponified  (C.  1905,  II.  1062).  Different  oxidising  agents  convert  it 
into  ccerulignone,  a  diphenyl  derivative. 

1,  2-Dimethyl  ether,  b.p.  235°  (C.  1904,  II.  1118). 

The  trimethyl  ether  melts  at  47°  and  boils  at  235°  (B.  21,  607, 

2020). 

The  ethyl,  diethyl,  and  triethyl  ethers  melt  at  95°,  79°,  and  39°.  The 
syrupy  dimethyl  acetate  yields  a  quinone,  C6H2(OCH3)2O2,  with 
chromic  acid  ;  the  triacetate  crystallises. 


TRIHYDRIC   PHENOLS  221 

Pyrogallol  carbonate   OHC6H3<^>CO,  m.p.   133°,  from  pyrogallol 

and  phosgene  in  pyridin  solution.  Hot  water  regenerates  the  pyrogallol 
(B.  37,  106). 

Trichloro-pyrogallol  C6C13(OH)3  melts  with  decomposition  at  177° 
(B.  20,  2035). 

4-Bromo-pyrogallol  Br[4]C6H2[i,2,3](OH)3,  m.p.  140°  with  decom- 
position ;  4, 6-dibromo-pyrogallol  Br2[4,6]C6H[i,2,3](OH)3,  m.p.  158° 
with  decomposition.  These  are  formed  by  brominating  the  pyro- 
gallol carboxylate. 

Tribromo-pyrogallol  C6Br3(OH)3,  from  pyrogallol  and  bromine, 
when  digested  with  bromine  yields  xanthogallol  C18H4Br14O6,  m.p. 

122°  (A.  245, 335). 

4-Nitro-  and  4,  6-dinitro-pyrogallol,  m.p.  162°  and  208°,  by  nitro- 
genation  of  pyrogallol  carboxylate.  By  reduction  we  obtain  the  cor- 
responding amido-compounds  as  easily  oxidisable  substances,  which, 
on  boiling  with  water  or  dilute  acids,  become  I,  2,  3,  4-tetra-oxy-  and 
penta-oxy-benzol  respectively  (B.  37,  114). 

Methyl-pyrogallol-dimethyl  ether  CH3.C6H2(OH)(OCH3)2,  m.p.  36° 
and  b.p.  265°,  occurs  in  beechwood  creosote  (B.  12,  1371).  1-Methyl- 
[3, 4, 5]-pyrogallol-[4, 5]-dimethyl  ether,  irodol,  m.p.  57°  and  b.p.  249°, 
is  formed  on  distilling  iridic  acid  CO2H.CH2.C6H2(OH)(OCH3)2 
(B.  26,  2018). 

Propyl-pyrogallol-dimethyl  ether,  picamar  C3H7.C6H2(OH)(OCH3)2, 
b.p.  245°,  was  discovered  in  beechwood  creosote  by  Reichenbach 
(B.  11,  329  ;  A.  8,  224).  5-Amido-pyrogallol-trimethyl  ether  (CH3O) 
C8H2NH2,  m.p.  114°,  from  trim  ethyl-gallic  amide  (A.  340,  224). 

Phloroglucin  C6H3[i,3,  5](OH)3  melts  at  219°  when  it  is  rapidly 
heated.  Hlasiwetz  first  obtained  it  (1855)  in  the  decomposition  of 
phloretin  (q.v.).  It  can  also  be  prepared  from  qiiercetin,  hesperidin,  and 
other  glucosides  (q.v.).  It  is  formed  from  different  resins  (catechu,  kino, 
gamboge,  dragon's  blood,  and  others),  on  fusion  with  caustic  potash. 
It  is  most  easily  made  by  fusing  resorcin  with  caustic  soda  (B.  14,  954  ; 
18,  1323)  ;  by  the  fusion  of  orcin  and  benzol-trisulphonic  acid  with 
sodium  hydroxide  ;  also  by  the  saponification  and  decomposition  of 
synthetically  prepared  phloroglucin-tricarboxylic  ester,  which  gives 
up  2 CO 2  (B.  18,  3454).  It  is  best  formed  from  sym.  triamido-benzol, 
which  is  not  isolated,  but  hydrolysed  by  boiling  the  solution  of  the 
double  tin-salt  obtained  direct  from  trinitro-benzol. 

In  the  same  way  homologous  phloroglucins  have  been  obtained  : 
mono-,  di-,  and  trimethyl-phloroglucm  C6H2(CH3)(OH)3,  C6H(CH3)2 
(OH)3,  C6(CH3)3OH3,  which  melt  at  215°,  163°,  and  184°  respectively 
(C.  1898,  II.  537  ;  1900,  I.  600). 

It  crystallises  in  large,  colourless  prisms  with  2H2O ;  these 
effloresce  in  the  air.  It  loses  all  its  water  of  crystallisation  at 
110°,  melts  at  218°,  and  sublimes  without  decomposition.  It  has 
a  sweetish  taste,  and  dissolves  readily  in  water,  alcohol,  and  ether. 
Lead  acetate  precipitates  it  ;  ferric  chloride  colours  its  solution  a 
dark  violet. 

Chlorine  oxidises  phloroglucin  to  dichloracetic  acid  and  tetrachlor- 
acetone.  One  of  the  first  intermediate  products  is  hexachloro-triketo- 
R-hexylene.  For  the  action  of  bromine,  see  B.  23,  1706.  It  is  con- 


222  ORGANIC  CHEMISTRY 

verted  by  reduction  into  phloroglucite  or  sym.   trioxy-hexamethylene 
(B.  27,  357). 

Phloroglucin,  in  most  of  its  reactions  —  for  example,  with  phenyl 
cyanate  (see  B.  23,  269),  —  conducts  itself  like  a  trihydric  phenol 
C6H3(OH)3  ;  on  the  other  hand,  it  unites  with  three  molecules  of  hydro- 
xylamine  to  form  a  trioxime  (see  below),  hence  it  may  be  considered  a 
triketone  —  [i,  3,  5]-triketo-hexamethylene  (B.  19,  159). 


Trioxy  benzol  Triketo-hexamethylene. 

In  order  to  explain  the  trioxime  formation  it  might  be  assumed 
that  the  [i,  3,  5]-trioxy-benzo-formula  is  the  unstable  pseudo-form  of 
phloroglucin. 

In  the  keto-form,  phloroglucin  also  reacts  in  the  methylation,  with 
methyl  iodide  and  alkali,  which  finally  leads  to  hexamethyl-phloro- 
glucin  or  hexamethyl-triketo-hexamethylene  C6(CH3)6O3,  m.p.  80°,  b.p. 
248°,  also  formed  by  methylation  of  the  homologous  methyl-phloro- 
glucins,  and  split  up  by  fuming  HC1  into  di-iso-propyl-ketone  and  iso- 
butyric  acid  (B.  23,  R.  462  ;  C.  1899,  II.  760).  A  peculiar  phenomenon 
is  the  condensation  of  phloroglucin  and  its  homologues  with  salicyl 
aldehyde  tofluorones  (q.v.),  a  reaction  in  which  part  of  the  phloroglucin 
molecule  acts  in  the  keto-form,  and  another  part  in  the  hydroxyl  form 
(M.  21,  62). 

Phloroglucin  easily  combines  with  formaldehyde  to  form  methylene- 
bis-phloroglucin  CH2[C6H2(OH)3]2,  a  diphenyl-methane  derivative, 
which,  on  reduction  with  zinc  dust  and  NaHO,  decomposes  into  phloro- 
glucin and  methyl-phloroglucin,  as  well  as  a  little  dimethyl-  and  tri- 
methyl-phloroglucin  (A.  329,  269).  This  has  a  close  connection  with 
Filix  acid  from  Aspidium  filix-mas,  which,  on  reduction  with  zinc 
dust  and  NaHO,  yields,  besides  mono-,  di-,  and  trimethyl-phloroglucin, 
also  butyryl-filicinic  acid.  On  prolonged  action  the  latter  is  split  up 
into  n-butyric  acid  and  filicinic  acid,  probably  represented  by  gem-di- 

methyl-dioxy-dihydro-keto-benzol  CH^  OH  R:°  (A>  307'  249  '  318' 
230). 

Phloroglucin  trioxime  C6H6(NOH)3,  a  crystalline  powder  exploding 
at  155°.  Phenyl-hydrazin  attaches  itself  to  phloroglucin  much  as  it 
does  to  oxalic  ester  and  dioxy-succinic  ester. 

Trinitroso-phlorogluein  C6(NO)3(OH)3  (B.  11,  1375)  and  trinitro- 
phloroglucin  C6(NO2)3(OH)3  yield  on  reduction  triamido-phloroglucin 
C6(NH2)3(OH)3,  which,  on  boiling  with  MnO2  and  soda,  yields  croconic 
acid  (B.  26,  2185). 

Phloroglucin  ethers  result  from  treating  phloroglucins  with  alco- 
hols and  HC1,  or  from  methylation  with  diazo-methane  or  dimethyl 
sulphate  in  etheric  solution  (C.  1906,  II.  1836).  Monomethyl  ether, 
m-P-  75°-78°,  b.p.16  213°,  gives  a  mononitroso-derivative,  which  may 
be  converted  into  oxy-methoxy-p-quinone  (C.  1903,  I.  285),  and  a  di- 
nitroso-derivative,  which,  on  reduction,  yields  diamido-dioxy-anisol. 

Dimethyl  ether,  m.p.  37°,  b.p.17  i72°-i75°,  forms  with  N2O3  an  o-  as 
well  as  a  p-nitroso-derivative,  3,  $-dimethoxy-quinone  oxime,  red  flakes, 
and  3,  5-dimethoxy-quinone  oxime,  yellow  needles  (M.  21,  15).  Tri- 


TRIHYDRIC  PHENOLS  223 

methyl  ether,  m.p.  52°,  b.p.  255°,  also  obtained  by  splitting  up  methyl- 
dihydro-cotoi'n  with  potash. 

Triphenyl  ether  C6H3(OC6H5)3,  m.p.  112°,  by  heating  sym.  tri- 
bromo-benzol  with  K  phenate  in  the  presence  of  Cu  bronze  (A.  350, 
102).  On  chlorination  products  of  phloroglucin  ether,  see  C.  1902, 
II.  739.  Phlorogluein  triacetate,  m.p.  105°.  Trithio-phloroglucin 
C6H3(SH)3,  m.p.  58°.  Triacetate,  m.p.  74°.  Trimethyl  ether,  m.p.  68° 
(B.  42,  3252). 

Oxy-hydroquinones  result  from  the  reduction  of  oxy-quinones. 

Oxy-hydroquinone  C6H3[i,  2,  4](OH)3  is  produced  on  fusing  hydro- 
quinone  with  KOH  (together  with  tetra-  and  hexa-oxy-diphenyl  (B. 
18,  R.  24).  It  is  crystalline,  very  soluble  in  water  and  ether,  and  in 
aqueous  solution  soon  acquires  a  dark  colour.  It  melts  at  140-5°. 
Ferric  chloride  colours  it  a  dark  greenish  brown.  Its  triethyl  ether 
C6H3(O.C2H5)3  is  obtained  from  trioxy-ethyl-benzoic  acid  (from  aescule- 
tin).  It  can  also  be  prepared  by  ethylating  ethoxy-hydroquinone. 
It  melts  at  34°  (B.  20, 1133).  The  trimethyl  ether  C6H3(O.CH3)3,  from 
methoxy-quinone,  boils  at  247°.  A  better  method  of  producing  oxy- 
hydroquinone  is  from  its  triacetate,  m.p.  97°  (A.  311,  341  ;  C.  1899,  I. 
1094)  : 

C6H4O2+2(CH3CO)2O  =  C6H3(OCOCH3)3+CH3COOH. 

Sodium  amalgam  reduces  it  to  dihydro-resorcin. 

Nitro-  and  halogen  oxy-hydroquinones,  see  B.  34,  2837.  Hydro- 
quinone  monomercaptan  C6H3(OH)2SH,  m.p.  120°,  is  obtained  by 
splitting  up  hydroquinone-thio-sulphonic  acid  C6H3(OH)2S.SO3H  and 
analogous  sulphuretted  hydroquinone  derivatives,  prepared  by  the 
action  of  sodium  thio-sulphate  and  other  thio-acids  upon  benzo-quinone. 
Iodine  oxidises  it  to  hydroquinone  disulphide  [C6H3(OH)2]2S2,  m.p. 
183°  (C.  1906,  II.  1467). 

TETRAHYDRIC  PHENOLS. 

There  are  three  possible  isomerides  :  (i)  Apionol,  v-tetraoxy- 
benzol  [phenetetrot]  C6H2[i,  2,3,4] (OH)4,  needles,  m.p.  l6l°>  by  boiling 
amido-pyrogallol  chlorohydrate  in  water.  Dimethyl-apionol  C6H2 
[i,  2,  3,  4](O.CH3)2(OH)2,  by  heating  apiolic  acid  with  caustic  potash. 
It  melts  at  106°  and  boils  at  298°.  Tetramethyl-apionol  C6H2(O.CH3)4 
melts  at  81°. 

[1, 2]  -  Methylene  -  3, 4  -  dimethyl  -  apionol  C6H2(O2  :  CH2)(O.CH3)2, 
apione,  is  formed  when  apiolic  acid  is  heated  with  dilute  sulphuric 
acid.  It  melts  at  69°  (B.  24,  2608  ;  29,  1806). 

l-n-Propyl-2, 3, 4, 5-tetraoxy-benzol  is  obtained  as  methylene- 
dimethyl  ether,  dihydro-apiol,  melting  at  25°  and  boiling  at  292°,  in  the 
reduction  of  isapiol. 

(2)  Unsym.  tetraoxy-benzol  C6H2[i,2,3, 5](OH)4  is  an  amorphous, 
glassy  mass  obtained  from  iretol  by  the  action  of  hydrochloric  acid 
at  150°.     The  1, 3-dimethyl  ether  is  prepared  by  reducing  i,  3-dimeth- 
oxy-2,  5-quinone.     It  melts  at  158°.     The  tetramethyl  ether  melts  at  - 
47°  and  boils  at  271°  (B.  23,  2291). 

Iretol  CH3O.C6H2(OH)3  melting  at  186°,  is  one  of  its  monomethyl 
ethers.  It  is  formed  together  with  iridic  acid  on  fusing  irigenin  with 
potash  (B.  26,  2015). 


224  ORGANIC   CHEMISTRY 

(3)  Sym.  tetraoxy-benzol  C6H2[i,  2, 4, 5](OH)4  is  obtained  by 
reducing  i,  4-dioxy-2, 5-quinone  with  stannous  chloride.  It  melts 
at  2I5°-220°.  Its  tetra-acetyl  ester  melts  at  217°  (B.  21,  3374). 

Dichloro-tetraoxy-benzol,  hydro-chloranilic  acid  C6C12(OH)4  results 
in  the  reduction  of  chloranilic  acid  with  sulphurous  acid  (A.  146,  32). 

Amido-s-tetraoxy-benzol  results  from  the  action  of  stannous 
chloride  upon  nitro-dioxy-quinone,  and  also  Nitro-amido-s-tetraoxy- 
benzol  and  diamido-s-tetraoxy-benzol  (B.  18,  502),  by  the  reduction 
of  nitranilic  acid.  Croconic  acid  and  ammonia  are  produced  on  boil- 
ing the  diamido-body  with  potash  ;  oxidising  agents  convert  it  into 
diamido-dioxy-quinone. 

Hydro-euthiochronic  alkali  salts,  see  Euthiochronic  acid,  below. 

Pentahydric  Phenols. — Pentaoxy-benzol  C6(OH)5H,  colourless  crys- 
tals, from  diamido-pyrogallol  on  boiling  in  water  (B.  37,  122).  Penta- 
acetate,  m.p.  165°.  Its  diethyl  ether,  see  C.  1903,  II.  829. 

Hexahydric  Phenols. — In  describing  the  benzene  ring  formations 
mention  was  made  of  the  remarkable  isolation  of  potassium  hexaoxy- 
benzene  or  potassium-carbon  monoxide  (discovered  by  Liebig  in 
1834),  which  results  upon  conducting  carbon  monoxide  over 
heated  potassium  (confirmed  by  Nietzki  and  Benkiser  in  1885). 
Dilute  hydrochloric  acid,  acting  upon  the  fresh  mass,  yields 
hexaoxy-benzene. 

Hexaoxy-benzene  C6(OH)6  is  obtained  from  triquinoyl  by  reduction 
with  stannous  chloride  and  hydrochloric  acid.  It  separates  in  the  form 
of  small,  grayish-white  needles,  which  acquire  a  reddish-violet  colour 
on  exposure  to  the  air.  They  are  not  fusible,  but  decompose  at  about 
200°.  Concentrated  nitric  acid  oxidises  it  to  triquinoyl. 

It  forms  the  hexacetyl  derivative  C6(O.C2H3O)6  when  heated  with 
acetic  acid  and  sodium  acetate.  It  is  a  crystalline  mass,  melting  at 
203°  (B.  18,  506). 

8.  Quinones. 

This  is  the  designation  ascribed  to  all  derivatives  of  benzene  in  which 
2H-atoms  are  replaced  by  2O-atoms.  The  replacement  is  either  in  the 
o-  or  the  p-position.  We  distinguish  ortho-quinones  and  para-quinones. 
The  latter  are  especially  characteristic  of  the  mono-nucleus  aromatic 
hydrocarbons.  Metaquinones  are  not  known. 

Constitution. — The  constitution  of  the  quinones  of  the  aromatic 
hydrocarbons  having  one  nucleus  is  not  fully  established.  They  are 
considered  either  as  benzene  derivatives,  the  oxygen  atoms  being  as- 
sumed to  be  linked  to  one  another,  or  as  p-dihydro-benzol  derivatives, 
containing  two  ketone  groups. 

The  first  view  compares  the  quinones  to  peroxides  ;  they  are  indeed 
powerful  oxidising  agents.  Upon  reduction  they  do  not  become  the 
p-diglycols  of  the  p-dihydro-benzols,  but  p-dioxy-benzols,  which  are 
true  benzene  derivatives.  The  p-quinones  yield  hydroquinones,  and 
the  o-quinones  the  pyrocatechins.  Further,  each  oxygen  atom,  by 
the  action  of  PC15,  is  replaced  by  one  chlorine  atom.  In  opposition  to 
the  peroxide  formula  of  the  para-quinones  we  have  the  p-diketone 
formula,  in  support  of  which  we  can  bring  forward  the  formation  of  a 
monoxime  and  a  dioxime,  as  well  as  the  absorption  of  2Br  and  4Br  by 
para-quinone  (/.  pr.  Ch.  2,  42,  61  ;  B.  23,  3141).  Nitroso-phenol  is 


QUINONES  225 

considered  by  most  chemists  to  be  quinone  monoxime.  The  various 
formulas  for  o-  and  p-quinone  are  : 

-O               CH                            CO  CH 


HC       CH  HC       CO 

II       II  II 

HC       CH  HC       CO 

CO  CH 


Peroxide  formula  for  p-  and  o-quinone.  Diketone  formula  for  p- 

and  o-quinone. 

At  the  present  time  the  diketone  formula  is  generally  preferred. 

Ortho-quinones.  —  The  ortho-quinones  are  much  less  stable  than  the 
para-quinones.  The  isolation  of  the  simplest  o-quinone  has  only  been 
successfully  accomplished  quite  recently  (Willstatter,  1904).  Chloro- 
and  bromo-substitution  products  of  o-quinone  have  been,  on  the  other 
hand,  known  for  some  time  (Zincke). 

o-Benzo-quinone  C6H4[i,  2]O2  is  formed  by  gentle  oxidation  of  pyro- 
catechin  with  silver  oxide  in  etheric  solution  (B.  37,  4744).  It  exists 
in  two  isomeric  forms  (B.  41,  2580).  When  freshly  prepared,  it  forms 
colourless  prisms,  which  shortly  change  into  the  more  stable  form  of 
bright-red  plates,  which  melt  with  decomposition  at  6o°-7O°.  Chemi- 
cally, both  forms  are  perfectly  equal.  They  are  strong  oxidisers,  and 
liberate  iodine  from  acidulated  KI  solution  ;  on  reduction  with  sul- 
phurous acid  they  yield  pyrocatechin.  The  two  isomers  perhaps  cor- 
respond to  the  above  peroxide  and  diketone  formulae.  The  o-benzol- 
quinone,  in  contrast  with  p-quinone,  is  odourless  and  not  volatile  ; 
in  this  respect  it  more  closely  resembles  the  o-quinones  of  the  hydro- 
carbons with  condensed  ring  systems  ;  cp.  naphtho-quinone  and  phen- 
anthrene-quinone. 

1,  2-Dimethyl-4,  5-benzo-quinone  (CH3)2[i,  2]C6H2[4,  5]O2,  long  red 
needles,  m.p.  102°,  by  oxidation  of  5-oxy-4-amido-i,  2-dimethyl-benzol 
with  potassium  bichromate  and  sulphuric  acid.  Tetraehloro-o-benzo- 
quinone  C6Cl4[i,  2]O2,  m.p.  131°,  and  tetrabromo-o-benzo-quinone 
C6Br4[i,  2]O2,  m.p.  195°,  are  formed  by  the  action  of  chlorine 
and  bromine  upon  pyrocatechin  dissolved  in  glacial  acetic  acid 
(Zincke,  B.  20,  1776).  Tetrachloro-benzo-quinone,  with  aniline,  trans- 
poses itself  into  dianilino-dichloro-o-benzo-quinone  C6C12(NHC6H5)2O2, 
which  on  further  action  of  aniline  passes  into  dianilino-monochloro- 
quinone-anile  C6HC1(NHC6H5)2(  :  O)(:  NC6H5),  m.p.  180°.  This  is  prob- 
ably a  derivative  of  p-quinone,  since  reduction  with  sulphurous  acid 
changes  it  to  dianilino-p-quinone-anile  (B.  38,  4103).  The  halogen- 
substituted  o-benzo-quinones  show  a  great  tendency  to  form  addition 
products  with  the  most  varied  classes  of  bodies.  Thus,  the  tetrabromo- 
o-benzo-quinone  forms  with  methyl  alcohol  a  very  stable  combination 
(C6Br4O2)2CH3OH,  m.p.  261°,  which  can  be  acetylated  (B.  36,  454). 

Homologous  chlorinated  ortho-quinones  are  formed  by  the  action 
of  chlorine  upon  the  corresponding  ortho-diamine  chlorohydrates. 
The  o-diketo-chlorides  first  formed  may  be  reduced  to  chlorinated 
o-dioxy-benzols,  which  then  give  the  chlorinated  o-quinones  by  oxida- 
tion (B.  27,  560). 

Ortho-benzo-quinone,  and  several  of  its  homologues,  have  been 

VOL.  II.  Q 


226  ORGANIC   CHEMISTRY 

obtained  in  the  form  of  dioximes  by  reduction  of  the  corresponding 
o-dinitroso-benzols  ;  o-nitroso-phenol  should  be  regarded  as  a  mon- 
oxime  of  o-benzo-quinone. 

PARA-QUINONES. 

Benzo-quinone  C6H4O2,  m.p.  116°,  was  first  obtained  in  1838  by 
Woskresensky  upon  oxidising  quinic  acid,  a  hexahydro-tetraoxy- 
benzoic  acid,  with  manganese  peroxide  and  sulphuric  acid.  Woskre- 
sensky named  the  new  body  quinoyl,  while  Berzelius  (Berz.  Jahresb. 
19,  407)  proposed  the  name  quinone. 

Quinone  results  from  the  electrolytic  oxidation  of  benzene  (C.  1901, 
I.  348)  or  from  oxidation  with  silver  peroxide  (B.  38,  3964)  ;  but  most 
easily  from  hydroquinone  or  p-dioxy-benzol  by  the  action  of  ferric 
chloride,  and  from  many  p-di-derivatives  of  benzene  by  oxidation, 
mostly  with  potassium  bichromate  and  sulphuric  acid  ;  thus,  from 
p-phenylene-diamine,  sulphanilic  acid,  p-amido-azo-benzene,  p-amido- 
phenol,  p-phenol-sulphonic  acid,  p-diamido-diphenyl,  or  benzidin. 
It  is  usually  prepared  by  oxidising  aniline  with  sodium  bichromate  and 
sulphuric  acid  (Nietzki,  B.  20,  2283),  in  which  process  a  black  dye,  ani- 
line black,  is  formed  as  an  intermediate  product  (B.  42,  2147).  It  has 
also  been  obtained  by  oxidising  quinite  (q.v.). 

Quinone  crystallises  in  golden-yellow  prisms.  It  possesses  a  peculiar, 
penetrating  odour.  It  is  poisonous  and  attacks  the  skin.  It  distils 
readily  with  steam,  and  dissolves  easily  in  hot  water,  alcohol,  and  ether. 
It  turns  brown  on  exposure  to  sunlight.  In  the  presence  of  the  latter 
it  combines  to  dioxy-benzo-phenones  with  benzaldehyde,  and  to  dioxy- 
aceto-phenone  with  acetaldehyde  (B.  31,  1214). 

From  acidulated  KI  solution  quinone  separates  iodine,  and  this 
circumstance  may  be  used  for  the  volumetric  estimation  of  quinone 
solutions  (C.  1899,  II.  906  ;  B.  43,  1171). 

Reducing  agents  (SO2,  Zn,  and  HC1)  convert  it  first  into  quinhydrone, 
an  addition  product  of  quinone  and  hydroquinone,  which  nascent 
hydrogen  changes  into  hydroquinone. 

Hydrogen,  in  the  presence  of  finely  divided  nickel,  also  reduces 
quinone  to  hydroquinone  at  i8o°-i90° ;  while  at  lower  temperatures 
a  further  set  of  six  H  atoms  is  embodied  and  I,  4-cyclohexane-diol  is 
formed  (C.  1908,  I.  1458). 

Concentrated  nitric  acid  dissolves  it  in  the  cold,  but  when  the  acid 
is  hot  it  is  decomposed,  oxalic  and  prussic  acids  being  formed.  Silver 
peroxide  splits  it  up  into  maleic  acid  and  CO2  (B.  39,  3715).  Bromine 
converts  quinone  into  quinone  di-  and  tetrabromides,  melting  at  80° 
and  at  I7O°-I75°.  p-Diketo-hexamethylene,  the  hydride  corresponding 
to  quinone  tetrabromide,  has  been  obtained  by  starting  with  succino- 
succinic  ester.  With  acetic  anhydride  and  concentrated  sulphuric 
acid  it  combines  to  form  the  triacetate  of  oxy-hydroquinone. 

Phosphorus  pentachloride  converts  quinone  into  p-dichloro-benzene ; 
hydroxylamine  chloride  changes  it  to  quinone  oxime  or  nitroso-phenol, 
and  quinone  dioxime.  Phenyl-hydrazin  reduces  it  to  hydroquinone  ; 
a-alkyl-phenyl-hydrazins  show  a  similar  reducing  power,  changing 
simultaneously  with  tetrazones.  Nitro-  and  a-acidyl-phenyl-hydrazins, 
on  the  other  hand,  yield  monohydrazins  of  the  quinones. 

The  nuclear  H  atoms  of  quinones  are  relatively  easy  to  replace. 


PHENOL  ADDITION   PRODUCTS  OF  QUINONE       227 

Substitution  takes  place  with  or  without  reduction  to  hydroquinone. 
With  HCN  dicyano-hydroquinone  is  formed,  C6H2[i,  4](OH)2[2,  3](CN)2. 
With  benzol-sulphinic  acid  quinone  combines  to  form  dioxy-diphenyl- 
sulphone  C6H5SO2C6H3(OH)2  (a  general  reaction  of  quinoid  sub- 
stances). Thio-acids  of  the  general  formula  RSH  (where  R  denotes 
an  acid  radicle),  like  thio-sulphuric  acid,  monothio-carboxylic  acids, 
xanthogenic  acids,  sulpho-cyanic  acid,  unite  with  quinone  to  sul- 
phuretted derivatives  of  oxy  -  hydroquinone  :  C6H3(OH)2S.SO3H, 
C6H3(OH)2S.COC6H5,  C6H3(OH)2S.CS.OC2H5,  etc.  (C.  1906,  II.  1466). 
With  benzo-hydrolene  (q.v.),  water  is  liberated  and  compounds  like 
C6H2O2[CH(C6H5)2]2  are  formed,  belonging  to  the  polynuclear  aromatic 
substances  (B.  32,  2146).  With  aniline,  quinone  gives  dianilido-quinone 
dianile.  With  pyridin  and  quinolin  salts,  quinone  gives  addition  pro- 
ducts (C.  1903,  I.  1408).  With  some  metal  haloids,  it  forms  addition 
products  of  a  dark  colour  (B.  41,  2568).  With  halogen  hydride,  mono- 
and  dihalogen  hydroquinone  are  formed  (A.  336,  108).  On  boiling 
with  primary  alcohols  and  adding  zinc  chloride,  quinone  forms  dialk- 
oxy-quinone  (B.  34,  3993). 

On  the  condensation  of  quinones  with  aceto-acetic  ester  to  form 
cumarone  derivatives,  see  the  latter.  On  the  addition  of  diazo- 
methane  to  quinone,  see  B.  32,  2292. 

PHENOL  ADDITION  PRODUCTS  OF  QUINONE  (A.  215,  134). 

Of  the  addition  products  of  quinone,  those  with  mono-  and  dihydric 
phenols  are  the  most  important.  In  general,  quinone  unites  with  two 
molecules  of  a  monohydric,  and  with  one  molecule  of  a  dihydric  phenol. 
But  there  are  exceptions  (B.  42,  1149).  These  phenol  addition  pro- 
ducts of  quinone  are  distinguished  by  their  intense  coloration,  and  by 
the  ease  with  which  they  break  up  into  their  components  on  solution. 

Pheno-quinone  C6H4O2.2C6H5OH,  m.p.  71°,  by  addition  of  quinone 
and  phenol.  It  is  easily  volatilised,  crystallises  in  red  needles,  and  is 
coloured  blue  by  potash  lye,  and  green  by  baryta  water.  Addition 
products  with  homologous  phenols,  see  C.  1898, 1.  887.  On  heating  the 
phenols  with  quinone,  with  or  without  H2SO4,  colourless  compounds 
are  formed  without  evolving  water.  They  differ  from  pheno-quinone, 
and  must  be  regarded  as  probably  hydroxylated  diphenyl  ethers,  e.g. 
OHC6H4OC6H3(OH)2  from  resorcin  and  quinone  (B.  30,  2563  ;  C.  1898, 

II.  156). 

Thio-pheno-quinone  C6H4O2.2C6H5SH  is  formed  similarly  from 
quinone  and  thio-phenol.  It  forms  crystals  of  a  dark-bronze  colour, 
colouring  blue  with  NaHO.  Gentle  oxidation  converts  it  into  3,  6- 
diphenyl-thio-quinone  (C6H5S)2[3, 6]C6H2[i,  4]O2,  m.p.  257°,  which 
is  easily  reduced  to  3,  6-diphenyl-hydroquinone.  On  acetylation  of 
thio-pheno-quinone,  hydroquinone  diacetate  is  formed,  with  splitting 
of  the  molecule  (A.  336,  85).  Compounds  resembling  thio-pheno- 
quinone  are  also  formed  from  quinone  with  aliphatic  mercaptans. 

Quinhydrone  C6H4O2.C6H4(OH)2.— This  is  produced  by  the  direct 
union  of  quinone  with  hydroquinone.  It  appears  as  an  intermediate 
product  in  the  reduction  of  quinone  or  in  the  oxidation  of  hydroquinone 
— e.g.  in  electrolysis  (B.  29,  R.  1122), — and  is  changed  by  continued 
oxidation  into  quinone,  and  by  reduction  into  hydroquinone.  It  con- 


228  ORGANIC  CHEMISTRY 

sists  of  green  prisms  or  leaflets  with  metallic  lustre,  has  a  quinone-like 
odour,  melts  readily,  and  dissolves  in  hot  water  with  a  brown,  in  alcohol 
and  ether  with  a  green,  colour.  When  it  is  boiled  with  water  it  decom- 
poses into  hydroquinone  and  quinone.  The  constitution  of  these  com- 
pounds probably  corresponds  to  the  following  formulas  (B.  28,  1615  ; 
29,  R.  903  ;  A.  336,  90),  in  which  the  two  bodies  appear  either  as  hemi- 
acetal  compounds,  or  as  derivatives  of  dioxy-p-diketo-hexamethylene  : 

HO— C— OC6H5  CO 

TT/~*          /~*TJ  ^•/6          5  \/"*  y^TT 

-LAV^          k^XT  -|--|-     /\-s  V_>ii2 

Pheno-quinone  ||       ||  or  |       |   /TT 

HC    CH  H2C     C< 

V  'x/XOCeH, 

C6H60— C— OH  CO 


Quinhydrone   C6H4< 


[i]O— C— OH 

/\ 
HC    CH 

II      II 
HC    CH 

v 

[4]O— C— OH 


or  C6H4 


H2C     CO 

i       I 


[4]0-CH 


Neither  formula,  however,  explains  the  intense  colour  or  the  easy 
dissociation  of  these  products.  There  is  therefore,  of  late,  a  tendency 
to  regard  the  pheno-quinones  and  quinhydrones  as  loose  molecular 
compounds,  whose  structure  cannot  be  numerically  expressed  by  changes 
of  valency  (B.  41,  1463  ;  /.  pr.  Ch.  2,  79,  418).  On  an  interpretation 
of  quinhydrones  as  oxonium  compounds,  see  B.  43,  3603. 

Homologous  p-Quinones. — They  are  produced  (i)  by  the  oxidation 
of  the  corresponding  p-dioxy-benzenes  or  hydroquinones  (even  with 
ferric  chloride),  of  the  corresponding  p-diamines,  p-amido-phenols,  such 
as  amido-thymol  and  many  other  di-substitution  products  belonging  to 
the  p-series,  with  ferric  chloride,  chromic  acid,  and  manganese  dioxide 
and  sulphuric  acid.  (2)  Even  mono-substituted  alkyl-benzenes  yield 
p-quinones,  especially  when  they  are  oxidised  with  chromic  acid.  This 
is  particularly  true  of  amido-  and  oxy-alkyl-benzenes  or  alkyl-phenols. 
Thus,  o-toluidin  yields  tolu-quinone,  while  thymol  and  carvacrol  yield 
thymo-quinone  or  thy  moil.  Frequently  an  alkyl  group  will  be  dis- 
placed, favouring  the  p-quinone  formation,  and  be  replaced  by  oxygen 
— e.g.  in  the  oxidation  of  amido-mesitylene  (B.  18,  1150)  to  m-xylo- 
quinone,  and  of  pseudo-cumidin  to  p-xylo-quinone.  (3)  p-Xylo- 
quinone  and  duro-quinone  have  been  synthesised  by  the  action  of 
caustic  potash  upon  the  aliphatic  a-diketones — diacetyl-  and  acetyl-pro- 
pionyl.  In  this  reaction  quinogens  are  first  produced ;  afterwards 
follow  the  p-quinones  : 

CH3.CO.CO.CH3  CH3.C(OH).CO.CH3  CH3.C— CO.CH 

CH3CO.CO.CH3  CH2— CO.CO.CH3  CH.CO.C.CH3 

Diacetyl  Dimethyl-quinogen  p-Xylo-quinone. 

p-Xylo-quinone  or  phlorone  occurs  in  the  tar  of  beech  wood. 

Properties. — The  homologous  p-quinones  are  very  similar  to  their 
prototype,  benzo-quinone.  They  are  also  yellow-coloured,  possess  an 
odour  similar  to  that  of  quinone,  sublime  readily,  and  behave  chemi- 


QUINONE   HALOIDS  229 

cally  like  p-benzo-quinone.  They  form  quinhydrones,  are  easily 
reduced  by  sulphurous  acid  to  p-hydroquinones,  and  combine  to 
nitroso-phenols  and  quinone  dioximes  with  hydroxylamine  : 


Tolu-quinone 
o-Xylo-quinone    . 
m-Xylo-quinone     . 
p-Xylo-quinone    . 
o-Ethyl-benzo-quinone  . 

Pseudo-cumo-quinon  e 

Duro-quinone     . 

Thymo-quinone  . 


CH,[i]C.H,[2,  5]O,  m  p.  67° 
55° 
102° 
123° 


,  2]C.H,[3,  6]02 
,  3]C.H,[2,  5]0, 
i,  4]C.H1[2,  5]02 
(C.Hs)[2]C.H,[i,  4]02 
),[i,  2,  4]C.H[3,  6]02 
i,  2,  4,  5]C,[3)  6]0, 
(CH,)(CsH7)[i,  4]C.H,[2,  5]0, 


38°  (B.  28,  R.  74i) 
11°  (B.  27,  1430) 
ni°  (B.  29,  2171  ;    42,  4161) 
45°,  b.p.  232°. 


When  an  ethereal  solution  of  thymo-quinone  is  allowed  to  stand 
in  sunlight  for  some  time,  polythymo-quinone,  m.p.  200°,  separates 
(B.  18,  3195).  See  B.  29,  2176,  for  diduro-quinone. 

QUINONE  HALOIDS  are  obtained  by  the  substitution  of  quinones 
or  by  the  oxidation  of  substituted  hydroquinones. 

A  mixture  of  tri-  and  tetrachloro-quinone,  called  chlomnile,  consists 
of  bright-yellow  flakes.  It  is  obtained  from  many  benzene  compounds 
(aniline,  phenol,  isatin)  by  the  action  of  chlorine  or  potassium  chlorate 
and  hydrochloric  acid  (B.  29,  R.  236).  It  oxidises,  and  serves  as  an 
oxidising  agent  in  the  manufacture  of  colouring  matters. 

Trichloro-  and  tetrachloro-quinone  are  separated  from  one  another 
by  the  insolubility  of  the  latter  in  water.  The  chloro-quinones  are 
obtained  from  chloro-hydroquinones  by  oxidation  with  nitric  acid 
(A.  146,  9  ;  210,  45  ;  234,  14)  : 


Monochloro-quinone  m.p.  57' 
[2,  5]-Dichloro-quinone  „  i59c 
[2, 6]-Diehloro-quinone  „  120° 

Trichloro-quinone        ,,     166° 


Monobromo-quinone  m.p.  55' 
[2, 5]-Dibromo-quinone  „  i88c 
[2,  6]-Dibromo-quinone  „  122* 

Tribromo-quinone         „     147* 


Tetrachloro-quinone  Tetrabromo-quinone 

Dibromo-di-iodo-quinone  m.p.  225°  (B.  38,  555). 

PC15  converts  tetrachloro-quinone  into  phosphorus-containing  deri- 
vatives C6C15.OPOC12(?),  and  then  into  hexachloro-benzol  (B.  24,  927). 
It  absorbs  two  atoms  of  chlorine  and  becomes  hexachloro-p-diketo-R- 
hexene,  which  caustic  soda  resolves  into  dichloro-maleic  acid  and 
trichloro-ethylene.  Potassium  hydroxide  converts  trichloro-quinone 
and  tetrachloro-quinone  into  potassium  chloranilate,  and  tribromo-  and 
tetrabromo-quinone  into  potassium  bromanilate  (see  B.  32,  1005). 

Amido-quinones. — Amido-quinone  is  obtained  in  the  form  of  its 
aceto-compound  C6H3O2(NHCOCH3),  m.p.  142°,  by  oxidation  of 

1,  3,  4-diacetamido-phenol,  while  the  I,  4,  5-diacetamido-phenol  yields 

2,  5-diamido-quinone  C6H2O2[2,  5](NH2)2  (B.  30,  2096  ;   31,  2399). 

Chloranile-amide  C6C12(NH2)2O2  is  obtained  from  chloranilic  acid. 
Aniline,  acting  upon  a  hot  alcoholic  solution  of  quinone,  produces  not 
only  hydroquinone,  but  also  dianilido-quinone,  dianilido-quinone-anile, 
and  -dianile,  as  well  as  2,  5-dioxy-i,  4-quinone  (see  below). 

Quinone-monosulphonic  acid  C6H3O2(SO3H),  in  yellow  prisms,  is 
formed  by  the  oxidation  of  hydroquinone-sulphonic  acid  and  of  the 
two  p-amido-phenol-sulphonic  acids  with  PbO2  in  sulphuric  acid  solu- 
tion. The  ammonium  salt,  golden  plates,  decomposes  at  i9O°-i95° 
(/.  pr.  Ch.  2,  69,  334). 


230  ORGANIC   CHEMISTRY 

OXY-QUINONES   AND   POLYQUINOYLS. 

Benzene  Oxy-quinones. — Methoxy-quinone  CH3O[2]C6H3  :  O2,  melt- 
ing at  140°,  is  produced  by  oxidising  o-amido-anisol  C6H4(NH2).O.CH3 
with  chromic  acid. 

Chloranilamic  acid  C6C12(NH2)(OH)O2  is  obtained  from  chloranile. 

2, 6-Dimethoxy-quinone  (CH3O)2[2,  6]C6H2O2,  melting  at  249°, 
results  from  the  oxidation  of  trimethyl-pyrogallol  and  trimethyl-phloro- 
glucin  (B.  26,  784). 

2, 5-Dioxy-quinone  (HO)2[2, 5]C6H2O2  is  obtained  from  dioxy- 
quinone-dicarboxylic  acid  by  boiling  with  hydrochloric  acid,  by  the 
oxidation  of  diamido-resorcin  (B.  21,  2374  ;  22,  1285),  and  by  the 
action  of  dilute  sulphuric  acid  upon  dianilido-quinone  (B.  23,  904  ; 
31,  2402)  ;  and  from  its  ethers  by  saponification.  2,  5-dimethoxy-, 
diethoxy-,  dipropoxy-quinone,  m.p.  166°,  183°,  and  187°  respectively, 
generated  from  quinone  by  boiling  with  alcohols  and  zinc  chloride 
(B.  34,3993).  Treating  with  stannous  chloride  converts  the  2,  5-dioxy- 
quinone  into  sym.  tetraoxy-benzol,  while  aniline  converts  it  into 
dianilido-quinone.  Substitution  products  of  2,  5-dioxy-quinone  have 
been  obtained  from  tetrachloro-  and  tetrabromo-quinone  as  substances. 
Two  of  their  halogen  atoms  are  exchanged  with  extreme  ease. 

Chloranilic  acid  C6C12(OH)2O2,  reddish,  shining  scales,  is  separated 
by  acids  from  potassium  chlomnilate  C6C12(OK)2O2+ H2O,  which 
crystallises  in  dark-red  needles,  dissolving  with  difficulty  in  water. 
Potassium  chloranilate  is  produced  as  well  from  tri-  as  from  tetrachloro- 
quinone  by  the  action  of  caustic  potash.  Hypochlorous  acid,  or  chlorine, 
acting  upon  chloranilic  acid,  produces  tri-  or  tetrachloro-tetraketo-hexa- 
methylene,  which  change  quite  readily  with  the  intermediate  production 
of  unstable  oxy-acids  into  trichloro-  and  tetrachloro-triketo-pentamethylene 
(B.  25,  827,  842). 

Bromanilic  acid  C6Br2(OH)2O2  corresponds  to  chloranilic  acid,  and 
with  bromine  yields  similar  transposition  products  to  those  obtained 
from  it  by  the  action  of  chlorine. 

Nitranilic  acid  C6(NO2)2O2(OH)2.  It  crystallises  with  water  in 
golden-yellow  needles  or  plates,  melts  in  its  water  of  crystallisation, 
becomes  anhydrous  at  100°,  and  detonates  at  170°  without  melting. 
It  is  obtained  from  hydroquinone  and  quinone  by  nitrous  acid  ;  on 
conducting  nitrous  acid  into  an  etheric  quinone  solution  and  cooling, 
nitranilic  quinone  is  produced,  C6N2O8H2.C6H4O2,  a  combination 
resembling  a  quinhydrone,  decomposed  by  dilute  potash  into  quinone 
and  nitranilic  acid  (B.  33,  3246).  The  latter  is  also  generated  from 
chloranile  with  sodium  nitrite,  and  from  terephthalic  acid  and  dioxy- 
quinone-terephthalic  acid  by  means  of  fuming  nitric  acid.  When 
nitro-anilic  acid  is  reduced,  it  yields  diamido-tetraoxy-benzene,  which 
renders  possible  the  transition  from  chloranile  to  triquinoyl  (see  below), 
and  potassium  hexaoxy-benzene. 

Amido-anilic  acid,  diamido-dioxy-quinone  C6(NH2)2(OH2)O2,  reddish- 
blue  needles,  formed  from  diamido-tetraoxy-benzene  by  oxidation  in 
the  air  or  by  nitrous  acid. 

Potassium  euthio-ehronate  C6(SO3K)2(OH)2O2,  see  Dichloro-hydro- 
quinone-disulphonic  acid. 

Tetraoxy-quinone  C6(O2)(OH)4,  formerly  called  dihydro-carboxylic 


OXY-QUINONES   AND   POLYQUINOYLS  231 

acid,  is  obtained  by  oxidising  the  aqueous  solution  of  hexaoxy-benzene 
by  exposure  to  the  air  (B.  18,  507,  1837).  It  may  also  be  obtained 
from  diamido-dioxy-quinone  by  boiling  with  hydrochloric  acid,  as  well 
as  by  the  action  of  concentrated  nitric  acid  upon  inosite.  Metallic 
black  needles,  with  a  green,  metallic  reflex.  It  is  a  strong  dibasic  acid. 

Nitro-dioxy-quinone-sulphonie  acid  C6NO2(OH)2O2(SO3H).  Its  tri- 
potassium  salt,  yellow  needles,  is  produced  by  the  action  of  K  nitrite 
upon  K-dichloro-hydroquinone  disulphonate  (B.  38,  453). 

Tetrathio-ethyl-quinone  C6O2(SC2H5)4,  colourless  prisms,  m.p.  59°, 
from  chloranil  and  sodium  mercaptan  (C.  1905,  II.  1427). 

Homologous  oxy-quinones  result  upon  treating  haloid  quinone  homo- 
logues  with  caustic  potash,  and  on  heating  amido-  or  anilido-quinones 
with  alcoholic  hydrochloric  acid  or  sulphuric  acid.  Dianilido-tolu- 
quinone,  melting  at  232°,  yields  anilido-oxy-tolu-quinone,  decomposing 
at  250°,  and  dioxy-tolu-quinone  CH3.C6H(OH)2O2,  melting  at  177° 
(B.  16,  1559).  Dioxy-m-xylo-quinone  C6(CH3)2O2(OH)2,  red  flakes, 
m.p.  167°,  from  amido-dimethyl-phloro-glucin  (M.  21,  i).  Oxy-thymo- 
quinone  (C3H7)(CH3)C6H(OH)  :  O2,  melting  at  166°,  is  obtained  from 
brom-  or  methyl-amido-thymo-quinone.  Dioxy-thymo-quinone  melts 
at  213°  (B.  14,  95). 

p-Dialkylated  dioxy-quinones,  like  p2-dimethyl-dioxy-benzo-quinone 
C6(CH3)2[3,  6](OH)2[2,  5]O2[i,  4],  are  formed  as  by-products  during 
the  production  of  homologous  oxal-acetic  esters  by  condensation  of 
oxalic  ester  with  fatty  acid  esters  by  means  of  sodium  in  etheric  solu- 
tion. They  form  red  or  yellowish-red  compounds,  dissolving  in 
alkalies  with  a  violet  colour.  By  reduction  they  give  homologous 
tetraoxy-benzols.  On  boiling  with  excess  of  soda  lye,  they  are  split 
up  into  formations  of  homologous  succinic  acids.  p2-Dimethyl,  diethyl-, 
and  di-iso-propyl-dioxy-benzo-quinone  melt  at  245°,  218°,  and  154° 
respectively  (A.  361,  363). 

It  is  also  very  probable  that  pipitzaholc  acid  C15H19(OH)  :  O2,  found 
in  the  root  of  Trixis  pipitzahuac,  and  melting  at  103°,  belongs  to  the 
oxy-quinones,  containing  but  one  nucleus.  It  recalls,  by  its  behaviour, 
oxy-thymo-quinone.  Oxy-pipitzahoic  acid  C9H18  :  C6(OH)2  :  O2  (?), 
melts  at  138°  (A.  237,  90). 

Polyquinoyl  Compounds. — As  mentioned  under  benzo-quinone 
(p.  226),  Woskresensky  originally  called  this  compound  quinoyl. 
Nietzki  and  Benckiser  introduced  this  name  in  a  different  sense.  They 
applied  it  to  the  quinone  group  O2,  when  they  discovered  dioxy- 
diquinoyl-benzene  and  triquinoyl-benzene  to  be  bodies  containing 
more  than  one  quinone  group  O2.  For  simplicity's  sake  they  abridged 
these  names  to  dioxy-diquinoyl  and  triquinoyl. 

Dioxy-diquinoyl  C6(O2)(O2)(OH)2,  called  rhodizonic  acid,  is  prepared 
by  reducing  triquinoyl  with  aqueous  sulphurous  acid  (B.  18,  513).  It 
consists  of  colourless  leaflets,  very  readily  soluble  in  water.  It  decom- 
poses quite  rapidly  in  aqueous  solution.  The  potassium  salt  C6O4(OK)2 
may  be  obtained  by  treating  the  acid  with  potashes,  and  also  by  washing 
potassium-hexaoxy-benzene  (potassium-carbon  monoxide)  with  alcohol. 
It  forms  dark-blue  needles,  dissolving  in  water  with  an  intense  yellow 
colour  (B.  18,  1838). 

Consult  B.  23,  3140  for  the  constitution  of  rhodizonic  acid. 

Triquinoyl  C6O6+8H2O  is  probably  hexaketo-hexamethylene  (B.  20, 


232  ORGANIC  CHEMISTRY 

322).  It  results  upon  oxidising  dioxy-diquinoyl  and  diamido-tetraoxy- 
benzene  with  nitric  acid.  It  is  a  white,  micro-crystalline  powder  (B.  18, 
504  ;  A.  350,  330).  It  melts  about  95°,  giving  up  water  and  CO2.  It 
is  likewise  decomposed  by  warming  it  with  water  to  90°.  Stannous 
chloride  reduces  it  to  hexaoxy-benzene,  which  is  oxidised  in  alkaline 
solution  to  tetraoxy-quinone  C6(O2)(OH)4  (see  above). 

Nietzki  and  Benckiser  (1885)  discovered  the  relations  existing 
between  potassium-carbon  monoxide  and  phenol.  Compare  the 
following  : 

Phenol  I  C,H&OH  C,(OK),  Potassium -carbon 

I  monoxide 

Tetrachloro-quinone          j'C.CljCl.O,  *  C«(OH2)(OH)2(OH),    A  Hexaoxy-benzene 


Nitranilic  acid  j  C,(NO2)2(OH)2O2  C,(OH)a(OH)2O2 

/f 
Diamido-tetraoxy-benzol  T  C«(NH2)2(OH)2(OH)»\/     C,(OH)2O2O, 

/  I 

Diamido-dioxy-quinone     *  C,(NH2)2(OH)2O,  '        ^C.O2OaOa 


Tetraoxy-quinone 

Rhodizonic  acid  or 
Dioxy-diquinoyl 
Triquinoyl. 


Addendum. — Pentacarbocyclic  compounds  are  readily  formed  from 
triquinoyl  and  dioxy-diquinoyl,  as  well  as  from  some  hexa-substitution 
derivatives  of  benzene,  from  which  these  polyquinoyl  bodies  arise — e.g. 
hexaoxy-benzene,  diamido-tetraoxy-benzene,  etc.  They  will  accord- 
ingly be  discussed  after  the  polyquinoyls. 

Groconic  acid  hydride  C5H4O5  is  formed  upon  treating  rhodizonic 
acid  with  excessive  alkali,  or  croconic  acid  with  hydriodic  acid.  It  is 
distinguished  by  its  barium  salt  C5H2BaO5+2H2O.  Its  formation  is 
probably  due  to  the  breaking  down  of  an  unstable  oxy-acid,  produced 
by  the  action  of  the  caustic  alkali  upon  two  of  the  combined  CO-groups 
of  the  rhodizonic  acid  (see  the  rearrangement  of  benzilic  acid)  : 

HO.C.CO.CO  /HOC.OX      /CO2H        \        HOC.COV     /H  HOC.CO, 

II         I      (?)->(         ||        >C<  (?)   )->        ||        >C<         (?)->        ||         >CO(?) 

HO.C.CO.CO         VHOC.CO/  \>H        /     HOC.CO/  XOH         HOC.CO/ 

Rhodizonic  acid  Unstable  oxy-acid  Croconic  acid  hydride  Croconic  acid. 

(B.  23,  3140) 

Croconic  acid  C5O3(OH)2+3H2O  consists  of  sulphur-yellow  leaflets  ; 
it  loses  its  water  of  crystallisation  at  100°.  It  dissolves  very  readily 
in  water  and  alcohol,  and  is  produced  by  the  alkaline  oxidation  of  most 
of  the  hexa-substituted  benzene  derivatives — e.g.  hexaoxy-benzene, 
dioxy-diquinoyl,  diamido-tetraoxy-benzene,  etc.  The  hydride  of 
croconic  acid  is  an  intermediate  product,  which  changes  quite  readily 
to  the  acid.  Triquinoyl,  when  boiled  with  water,  decomposes  into 
carbon  dioxide  and  croconic  acid  : 

C606+H20  =  =  C5H205+C02. 

Its  potassium  salt  C5O5K2+3H2O  crystallises  in  orange-yellow  needles ; 
hence  the  name,  from  xpdKos,  safran  (Gmelin,  1825).  When  oxidised 
with  nitric  acid  or  chlorine  the  product  is  : 

Leuconic  acid  C5O5+4tI2O,  pentaketo-cyclo-pentane,  which  is  recon- 
verted into  croconic  acid  by  sulphur  dioxide.  This  acid  bears  the  same 
relation  to  croconic  acid  that  rhodizonic  acid  bears  to  triquinoyl.  It 
is  very  soluble  in  water,  but  dissolves  with  difficulty  in  alcohol  and 
ether.  It  crystallises  in  small  colourless  needles.  The  penta-oxime 
C5(:  N.OH)6,  decomposing  at  172°,  is  isomeric  with  fulminic  acid, 


QUINONE-NITROGEN   DERIVATIVES  233 

cyanic  acid,  cyanuric  acid,  and  by  reduction  yields  penta-amido-pentol 
C5H(NH2)5,  penta-amido-cyclo-pentadiene  (B.  22,  916). 

QUINONE-NITROGEN  DERIVATIVES. 

The  quinone  oxygen  atoms  can  be  replaced  by  N(OH),  NCI,  NH, 
NC6H5,  and  similar  groups. 

Quinone  Dioximes. — In  connection  with  the  p-nitroso-phenols,  and 
in  the  explanation  of  Fittig's  diketone  formula  for  p-quinone,  it  was 
indicated  that  many  chemists  regarded  the  p-nitroso-phenols,  resulting 
from  the  action  of  hydroxylamine  hydrochloride  upon  the  p-quinones, 
as  monoximes  of  the  latter.  Indeed,  the  p-nitroso-phenols,  by  action 
of  hydroxylamine  hydrochloride,  change  to  p-quinone  dioximes.  It  is 
true  these  two  classes  can  be  viewed  as  constituted  according  to  the 
peroxide  formula  of  the  p-quinones.  o-Quinone  dioximes  are  formed 
by  the  reduction  of  o-dinitroso-benzols  ;  by  splitting  off  water  they 
easily  pass  into  anhydrides,  the  so-called  furazane  derivatives  (A. 
307,  28). 

Their  dioximes  unite  with  acetic  anhydride  to  diacetyl  compounds. 
p-Dinitroso-benzols  are  produced  by  the  oxidation  of  their  alkaline 
solutions  (also  on  exposure  to  the  air).  Nitric  acid  oxidises  them  to 
p-dinitro-benzols  (B.  21,  428). 

p-Quinone  dioxime  C6H4(N.OH)2  consists  of  colourless  or  yellow 
needles,  which  decompose  at  240°. 

Tolu-quinone  dioxime  deflagrates  at  220°  (B.  21,  679).  p-Xylo- 
quinone  dioxime  melts  at  about  272 °  (B.  20, 978) .  Mono-  and  dibenzoyl- 
quinone  dioxime,  see  C.  1903,  I.  1409. 

o-Quinone  dioxime  C6H4[i,  2](NOH)2,  small  yellow  needles,  dissolves 
in  alkalies  with  a  blood-red  colour,  and  passes  into  its  colourless 
anhydride  C6H4N2O  on  simply  standing,  or  warming  in  alkaline  solution 

(B.  40,4344). 

Dinitro-resorcin  and  hydroxylamine  yield  diquinoyl  trioxime 
C6H2O(NOH)3,  and  diquinoyl  tetroxime  C6H2(NOH)4.  The  latter, 
oxidised  with  sodium  hypochlorite,  yields  tetranitroso-benzol  (B.  30, 
181  ;  32,  508). 

Quinone  imines  are  to  be  regarded  as  diketones,  or  as  peroxides  in 
which  the  oxygen  is  represented  by  the  imino-group  (:  NH)  or  the 
alkyl-imino-group  (:  NR),  corresponding  to  the  formulae 

C'<NH     OT     C«H'<L      and      C«H'\NH     OT    C' 
Quinone-mono-imine  Quinone  di-imine. 

They  are  formed  from  p-amido-phenol  or  p-phenylene-diamine,  by 
gentle  oxidation  with  silver  oxide  and  lead  peroxide  in  etheric  solution. 
In  contrast  with  the  quinones,  they  are  colourless  and  exceedingly 
unstable.  They  are  strong  oxidisers,  smell  like  quinones,  and  are 
volatile.  On  warming  with  mineral  acids  they  decompose  into  ammonia 
and  quinone.  By  reduction  with  sulphurous  acid  or  stannous  chloride 
and  HC1,  they  are  reconverted  into  the  original  substances,  p-amido- 
phenol  and  p-phenylene-diamine.  Owing  to  the  easy  decomposition 
of  the  o-quinones,  the  isolation  of  the  o-quinone  imines,  which  are  prob- 
ably even  more  unstable,  has  not  been  accomplished.  The  o-quinone 


234  ORGANIC   CHEMISTRY 

di-imine,  probably   first   formed  by   the    oxidation   of  o-phenylene- 
diamine,  polymerises  at  once  to  o-azo-aniline. 

/[i]N=N[i] 
4  \[2]NH2H2N[2] 

(B.  38,  2348). 

Quinone  mono-imine  O[i]C6H4[4]NH,  colourless  prismatic  crystals, 
which  quickly  turn  dark  in  solution,  and  decompose  in  a  short  time 
when  dry  (B.  37,  4607). 

Quinone  monomethyl-imine  O[i]C6H4[4]NCH3,  formed  by  oxida- 
tion of  p-methyl-amido-phenol  OHC6H4NHCH3  with  Ag2O  or  PbO2. 
It  is  still  more  unstable  than  the  unmethylated  imine,  and  deflagrates 
immediately  on  formation  (B.  38,  2251). 

Quinone  di-imine  NH[i]C?H4[4]NH,  m.p.  about  129°,  is  also  formed 
by  reduction  of  p-quinone  dichlor-imine  with  HC1  in  etheric  solution. 
It  forms  colourless  monoclinic  prisms,  which  are  quickly  browned 
in  air  (B.  37,  4606).  With  sodium  disulphite  it  unites  to  form  a 
mixture  of  p-amido-phenol-sulphonic  acid  and  p-phenylene-diamine- 
sulphonic  acid. 

Quinone  monomethyl-di-imine  NH[i]C6H4[4]NCH3,  m.p.  64°-67°, 
and  quinone  dimethyl-di-imine  CH3N[i]C6H4[4]NCH3,  m.p.  93°,  result, 
like  the  simple  quinone  di-imines,  from  the  oxidation  of  monomethyl- 
or  sym.  dimethyl-p-phenylene-diamine.  They  form  almost  colourless 
crystals,  dissolving  with  a  light-yellow  coloration.  They  are  as 
unstable  as  the  non-methylated  quinone  di-imine  (B.  38,  2249 ;  40, 
2672). 

Unsym.  quinone-dimethyl-di-imonium  nitrate  NH  :  [i]C6H4[4]  : 
N(CH3)2NO3,  HNO3  is  obtained  in  the  form  of  very  unstable  light- 
yellow  prisms  by  the  oxidation  of  unsym.  dimethyl-p-phenylene- 
diamine  with  nitrous  gases.  It  decomposes  rapidly,  and  deflagrates 
on  heating.  With  one  molecule  of  its  hydro-compound  the  unsym- 
metrical  dimethyl-p-phenylene-diamine,  it  unites  to  form  a  body, 
[NO3NH2:C6H4:N(CH3)2N03+NH2C6H4N(CH3)2],  of  a  structure 
resembling  quinhydrone,  green  crystals  dissolving  in  water  with  a 
red  fuchsine  coloration.  These  interesting  compounds,  called 
Wurster's  red  after  their  discoverer,  result  from  the  partial  oxidation 
of  salts  of  unsym.  dimethyl-p-phenylene-diamine  (B.  12,  1803,  2071). 
The  corresponding  bromo-hydrate,  m.p.  147°  with  decomposition,  in 
green  crystals,  results  from  the  action  of  one  atom  bromine  upon 
unsym.  dimethyl-p-phenylene-diamine  in  glacial  acetic  acid  solution. 
Reducers  bleach  the  deep-red  solution,  with  formation  of  phenylene- 
diamine.  Oxidisers  do  the  same,  and  form  the  entirely  quinoid  com- 
pound (B.  41,  1458). 

Analogous  blue  compounds  are  obtained  by  starting  from  tetra- 
methyl-p-phenylene-diamine  (Wurster's  blue,  B.  12,  1807  ;  41,  1473). 
Unstable  oxidation  products  coloured  an  intense  green,  or  blue,  have 
also  been  obtained  from  p-phenylene-diamine  and  dibromo-p-phenylene- 
diamine  (C.  1904,  I.  1073  ;  B.  38,  3354). 

Amido-quinone  imine  NH2[2]C6H3[i]O[4]NH  and  its  homologues 
are  formed  by  oxidation  of  2,  4-diamido-phenols  with  ferric  chloride. 
The  bichromate  forms  greenish-black,  brilliant  grains,  dissolving  in 
water  with  a  red  colour  (B.  39,  3437). 


QUINONE-NITROGEN   DERIVATIVES  235 

Diamido-quinone  imine  (NH2)2C6H2(O)(NH)(?)  is  obtained  from 
triamido-phenol  (A.  215,  351). 

Quinone  Chlorimines. — They  are  produced  from  p-amido-phenols 
and  p-phenylene-diamines  (their  HC1  salts)  by  oxidation  with  an 
aqueous  solution  of  bleaching  lime.  They  revert  to  p-amido-phenols 
or  p-phenylene-diamines  upon  reduction.  The  monochlorimines  form 
the  indo-phenol  dyestuffs  with  phenols  and  tertiary  anilines. 

Quinone  monoehlorimine  O[i]C6H4[4]NCl  forms  golden-yellow 
crystals,  which  melt  at  85°,  volatilise  readily  with  steam,  and  smell 
like  quinone.  It  is  easily  soluble  in  hot  water,  alcohol,  and  ether. 
When  boiled  with  water  it  decomposes  into  NH4C1  and  quinone  (/. 
pr.  Ch.  2,23,435). 

Quinone  dichlorimine  C6H4[i,  4](N2C12)  crystallises  in  needles 
which  deflagrate  at  124°  (B.  12,  47). 

Trichloro-quinone  chlorimine,  m.p.  118°  (/.  pr.  Ch.  2,  24,  429). 

Dibromo-quinone  chlorimine,  m.p.  80°  (B.  16,  2845). 

Quinone-phenyl-hydrazones. — While  phenyl-hydrazin  and  alkylated 
phenyl-hydrazins  are  oxidised  by  quinone,  o-nitro-  and  o,  p-dinitro- 
phenyl-hydrazins  give  condensation  products  which  may  be  interpreted 
as  p-oxy-azo-compounds,  being  identical  with  the  coupling  products 
of  diazotised  o-nitro-  or  o,  p-dinitraniline  and  phenol  (A.  357,  171). 
With  a-acetyl-  and  benzoyl-phenyl-hydrazins,  on  the  other  hand,  true 
quinone-phenyl-hydrazones  are  generated. 

Quinone  -  acetyl-  and  benzoyl  -  phenyl  -  hydrazone  O  :  C6H4 :  NN 
(Ac)C6H5,  m.p.  118°  and  171°  respectively,  which,  however,  are  easily 
transposed  into  the  acylated  p-oxy-azo-compounds  AcOC6H4N2C6H5 
(B.  40,  1432).  This  reaction  has  acquired  a  special  importance  for 
determining  the  constitution  of  the  oxy-azo-compounds.  The  o- 
quinone-benzoyl-phenyl-hydrazone  (?)  yields,  by  its  hydrolytic  decom- 
position, o-oxy-azo-benzol  (C.  1909,  I.  1093). 

Quinone-oxime-hydrazones  result  from  the  action  of  benzoyl-hydra- 
zin  and  benzoyl-phenyl-hydrazin  upon  nitroso-phenols.  Quinone- 
oxime-benzoyl-hydrazone  (HON)  :  C6H4 :  NNH.COC6H5,  m.p.  210° 
with  decomposition.  Quinone-oxime-benzoyl-phenyl-hydrazone  (HON) : 
C6H4  :  NN(COC6H5)C6H5,  on  boiling  with  HNO3,  yields  p-nitro-azo- 
benzol  (A.  343,  176). 

Quinone  semi-carbazone  and  Amido-guanidone. — The  quinones 
react  more  readily  with  semi-carbazide  and  with  amido-guanidin  than 
with  phenyl-hydrazin.  Quinone  mono-  and  bi-semi-carbazone  C6H4O 
(NNHCONH2)  and  C6H4(NNHCONH2)2,  m.p.  171°  and  243°  respect- 
ively, are  obtained  from  quinone  and  HC1  semi-carbazide.  Quinone 
mono-  and  bis-amido-guanidone  C6H4O[NNHC(NH)NH2]  and  C6H4 
[NNHCtNHJNHJg  are  obtained  from  amido-guanidin  nitrate  and 
quinone  in  the  presence  of  nitric  acid  (A.  302,  311).  The  quinone 
mono-semi-carbazone  and  mono-amido-guanidone  are  probably  oxy- 
azo-compounds  (A.  334,  143). 

Quinone  Azines.  —  p-Quinone  azine  O[4]C6H4[i]N.N[i]C6H4[4]O 
deflagrates  at  158°.  It  is  formed  by  oxidation  of  p-azo-phenol 
with  Ag2O  and  PbO2  in  etheric  solution.  It  is  obtained  in  the 
form  of  dark  orange  prisms  or  dark  yellow  rhombohedral  flakes. 
It  is  stable  in  air,  and  is  odourless  and  not  volatile.  Reduction  with 
sulphurous  acid  or  phenyl-hydrazin  reconverts  it  into  p-azo-phenol, 


236  ORGANIC   CHEMISTRY 

while  stannous  chloride  and  HC1  produce  p-amido-phenol.  With  one 
molecule  of  p-azo-phenol  it  combines  to  form  a  compound  resembling 
quinhydrone,  blue-black  needles  of  m.p.  182°,  also  obtainable  by  direct 
oxidation  of  p-azo-phenol.  o-  and  m-Azo-phenol  yield  no  quinone 
azines. 

Quinone  Dlazides. — It  has  been  already  pointed  out  in  connection 
with  the  diazo-salts  of  the  o-  and  p-amido-phenols  that  the  correspond- 
ing diazo-hydrates  easily  pass  into  yellow  anhydrides  related  to  the 
quinones,  and  probably  interpretable  as  o-  and  p-quinone  diazides 

..^>C6H4 :  O.  Similar  behaviour  is  shown  by  the  diazonium  salts  of 
p-amido-diphenyl-amine  NH2C6H4NHC6H5,  which,  on  treatment  with 

N\ 

ammonia,  form  p-quinone  diazide  anile  II    >C6H4 :  NC6H5  (B.  35,  888). 

»/ 

/o 
Quinone-phenyl    mono-imine,    quinone  monoanil  c^/   |  or 

\JN  v^^iri-^ 

C6H4^  ,  m.p.  97°,  consists  of  fiery-red  crystals.      It  is   formed 

upon  oxidising  p-oxy-diphenyl-amine  in  benzene  solution  with  mercuric 
oxide,  and  upon  reduction  reverts  to  the  same  (B.  21,  R.  434). 

Indo-phenols  and  Indo-anilines. — These  compounds  are  obtained 
from  quinone  monoanile  or  quinone  phenyl-imide  by  replacing  the 
p-hydrogen  atom  of  the  anile  group  by  an  OH  or  an  NH2  group. 
They  are  dyes.  Like  many  members  of  this  class,  they  are  de- 
colorised by  the  addition  of  hydrogen.  The  resulting  bodies  are 
leuco-compounds,  p-di-substituted  diphenyl-amines.  (Nomenclature, 
B.  29,  R.  94.) 

Indo-phenols  are  produced  (i)  by  allowing  the  quinone  chlorimines 
to  act  upon  phenols  ;  (2)  by  oxidising  a  mixture  of  a  p-amido-phenol 
and  phenol.  They  dissolve  in  alcohol  with  a  red  colour,  and  possess 
a  character  similar  to  phenol.  Their  salts,  with  the  alkalies  and  am- 
monia, dissolve  in  water  with  a  blue  colour. 

/N.C6H4OH 

Quinone  phenol-imine  C6H4/  |  also  results  upon  heating 

phenol  blue  with  soda  lye  (B.  18,  2916),  but,  owing  to  its  instability, 
cannot  be  obtained  in  a  free  condition.  By  reduction  it  changes  to 
colourless  p-dioxy-diphenyl-amine  from  which  it  can  be  recovered  by 

HgO  (B.  32,  689).     Dibromo-quinone  phenol-imine  c^Br/  \  '  * 

\o 

from  dibromo-quinone  chlorimine,  is  more  stable  than  quinone-phenol- 
imine.  Free  dibromo-phenol-imine  crystallises  in  dark-red  prisms 
having  a  metallic  lustre  ;  they  dissolve  in  alcohol  and  ether  with  a 
fuchsine-red  colour.  Strong  mineral  acids  decompose  it  into  dibromo- 
phenol  and  quinone. 

The  Indo-anilines  are  produced  (i)  by  the  action  of  quinone  chlori- 
mine upon  dimethyl-aniline  in  alcoholic  solution  ;  (2)  by  the  action 
of  nitroso-  and  nitro-dimethyl-aniline  upon  phenol  in  alkaline  solution, 
especially  in  the  presence  of  reducing  agents  (Witt,  1879) ;  (3)  by  the 
oxidation  in  alkaline  solution  (with  sodium  hypochlorite)  of  a  mixture 
of  a  p-phenylene-diamine  with  a  phenol,  or  of  a  p-amido-phenol  with 
a  primary  monamine,  or  by  means  of  lead  peroxide  or  manganese 


QUINONE  PHENYL-DI-IMINES  237 

peroxide  in  the  presence  of  di-sodium  phosphate  (1877,  Nietzki ;  B. 
28,  R.  470  ;  C.  1908,  I.  437  ;  1906,  II.  477). 

The  indo-anilines  are  feeble  bases.  They  are  rather  stable  towards 
the  alkalies  ;  acids  quickly  decompose  them  into  quinones  and  the 
p-phenylene-diamines.  They  are  changed  to  the  leuco-compounds  ; 
amido-oxy-diphenyl-amines,  by  reduction  (absorption  of  two  hydrogen 
atoms)  ;  these  dissolve  readily  in  alkalies,  and  are  readily  reconverted 
(oxidised)  into  indo-anilines  (by  exposure  of  their  alkaline  solution 
to  the  air).  The  free  indo-anilines  have  a  deep-blue  colour,  and  can 
be  applied  as  dyestuffs.  For  this  purpose  they  are  converted  into 
their  alkaline  leuco-derivatives,  which  are  soluble,  and  the  material 
is  impregnated  or  printed  with  these.  Oxidation  (by  exposure  to  the 
air  or  with  K2Cr2O7)  develops  the  colour.  The  simplest  aniline  is 

/N.C6H4.NH2 
quinone  anilin-imine  C,H4(   |  ,  a  violet  dye,  formed  by  the 

\O 

oxidation  of  p-phenylene-diamine  C6H4(NH2)2  with  phenol.     Quinone 

/N.C6H4.N(CH3)2 

dimethyl-anilin-imine  (phenol  blue)  C8H4^  |  results  from 

unsym.  dimethyl-p-phenylene-diamine  and  phenol.  It  has  a  greenish- 
blue  colour  and  dissolves  in  acids  with  a  blue  colour.  When  boiled 
with  soda  lye  it  splits  off  dimethyl-amine  and  becomes  quinone-pheno- 
limine.  Sulphuric  acid  decomposes  it  into  quinone  and  dimethyl-p- 
phenylene-diamine.  This  is  a  general  reaction,  hence  can  be  used 
opportunely  for  the  preparation  of  quinones  (B.  28,  R.  471  ;  29,  R.  24). 

QUINONE  PHENYL-DI-IMINES. 

Quinone  mbnophenyl-di-imine  C6H5N  :  C6H4  :  NH,  light-yellow 
prisms,  m.p.  89°,  by  oxidation  of  p-amido-diphenyl-amine  with  silver 
oxide  or  lead  peroxide  in  etheric  solution.  It  is  also  formed,  besides 
quinone  monoanile,  during  the  gentle  oxidation  of  aniline  in  an  aqueous 
alkaline  solution.  Water  splits  it  up,  even  when  cold,  into  ammonia 
and  quinone  monoanile.  On  heating  with  dilute  sulphuric  acid  it 
passes  into  quinone.  Mineral  acids  readily  polymerise  it  to  form  a 
green  dye,  enter aldin.  The  latter  is  also  formed  when  p-amido- 
diphenyl-amine  is  oxidised  in  an  acid  solution  with  ferric  chloride  or 
hydrogen  peroxide,  also  by  reduction  of  nitro-benzol  in  a  hydrofluo- 
silicic  acid  solution,  the  body  first  formed  being  p-amido-diphenyl- 
amine.  The  free  base  separated  from  emeraldin,  the  so-called  azurin, 
m.p.  165°,  forms  deep-blue  prisms,  and  probably  has  the  con- 
stitution C6H6NH.C6H4NH.C6H4N  :  C6H4  :  NH.  By  oxidation  with  lead 
peroxide  in  benzene  solution  this  half-quinoid  azurin  or  emeraldin, 
respectively,  may  pass  into  a  doubly  quinoid  red  imine  C6H4N  : 
C6H4N  :  C6H4N  :  CgH4  :  NH,  which,  after  the  manner  of  quinone 
monophenyl-di-imine,  polymerises,  under  various  conditions,  to  a 
black  dye  called  aniline  black  (B.  40,  2665  ;  42,  4123). 

Aniline  black*  is  one  of  the  oldest  known  organic  dyestuffs,  and  is 
distinguished  by  its  permanence.  It  is  formed  by  the  oxidation  of 
aniline  salts  with  potassium  bichromate  and  sulphuric  acid,  ammonium 

*  E.  Noelting  and  R.  Lehne,  AnilinscJiwarz  und  seine  Anwendung  in  Farberei 
und  Zeugdruck,  2nd  ed.,  Berlin,  190.},  Springer. 


238  ORGANIC  CHEMISTRY 

persulphate,  or  potassium  chlorate,  in  the  presence  of  oxygen  carriers 
such  as  copper  sulphate,  potassium  ferrocyanide,  ammonium  vanadate, 
etc.  In  its  applications  to  cotton-dyeing  aniline  black  is  produced  in 
the  fibre,  by  printing  the  fabric  with  a  mixture  of  aniline  salt  and  one 
of  the  above-mentioned  oxidisers,  and  then  developing  the  dye  by 
steaming  at  a  low  temperature. 

Aniline  black  has  a  relation  to  the  red  oxidation  product  of  emer- 
aldin,  resembling  the  relation  between  emeraldin  and  quinone  mono- 
phenyl-di-imine.  It  cannot  be  looked  upon  as  a  unitary  compound. 
It  consists  of  a  mixture  varying  with  the  degree  of  oxidation,  a  triple 
or  quadruple  quinoid  combination,  to  which  the  following  constitu- 
tional formulae  are  attributed  : 

I.  C6H6N  :  CflH4 :  NC6H4NHC6H4NHC6H4N  :  C6H4 :  NC6H4N  :  C6H4 :  NH. 
II.  C6H6N :  C6H4  :  NC6H4N  :  C8H4  :  NC6H4N :  C6H4 :  NC6H4N  :  C6H4 :  NH. 

On  heating  with  dilute  H2SO4,  one-eighth  of  the  total  nitrogen  is 
split  off  in  the  form  of  ammonia,  the  imino-group  being  replaced  by 
oxygen.  This  is  accompanied  by  an  increase  in  the  depth  of  the  colour. 
These  oxygen-bearing  substances  are  contained  in  aniline  black  in 
proportions  varying  according  to  the  method  of  preparation.  Strong 
oxidation  with  chromic  acid  or  lead  peroxide  and  H2SO4  converts  it 
almost  quantitatively  into  quinone  (B.  42,  2147,  4118). 

Quinone  diphenyl - di - imine,  diphenyl-p-azo-phenylene,  quinone 
dianile  C6H4(NC6H5)2  m.p.  i76°-i8o°,  is  obtained  by  the  oxidation 
of  diphenyl-amine  and  diphenyl-p-phenylene-diamine  (B.  21,  R.  656). 
By  reduction,  quinone  dianile  passes  into  diphenyl-p-phenylene-di- 
amine, with  which  it  is  related  as  quinone  is  to  hydroquinone. 

Two  phenyl-amido-groups  may  be  introduced  into  the  benzene 
residue  of  quinone  anile  and  quinone  dianile  with  the  same  facility  as 
into  quinone  itself,  which,  as  mentioned  before,  gives  rise  to  di-anilido- 
quinone  and  hydroquinone  on  boiling  its  alcoholic  solution  with  aniline. 
If  acetic  acid  is  present  (B.  18,  787),  dianilido-quinone  anile  is  formed, 
(C6H5NH)2C6H2(O)(NC6H5),  m.p.  202°,  brownish-red  needles.  This  is 
also  formed  on  heating  quinone  mono-anil  with  aniline  besides  p-oxy- 
diphenyl-amine  (B.  21,  R.  656)  and  on  oxidising  aniline  with  H2O2  in  a 
feebly  acid  solution  (B.  15,  3574). 

Dianilido-quinone  dianile,  azo-phenin  (CeHjNHJ^H^NCjjHg),,  m.p. 
241°,  garnet-red  flakes,  results  (i)  on  heating  quinone  dianile  with 
aniline  (B.  21,  R.  656)  ;  (2)  on  melting  quinone  with  aniline  and  aniline 
chlorohydrate  (B.  21,  683)  ;  (3)  from  amido-azo-benzol,  p-nitroso- 
phenol,  p-nitroso-diphenyl-amine  by  the  action  of  aniline  (B.  20,  2480). 
On  heating  it  is  converted  into  fluorindin  (B.  23,  2791 ;  31, 1789). 

The  quinone  dianiles  are  important  links  in  the  formation  of 
indulin  dyes  (B.  25,  2731  ;  A.  262,  247). 

Indamines. — These  are  derived  from  the  indo-anilines  by  the  re- 
placement of  the  quinone-oxygen  atom  by  the  imido-  or  alkyl-imido- 
group.  They  are  therefore  derivatives  of  the  unknown  quinone  di- 
imide,  and  bear  an  intimate  relation  to  p-diamido-diphenyl-amine, 
which  is  formed  by  the  reduction  of  the  simplest  indamine  and  is  the 
leuco-derivative  of  the  latter. 

The  indamines  arise  (i)  by  oxidation,  in  neutral  solution  and  in  the 
cold,  of  a  mixture  of  a  p-phenylene-diamine  with  an  aniline  (Nietzki), 


INDAMINES  239 

or  (2)  by  the  action  of  nitroso-dimethyl-aniline  upon  anilines  or  m-di- 
amines  (Witt).  They  are  feeble  bases,  forming  blue-  or  green-coloured 
salts  with  acids  ;  but  with  an  excess  of  the  latter  are  very  easily  split  up 
into  quinone  and  the  diamine.  Because  of  their  instability  they  find 
no  application,  and  are  only  important  as  intermediate  products  in  the 
manufacture  of  thionin  and  safranin  dyestuffs  (into  which  they  can  be 
readily  transposed).  For  the  relations  of  the  indo-phenols,  indanilines, 
and  indamines  to  the  dyes  of  the  oxazin-,  thiazin-,  and  diazin-series  — 
e.g.  resorufm,  methylene  blue  —  the  indulins  and  safranins,  see  the 
latter.  The  simplest  indamine  is  : 

/N.C«H4NH2 
Phenylene  blue  C6H4<^  |  .     This  is  produced  by  the  oxida- 

tion of  p-phenylene-diamine  with  aniline.  Its  salts  are  greenish-blue 
in  colour.  It  yields  diamido-diphenyl-amine  by  reduction.  Its  tetra- 
methyl  derivative  is  : 

Dimethyl-phenylene  green  N<^624'SSv,  (Bindschedler's  green). 


This  is  obtained  by  oxidising  dimethyl-paraphenylene-diamine  with 
dimethyl-aniline.  Its  salts  dissolve  in  water  with  a  beautiful  green 
colour.  Its  reduction  yields  tetramethyl-diamido-diphenyl-amine. 
Digestion  with  dilute  acids  resolves  it  into  quinone  and  dimethyl-amine 
(B.  16,  865  ;  17,  223).  On  standing  with  soda  lye,  dimethyl-amine 
splits  off  and  phenol  blue  is  produced  ;  this  further  separates  into 
quinone  phenol-imide  (B.  18,  2915). 

Toluylene  blue  N<fS*S4*^£^U  results  from  ordinary  toluylene- 


diamine  by  oxidising  it  mixed  with  dimethyl-p-phenylene-diamine,  01 
by  the  action  of  HCl-nitroso-dimethyl-aniline.  Its  salts  with  one  equi- 
valent of  acid  are  of  a  beautiful  blue  colour,  and  are  decolorised  by 
an  excess  of  mineral  acids  with  formation  of  the  diacid  salts.  It  is 
converted  into  toluylene  red  on  boiling  with  water. 

The  genetic  connection  of  the  indamines  with  the  indo-anilines  and 
indo-phenol  is  shown  in  the  possibility  of  converting  the  simplest  ind- 
amine into  quinone-aniline-imine,  and  the  latter  into  quinone-phenol- 
imine  (Mohlau,  B.  16,  2843  ;  18,  2915). 

Representatives  of  the  indo-phenols,  indo-anilines,  and  indamines 
containing  the  naphthalin  residue  are  also  known  in  great  numbers, 
and  many,  likenaphthol  blue  (q.v.}  or  "  indo-phenol,"  have  been  applied 
technically  (B.  18,  2916). 

On  quinoid  sulphur  compounds,  see  B.  40,  3039  ;  41,  902. 


9.  Phenyl-paraffin  Alcohols  and  their  Oxidation  Products. 

In  the  preceding  sections  those  classes  of  aromatic  hydrocarbons 
containing  one  nucleus  were  described,  which  resulted  from  the  sub- 
stitution of  the  hydrogen  atoms  of  benzene  or  the  benzene  residue  of 
the  alkyl-benzenes  by  atoms  of  other  elements  or  by  atomic  groups  : 
the  halogen  substitution  products,  the  nitrogen-containing  derivatives 
of  the  benzene  hydrocarbons,  the  aromatic  phosphorus,  arsenic,  anti- 
mony, bismuth,  boron,  silicon,  and  tin  derivatives,  the  phenyl  metal 


240  ORGANIC   CHEMISTRY 

compounds,  the  sulpho-acids  and  their  relatives,  the  phenols,  and  the 
quinones. 

Attached  to  these  are  those  classes  of  bodies  formed  by  the  replace- 
ment of  hydrogen  atoms  in  the  side  groups  of  the  alkyl-benzols.  As  in 
the  aliphatic  series,  the  oxygen-containing  products  are  considered  the 
most  important.  Each  class  of  these  derivatives  is  followed  by  the 
corresponding  halogen,  sulphur,  and  nitrogen  compounds,  in  which  all, 
or  at  least  a  part,  of  the  carbon  valences,  saturated  in  the  principal 
compounds  by  oxygen,  are  taken  up  with  the  elements  just  named. 
Prominent  among  these,  as  with  the  aliphatic  derivatives,  are  those 
bodies  in  which  one  carbon  atom  of  an  alkyl  side  chain  is  combined 
with  oxygen  : 

(i#)  The  monohydric  phenyl-paraffin  alcohols  and  their  oxidation 
products  :  aldehydes,  ketones,  carboxylic  acids. 

Naturally  these  compounds,  as  far  as  the  reactivity  of  the  aliphatic 
residue  is  concerned,  manifest  great  similarity  to  the  monohydric  ali- 
phatic alcohols  and  their  oxidation  products  (Vol.  I.).  This  is  recalled 
by  their  nomenclature  and  the  view  that  they  are  phenyl-substitution 
products  of  aliphatic  substances. 

Each  of  these  alkyl-benzene  derivatives  constitutes  a  fundamental 
substance  from  which,  by  the  replacement  of  hydrogen  atoms  of  the 
phenyl  residue,  as  with  benzene  itself,  numerous  derivatives  can  be 
deduced.  In  general  the  benzene  substitution  products  of  the  phenyl 
fatty  bodies,  so  far  as  they  are  worth  mention,  will  be  introduced  after 
the  corresponding  principal  bodies.  Only  the  derivatives  of  mono- 
hydric aromatic  alcohols,  having  hydroxyl  in  their  benzene  residue, 
and  their  oxidation  products,  which  manifest  at  the  same  time  a  phenol 
character,  will  be  grouped  together  as  : 

(ib)  Monohydric  oxy -phenyl-paraffin  alcohols  and  their  oxidation 
products. 

Then  will  follow  (2)  polyhydric  phenyl-paraffin  alcohols,  in  which  but 
one  hydroxyl  group  is  joined  to  a  side  chain,  and  their  oxidation  products. 
The  conclusion  of  this  section  will  be  (3)  polyhydric  phenyl-paraffin 
alcohols,  in  which  more  than  one  hydroxyl  group  is  attached  to  a  side  chain, 
and  their  oxidation  products. 

In  the  subsequent  sections  the  mononuclear  derivatives  with 
unsaturated  side  chains  will  be  summarised. 

(a)  MONOHYDRIC  PHENYL-PARAFFIN  ALCOHOLS  AND  THEIR 
OXIDATION  PRODUCTS. 

i.  Monohydric  Phenyl-paraffin  Alcohols. — The  true  alcohols  of  the 
benzene  series  are  produced  by  the  entrance  of  an  hydroxyl  group 
into  the  side  chain  of  an  alkyl-benzol, — primary,  secondary,  and  tertiary. 
The  primary  alcohols,  upon  oxidation,  yield  aldehydes  and  acids.  The 
secondary  change  to  ketones  : 

I  Benzyl  alcohol  C6H5CH2OH       I  Phenyl-methyl-carbinol  C6H5CH(OH)CH3 
I  Benzaldehyde   C6HBCHO  *  Acetophenone     .         .     C6H5COCH3. 

i  Benzole  acid     C6H5COOH. 

Formation. — The  similarity  of  benzyl  alcohol  and  its  homologues 
to  ethyl  alcohol  finds  expression  at  the  very  outset  in  the  methods  of 


MONOHYDRIC   PHENYL-PARAFFIN   ALCOHOLS         241 

producing  both  classes  : — (i)  by  saponification  of  alkyl-benzols  con- 
taining an  halogen  atom  in  the  side  chain — the  haloid  acid  esters  of 
the  benzyl  alcohols — e.g.  benzyl  chloride  with  water  alone  (A.  196,  353), 
with  water  and  lead  oxide  (A.  143,  81),  or  with  potashes.  Benzyl 
alcohols  are  also  produced  by  converting  the  chlorides  into  acetates 
and  saponifying  the  latter. 

(2)  By  the  action  of  nitrous  acid  upon  primary  amines,  the  reduction 
products  of  aromatic  acid  nitriles — e.g.  cumo-  and  hemimelli-benzyl 
alcohol. 

(3)  By  the  action  of  nascent  hydrogen  on  the  corresponding  alde- 
hydes and  ketones. 

(4)  The  phenyl-paraffin  alcohols  are  obtained  from  the  aromatic 
aldehydes  by  treating  with  alcoholic  or  aqueous  potash.     This  reaction, 
in  which  the  corresponding  carboxylic  acids  are  also  formed,  occurs 
only  exceptionally  in  the  paraffin  aldehydes  (B.  14,  2394  ;    C.  1902, 
I.    1212)  ;     from    two  molecules  benzaldehyde,   benzyl   alcohol    and 
potassium  benzoate  are  produced,  benzoic  benzyl  ester  being  probably 
an  intermediate  product  (C.  1899,  II.  mi)  : 

2C6H5CHO  — >  C6H5COOCH2C6H5  — ->  C6H5COOK-f  C6H6CH2OH. 

(5#)  From  the  aromatic  carboxylic  acids  or  their  esters  by  electro- 
lytic reduction  in  alcoholic  sulphuric- acid  solution,  with  great  excess 
of  cathode  voltage.  The  reduction  of  the  acid  esters  leads  simul- 
taneously to  the  formation  of  the  corresponding  ethers ;  benzoic 
methyl  ester  gives  benzyl  alcohol  and  benzyl-methyl  ether  C6H5CH2 
OCH3  (B.  38,  1745  ;  39,  2933  ;  C.  1908,  II.  1863). 

(56)  From  the  esters  of  the  phenyl  fatty  acids  (except  benzoic  acid) 
by  reduction  with  sodium  and  alcohol  (German  patent  164,294). 

(5c)  By  reducing  amides  of  aromatic  carboxylic  acids,  containing 
the  carboxylic  group  attached  to  the  benzene  nucleus,  with  sodium 
amalgam  in  acid  solution  (B.  24,  173). 

(6)  By  the  reduction  of  unsaturated  alcohols.     Cinnamyl  alcohol 
C6H6CH=CH.CH2OH  becomes  hydro-cinnamyl  alcohol  C6H5.CH2.CH2. 
CH2OH  (see  Allyl  Alcohol). 

(7)  They  are  formed  in  the  nuclear  synthesis  by  the  action  of 
metallic  alkylates  upon  aldehydes,  ketones,  acid  esters  or  acid  chlorides, 
and   halogen    hydrins.     Thus    (a)    phenyl-magnesium    bromide    and 
acetone  yield  phenyl-dimethyl-carbinol  C6H6C(OH)  (CH3)  2 ;   (b)  aromatic 
aldehydes,   ketones,   acid  esters,   or  chlorides  with  zinc  alkyls,   and 
especially    magnesium-alkyl   haloids    (Vol.    I.),    give   secondary    and 
tertiary  phenyl-paraffin  alcohols,  the  latter  easily  losing  water,  and 
passing  into  olefin  benzols  (C.  1901,  I.  1357  >    H-  623  '>    B.  35,  2633)  ; 
(c)  phenyl-magnesium  bromide  and  ethylene  chlorohydrin  yield  phenyl- 
ethyl  alcohol  C6H5CH2CH2OH  (C.  1907,  I.  1033). 

Benzyl  alcohol,  phenyl-carbinol  [phenyl-methylol]  C6H5CH2OH,  m.p. 
206°,  with  specific  gravity  1-062  (o°),  is  isomeric  with  the  cresols.  It 
occurs  as  benzoic  ester  and  benzyl-cinnamic  ester  in  the  balsams  of 
Peru  and  Tolu,  and  in  storax  (A.  169,  289)  ;  as  an  acetic  ester,  and 
sometimes  free  in  certain  etheric  oils,  e.g.  the  oil  of  jasmine  flowers 
(B.  32,  567). 

It  is  produced  by  the  methods  (i),  (2),  (3),  (4),  (5«),  and  (5c),  given 
VOL.  II.  E 


242  ORGANIC  CHEMISTRY 

above,  from  benzaldehyde,  benzyl  chloride,  benzole  acid,  and  benz- 
amide.  Reactions  (i)  and  (3)  are  used  as  methods  of  preparation.  It 
is  a  colourless  liquid,  with  a  faint  aromatic  odour.  It  dissolves  with 
difficulty  in  water,  but  readily  in  alcohol  and  ether.  It  yields  benz- 
al^lehyde  and  benzoic  acid  when  oxidised.  On  heating  with  hydro- 
chloric acid  or  hydrobromic  acid,  the  OH  group  is  replaced  by  halogens. 
Benzoic  acid  and  toluol  result  on  distilling  it  with  concentrated  potash. 
History. — As  early  as  1832  Liebig  and  Wohler,  in  the  course  of 
their  celebrated  investigation  upon  the  radical  benzoyl,  obtained 
this  alcohol  as  the  result  of  the  interaction  of  alcoholic  potash  and 
benzaldehyde  (A.  3,  254,  261).  Cannizzaro  (1853)  was  the  first  to 
discover  the  alcohol  in  studying  this  reaction. 

Homologous  Phenyl-paraffin  Alcohols. — The  primary  alcohols  are 
chiefly  made  by  methods  (i),  (2),  (3),  (4),  (50),  (56),  (5c),  and  (jc) ; 
hydro-cinnamyl  alcohol  by  method  (6)  ;  the  secondary  alcohols  by 
method  (i),  or  by  the  reduction  of  the  ketones  according  to  method  (3), 
and  the  tertiary  alcohols,  like  benzyl-dimethyl  carbinol,  by  method  (7) . 
Nucleus  homologous  benzyl  alcohols  : 

M.p.  B.p. 

o-Tolyl  carbinol      .   CH3[2]C6H4[i]CH2OH  34°    223°     (B.  24,  174) 

m-Tolyl  carbinol      .   CH3[3]C6H4[i]CH2OH  liquid   217°     (B.  18,  R.  66) 

p-Tolyl  carbinol      .   CH3[4]C6H4[i]CH2.OH  59°    217°     (A.  124,  255) 

2,  4-Dimethyl-benzyl 

alcohol    .          .    (CH3)2[2,  4]C6H3[i]CH2.OH      22°    232°     (B.  21,  3085) 

3,  5-Mesityl  alcohol    .    (CH3)2[3,  5]C6H3[i]CH2.OH  liquid   220°     (B.  16,  157?) 

2,  4,  5-Cumo-benzyl     al-  \ 

cohol       .          .    (CH3)3[2,4,5]C6H2[i]CH2.OH  168°       ..    I(B    „.  } 

3,  4,  5-Hemimelli-benzyl  (v 

alcohol    .          .    (CH3)3[3,4,5]C6H2[i]CH2.OH    78°       ..    J 
Mellithyl  alcohol     (CH3)5C6.CH2OH  160°       ..       (6.22,1217) 

p-Cumin  alcohol      .    (CH3)2CH[4]C6H4[i]CH2.OH     . .       246°. 

Other  homologues  are  the  phenyl-ether  alcohols  : 

Benzyl  carbinol  C6H5CH2.CH2OH,  p-phenyl- ethyl  alcohol,  a  main 
constituent  of  the  etheric  oil  of  roses  (B.  34,  2803),  boils  at  219° 
(B.  9,  373). 

Phenyl-methyl  carbinol  C6H5.CH(OH)CH3  boils  at  203°,  from 
benzaldehyde  and  CH3MgI  (C.  1901,  II.  623). 

o-,  m-,  and  p-tolyl-ethyl  alcohol  CH3C6H4CH2CH2OH,  b.p.  243-5°, 
243°,  and  245°,  from  the  tolyl-magnesium  bromides  with  ethylene 
chlorohydrin  (C.  1907,  I.  1033),  or  by  electrolytic  reduction  of  the 
three  isomeric  tolyl-acetic  acids  (C.  1908,  II.  1863). 

Phenyl-propyl  Alcohols. — Hydro-cinnamyl  alcohol  C6H5.CH2.CH2. 
CH2OH  boils  at  235°.  It  is  obtained  from  its  cinnamic  acid  ester,' 
which  is  present  in  storax  (A.  188,  202).  Benzyl-methyl  earbinol 
C6H5.CH2.CH(OH).CH3  boils  at  215°.  Phenyl-ethyl  carbinol  C6H5 
CH(OH)CH2CH3,  b.p.  221°,  obtained  like  phenyl-propyl. 

Phenyl-iso-propyl,  phenyl-iso-butyl,  and  phenyl-iso-amyl  carbinol, 
b.p.10  114°,  b.p.15  113°,  b.p. 9  122°  and  b.p.8  132°  respectively,  from 
benzaldehyde,  with  the  corresponding  alkyl-magnesium  iodides 
(C.  1901,  II.  623). 

Phenyl-dimethyl  carbinol  C6H5C(OH)(CH3)2,  m.p.  23°,  b.p.10  94°, 


DERIVATIVES  OF  PHENYL-PARAFFIN   ALCOHOLS    243 

is  obtained  from  phenyl-magnesium  bromide  with  acetones,  or  from 
aceto-phenone  and  benzoic  methyl  ester  with  magnesium-methyl 
iodide.  Benzyl-dimethyl  carbinol  C6H6.CH2.C(OH)(CH3)2,  m.p.  21°, 
b.p.  225°.  For  further  dialkyl-benzyl  carbinols,  see  C.  1904,  I.  1496. 
DERIVATIVES  OF  THE  PHENYL-PARAFFIN  ALCOHOLS. —  Haloid  Esters. 
— Benzyl  chloride  and  benzyl  bromide  are  produced  when  chlorine  or 
bromine  acts  upon  boiling  toluol  (Beilstein,  A.  143,  369).  The  action 
is  favoured  by  sunlight  (C.  1898,  I.  1019).  Benzyl  chloride,  bromide, 
and  iodide  are  also  formed  from  benzyl  alcohol  and  the  haloid  acids, 
and  benzyl  iodide  by  the  action  of  potassium  iodide  upon  benzyl 
chloride  (A.  224,  126)  : 

Benzyl  chloride    .        .  C6H5.CH2C1  liquid  b.p.  176° 

Benzyl  bromide  ..        .  C6H5.CH2Br  „  „    210° 

Benzyl  iodide       .        .  C6H5.CH2I    melts  at  24°  and  decomposes. 

Benzyl  chloride,  isomeric  with  the  three  chloro-toluols,  is  an  im- 
portant reagent,  by  means  of  which  numerous  derivatives  of  benzyl 
alcohol  have  been  prepared,  as  its  chlorine  atom  is  readily  exchanged. 
It  passes  into  benzyl  alcohol  when  boiled  with  water.  Heated  with 
water  and  lead  nitrate  it  yields  benzaldehyde,  and  by  oxidation 
benzoic  acid  : 

r  TJ  I-TJ  r  TI   rw  ri       S >  C6H5.CH,OH 

C6H5CHS  -        >  C,H6.CH2U-  -  J ^  C8H5.CHO >  C6H5COOH. 

The  following  ethers  have  been  made  by  the  action  of  sodium 
alcoholates  upon  benzyl  chloride,  or  by  electrolytic  reduction  of  benzoic 
esters  (B.  38,  1752).  Benzyl-methyl  ether  boils  at  168°,  obtained  from 
phenyl-magnesium  bromide  and  monochloro-methyl  ether  (C.  1908, 
I.  716).  The  ethyl  ether  boils  at  185°.  The  benzyl  ether  (A.  241,  374) 
(C6H5CH2)2O,  boiling  at  296°,  results  from  the  action  of  boron  trioxide 
upon  benzyl  alcohol.  Methylene-dibenzyl  ether  CH2(OCH2.C6H6)2 
(A.  240,  200).  Benzyl-arabinoside  C5H9O5.CH2.C6H5  melts  at  172° 
(B.  27,  2482).  Benzyl-phenyl  ether  melts  at  39°  and  boils  at  287°. 

Homologous  Phenyl-alkyl  Chlorides. — a-Chlorethyl  benzol  C6H5CHC1. 
CH3  boils  at  194° ;  cp.  B.  39,  2209.  (co-)  £-Chlorethyl  benzol  C6H6. 
CH2.CH2C1,  boils  at  93°  (17  mm.),  o-,  m-,  p-Methyl-benzyl  chloride 
CH3.C6H4CH2C1  boil  at  198°,  195°,  and  192°  respectively.  a-Chloro- 
propyl  benzol  C6H5.CHC1.CH2.CH3  and  j3-chloro-propyl  benzol  C6H5. 
CH2CHC1CH3  boil  about  203°-2O7°,  with  the  splitting  off  of  hydro- 
chloric acid  and  the  production  of  a-phenyl-propylene  C6H5.CH  : 
CH.CH3  and  allyl  benzol  C6H6CH2CH=CH2  ^-Bromo-propyl  benzol 
C6H6CH2.CH2.CH2Br,  b.p.u  109°  (B.  43,  178). 

Benzyl  phosphates :  the  mono-  melts  at  78°,  the  di-  is  liquid,  and 
the  tri-  melts  at  64°  (A.  262,  211).  Benzyl-sulphuric  acid  C6H5CH2. 
OSO3H,  formed  besides  dibenzyl  formal  CH2(OCH2C6H5)2  from  benzyl 
alcohol  and  methylene  sulphate  SO4  :  CH2  (C.  1900,  I.  101,  249). 
Benzyl  nitrite  C6H5CH2ONO,  b.p.35  81°,  from  benzyl  alcohol  and  HNO2 
in  aqueous  solution  (B.  34,  755). 

Esters  of  Carboxylic  Acid. — Benzyl  acetate  C6H5CH2.O.CO.CH3,  b.p. 
216°.  The  action  of  sodium  upon  the  benzyl  esters  of  the  fatty  acids 
is  peculiar,  and  tends  to  the  formation  of  benzyl  esters  of  higher  phenyl 
fatty  acids  (q.v.).  Benzyl  acetate  yields  phenyl-propionic  benzyl  ester. 


244  ORGANIC  CHEMISTRY 

Dibenzyl  oxalate  (C6H5.CH2O.CO)2  melts  at  80°. 

SULPHUR  DERIVATIVES  OF  BENZYL  ALCOHOL  are  formed  just  like 
the  sulphur  compounds  of  the  fatty  alcohols. 

Benzyl  sulphydrate,  benzyl  mercaptan  C6H5.CH2.SH.  It  is  a  liquid 
with  a  leek-like  odour  ;  boils  at  194°,  and  at  20°  has  a  specific  gravity 
-1-058  (A.  140,  86). 

Benzyl  disulphide  (C6H5CH2)2S2,  m.p.  71°  (B.  20,  15),  results  from 
the  oxidation  of  benzyl  sulphydrate  in  the  air  (A.  136,  86).  Also  from 
sodium-benzyl  hyposulphite  by  electrolysis  (C.  1908,  I.  1173),  or  by 
the  action  of  iodine  (C.  1909,  II.  1739). 

Benzyl  sulphide  (C6H5.CH2)2S,  m.p.  49°,  when  subjected  to  dry 
distillation  yields  stilbene  (q.v.),  stilbene  sulphide,  dibenzyl  (q.v.), 
thionessal  or  tetraphenyl-thiophene  (q.v.),  and  toluol.  The  sulphone 
(C6H5.CH2)2SO2,  m.p.  150°.  It  results  when  the  sulphoxide  in  glacial 
acetic  acid  is  acted  upon  by  KMnO4  (B.  13,  1284  ;  36,  534). 

Benzyl-dimethyl-sulphine  iodide  C6H5CH2S(CH3)2I  is  an  orange-red 
coloured  compound  (B.  7,  1274). 

Tribenzyl-sulphinic  chloride  (C6H5CH2)3SC1.  The  ferric  chloride 
double  salt  is  obtained  in  the  form  of  light-green  flakes,  of  m.p.  98°, 
by  the  action  of  ferric  chloride  upon  an  etheric  solution  of  benzyl 
chloride  and  benzyl  sulphide.  Tribenzyl-sulphinic  iodide,  m.p.  75° 
(B.  40,  4932). 

Benzyl  sulphoxide  (C6H5CH2)2SO,  m.p.  133°,  is  formed  by  oxidising 
benzyl  sulphide  with  nitric  acid  (B.  13,  1284).  Benzyl  sulphone 
(C6H5CH2)2SO2,  m.p.  150°,  from  benzyl  sulphoxide  with  MnO^K  in 
glacial  acetic  acid  (B.  13,  1284).  Benzyl  disulphoxide  C6H5CH2 
SOSOCH2C6H5,  m.p.  108°,  from  benzyl  disulphide  and  H2O2. 

Methyl-  and  ethyl-benzyl  sulphone,  m.p.  127°  and  84°,  from  sodium- 
benzyl  sulphinate  and  CH3I  and  C2H5I  respectively  (B.  39,  3315). 

Benzyl-sulphinic  acid  C6H6CH2SO2H,  obtained  by  the  reduction 
of  benzyl  sulpho-chloride.  It  easily  splits  into  benzaldehyde  and 
sulphurous  acid  (B.  39,  3308). 

Benzyl-sul phonic  acid  C6H6.CH2.SO3H  is  a  deliquescent  crystalline 
mass  ;  it  is  isomeric  with  toluol-sulphonic  acid.  The  potassium  salt 
is  formed  on  boiling  benzyl  chloride  with  potassium  sulphite.  The 
chloride  melts  at  92°  (B.  13,  1287). 

Benzyl-hyposulphurous  acid  C6H6CH2SSO3H,  m.p.  74°  (B.  23, 
R.  284). 

NITROGEN  DERIVATIVES  OF  THE  PHENYL-PARAFFIN  ALCOHOLS. 

PHENYL-NITRO-PARAFFINS. — When  the  homologous  benzols  are 
heated  in  sealed  tubes  with  dilute  nitric  acid,  the  nitro-groups  usually 
enter  the  side  chains  with  the  formation  of  phenyl-nitro-paraffins 
(Konowaloff,  B.  28,  1850,  R.  235  ;  29,  2199  ;  C.  1899,  I.  1237). 

By  this  treatment  toluol  yields  phenyl-nitro-methane  C6H5.CH2.NO2. 
This  body  has  also  been  prepared  from  nitro-benzal-phthalide,  as  well 
as  from  benzyl  haloids,  but  best  from  the  iodide  (B.  29,  700)  by  the 
action  of  silver  nitrite.  It  is  an  oil,  boiling  with  decomposition  at 
226°.  It  is  most  easily  obtained  from  phenyl-nitro-aceto-nitrile 
C6H5CH(NO2)CN  (q.v.)  by  boiling  with  NaHO,  or  by  the  action  of 
ethyl  nitrate  and  potassium  ethylate  upon  phenyl-acetic  ester,  a  reaction 


DERIVATIVES   OF   PHENYL-PARAFFIN   ALCOHOLS     245 

in  which  the  carbox-ethyl  group  is  split  off  in  the  form  of  carbonic 
acid  ester  (B.  42,  1930).  On  heating  with  NaHO  to  160°  the  phenyl- 
nitro-methane  is  further  changed,  nitrogen  oxides  being  split  off  and 
stilbene  formed  (B.  36,  1194  ;  38,  502). 

Phenyl-nitro-methane  dissolves,  like  the  nitre-paraffins  (Vol.  I.),  in 
sodium  hydroxide,  forming  a  sodium  salt,  from  which  the  oily  phenyl- 
nitro-methane  is  regained  by  the  action  of  CO2  or  acetic  acid.  If, 
however,  the  sodium  salt  be  precipitated  with  mineral  acids,  a  crystal- 
line substance,  m.p.  84°,  is  obtained.  This  is  isomeric  with  the  oily 
body,  and  is  distinguished  from  it  by  the  red  coloration  it  yields  with 
ferric  chloride,  as  well  as  by  its  electric  conductivity.  It  quickly 
changes,  both  in  solution  and  when  in  a  free  state,  into  the  oily  isomeride. 
Its  constitution  certainly  corresponds  to  the  formula  adopted  for  the 
sodium  salts  of  the  nitro-paramns,  from  which,  however,  the  correspond- 
ing free  bodies  in  the  fatty  series  have  not  been  successfully  isolated 
(Hantzsch  and  O.  W.  Schultze,  B.  29,  2251)  : 


C8H5CH2N<° ,  c6H5.CH  :  N^ >  C,H5CH  : 

Similar  stable  and  unstable  isomerides  have  also  been  obtained  from 
the  nucleus  homologues  and  substituted  phenyl-nitro-parafBns  (B.  29, 
2193,  2253,  R.  40). 

The  action  of  acid  chlorides  upon  the  sodium  salts  of  the  phenyl- 
nitro-methanes  usually  gives  acyl  derivatives  of  benzo-hydroxamic 
acid,  in  consequence  of  an  intramolecular  oxidation  process  ;  sodium 
phenyl-nitro-methane  and  acetyl  chloride  give  aceto-benzo-hydroxamic 
acidC6HgC(OCOCH3)NOH  (C.  1900,  I.  177).  On  ammonium  salts  of 
phenyl-nitro-methane,  see  C.  1900^  I.  1092. 

Tolyl-nitro-methane,  see  B.  38,  503  ;  C.  1905,  II.  817.  co-Nitro- 
durol  (CH3)3[2,  4,  5]C6H2[i]CH2NO2,  m.p.  52°  ;  iso-nitro-compound, 
m.p.  I02°-io6°,  is  easily  obtained  by  nitrogenation  of  durol  with  benzoyl 
nitrate  (B.  42,  4154). 

Phenyl-methyl-nitro-methane  C6H5CH(CH3)NO2,  b.p.  115°,  from 
aceto-phenone  monoxime  (q.v.)  by  oxidation  with  Caro's  acid  ;  the 
corresponding  unstable  nitronic  acid  C6H5C(CH3)  :  NOOH  melts  about 
45°  (B.  36,  706). 

Phenyl-paraffin  Amines,  Benzyl-amines. — (i)  Alcoholic  ammonia 
converts  benzyl  chloride  into  mono-,  di-,  and  tribenzy  I- amines  (B.  23, 
2971  :  C.  1901,  II.  1155). 

Most  of  the  other  methods  of  producing  benzyl-amine  are  reactions 
which  have  been  fully  discussed  in  connection  with  the  primary 
alkyl-amines. 

Benzyl-amine  is  formed  (2)  by  the  reduction  of  phenyl-nitro-methane, 
benzaldoxime,  and  benzylidene-phenyl-hydrazone  (B.  19,  1928  ;  35, 
1513  ;  42,  1559)  '>  (3)  and  (4)  by  heating  benzaldehyde  with  ammonium 
formate  or  formamide  (B.  19,  2128  ;  20,  104  ;  A.  343,  54),  together 
with  di-  and  tribenzyl-amine  ;  (5)  by  the  reduction  of  benzo-nitrile 
(B.  20,  1709)  and  (6)  of  benzo-thiamide  (B.  21,  51)  ;  (7)  of  benzamide 
(C.  1899,  II.  623)  ;  (8)  by  saponifying  benzyl  iso-cyanide  or  benzyl 
carbon-imide  C6H5CH2NCO  (B.  5,  692),  and  (9)  benzyl  acetamide 
C6H5CH2NHCOCH3  (B.  12,  1297)  ;  (to)  by  the  distillation  of  the 


246  ORGANIC   CHEMISTRY 

phenyl-amido-acetic  acid  C6H5CH(NH2)CO2H  (B.  14,  1969)  ;  and  (n) 
by  the  action  of  caustic  alkali  and  bromine  upon  phenyl-acetic  amide. 
Benzyl-amine  is  a  liquid,  dissolving  readily  in  water.  It  differs  from 
its  isomeric  toluidin  in  being  a  strong  base,  which  attracts  CO2  from 
the  air. 

Caro's  acid  oxidises  benzyl-amine  to  benzaldoxime,  phenyl-nitro- 
methane,  and  benzo-hydroxamic  acid,  besides  benzaldehyde  and 
benzoic  acid  (B.  34,  2262). 

Dibenzyl-amine  (C6H5CH2)2NH,  b.p.  300°,  is  also  obtained  from 
benzalazin  C6H5CH  :  N.N  :  CHC6H5  by  reduction  with  zinc  dust  and 
acetic  acid,  and  (with  benzyl-amine)  by  reduction  of  benzo-nitrile. 

Nitroso-dibenzyl-amine  (C6H5CH2)2NNO,  m.p.  61°  (B.  34,  557). 

Tribenzyl-amine  (C6H6CH2)3N,  m.p.  91°. 

Homologous  benzyl-amines  are  isomeric  with  corresponding  alphyl- 
amines.  They  are  mostly  formed  by  reducing  nitriles  with  alcohol  and 
sodium  ;  some  by  the  reduction  of  oximes  or  nitro-compounds,  while 
others  are  obtained  by  the  methods  indicated  under  benzyl-amine. 

/3-Phenyl-ethyl-amine  .  .  C6H5CH2CH2NH2  b.p.    197° 

a-Phenyl-ethyl-amine  .  .  C6H5CH(NH2)CH3                         „      187° 

y-Phenyl-propyl-amine  .  .  C8H5.CH2.CH2CH2NH2                  „     221° 

0-Phenyl-propyl-amine  .  .  C6H5CH(CH3).CH2NH2                  „     210° 

a-Phenyl-propyl-amine  .  .  C6H5CH(NH2).CH2.CH3                 „     205° 

0-Phenyl-iso-propyl-amine  .  C6H5CH2.CH(NH2)CH3  ,,     203° 

o-Tolu-benzyl-amine  .  .  CH3[2]C6H4[i]CH2NH2                  „     205° 

m-Tolu-benzyl-amine  .  .  CH3[3]C6H4[i]CH2NH2                  „     201°  ' 

p-Tolu-benzyl-amine  .  .  CH3[4]C6H4[i]CH2NH3                  „      195°  « 

co-Pseudo-cumyl-amine  .  .  (CH3)2[2,4]C6H3[i]CH2NH2           „     218°  » 

co-Mesityl-amine       .  .  .  (CH3)2[3>  5]C6H3[i]CH2NH2           „     221°" 

co-Duryl-amine         .  .  .  (CH3)3[2,4,5]C6H2[i]CH2NH2  m.p.    52°  " 

Cumyl-amine  .  (CH3)2CH[4]C6H4[i]CH2NH2  b.p.  226°  ™ 

Cumo-benzyl-amine  .  . '  (CH3)3[2,  4, 5]C6H2[i]CH2NH2  m.p.    64° 13 

Hemimelli-benzyl-amine  .  (CH3)3]3, 4, 5]C6H2[i]CH2NH2       „     123°" 

Literature.—1  B.  26,  1904  ;    2  B.  27,  2306  ;  3  B.   27,  2309  ;    *  B.  26,  2875  ; 

*  B  20,  618  ;  8  B.  23,  1026  ;  33,  1013  ;  C.  1899,  I.  1238  ;  7  B.  23,  3165  ;  8  B.  20, 

1719;  •  B.  21,  3083;  10C.  1899,  I.  1238;  «  B.  42,  4i56;  12  B.  20,  2414; 
13  B.  24,  24o9;  "  B.  24,2411. 

a-Phenyl-ethyl-amine  C6HiCH(NH2)CH3  is  obtained  by  electrolytic 
reduction  of  aceto-phenone  oxime  (B.  35,  1515)  ;  it  contains  an  un- 
symmetrical  C  atom,  and  has  been  split  up  into  its  optically  active 
components  by  means  of  its  maleic  salt  (C.  1899,  II.  1123  ;  1905  II 

1583). 

The  pure  benzyl-amines  are  associated  with  benzyl-alkyi-  and 
benzyl-aryl-amines,  as  well  as  benzyl-alkyl-ammonium  compounds. 
Benzyl-alkyl-amines,  like  benzyl-ethyl-amine  C6H5.CH2NHC2H5,  and 
cumyl-ethyl-amine  C3H7C6H4CH2NHC2H5,  are  obtained  from  the  cor- 
responding benzylidene-alkyl-amines  by  reduction  with  Na  and  alcohol, 
or  by  heating  benzaldehyde  with  organic  formates  (B.  35,  410  •  A! 
343,  54).  Dibenzyl-ethylene-diamine  (C6H5CH2NH)2C2H4,  b.p.  175°- 
182°,  from  dibenzylidene-ethylene-diamine  ;  it  condenses  with  ethylene 
bromide  to  dibenzyl-piperazin  (C.  1898,  II.  743).  Pheno-propyl-methyl- 
amine  C6H5CH2CH2CH2NHCH3,  b.p.18  134°,  is  obtained  from  cin- 


DERIVATIVES   OF   PHENYL-PARAFFIN   ALCOHOLS    247 

namylidene-methyl-amine  C6H5CH  :  CH.CH  :  NCH3  with  sodium  and 
alcohol  (C.  1902,  I.  662).  a-Phenyl-ethyl-methyl-amine  C6H5(CH3) 
CHNHCH3,  b.p.ls  87°,  and  a-phenyl-propyl-methyl-amine,  b.p.^  96°, 
are  obtained  by  the  action  of  methyl-  and  ethyl-magnesium  iodide 
respectively  upon  benzal-methyl-amine  (/.  pr.  Ch.  2,  77,  20). 

Benzyl  -  phenyl  -  allyl  -  methyl  -  ammonium  iodide  (C6H5CH2)  (CgHg) 
(C3H5)(CH3)NI  contains  an  unsymmetrical  N  atom,  and  has  been  split 
up  into  optically  active  components  by  means  of  campho-sulphonic 
acid  (B.  32,  3561 ;  C.  1901,  II.  206).  Similarly,  the  splitting  up  of  many 
other  quaternary  benzyl-ammonium  compounds,  with  four  different 
radicles,  has  been  accomplished  (see  E.  Wedekind,  Stereo-chemistry 
of  Qiiinquevalent  Nitrogen,  Leipzig,  1907). 

Benzyl-aniline  C6H5.CH2.NH.C6H5  melts  at  32°,  and  is  formed  from 
aniline  and  benzyl  chloride  (A.  138,  225),  or  by  the  reduction  of 
benzylidene-aniline  with  sodium  in  alcoholic  solution  (A.  241,  330),  or 
by  electrolytic  reduction  (B.  42,  3460).  When  heated  to  220°  with 
sulphur  it  yields  thio-benzanilide,  and  benzenyl-amido-thio-phenol  at  250° 
(A.  259,  300).  For  acid  derivatives  of  benzyl -aniline,  see  B.  32,  2672. 

Dibenzyl-aniline  (C?H5.CH2)2.N.C6H5,  m.p.  67°  (B.  20,  1611). 

C-alkyl-benzyl-anilines  like  C6H5CH(CH3)NHC6H5  are  produced 
by  the  attachment  of  alkyl-magnesium  haloids  to  benzal-aniline  : 

C6H5CH  :  NC6H5  £5l?_$!  CflH6CH(CH3).N(MgI)C,H5  J^  CaH5CH(CH3)NHC8H5. 

The  chlorohydrates  of  these  bases,  when  heated  to  220°  with  aniline 
chlorohydrate,  undergo  an  atomic  displacement  analogous  to  Hof- 
mann's  transposition,  with  formation  of  C-alkyl-p-amido-diphenyl- 
methanes,  e.g. 

C6H5CH(CH3)NHC6H5 >  NH2C6H4CH(CH3)C6H6. 

C-Methyl-,  -ethyl-,  -propyl-,  and  -amyl-benzyl-aniline,  b.p.20  183°, 
192°,  200°,  and  215°  (B.  38,  1761). 

Benzyl-oxethyl-amine  C6H5.CH2.NH.CH2.CH2OH,  picrate,  melt- 
ing at  136°,  results  from  the  rupture  of  the  phenyl-oxazolin  ring 

C6H5.C/°;^2  by  sodium  and  alcohol  (B.  29,  2382). 

The  following  representatives  of  the  numerous  benzylated  acid 
amides  and  benzylated  nitrogen  derivatives  of  carbonic  acid  may  be 
mentioned  : 

Benzyl  acetamide  C6H5CH2NHCOCH3,  m.p.  60°  (B.  19,  1286).  Its 
nitroso-derivative  C6H5CH2N(NO)COCH3  is  decomposed  by  alcohols 
with  elimination  of  nitrogen,  and  formation  of  benzyl-alkyl  ethers  ; 
this  decomposition,  recalling  the  diazo-bodies,  is  also  shown  by  other 
nitrosated  acid  derivatives  of  benzyl- amine  (B.  31,  2640  ;  32,  78). 

Dibenzyl-urea  chloride  (C6H5CH2)2NCOC1  is  an  oil  (B.  25,  1819). 
Benzyl-urethane  C6H5CH2NHCO2C2H5,  m.p.  44°. 

Benzyl-urea  C6H5CH2NHCONH2,  m.p.  147°.  Sym.  and  unsym. 
di-benzyl-urea  melt  at  167°  and  124°  (B.  9,  81).  Tri-  and  tetrabenzyl- 
urea  melt  at  119°  and  85°  (B.  25, 1826). 

Benzyl-thio-urea  melts  at  164°  (B.  24,  2727  ;  25,  817). 

Dibenzyl-guanidin  (C6H5CH2NH)2C  :  NH,  m.p.  100°  (B.  5,  695). 

Benzyl  iso-eyanate,  benzyl  carbonimide  C6H5CH2N  :  CO,  is  a  liquid 
with  a  penetrating  odour.  Benzyl  cyanurate  melts  at  157°  (B.  5,  692). 


248  ORGANIC  CHEMISTRY 

Benzyl-mustard  oil  C6H5CH2N  :  CS,  b.p.  243°,  forms  the  chief  in- 
gredient of  the  ethereal  oils  of  various  cresses  (B.  32,  2336). 

BENZYL -HYDRAZINS. — Benzyl  -  hydrazin  C6H5CH2NH.NH2,  b.p.41 
103°,  is  obtained  by  decomposition  of  its  benzylidene  compound 
C6H5CH2NH.N  :  CHC6H5  with  acids.  This  compound  is  obtained  by 
a  partial  reduction  of  benzal-azin  with  Na  amalgam  and  alcohol.  With 
HNO2,  benzyl-hydrazin  gives  a  very  stable  nitroso-compound  C6H5CH2N 
(NO)NH2,  m.p.  71°  (B.  33,  2736). 

Unsym.  dibenzyl-hydrazin  (C6H5CH2)2N.NH2,  m.p.  65°,  from  benzyl 
chloride  with  hydrazin  hydrate  ;  also  from  dibenzyl  nitrosamine  by 
reduction  with  zinc  dust  and  acetic  acid  ;  by  oxidation  with  HgO  it 
yields  a  tetrazone,  m.p.  97° ;  but  under  other  conditions  nitrogen 
seems  to  be  liberated,  with  the  formation  of  dibenzyl  (B.  33,  2701  ; 
34,552). 

Sym.  benzyl-phenyl-hydrazin  C6H5CH2NHNHC6H5,  m.p.  35°,  b.p. 
about  290°,  is  obtained  by  the  reduction  of  benzal-phenyl-hydrazone 
with  Na  amalgam  in  alkaline  solution.  Oxidation  in  air  readily  re- 
converts it  into  the  phenyl-hydrazone  (/.  pr.  Ch.  2,  78,  49).  Unsym. 
benzyl-phenyl-hydrazin  C6H5CH2N(C6H5)NH2,  m.p.  26°,  from  phenyl- 
hydrazin  and  benzyl  chloride,  is  suitable  for  separating  sugars  in  the 
form  of  hydrazones  (B.  32,  3234  ;  C.  1904,  II.  1293).  On  oxidation  it 
passes  into  dibenzyl  -  diphenyl  -  tetrazone  C6H5CH2(C6H5)N.N  :  N.N 
(C6H5)CH2C6H5,  m.p.  145°,  which  on  heating  in  xylene  solution  de- 
composes into  Na  and  sym.  dibenzyl-diphenyl-hydrazin,  b.p.22  181° 
(B.  39,  2566). 

BENZYL-DIAZOCOMPOUNDS.    BENZYL-TRIAZENES.    BENZYL-AZIDES. 

Potassium-benzyl  diazotate  C6H5CH2N  :  NOK  (?)  is  obtained  by 
the  action  of  highly  concentrated  potash  lye  upon  nitroso-benzyl- 
urethane  C6H5CH2N(NO)CO2C2H5.  It  forms  a  white  crystalline 
powder,  which,  on  wetting  with  water,  splits  up  into  KOH  and  phenyl- 

N 

diazo-methane  C6H-CH/ 1| ;  the  latter  is  a  reddish-brown  oil,  which, 

N. 
on  distillation,  breaks  up  into  nitrogen  and  stilbene  C6H5CH  :  CHC6H5  ; 

on  warming  with  water,  into  N2  and  benzyl  alcohol ;  with  alcohol, 
into  N2  and  benzyl  ether  ;  and  with  HC1,  into  Na  and  benzyl  chloride 
(B.  35,  903  ;  cp.  also  Diazo-methane,  Vol.  I.). 

Sodium-benzyl  iso-azotate  C6H5CH2.N  :  NONa,  colourless  needles, 
is  formed  by  the  action  of  ethyl  nitrite  and  sodium  methylate  upon 
unsym.  nitroso-phenyl-hydrazin,  with  simultaneous  liberation  of  nitrous 
oxide.  It  differs  decidedly  from  the  corresponding  K  salt.  In  cold 
water  it  dissolves  unchanged,  but  on  heating,  or  with  dilute  acids,  it 
decomposes  into  N2  and  benzyl  alcohol.  On  reduction  it  passes  into 
benzyl-hydrazin  ;  on  oxidation,  into  benzyl-nitramine  C6H5CH2NHNO2 
m-P-  39°>  from  which  it  may  be  recovered  by  reduction  with  aluminium 
and  soda  (A.  376,  255). 

Benzyl-methyl-triazene  C6H5CH2N  :  N.NHCH3,  a  colourless  oil, 
resembling  in  its  instability  the  aliphatic  diazo-amido-compounds 
(Vol.  I.),  and  readily  decomposed  even  by  CO2.  Obtained  from  ben- 
zyl azide  and  CH3MgI.  The  cupro-salt  melts  at  114°,  and  consists  of 
pale-yellow  grains  ;  silver  salt,  m.p.  125°,  colourless  needles  (B.  38, 684). 


BENZYL-HYDROXYLAMINES  249 

Benzyl-phenyl-triazene  C6H5CH2NH.N  :  NC?H5  or  C6H5CH2N  : 
N.NHC6H5,  m.p.  75°,  colourless  flakes,  is  obtained  by  transforming 
benzyl  azide  with  C6H5MgBr,  or  phenyl  azide  with  C6H5CH2MgCl. 
Dilute  HC1  splits  it  up  into  benzyl  chloride,  aniline  chlorohydrate, 
and  nitrogen  (B.  38,  682). 

Benzyl-azide  C6H5CH2N<,  b.p.n  74°,  from  C6H5CH2N<2,  benzyl- 


nitroso-hydrazin,  on  boiling  with  dilute  H2SO4,  or  from  benzyl  iodide 
with  silver  nitride,  is  a  very  stable  ether  of  nitro-hydric  acid  ;  it  is 
only  decomposed  by  fairly  concentrated  H2SO4,  yielding,  with  liberation 
of  N,  (i)  benzaldehyde  and  NH3  ;  (2)  formaldehyde  and  aniline  ;  (3) 
benzyl-amine  and  N2O  (?)  ;  or  (4)  benzyl  alcohol  (and  NH3)  (/.  pr.  Ch. 
2,  63,  428  ;  B.  35,  3229). 

Benzyl-hydroxylamines.  —  a-Benzyl-hydroxylamine,  b.p.5n  123°,  best 
obtained  by  splitting  up  benzyl  acetoxime  C6H5CH2ON  :  C(CH3)2 
with  HC1  ;  in  a  similar  manner  a,  p-ehloro-benzyl-hydroxylamine,  m.p. 
38°,  b.p.17  128°,  and  a,  p-bromo-benzyl-hydroxylamine,  m.p.  37°,  b.p.  10 
133°,  have  been  prepared.  The  a-benzyl-hydroxylamine,  on  heating 
in  a  pressure  tube,  breaks  up,  partly  into  NH3,  water,  and  benzal- 
doxime-benzyl  ether.  With  SOC12  it  yields  thionyl-benzyl-hydroxyl- 
amine  C6H5CH2ON  :  SO,  b.p.50  154°  ;  with  COC12,  dibenzyl-oxy-urea 
(C6H5CH2ONH)2CO,  m.p.  88°;  with  formimido-ether  chlorohydrate, 
dibenzyl-formo-hydroxamoxime  C8H5CH2ONH.CH  :  NOCH2C6H5,  m.p. 
42°  (B.  26,  2155  ;  33,  1975).  Treated  with  benzyl  chloride,  the 
a-benzyl-hydroxylamine  passes  into  aj8-dibenzyl  -  hydroxylamine 
C6H5CH2O.NHCH2C6H5,  a  liquid,  and  tribenzyl-hydroxylamine  C6H5 
CH2ON(CH2C6H5)2,  liquid.  The  former,  split  up  with  HC1,  gives 
0-benzyl-hydroxylamine  C6H5CH2.NHOH,  m.p.  57°,  which,  with  benzyl 
chloride,  yields  jS-dibenzyl-hydroxylamine  (C6H5CH2)2NOH,  m.p.  123° 
(A.  275,  133).  The  jS-benzyl-hydroxylamine  combines  with  aldehydes  to 
form  N-benzyl-aldoximes  .  With  oxidisers,  like  bromine  water  or  chromic 
acid,  it  is  converted  mainly  into  bis-nitroso-benzyl  (C6H5CH2NO)2. 
The  latter  is  converted  by  HC1  into  benzal-benzoyl-hydrazin  and  its 
disintegration  product  : 

(C6H5CH2NO)2  ---  >  C6H5CH  :  N.NHCOC6H5+H2O. 

Atmospheric  oxygen  produces  mainly  benzaldoxime  (B.  33,  3193  ; 
A.  323,  265).  Oxidation  of  the  j3-dibenzyl-hydroxylamine  produces 
N-benzyl-benzaldoxime. 

Substituted  benzyl  alcohols  are  derived  from  substituted  benzyl 
chlorides  when  they  are  heated  with  aqueous  potash  (B.  25,  3290),  or 
by  means  of  acetic  esters.  Many,  like  m-nitro-benzyl  alcohol,  are  also 
obtained  by  the  action  of  alcoholic  potash  upon  the  corresponding 
aldehydes.  They  have  also  been  prepared  by  the  electrolytic  reduc- 
tion of  substituted  benzoic  acids. 

Ortho-  Meta-  Para- 

Chloro-benzyl  alcohol    .         .      m.p.        72°  liquid  73° 

Bromo-benzyl  alcohol   .         .        „           80°  „  72° 

Bromo-benzyl  bromide  .         .        ,,           30°  41°  61° 

Nitro-benzyl  alcohol      .         .        „           74°  27°  93° 

Nitro-benzyl  chloride     .         .                   47°  46°  71° 


250  ORGANIC   CHEMISTRY 

o-Nitro-benzyl  alcohol  results  also  from  the  electrolytic  oxidation 
of  o-nitro-toluol  (C.  1901,  II.  1051)  ;  and  p-nitro-benzyl  alcohol  by 
oxidation  of  p-nitro-toluol  with  MnO2  and  concentrated  SO4H2 
(German  patent  212,949).  The  o-nitro-benzyl  alcohol  is  reduced 
by  zinc  dust  and  sal-ammoniac  solution  to  o-hydroxylamino-benzyl 
alcohol  HONH[2]C6H4CH2OH,  m.p.  104°,  which  is  oxidised  by 
chromic  acid  to  azoxy-benzyl  alcohol  ON2(C6H4CH2OH)2,  m.p.  123°  ; 
and  by  Caro's  acid  or  ferric  chloride  to  o-nitroso-benzyl  alcohol 
ON[2]C6H4CH2OH,  m.p.  101°.  The  latter,  on  being  boiled  in  water, 
loses  H2O  and  passes  into  anthranile  (B.  36,  836),  and  forms  the  link  in 
the  transition  of  o-nitro-toluol  into  anthranilic  acid  on  heating  with 
alkaline  hydroxide. 

Reduction  of  the  nitro-benzyl  alcohols,  as  well  as  the  electrolytic 
reduction  of  nitro-  and  amido-benzoic  acids  in  acid  solution,  produce 
amido-benzyl  alcohols.  p-Amido-benzyl  alcohol,  m.p.  64°  (A.  305, 119), 

*  /~»T_T 

is  converted  by  acids  into  an  anhydro-lorm  ^CeH4<^  |      ),   which   is 

also  obtained,  with  other  derivatives,  by  direct  action  of  formaldehyde 
upon  the  corresponding  anilines  in  the  presence  of  acids  (B.  31,  2037  ; 
33,  250  ;  35,  739  ;  C.  1898,  II.  159  ;  Ch.  Ztg.  24,  284). 

p-Amido-benzyl-amine  NH2C6H4CH2NH2  b.p.  269° ;  p-Acetyl- 
amido-N-ehloracetyl-benzyl-amine  CH3CONHC6H4CH2NHCOCH2C1  is 
produced  by  nuclear  synthesis  in  the  condensation  of  acetanilide 
with  methylol-chloracetamide  CH2C1CONH.CH2OH  under  the  action 
of  concentrated  H2SO4.  On  boiling  with  HC1  the  acetyl  and  chlor- 
acetyl  groups  are  split  off  (A.  343,  299). 

p-Amido-benzyl-aniline  NH2C6H4CH2NHC6H5  a  viscous  oil,  from 
anhydro-formaldehyde-aniline  with  aniline  ;  easily  transposed  to  di- 
amido-diphenyl-methane  (B.  29,  R.  746  ;  C.  1900,  I.  1112).  p-Nitro- 
benzyl-amine,  see  B.  30,  61. 

m-Amido-benzyl  alcohol  NH2[3]C6H4[i]CH2OH,  m.p.  92°,  from 
m-nitro-benzoic  acid  by  electrolytic  reduction  (B.  38,  1751). 

o-Amido-benzyl  alcohol  NH2[2]C6H4CH2OH,  m.p.  82°,  b.p.10  160°, 
is  formed  from  o-nitro-benzyl  alcohol  or  from  anthranile  by  reduction 
with  zinc  dust  and  HC1  (B.  25,  2968  ;  27,  3513)  ;  from  anthranilic 
ester  with  Na  amalgam  in  acid  solution  (B.  38,  2062)  ;  and  by 
electrolytic  reduction  of  o-nitro-benzoic  acid  or  anthranilic  acid 
(B.  38,  1751). 

0-Acetyl-o-amido-benzyl  alcohol  NH2C6H4CH2OCOCH3,  an  oil 
smelling  of  aniline,  with  a  chlorohydrate  melting  at  116°,  is  formed  by 
the  reduction  of  o-nitro-benzyl  acetate.  The  free  base  is  unstable, 
and  on  standing,  or  (rapidly)  on  heating,  it  passes  into  the  crystalline 
N-acetate  CH3CONHC6H4CH2OH,  m.p.  116°.  Cold  HBr  converts  the 
latter  into  the  bromohydrate  of  /x-methyl-pheno-pentoxazol,  which, 
on  standing  in  water,  takes  up  water  and  splits  up  to  form  O-acetyl- 
o-amido-benzyl  alcohol  (B.  37,  2249). 

Formation  of  Hetero-rings  from  Derivatives  of  o-Amido-benzyl 
Alcohol. — Just  like  the  o-diamines,  o-amido-phenols,  and  o-amido- 
thio-phenols,  many  o-amido-benzyl  alcohol  derivatives,  and  also  those 
of  o-nitro-benzyl  alcohol,  so  far  as  they  yield  o-amido-benzyl  alcohol 
compounds  upon  reduction,  show  ability  to  form  hetero-rings.  Some 


DERIVATIVES   OF   O-AMIDO-BENZYL  ALCOHOL       251 

of  the  derivatives  of  these  two  alcohols  capable  of  yielding  hetero-rings 
are  the  following  : 

o-Amido-benzyl  alcohol  combines  with  nitroso-benzol  to  o-benzol- 
azo-benzyl  alcohol  C6H5N  :  NCgH4CH2OH,  m.p.  78°,  which,  on  heating 
with  H2SO4,  becomes  phenyl-indazol  (C.  1903,  I.  1416).  It  becomes 
thio-cumazone  (B.  27,  1866)  when  it  is  boiled  with  alcoholic  CS2,  and 
thio-cumo-thiazone  (B.  27,  2427)  when  the  CS2  and  alcoholic  potash  are 
used.  The  urea  derivatives  of  o-amido-benzyl  alcohol  lead  to  similar 
rings  (B.  27,  2413). 

o-Nitro-benzyl  sulpho-cyanide  NO2C6H4CH2S.CN,  m.p.  75°  (B.  25, 
3028),  yields  o-benzylene-0-thio-urea.  Sulphuric  acid  reduces  it  to 
o-nitro-benzyl-carbamine-thiolic  ester  NO2.C6H4CH2.SCONH2,  m.p. 
116°.  Hydrochloric  acid  saponifies  this  to  o-nitro-benzyl  mereaptan 
NO2[2]C6H4[i]CH2SH,  m.p.  43°.  Both  bodies  yield  benz-iso-thiazol 
upon  reduction  (B.  28,  1027  ;  29,  160). 

o-Amido-benzyl  chloride  hydrochloride  HC1.NH2.C6H4CH2C1  is 
formed  by  the  action  of  concentrated  hydrochloric  acid  upon  o-amido- 
benzyl  alcohol.  With  caustic  potash  this  yields  poly-o-benzylene- 
imide  (C7H7N)X(B.  19,  1611  ;  28,  918,  1651)  ;  with  acetic  anhydride, 
H-methyl-pheno-pentoxazol ;  with  thiacetamide,  ^-methyl-pheno-penthi- 
azol  (B.  27,  3515) ;  and  with  thio-urea,  o-benzylene-ip-thio-urea  (B.  28, 
1039) : 


C.H4j        2             -       ~H2° >    C,H4  <   -    ^>NC4H8  Phenyl-indazol  (i) 

(  CH.OH          I  ~  ^ -*    C'H*{  NH^S  Thio-cumazone  (a) 

*  t  NHa  [    CS.KOH    ^    QH4 1  CH,^  Thio.cumo.thiazone  (3) 

f  CH2SCN  H 

9    *1  NO,  \c  H    (  CH,— S  (  CH,— S 

j  CH.C1  -f  Thio-carbamide       J     *    *  (  NH — C  :  NH  C          •    «  (  N=C.NH, 

1  NH'HCI  o-Benzylene-^-thio-urea 


Benz-iso-thiazol  (5) 
JT  ,.MethyI-phen0-pentoxazol(6) 


+Thiacetamide  M-Methyl-pheno-penthiazol  (7). 


The  anhydride  of  an  o-benzyl-alcohol-sulphonic  acid,  sulpho-benzide 

C6H4{[2]CH22)>O'  m-p-  II3°'  is  obtamed  bY  tne  reduction  of  the  stable 
o-sulpho-benzoic  acid  chloride,  much  as  the  phthalide  is  obtained  from 
phthalyl  chloride  ;  also  by  reduction  of  the  product  of  the  action  of 
PC15  upon  o-benzaldehyde-sulphonic  acid  (B.  31,  1666). 

o-Nitro-benzyl-amine  C6H4(N02).CH2.NH2,  obtained  from  o-nitro- 
benzyl  chloride  by  the  saponification  of  its  phthalimide  derivative,  is 
a  strong,  oily  base  (B.  20,  2227). 

o-Nitro-benzyl-formamide  NO2.C6H4.CH2.NH.CHO,  melting  at  89°, 
is  reduced  to  dihydro-quinazolin  (B.  25,  3031  ;  36,  806). 

o-Nitro-benzyl-amline  NO2.C6H4.CH2.NHC6H5,  melts  at  44°  (B. 
19,  1607). 

o-Nitro-benzyl-phenyl-nitrosamme  NO2C6H4CH2N(NO)C6H5  is  con- 
verted by  tin  and  hydrochloric  acid  into  n-phenyl-indazol  (B.  27,  2899), 


252 


ORGANIC   CHEMISTRY 


o-Amido-benzyl-amine,  o-benzylene-diamine  NH2C6H4CH2NH2  is 
a  radiating  crystalline  mass,  obtained  from  o-nitro-benzyl-amine. 
With  aldehydes  like  benzaldehyde  it  forms  phenyl-tetrahydro-keto- 
quinazolin ;  with  phosgene,  tetrahydro-keto-quinazolin  ;  with  carbon 
disulphide,  tetrahydro-thio-quinazolin  (B.  28,  R. .  238).  o-Amido- 
benzyl-aniline  NH2.C6H4.CH2.NH.C6H5,  melting  at  86°,  forms  ]8- 
pheno-phenyl-dihydro-triazin  with  nitrous  acid  (B.  25,  448). 


r  TT  JCH2— NHCHO 
L/g.ri.,i  -<          * 
4\N02 

CgH  /CH2N(NO)C6H5 


CH2NH2 


H 


sn 


.  „   fCH2— NH 

6       I  isi      —  '  Dihydro-quinazoli 

T   fCH^ 
/i*HJj   i    ^>NC6H5      n-Phenyl-indazol 

-  H  fCH2— NH          c-Phenyl-tetrahydi 
4  \  NH  — CHC6H5       quinazolin 


— go ^^8A14^   i    xx>i>L,6n5  n-jrnenyi-maazoi 

\N 

C,H5CHO    >c  H  (CH2— NH  c-Phenyl-tetrahydro- 

4  \  NH  — CHC6H5       quinazolin 

CQC12       >c  H  J'CH2 — NH  Tetrahydro-keto-quin- 

4  INH  -co  azolin 

fCH2 — NH  Tetrahydro-thio-quin- 
[NH— CS  azolin 

'CH2 — N.C6H5  ^-Pheno-phenyl-dihydro- 
y         jj-  triazin. 


NOOH         r  TT    fCH, 

yC'HHN=N 


(2)  AROMATIC  MONALDEHYDES. 

The  aromatic  monaldehydes  are  the  first  oxidation  products,  and 
correspond  to  the  primary  aromatic  monohydric  alcohols.  They  are 
very  similar  to  the  fatty  aldehydes  so  far  as  their  rearrangements,  de- 
pendent upon  the  reactivity  of  the  aldehyde  group,  are  concerned. 

Formation. — (i)  By  the  oxidation  of  the  primary  monohydric, 
aromatic  alcohols.  (2)  By  the  distillation  of  the  calcium  salts  of  the 
aromatic  monocarboxylic  acids  with  calcium  formate.  (3)  From  their 
halogen  derivatives  C6H5.CHC12,  with  water,  especially  in  the  presence  of 
sodium  carbonate,  lime,  or  lead  oxide,  or  by  heating  with  anhydrous 
oxalic  acid.  (4)  Technically,  by  oxidising  benzyl  chloride  with  lead 
nitrate.  (5)  A  very  interesting  and  direct  conversion  of  homologous 
benzenes  into  aldehydes  is  that  occurring  in  the  action  of  chromyl 
chloride  CrO2Cl2.  The  first  products  are  pulverulent,  brown  addition 
compounds  C6H5CH3(CrO2Cl2)2,  which  decompose  into  aldehydes  when 
they  are  introduced  into  water  (B.  17,  1462;  21,  R.  714;  32,  1050). 
On  oxidising  methyl-benzols  with  chromic  acid  in  the  presence  of  acetic 
anhydride  at  o°,  diacetates  of  ortho-aldehydes  are  formed,  e.g.  NO2C6H4 
CH(OCOCH3)2,  C6H4[CH(OCOCH3)2]2.  Manganese  peroxide,  cerium 
oxide  with  sulphuric  acid,  or  manganese  persulphate  also  oxidise  alkyl- 
benzols  in  the  cold  to  aromatic  aldehydes  (C.  1901,  II.  70,  1154  ;  1906, 
II.  1297,  1589).  By  electrolytic  oxidation  also,  aldehydes  can  be 
obtained  from  alkyl-benzols  (C.  1905,  II.  763).  (6)  During  oxidation 
of  olenn-benzols  with  ozone,  they  are  split  at  the  ethylene  link,  with 
formation  of  aldehydes  (B.  37,  842,  2304  ;  41,  2751  ;  A.  343,  311)  : 

C6H5CH2CH  :  CHCH3 >  C6H5CH2CHO. 

(7)  From  the  aromatic  primary-secondary    and  primary-tertiary 


AROMATIC  MONALDEHYDES  253 

ethylene  glycols,  and  from  the  corresponding  ethylene  oxides,  by  heat- 
ing with  dilute  H2SO4  or  alone  (C.  1905,  II.  1628  ;  B.  39,  2288)  : 

/°\ 
C8H6(CH3)COHCH2OH  -  >  C6H5(CH3)CH.CHO  <  -  C6H5(CH3)CH—  CH,. 

The  secondary-tertiary  phenyl-ethylene  glycols,  in  which  phenyl 
is  held  by  a  secondary  link,  yield  aldehydes  on  displacement  of  the 
phenyl  group  : 

C,H6CH(OH)C(OH)(CH3)2 

The  formation  of  aldehydes  from  the  iodo-hydrins  of  some  olefm- 
benzols  by  treatment  with  NO3Ag  or  HgO  (C.  1907,  I.  1577  ;  1909, 
I-  1335)  : 

C,H5CH(OH).CHI.CH3  -  >  OCH.CH^^5 

also  leads  to  the  formation  of  aldehydes. 

(8)  From  phenyl-nitro-methanes  by  reduction,  and  from  j8-benzyl- 
hydroxylamines  by  oxidation,  oximes  of  the  aromatic  aldehydes  are 
obtained,  and  from  these  the  aldehydes  may  be  obtained  by  hydrolysis 
(C.  1899,  I.  1073). 

(go)  Synthetically,  the  aldehydes  are  obtained  from  the  aromatic 
hydrocarbons  by  the  action  of  carbon  monoxide  and  HC1  in  the  presence 
of  Cu2Cl2  and  Al  chloride  or  bromide  (A.  347,  347)  : 

C6H6+CO+HC1  c^  C6H5CHO. 

(96)  Benzaldoximes  C6H5CH  :  NOH  are  similarly  produced  from 
benzene,  detonating  mercury  C  :  NHgO,  and  Al  chloride  containing 
water  of  crystallisation.  Dry  Al  chloride  forms  chiefly  nitriles  (B. 
36,  322). 

(10)  Aromatic  aldehydes  are  also  formed  by  the  action  of  aryl- 
magnesium  haloids  on  excess  of  formic  ester  (B.  36,  4152  ;  C.  1905, 
I.  309  ;  cp.  also  Ch.  Ztg.  29,  667)  : 

C6H5CH2MgCl+HCOOC2H5  --  >  C6H5CH2CHO+ClMgOC2H5. 

By  using  ortho-formic  ester  the  corresponding  acetals  are  obtained 
(C.  1904,  I.  509,  1077  ;  B.  37,  1  86). 

The  formic  ester  can  often  be  advantageously  replaced  by  ethoxy- 
methylene-aniline  C6H5N  :  CHOC2H5.  From  the  benzylidene-anilines 
first  formed  the  aldehydes  are  easily  obtained  by  boiling  with  dilute 
acids  (C.  1906,  I.  1487). 

(n)  The  condensation  products  ArCHOH.CQ3,  obtained  from  aryl- 
magnesium  haloids  and  chloral  on  boiling  with  potassium  carbonate 
solution,  split  up  into  chloroform  and  aldehydes  (C.  1908,  1.  1388)  : 


C6H5MgBr  cidHo^  C6H5CH(OH)CC13  --  >  C6H5CHO+CHC13. 

(12)  The  aryl-glycidic  acids  obtained  from  aromatic  ketones  by 
condensation  with  chloracetic  ester,  and  Na  ethylate  or  amide,  easily 
break  up  into  CO2  and  aldehydes  (C.  1905,  I.  346  ;  B.  38,  699)  : 

/°\ 
C,H6COCH3  CH«CLCO«R-»  C6H6(CH3)C  -  CH.COaH  ~co'->  C,H6(CH3)CH.CHO. 


254  ORGANIC  CHEMISTRY 

(13)  Benzoyl-formic    acid    C6H5.CO.COOH    and    its    homologues, 
easily  formed  by  synthesis,  are  converted,  by  heating  with  aniline,  into 
benzylidene-anilines,  which  may  be  readily  split   up  into  aldehydes 
and  aniline  (C.  1903,  I.  832,  etc.). 

(14)  The  acidyl-phenyl-glycolic  esters   (q.v.)   and  phenyl-tartronic 
esters  (cj.v.),  obtained  by  the  condensation  of  ajS-diketone-carboxylie 
esters  or  mesoxalic  esters  with  benzols,  tertiary  anilines,  or  phenols, 
may  be  converted  into  the  corresponding  aldehydes,  (I.)  by  warming 
with  concentrated  H2SO4,  or  (II.)  by  oxidation  with  copper  acetate 
and  decomposition  of  the  resulting  benzoyl-formic  acids   (C.   1910, 
I-  25)  : 

I.  C6H5C(OH)(COCH8)C02CH8+H,0         =  C6H6CHO+CH,COOH  +  CH3OH  +  CO. 
II.  C6H6C(OH)(COCHS)C02CH8+0  +  H,0  =  C6HSCO.COOH+CH3COOH  +  CH3OH. 


Properties.  —  Benzaldehyde  and  its  homologues  are  mostly  liquid 
bodies,  which  possess  an  aromatic  odour,  and  reduce  ammoniacal 
silver  solutions  with  the  production  of  a  metallic  mirror,  (i)  They 
are  readily  oxidised  to  carboxylic  acid.  (2)  They  differ  from  the  fatty 
aldehydes  in  that  they  are,  as  a  general  rule,  readily  oxidised  to 
alcohols  and  acids  by  alcoholic  or  aqueous  alkalies  ;  it  appears  that 
this  reaction  is,  however,  only  peculiar  to  those  aldehydes  in  which 
the  CHO  group  is  in  direct  union  with  the  benzene  nucleus.  (3)  Nascent 
hydrogen  reduces  them  to  alcohols  when  they  are  in  part,  through  the 
union  of  two  aldehyde  residues,  converted  into  hydro-benzo'ins.  (4) 
They  combine  with  acid  alkaline  sulphites.  (5)  With  hydroxylamine 
they  yield  aldoximes,  which  manifest  rather  remarkable  isomeric 
relations.  (6)  They  form  phenyl-hydrazones  with  phenyl-hydrazin. 
(7)  With  primary  amines  :  aldehyde  imines  (Schiff's  bases).  (8)  With 
the  salts  of  nitro-hydroxylaminic  acid  NaON  :  NOONa  and  benzol- 
sulphydroxamic  acid  they  form  hydroxamic  acids  (C.  1904,  I.  1204). 
(9)  Phosphorus  pentachloride  replaces  their  aldehyde  oxygen  by  two 
atoms  of  chlorine.  (10)  Chlorine  substitutes  aldehyde  hydrogen. 

They  do  not  polymerise,  as  do  the  first  members  of  the  group  of 
fatty  aldehydes. 

Nuclear  Syntheses.  —  (i)  In  the  reduction  of  aromatic  aldehydes  — 
e.g.  in  the  electrolytic  reduction  (B.  29,  R.  229  ;  C.  1907,  I.  339)  —  there 
occurs,  along  with  alcohol  formation,  a  production  of  hydro-benzoin 
analogous  to  the  pinacone  formation  : 

2C6H5CHO+2H  =  C6H5CH(OH)—  CH(OH).C6H6  hydro-benzoin. 

(2)  A  very  interesting  reaction  of  the  aldehydes  is  their  conversion 
into  benzoins,   through  the  agency  of  alcoholic  potassium  cyanide. 
Two  aldehyde  molecules  combine  to  a  polymeric  body  : 

2C6H5CHO  =  C6H5CH(OH).CO.C6H5  benzoin. 

See   B.   29,   1729  ;    31,  2699,  for  the  condensations  of  benzylidene- 
aniline  and  benzaldehyde  by  potassium  cyanide. 

(3)  The  aromatic  aldehydes  combine  with  the  most  heterogeneous 
bodies  —  e.g.   aldehydes,   ketones,   monocarboxylic  acids,   dicarboxylic 
acids,  etc.  —  water  always  disappearing. 

These  so-called  condensation  reactions  proceed  similarly  to  the  aldol- 
condensation,  only  there  is  generally  an  elimination  of  water,  as  in  the 


BENZALDEHYDE 


255 


conversion  of  aldol  into  croton-aldehyde.  The  condensation  agents  are 
HC1  gas,  zinc  chloride,  sulphuric  acid,  glacial  acetic  acid,  acetic  anhy- 
dride, dilute  sodium  hydroxide,  baryta  water,  a  solution  of  potassium 
acetate,  and  potassium  cyanide  (primary,  secondary,  and  tertiary  bases). 
In  this  manner  benzaldehyde  can  undergo  the  following  rearrange- 
ments without  difficulty  : 

CH,COOH 


C8H5CHO— 


CH,CHO 


CH.COCH, 


CH,(COOH)2 


CH,COCH,CO,C,H5 


C6H5CH=CH.COOH        Cinnamic  acid 
C6H5CH=CH.CHO  Cinnamic  aldehyde 

C6H5CH=CH.CO.CH3      Benzal-acetone 

C8H6CH=C(COOH)2        Benzal-malonic  acid 

p  jj  £jj_Q/CO2C2H5     Benzal-aceto-acetic 

\COCH3  ester. 

Pyrones  CO[C(CH3)  :  C(C6H5)]2O  (B.  29,  1352)  result  when  two 
molecules  of  benzaldehyde  condense  with  ketones  like  diethyl-ketone. 
Pyridin  derivatives  result  when  benzaldehyde  and  aceto-acetic  ester 
condense  with  ammonia  and  aniline  ;  whereas  benzylidene-diaceto- 
acetic  esters  are  formed  under  the  influence  of  aliphatic  amines  (B.  29, 
R.  841). 

The  benzaldehydes  also  condense  with  phenols  and  anilines,  forming 
derivatives  of  triphenyl-methane. 

Benzaldehyde,  bitter-almond  oil,  benzyl  hydride  C6H5.CHO,  b.p.  179°, 
with  specific  gravity  1-050  (15°),  is  a  colourless  liquid  with  high  refrac- 
tive power.  Formerly  it  was  prepared  exclusively  from  its  glucoside 
amygdalin  (see  below) .  At  present  it  is  only  the  officinal  bitter-almond 
oil  water,  aqua  amygdalarum  amararum,  in  which  hydrocyanic  acid  is 
the  active  ingredient,  that  is  made  from  the  amygdalin.  It  has  the 
characteristic  agreeable  "  bitter-almond  oil  "  odour.  It  is  soluble  in 
thirty  parts  water,  and  is  miscible  with  alcohol  and  ether.  Benzalde- 
hyde does  not  occur  already  formed  in  the  bitter  almonds,  but  is 
produced,  as  demonstrated  by  Wohler  and  Liebig  in  1831,  from 
the  glucoside  amygdalin  contained  in  the  oil.  This  is  easily  converted, 
by  boiling  with  dilute  acids  or  upon  standing  in  contact  with  the 
unorganised  ferment  emulsin,  also  present  in  bitter  almonds,  into  benz- 
aldehyde, glucose,  and  hydrocyanic  acid. 

Amygdalin  :  C20H27NO11-f2H2O=C6H5CHO+2C6H12O6-fCNH. 

In  the  general  methods  common  to  the  formation  of  all  aldehydes, 
reactions  were  indicated  which  would  lead  to  the  production  of  benz- 
aldehyde. Thus  it  is  formed  (i)  from  benzyl  alcohol ;  (2)  from  calcium 
benzoate  and  formate  ;  (3)  from  benzal  chloride  ;  (4)  from  benzyl 
chloride,  from  which  it  is  prepared  technically  by  oxidation  with  lead 
nitrate  ;  (5)  from  toluol  and  chromyl  chloride  CrO2Cl2 ;  (6)  from 
benzene  and  CO  with  HC1,  Cu2Cl2,  and  Al2Br6  ;  and  (7)  from  phenyl- 
magnesium  bromide  and  formic  ester  or  its  derivatives. 

In  describing  the  transformations  of  the  aldehydes,  benzaldehyde 
was  chosen  as  the  example.  It  even  absorbs  oxygen  from  the  air  and 
becomes  benzoic  acid,  and  when  mixed  with  acetic  anhydride  and  sand 
it  not  only  yields  benzoic  acid  but  also  benzoyl-hydrogen  peroxide 


256  ORGANIC  CHEMISTRY 

(C6H5COO)2  (B.  27,  1959).  Sodium  amalgam  reduces  it  to  benzyl 
alcohol  and  hydro-benzoin,  while  PC15  changes  it  to  benzal  chloride. 
It  shows  both  oxime  and  phenyl-hydrazone  formation,  etc. 

With  sulphurous  acid  it  combines  to  an  oxy-sulphonic  acid  soluble 
in  water,  from  which  the  aldehyde  can  be  recovered  by  simple  heating. 
This  process  can  be  utilised  for  regenerating  benzaldehyde  (C.  1904, 

1.  1145). 

Homologous  Benzaldehydes. — o-}  m-,  and  p-  Toluic  aldehydes  boil  at 
200°,  199°,  and  204°.  The  o-  and  m-bodies  smell  like  benzaldehyde, 
while  the  p-compound  has  an  odour  like  that  of  pepper. 

a-Toluic  aldehyde,  phenyl-aeetaldehyde  C6H.C5H2.CHO,  boiling  at 
206°,  and  isomeric  with  the  three  toluic  aldehydes,  is  produced  (i)  by 
distillation  of  a-toluate  of  calcium  and  calcium  formate  ;  (2)  when 
chromyl  chloride  and  water  act  upon  ethyl-benzene  ;  (3)  by  acting 
with  water  on  j8-bromo-styrolene  ;  (4)  by  heating  phenyl-lactic  acid  or 
phenyl-glycidic  acid  with  dilute  sulphuric  acid  ;  (5)  from  phenyl-a- 
chloro-lactic  acid  CiiH5.CH(OH).CHCl.CO2H,  by  the  action  of  alkalies 
(B.  16,  1286 ;  A.  219,  179) ;  and  (6)  from  phenyl-glycerie  acid  or  its 
j8-lactone  C6H6CH(O)CH(OH)CO,  by  heating  alone  or  in  water  (C. 
1900,  I.  887).  Phenyl-acetaldehyde  has  a  sweetish  odour  resembling 
that  of  hyacinths,  and  is  used  in  perfumery.  It  polymerises  easily  on 
keeping.  On  heating  with  alcoholic  potash  it  forms  a  mixture  of 
triphenyl  -  benzol  and  1, 3-diphenyl-tetramethylene  (B.  38,  1965). 
a-Phenyl-propyl-aldehyde,  hydro-atropa-aldehyde  C6H5(CH3)CH.CHO, 
b.p.  204°,  is  obtained  from  unsym.  phenyl-methyl-glycol  by  heating  with 
dilute  H2SO4  (B.  39,  2297),  from  phenyl-methyl-glycidic  acid  or  unsym. 
phenyl-methyl-ethylene  oxide  on  heating  alone  (B.  38,  704  ;  C.  1905, 
II.  1628).  a-Phenyl-butyraldehyde  (C6H5)CH.CHO,  b.p.  211°,  from 
unsym.  phenyl-ethyl-glycol  (B.  39,  2300).  a-Propyl-  and  a-iso-butyl- 
phenyl-acetaldehyde,  b.p.28  122°,  b.p.30  153°,  a-Methyl-phenyl-propyl- 
aldehyde,  b.p.19  130°,  from  the  corresponding  glycidic  acids  by  method 
12  (C.  1905,  I.  347). 

Phenyl-propyl-aldehyde,  hydro-cinnamic  aldehyde  C6H6CH2CH2CHO, 
b.p.13  105°  (B.  31,  1992),  is  best  obtained  by  reduction  of  cinnamic 
aldehyde  acetal.  3,  5-Dimethyl-benzaldehyde,  mesityl-aldehyde  (CH3)  2 
C6H3CHO,  b.p.  221°,  from  mesitylene  bromide  (/.  pr.  Ch.  2,  58,  359). 

2,  5-Dimethyl-benzaldehyde,  b.p.10  100°,  is  obtained  from  p-xylol-gly- 
oxylic  acid  by  method  13  ;  while  from  p-xylol,  CO,  and  HC1,  etc.,  by 
method  9,  2,  4-dimethyl-benzaldehyde  is  formed,  with  migration  of 
atoms  (C.  1903,  I.  830). 

Cumic  aldehyde,  cuminol,  p-iso-propyl-benzaldehyde  (CH3)2CH 
[4]C6H4[i]CHO,  boiling  at  235°,  with  specific  gravity  0-973  (13°), 
occurs,  together  with  cymene,  in  Roman  carraway  oil,  and  in  oil  of 
Cicuta  virosa,  or  water-hemlock  (B.  26,  R.  684).  Cuminol  possesses  an 
aromatic  odour.  Dilute  nitric  acid  oxidises  it  to  cumic  acid  ;  chromic 
acid  converts  it  into  terephthalic  acid.  Cumic  acid  (q.v.)  and  cumyl 
alcohol  are  produced  when  it  is  digested  with  alcoholic  potash.  When 
distilled  with  zinc  dust,  cymol  results. 

DERIVATIVES  OF  BENZALDEHYDE. 

Haloid  Derivatives. — The  halogen  compounds  corresponding  to 
benzaldehyde  are  obtained  by  the  action  of  PC15  or  PBr6  upon  it. 


DERIVATIVES  OF   BENZALDEHYDE  257 

Benzol  chloride,  benzylidene  chloride,  chloro-benzene,  chloride  of 
bitter-almond  oil,  C6H5CHC12,  boiling  at  213°,  with  specific  gravity  1-295 
(16°),  results  from  the  action  of  chlorine  upon  boiling  toluene,  from 
toluene  (A.  139,  318  ;  146,  322)  and  PC15  at  I7O°-200°,  as  well  as  from 
benzaldehyde  and  COC12  (Z.  /.  Ch.  2,  7,  79).  It  changes  to  benzal- 
dehyde  when  it  is  heated  to  I4o°-i6o°  with  water,  or  to  6o°-70°  with 
anhydrous  oxalic  acid.  Benzal  bromide  boils  at  I3O°-I4O°  (20  mm.). 
Acetals  of  the  aromatic  aldehydes  are  obtained  from  these  with  dilute 
alcoholic  HC1,  or  with  orthoformic  ester,  and  from  the  aldehyde 
chlorides  with  sodium  alcoholates  (B.  31,  1989  ;  40,  3903). 

Benzal  dimethyl  and  diethyl  ether,  boiling  at  208°  and  220°,  benzol 
diacetyl  ester,  melting  at  44°  and  boiling  at  220°  (A.  102,  368  ;  146,  323), 
are  produced  when  sodium  methylate,  sodium  ethylate,  and  silver 
acetate  act  upon  benzal  chloride.  The  diethyl  ether  is  also  formed 
from  benzaldehyde  and  orthoformic  ester  (B.  29,  247),  as  well  as  from 
benzylidene-imide  hydrochloride  with  alcohol. 

Sulphur  Derivatives  of  Benzaldehyde. — Compare  the  thio-acetalde- 
hydes  :  a-  and  fi-trithio-benzaldehyde  melt  at  167°  and  225°  (B.  29,  159). 
Polymeric  thio-benzaldehyde  melts  at  83°  (B.  24,  1428).  When  heated 
with  finely  divided  copper  they  yield  stilbene  C6H5.CH=CH.C6H5. 

On  mercaptals  and  sulphones  from  benzaldehydes,  see  B.  35,  2343. 

Benzaldehyde-potassium  bisulphite,  potassium-oxy-benzyl  sulphonate 
C6H5CH(OH)SO3K+ JH2O,  see  A.  85,  186. 

Sodium-benzaldehyde  sulphoxylate  C6H5CH(OH)O.SONa  ;  on  addi- 
tion of  benzaldehyde  to  a  feebly  alkaline  sodium  hydrosulphite  solu- 
tion, it  is  precipitated  in  flakes.  The  secondary  salt  is  more  stable  than 
the  primary  (B.  42,  4634). 

Nitrogenated  Benzaldehyde  Derivatives.  —  Phenyl-dinitro-methane 
C6H5CH(NO2)2,  m.p.  79°,  is  formed  by  the  action  of  N2O4  upon  benzal- 
doxime  or  acetyl-benzoyl  oxime  C6H5C(NOH).COCH3 ;  on  heating  to 
130°  it  forms  benzaldehyde,  and  by  reduction  with  Al  amalgam  benzyl- 
amine  and  NH3  (/.  pr.  Ch.  2,  65,  197  ;  73,  494 ;  C.  1901,  II.  1007  ; 
1906,  II.  1003).  On  the  action  of  diazo-benzol  chloride  upon  phenyl- 
dinitro-methane,  see  C.  1909,  II.  905. 

When  ammonia  acts  at  —20°  upon  a  concentrated  alcoholic  solution 
of  benzaldehyde,  the  first  product  is  the  very  unstable  benzaldehyde 
ammonia  (C6H5CHOH)2NH,  m.p.  45°,  which  quickly  breaks  up  into 
benzaldehyde,  water,  and  hydrobenzamide,  tribenzal-diamine  (C6H5 
CH)3N2,  melting  at  110°.  When  this  body  is  heated  it  is  transposed 
to  amarine  or  triphenyl  -  dihydro  -  glyoxaline  (q.v.).  When  hydro- 
chloric acid  gas  is  conducted  into  the  alcoholic  benzene  solution  of 
hydro-benzamide,  benzylidene  imide  C6H5CH  :  NH.HC1,  melting  with 
decomposition  at  180°,  separates.  Water  immediately  resolves  this 
body  into  benzaldehyde  and  ammonium  chloride  (B.  29, 2144 ;  42, 2216). 

Benzal-ethyl-amine  C6H5.CH  :  N.C2H5,  b.p.  195°.  Benzal-aniline, 
benzylidene-aniline  C6H5.CH  :  N.C6H5,  m.p.  45°,  from  benzaldehyde 
and  aniline,  with  elimination  of  water.  In  the  presence  of  concen- 
trated HC1  the  aromatic  aldehydes  combine  with  anilines  to  chloro- 
hydrates  of  the  aldehyde-anilines,  like  C6H5CH(OH)NHC6H5.HC1, 
which  sometimes,  especially  in  the  oxy-benzaldehydes,  represent  fairly 
stable  compounds  ;  the  free  hydrates,  on  the  other  hand,  usually  lose 
H2O  readily,  and  pass  into  the  benzylidene  compounds  (SchifFs  bases. 
VOL.  II.  S 


258  ORGANIC   CHEMISTRY 

B.  35,  984).  In  a  few  cases  Schiff's  bases,  like  the  benzaldoximes, 
occur  in  two  isomeric  forms  (B.  43,  3359).  On  the  nitrogenation  and 
sulphuration  of  benzylidene-anilines,  see  C.  1903,  I.  231.  With 
benzaldehyde  in  alcoholic  KCN  solution  benzaniline  does  not  give  the 
benzoin  reaction,  but  a  complex  condensation  takes  place  with  the  help 
of  hydrocyanic  acid  (see  B.  38,  1761).  On  the  condensation  of  benz- 
aniline with  malonic  ester,  aceto-acetic  ester,  and  similar  bodies,  see 
B.  31,  2596  ;  32,  332  ;  36,  937. 

Benzylidene-p-amido-dimethyl-aniline  C6H5CH  :  NC6H4N  (CH3)  2, 
m.p.  99°,  yellow  needles,  forms,  with  one  molecule  HC1  a  red,  and  with 
two  molecules  HC1  a  white,  chlorohydrate  (C.  1908,  I.  1539). 

When  the  o-phenylene-diamines  and  benzaldehyde  interact,  the 
bodies  resulting  at  first  are  :  benzylidene-o-phenylene-diamine  NH2. 
C6H4N  :  CH.C6H5,  m.p.  61°,  and  dibenzylidene-o-phenylene-diamine 
C6H4[N  :  CH.C6H5]2.  However,  they  readily  rearrange  themselves 
into  isomeric,  ring-shaped  imidazole  derivatives,  or  aldehydes  (B.  29, 
1497).  The  amidated  benzylidene-anilines  and  bis-benzylidene-p- 
phenylene-diamines,  like  NH2C6H4.CH  :  N.C6H4N  :  CHC6H4NH2  have 
dyeing  properties  similar  to  those  of  the  amido-azo-bodies ;  the  azo- 
methine  group  — CH  :  N —  is  a  "  chromophore,"  like  the  azo-group 
— N=N — ,  but  to  a  much  smaller  extent  (B.  31,  2250).  In  both  cases 
the  introduction  of  "  auxo-chromic  "  groups  (NH2,  OH,  etc.)  produces 
a  deepening  of  the  colour  (C.  1907,  I.  106). 

Benzylidene-hydrazin,  benzal-hydrazin  C6H5CH  :  NNH2,  m.p.  16°, 
b.p.14  140°,  is  formed  from  hydrazin  hydrate  with  benzaldehyde  and 
barium  oxide,  and  from  benzalazin  by  boiling  with  hydrazin  hydrate. 
It  easily  passes  into  benzalazin  in  various  ways  ;  with  acetic  anhydride 
it  gives  benzal-acetyl-hydrazin  C6H5CH  :  N.NHCOCH3,  m.p.  134°, 
which  is  also  formed  from  acetyl-hydrazin  and  benzaldehyde  (B.  35, 

Benzalazin  C6H5CH  :  N.N  :  CHC6H5,  m.p.  93°,  from  benzaldehyde 
and  hydrazin,  decomposed  by  heat  into  nitrogen  and  stilbene.  By 
reduction  with  zinc  dust  and  glacial  acetic  acid  it  splits  off  NH3  and 
yields  dibenzyl-amine.  By  sodium  amalgam  it  is  first  converted  into 
benzyl-benzyhdene-hydrazin  and  further  into  sym.  dibenzyl-hydrazin. 
With  bromine  it  unites  to  form  a  tetrabromide,  which  readily  decom- 
poses with  evolution  of  nitrogen  (cp.  /.  pr.  Ch.  2,  58,  372).  "With  di- 
methyl sulphate  the  benzalazin  combines  to  form  an  ammonium  com- 
pound C6H5CH:N(CH3)(OS03CH3)N  :CHC6H5  which,  with  water, 
breaks  up  into  benzaldehyde  and  methyl-hydrazin  (A.  376,  244).  On 
the  influence  of  magnesium  organic  compounds  upon  benzalazin,  see 
B.  43,  740. 

Benzal-phenyl-hydrazone  C6H5CH  :  NNHC6H5,  m.p.  152°  (A.  190, 
134),  is  converted  by  acetic  anhydride  and  H2SO4  into  a  stereo-isomeric 
body  of  m.p.  136° ;  sodium  amalgam  reduces  it  to  sym.  benzyl-phenyl- 
hydrazin.  On  oxidation,  the  benzal-phenyl-hydrazones  yield  dibenzal- 
diphenyl-hydro-tetrazone,  benzile-osazone,  dehydro-benzal-phenyl-hydra- 

zone  and  tetraphenyl-tetrazolin  c625KT=N~?r6H5  ^'  ^  523)- 

Numerous  benzal  compounds  of  hydrazin  derivatives  have  been 

prepared  ;  they  serve  to  characterise  the  latter. 

Benzaldoximes.— The  interaction  of  hydroxylamine  and  benzalde- 


BENZALDOXIMES  259 

hyde  produces  a-benzaldoxime,  benzantialdoxime,  m.p.  35°  and  b.p. 
117°  (14  mm.).  Hydrochloric  acid,  sulphuric  acid,  or  bromine  changes 
it,  with  the  simultaneous  production  of  unstable  salts  (B.  27,  R.  599), 
into  /3-benzaldoxime,  iso-benzaldoxime,  benzo-synaldoxime,  m.p. 
125°.  For  another  method,  see  A.  365,  202.  When  this  body  is  dis- 
tilled under  reduced  pressure,  it  passes  into  the  a-derivative.  Each  of 
these  isomerides  gives  rise  to  two  structurally  isomeric  series  of  alkyl 
ethers,  in  one  of  which  the  alkyl  is  joined  to  oxygen,  in  the  other  to 
nitrogen,  as  the  first,  upon  decomposition,  yield  a-,  and  the  second 
j8-alkyl-hydroxylamines.  Hantzsch  and  Werner  attribute  the  iso- 
merism  of  the  a-  and  /2-aldoximes  to  the  spatial  arrangement  of  the 
hydroxyl  group  with  reference  to  nitrogen.  The  oximes  are  distin- 
guished as  benzanti-  and  benzo-synaldoxime  (B.  24,  3481).  The  sym. 
configuration  would  fall  to  the  /J-aldoxime,  because  in  a  series  of  re- 
actions— e.g.  treatment  of  the  acid  ester  with  alkalies — it  changes  more 
readily  and  completely  to  benzo-nitrile  than  the  a-body  : 

P  TT  PTT  O  TT  CTT 

(a-)  Benzantialdoxime    UT  (/M  Benzo-synaldoxime     ' 


The  following  formulae  would  then  correspond  to  the  N-  and  O- 
alkyl  ethers  of  these  compounds  : 

X6H5 CH  f— >  C6H5CHO  « ^        C6H6— CH 

Anti- 
alkyl 


fC6H5 CH  — >  C6H5CHO  « ,        C 

I  CH30— N  ^— >  CH3ONH2  < * 


N— OCH         Syn- 


ether.     |C6H5— CH.  f_>  C6H5CHO       4-,        C6H5— CH> 


-.  ^6n5 »^*»\ 

1  I        >< 

CH3 N— /          ' — >  CH3NH(OH)  <—>  N^±l( 


byn 
alky 
ether. 


The  benzaldoximes  and  phenyl  cyanate  combine  to  isomeric 
phenyl-urethane  derivatives  C6H5CH  :  NOCONHC6H5.  The  N-alkyl 
ethers  also  unite  with  phenyl  cyanate,  forming  azoxazol  (iuTO-ab'- 
diazol)  derivatives  (B.  27,  1957)  : 


C6H5CH\         cgH6NCQ       C6H5CH.N(C6H5)\  CQ 
C7H7^_/(  >  C7H7*  -  O/ 

Benzaldoxime  is  also  produced  from  benzyl-amine  by  oxidation 
with  Caro's  acid,  and  is  further  oxidised  by  that  agent  to  phenyl-nitro- 
methane  and  benzo-hydroxamic  acid  (B.  34,  2023,  2262). 

Anti-benzaldoxime-o-methyl  ether  is  an  oil,  b.p.  191°.  It  results 
from  the  interaction  of  a-benzaldoxime  with  sodium  alcoholate  and 
methyl  iodide  or  with  diazo-methane  (C.  1909,  1.  1754).  Hydrochloric 
acid  resolves  it  into  benzaldehyde  and  a-methyl-hydroxylamine.  N- 
Methyl  ether  melts  at  45°-49°.  Its  hydrobromide  is  formed  on  heat- 
ing a-benzaldoxime,  methyl,  bromide,  and  methyl  alcohol  in  a  sealed 
tube  to  85°.  On  exposure  it  rearranges  itself  into  the  syn-form  (B.  29, 
R.  866  ;  A.  365,  215).  Syn-benzaldoxime-N-methyl  ether,  melting  at 
82°,  is  formed,  together  with  the  isomeric  o-ether,  from  syn-benzal- 
doxime,  methyl  iodide,  and  sodium  ethylate  (B.  24,  2812),  or  by  the 
action  of  the  chloride  of  j8-methyl-hydroxylamine  upon  benzaldehyde 
(A.  365,  205).  By  the  action  of  PC15  in  etheric  solution  it  is  transposed 
into  the  isomeric  monomethyl-benzamide  : 

C6H5CH.O.NCH3  -  >  C6H5CO.NHCH3. 


260  ORGANIC  CHEMISTRY 

Benzaldoxime-0-benzyl  ether  C6H5CH  :  NOCH2C6H5  is  also  known 
in  a  liquid  and  a  solid  modification,  m.p.  31°.  p-Chloro-benzaldoxime- 
p-chloro-benzylj.ether,  m.p.  114°,  and  p-bromo-benzaldoxime-p-bromo- 
benzyl  ether,  m.p.  130°,  see  B.  33,  1975.  These  substances  can  only 
be  split  up  with  difficulty  into  aldehydes  and  hydroxylamines. 

Benzaldoxime-N-benzyl  ether  C6H/H.O.NCH2C6H5,  m.p.  82°,  is 
obtained  from  sodium  iso-benzaldoxime  with  benzyl  chloride,  and 
from  j8-dibenzyl-hydroxylamine  by  oxidation.  Benzaldoxime-N- 
benzyl  ethers  with  nuclear  substitution  are  transposed  in  a  peculiar 
manner  by  sodium  ethylate  (A.  298,  187)  : 

XCeH/H.O.NCHjjCgHg >  XC6H4CH2N.O.CHC6H5. 

/° 
N-Phenyl-benzaldoxime    CCH6CH^  |         ,  melting   at   109°,  results 

pJOgHg 

from  the  union  of  benzaldehyde  with  ^-phenyl-hydroxylamine  (p.  78) 
(B.  27,  1958  ;  C.  1898,  II.  80). 

Benzantialdoxime  acetate  C6H6CHNO(OC.CH3)  melts  at  15° 
(B.  27,  R.  599). 

.Benzaldoxime  peroxide  C6H6CH  :  N.O.ON  :  CHC6H5,  m.p.  105° 
with  decomposition,  results  from  the  oxidation  of  benzaldoxime  with 
sodium  hypochlorite,  or  amyl  nitrite,  and  also,  together  with  benzo- 
nitrolic  acid,  from  the  action  of  nitrous  acid  upon  phenyl-iso-nitro- 
methane.  On  heating  with  chloroform  it  undergoes  a  peculiar  trans- 
formation into  dibenzenyl-azoximeC6H6C^~^c«H*  (B.  39,  2522). 

Benzaldoxime-N-carbonamide  C6H5CH.O.N.CONH2,  m.p.  125°, 
from  benzaldehyde  and  hydroxyl-urea  (Vol.  I.).  On  heating  it  breaks 
up  into  a-benzaldoxime,  benzo-nitrile,  and  cyanic  acid  (C.  1908, 1.  948). 

Benzaldoxime-0-aeetic  acid  C6H5CHN(OCH2COOH)  melts  at  98°, 

/N.CH2.COOH 

the  N -derivative  CeHgCH^  |  at    183°    with    decomposition. 

They  are  formed  when  chloracetic  acid  acts  upon  potassium  benzal- 
doxime. When  decomposed,  the  first  yields  gly collie  acid  and  the  second 
amidoxyl-acetic  acid  HO.NH.CH2.COOH  (I.  350)  (B.  29,  R.  169). 
Isomerisms  similar  to  those  of  the  benzaldoximes  are  shown  by  many 
substituted  benzaldoximes,  ketoximes,  the  benzile-dioximes,  etc. 

Benzal-amido-sulphonie  acid  C6H6.CH  :  NSO3H  results  from  benz- 
aldehyde and  amido-sulphonic  acid  (B.  25,  472). 

Substituted  benzaldehydes  behave  towards  oxidising  and  condensing 
agents  like  benzaldehyde  itself.  The  formation  of  heterocyclic  bodies 
from  o-nitro-  and  o  -amido-benzaldehyde  is  especially  worthy  of  notice. 

Haloid  benzaldehydes  are  formed  when  oxalic  acid  or  sulphuric 
acid  (A.  272, 148)  acts  upon  the  halogen  benzal  chlorides  ;  or  by  oxidis- 
ing cinnamic  acids  containing  halogens  in  the  nucleus  : 

o-Chloro-benzaldehyde  melts  at  -4°  ;  boils  at  213° ;   the  oxime  melts  at    75° 

m-Chloro-benzaldehyde       „          17°;  „       213°;             ,,           „          70° 

p-Chloro-benzaldehyde       ,,          47° ;  ,,        213° ;             ,,           ,,        106° 

o-Bro  mo- benzaldehyde       ..          21°  ;  o-Io do- benzaldehyde          ,,          37° 

p-Bromo-benzaldehyde       ,,          57° ;  p-Iodo-benzaldehyde          ,,          73°. 

See  B.  29,  875,  for  the  di-  and  tetrachloro-benzaldehydes. 


NITRO-BENZALDEHYDES  261 

o-,  m-,  p-Iodoso-benzaldehydes  C6H4(IO)CHO,  and  o-  m-,  p- 
iodo-benzaldehydes  C6H4(IO2)(CHO),  have  been  obtained  from  the  cor- 
responding iodide-chlorides  (B.  29,  R.  774). 

Nitro-benzaldehydes  NO2C6H4CHO.  On  dissolving  benzaldehyde 
in  nitro-sulphuric  acid,  the  chief  product  is  meta-nitro-benzaldehyde. 
o-Nitro-benzaldehyde  is  formed  simultaneously  (B.  14,  2803).  o-Nitro- 
benzaldehyde  is  obtained  by  the  oxidation  of  o-nitro-benzyl  alcohol 
(C.  1899,  II.  950)  or  from  o-nitro-cinnamic  acid  or  its  ester  (B.  17,  121). 
It  results  also  from  o-nitro-toluol  by  oxidation  with  manganese  per- 
oxide and  sulphuric  acid  (C.  1907,  I.  383)  or  manganese  persulphate 
(SO4)2Mn  (C.  1906,  II.  1590).  Also,  with  its  oxime,  from  the  di-mercury 
compound  of  o-nitro-toluol  by  oxidation  with  HNO2  (C.  1908,  II.  209). 

Para-nitro-benzaldehyde  results  (i)  by  the  oxidation  of  p-nitro- 
cinnamic  acid  (B.  14,  2577)  ;  (2)  by  allowing  CrO2Cl2  and  water  to  act 
upon  p-nitro-toluol  in  carbon  disulphide  (B.  19,  1061)  ;  (3)  when 
p-nitro-benzyl  chloride  is  boiled  with  water  and  lead  nitrate,  or  when 
sulphuric  acid  acts  upon  p-nitro-benzal  chloride. 

The  oximes  of  o-  and  p-nitro-benzaldehyde  are  obtained  from  o- 
and  p-nitro-toluol  by  the  action  of  amyl  nitrite  and  sodium  ethylate 
(C.  1899,  II.  371  ;  1900,  I.  886,  1273).  In  the  form  of  their  acetates 
C6H4(NO2)CH(OCOCH3)2  they  are  obtained  from  o-  and  p-nitro-benz- 
aldehyde by  the  oxidation  of  a  solution  of  o-  and  p-nitro-toluol  in  acetic 
anhydride  sulphuric  acid  with  chromic  acid  (A.  311,  355)  : 

M.p.  M.p.  M.p. 

o-Nitro-benzaldehyde,    46°;  oxime,  103°  (a),  149°  (0)  ;  hydrazone,  153* 

m-Nitro-benzaldehyde,    58°;       „      117°  (a),  118°  (0)  ;          „          121° 

p-Nitro-benzaldehyde,  107°;       „      130°  (a),  174°  (0)  ;          „         155°. 

o-  and  p-Nitro-a-  or  anti-benzaldoximes  pass,  on  illumination  of 
their  benzene  solution,  into  the  more  stable  6-  or  syn-aldoximes  (B.  36, 
4268). 

On  the  behaviour  of  the  nitro-benzaldehydes  in  the  animal  organ- 
ism, see  B.  25,  2457. 

The  effect  of  light  on  o-nitro-benzaldehyde  in  indifferent  solvents 
is  to  transpose  it  entirely  into  o-nitroso-benzbie  acid  (q.v.).  In  alcoholic 
solution  the  corresponding  o-nitroso-benzoic  esters  are  produced,  with 
the  acetals  of  o-nitroso-benzaldehyde  as  intermediate  products.  The 
entry  of  a  second  substituent  in  o-position  to  the  aldehyde  group,  con- 
nects the  acetal  formation  and  the  power  of  transposition  ("  Steric  Hin- 
drance," A.  371,  319).  o-Nitro-benzaldehyde  condenses  with  aldehyde 
and  acetone,  through  the  action  of  dilute  caustic  soda,  to  o-nitro-phenyl- 
lactic  acid  aldehyde  and  o-nitro-phenyl-lactic  methyl  ketone,  which 
caustic  soda  converts  into  indigo  : 

CH,.CHO  fCH(OH).CH,.CHO_ 

c        ,  [i]CHO  •    '  I  NO,  i  CO         .         CO     c  H 

-- 


5-Nitro-2-chloro-benzaldehyde  NO2.C6H3C1.CHO,  melts  at  80°  ;  its 
oxime  at  147°.  The  latter  is  readily  converted  by  boiling  alkali  into 
nitre-salicylic  acid  (B.  26,  1253).  3-Nitro-4-bromo-benzaldehyde  NO2. 
C6H3BrCHO  melts  at  103°  ;  its  oxime  at  145°  (B.  24,  3775).  2-Nitro- 
5-chloro-  and  -bromo-benzaldehyde,  m.p.  76°  and  74°  respectively,  by 


262  ORGANIC  CHEMISTRY 

nitrogenation  of  m-chloro-  and  m-bromo-benzaldehyde  respectively 
(B.  38,  2811).  2-Nitro-4-chloro-  and  -bromo-benzaldehyde,  m.p.  67° 
and  98°  respectively,  are  formed  by  a  peculiar  reaction  from  4-amido- 
2-nitro-benzaldoxime  on  treatment  with  ferric  sulphate  and  concen- 
trated HC1,  and  HBr  respectively  (B.  37,  1861). 

2, 4-Dinitro-benzaldehyde  (NO2)2[2,  4]C6H3CHO,  m.p.  72°,  is  ob- 
tained by  the  oxidation  of  2,  4-dinitro-benzyl-aniline  or  its  sulphonic 
acid  (NO2)2C6H3CH2NHC6H4SO3H  with  permanganate  or  chromic  acid, 
the  Schiff  bases  first  formed  being  split  up  by  the  acid  ;  it  is  also  pro- 
duced by  the  breaking  up  of  its  dimethyl-amido-anile  (NO2)2C6H3CH  : 
NC6H4N  (CH3)  2,  obtained  by  the  action  of  p-nitroso-dimethyl-aniline 
upon  2, 4-dinitro-toluol.  From  2, 4,  6-trinitro-toluol  we  obtain  in 
this  manner  the  2,  4,  6-trinitro-benzaldehyde  (NO2)3[2,  4,  6]C6H2CHO, 
m.p.  119°.  Like  the  o-nitro-benzaldehyde,  the  o,  p-dinitro-  and  the 
sym.  trinitro-benzaldehyde  are  easily  transposed  by  light  into  p-nitro- 
o-nitroso-  and  dinitro-o-nitroso-benzoic  acid  (B.  35,  2704  ;  36,  959  ; 
C.  1902,  II.  741). 

Hydroxylamino-,  Nitroso-,  Azoxy-,  and  Azo-benzaldehydes. — By 
electrolytic  reduction  in  sulphuric  acid,  and  by  reduction  with  zinc  dust, 
we  obtain  from  m-  and  p-nitro-benzaldehyde  in  the  first  place  aldehydo- 
phenyl-hydroxylamines  CHO.C6H4NHOH,  which,  with  unchanged 
nitro-aldehyde,  combine  to  form  aldehydo-phenyl-nitro-n-benzal- 
doximes  NO2C6H4CH<^C8H*CHa  The  o-nitro-benzaldehyde  may  be 

reduced  to  the  very  unstable  hydroxylamino-benzaldehyde,  which  is 
easily  condensed  to  its  inner  anhydride  anthranile.  In  the  form  of  its 
nitroso-compound  CHO.C6H4N(NO)OH,  m.p.  52-5°,  we  obtain  o-hydro- 
xylamino-benzaldehyde  by  reducing  o-nitro-benzaldehyde  with  zinc 
dust  in  the  presence  of  amyl  nitrite  (B.  42,  2574).  The  same  nitroso- 
compound  also  results  from  anthranile  with  HNO2.  With  alkalies  it 
gives  stable  salts,  while  with  acids  it  is  converted  into  a  mixture  of 
diazotised  o-amido-benzaldehyde  and  o-nitroso-benzaldehyde  CHO 
[i]C6H4[2]NO,  white  needles  of  m.p.  110°  (B.  42,  2573). 

o-  Hydroxylamino  -  benzaldoxime  HONH[2]C6H4CH  :  NOH,  m.p. 
120°,  is  formed  by  reduction  of  o-nitro-benzaldoxime.  This  oxime  is 
also  formed  from  anthranile  with  hydroxylamine,  and  is  reconverted 
into  anthranile  by  acids.  By  oxidation,  in  air,  it  passes  into  the  oxime 
of  2-azoxy-benzaldehyde  ON2(C6H4[2]CHO)2,  m.p.  211°  (B.  36,  3654). 
The  aldehyde  melts  at  119° ;  it  is  more  easily  obtained  by  the  reduction 
of  o-nitro-benzaldehyde  acetic  acid  splitting  (B.  39,  4265).  On  a 
peculiar  reduction  product  of  o-nitro-benzaldehyde  C14H12N2O5,  m.p.  99°, 
which  reacts  like  a  molecular  combination  of  o-nitro-  and  o-hydroxyl- 
amino-benzaldehyde,  see  B.  39,  4252.  By  a  further  reduction  of 
m-  and  p-nitro-benzaldoxime-n-aldehydo-phenol  ether,  we  obtain 
the  corresponding  derivatives  of  azoxy-benzaldoximes,  which  are  split 
up  by  ferric  chloride  into  the  azoxy-benzaldehydes  ON2(C6H4CHO)2, 
m  m.p.  129°,  p-  m.p.  190°,  and  nitroso-benzaldehydes  NO.CgH4.CHO. 
p-Azoxy-benzaldehyde  is  also  obtained  in  the  form  of  its  aniline  com- 
pound ON2(C6H4CH  :NC6H5)2  from  p-nitro-benzyl-aniline  NO2C6H4 
CH2NHC6H5  by  the  action  of  potash  (see  also  B.  36,  3469).  p-Nitroso- 
benzaldehyde  combines  with  aniline  to  form  the  anile  of  p-benzol-azo- 
benzaldehyde  C6H5N  :  NC6H4CHO,  m.p.  120°,  whose  acetal  is  also  pro- 


AMIDO-BENZALDEHYDES  263 

duced  by  the  reduction  of  a  mixture  of  nitro-benzol  and  p-nitro-benz- 
aldehyde  alcohol,  beside  the  acetal  of  p-azo-benzaldehyde  CHO.C6H4N  : 
NC6H4CHO,  m.p.  238°  (B.  35,  2434  ;  36,  793  ;  C.  1902,  II.  195,  700  ; 
1903,  I.  286).  o-  and  m-azo-benzaldehyde-aeetal,  m.p.  144°  and  150°, 
are  formed  by  reduction  of  the  nitro-benzaldehyde  acetals  with  zinc 
dust  and  sodium  hydrate  (C.  1904,  I.  1498).  The  o-azo-benzaldehyde- 
acetal  yields  on  saponification  with  dilute  SO4H2  y-oxy-B-phenyl- 

c^otn 
indazol  C.H4<^>NCiHj|  (C.  1907,  I.  1575). 

Amido-benzaldehydes  NH2C6H4CHO.  The  o-  and  p-bodies  are 
obtained  in  the  action  of  ferric  chloride  upon  their  oximes,  which  are 
formed  by  the  reduction  of  o-  and  p-nitro-benzaldoximes  with 
ammonium  sulphide  (B.  15,  2004  ;  16,  1998). 

o-Amido-benzaldehyde  is  also  obtained  by  reducing  o-nitro-benz- 
aldehyde  and  anthranile  (see  this)  with  ferrous  sulphate  and  ammonia 
(B.  17,  456).  m-Amido-benzaldehyde  is  formed  when  m-nitro- 
benzaldehyde  is  reduced  with  tin  and  glacial  acetic  acid. 

A  further  process  for  preparing  o-  and  p-amidated  benzaldehydes 
uses  the  action  of  sulphur  alkalies  upon  nitro-benzyl  alcohols  and  their 
derivatives  ;  a  reduction  of  the  nitro-group  and  an  oxidation  of  the 
alcohol  group  takes  place  (C.  1900,  I.  1084). 

o-Amido-benzaldehyde        .         .    melts  at  39°  :  its  oxime  at  135°  (B.  36,  803) 
m-Amido-benzaldehyde  is  yellow  and  amorphous  ;  „  88° 

p-Amido-benzaldehyde        .         .    melts  at  70° :  „          124°  (/.  pr.  Ch.  2,  56,  97). 

For  preparing  the  derivatives  of  the  amido-benzaldehydes,  very 
unstable  in  themselves,  their  acetyl  derivatives  are  specially  suitable. 
Their  melting-points  are  :  o-,  71°  ;  m-,  84°  ;  and  p-,  161°  (C.  1903,  I. 

775,  921)- 

p-Dimethyl-  and  p-diethyl-amido-benzaldehydes,  melting  at  73°  and 
81°,  are  obtained  when  the  condensation  products  from  chloral  and 
dialkyl-aniline —  e.g.  p-dimethyl-amido-phenyl-trichlorethyl  alcohol 
(CH3)2NC6H4CH(OH)CC13— are  acted  upon  "with  alcoholic  potash 
(B.  19,  365).  p-Dimethyl-amido-benzaldehyde  condenses  to  hexa- 
methyl-leucaniline  (see  Triphenyl-methane  dyes)  with  dimethyl- 
aniline. 

For  further  condensation  products  of  p- dimethyl- amido-benz- 
aldehyde,  see  B.  35,  3569. 

Tetramethyl-2,  4-diamido-benzaldehyde,  m.p.  8°,  b.p.14  203°,  from 
tetramethyl-m-phenylene-diamine  and  chloral  (B.  41,  91). 

The  o-amido-benzaldehyde  is  easily  diazotated  with  concentrated 
HC1 ;  on  treating  the  diazonium  salt  with  sodium  nitride  we  obtain 

o-azido-benzaldehyde  ^>N|>]C6H4CHO,  m.p.  37°.  This  body  is  also 
produced  by  a  peculiar  transposition  of  the  diazo^benzaldoxime  an- 
hydride, indiazonoxime,  N  :  N[2]C6H4C  :  NOH,  m.p.  166°,  formed  during 
the  diazotation  of  o-amido-benzal-dioxime,  performed  by  warming  in 
water,  or  treating  with  cold  alkali.  The  same  reactions  have  been 
carried  out  with  dimethyl-,  dichloro-,  and  dibromo-o-amido-benz- 
aldehyde. 

o-Azido-benzaldehyde,  on  heating  alone,  or  with  water,  loses 
nitrogen,  and  passes  into  anthranile.  A  similar  behaviour  is  shown 


264  ORGANIC  CHEMISTRY 

by  the  o-aziflo-benzaldoxime  N3[2]C6H4CH  :  NOH,  m.p.  103°,  which, 
on  boiling  with  NaHO,  gives  n-oxy-indazol  (B.  35,  1885)  : 


n-Oxy-indazol  Anthranile  (?). 

The  Hetero-ring  Formations  of  o-Amido-benzaldehyde. — o-Amido- 
benzaldehyde  combines  especially  readily  with  compounds  containing 
a  CH2-CO  group,  in  the  presence  of  dilute  caustic  soda.  The  products 
resulting  at  first  are  of  an  aldol  nature,  for  they  immediately  split  off 
water  and  yield  quinolin  or  its  derivatives.  o-Amido-benzaldehyde 
combines  with  acetaldehyde  to  quinolin,  with  acetone  to  quinaldin, 
with  malonic  acid  to  fi-carbostyrile-carboxylic  acid  (B.  25,  1752),  and 
with  urea  to  quinazolone  (B.  28, 1037).  Alcoholic  ammonia  transposes 
the  acidyl-o-amido-benzaldehydes  into  quinazolins  : 

ru   rwn  f  CH  =  CH 

CH"CHO — >  C6H  J  Quinolin 


CH —  CH 


<CH'>'CQ    ->C6H44  Quinaldin 

lN-=C-CH3 


l[2]NH 

Vsn^vs^A/s       ^    /"»   IT      J  I  f 

lie  acid 


CH.(CO,H),       r  „  JCH-C— COOH  £_carbostyrile-carboxy- 


-NH,,-H,0 


(CH=N 
C4H4  J  Quinazolone 

NH—  CO 


rv-\rtir\  NH  fCH^N  Pheno-5-methyl-meta- 

iMT/^n  r  w    -  ^—+  C*H*  I  I  diazin«  «-Methyl-quin- 

[2]NH.CO.CH3  (N=C.CH3  azolin. 

On  the  condensation  of  o-amido-benzaldehyde  by  means  of  zinc 
chloride  to  anhydro-o-amido-benzaldehyde  (C7H6N)a.,  see  B.  31,  658. 

Benzaldehyde-m-sulphonic  acid  SO3H.C6H4CHO,  white  deliquescent 
crystals  (B.  24,  791).  Benzaldehyde-o-sulphonic  acid  is  obtained  from 
o-chloro-benzaldehyde  with  sodium  sulphite,  as  well  as  by  oxidation  of 
o2-stilbene-disulphonic  acid.  The  chloride,  m.p.  114°,  treated  with 
NH3  and  then  oxidised  in  air,  yields  saccharin  (C.  1898,  I.  540  ;  1901, 
I.  806).  Benzaldehyde-mono-  and  -disulphonic  acids  are  also  produced 
by  oxidation  of  toluol-sulphonic  acids  with  MnO2  and  fuming  sulphuric 
acid  (C.  1904,  II.  1269). 

(3)  AROMATIC  MONOKETONES. 

The  oxidation  products  of  the  secondary  phenyl-paraffin  alcohols 
are  mixed  ketones,  in  which  an  aromatic  and  an  aliphatic  hydrocarbon 
residue  are  joined  by  the  CO  group.  The  ketones  containing  two 
benzene  residues  linked  by  carbonyl,  such  as  benzo-phenone  or  diphenyl- 
ketone,  will  be  discussed  later  in  connection  with  the  corresponding 
hydrocarbons,  like  diphenyl-methane. 

Formation.  —  Mixed  aromatic-aliphatic  ketones  are  usually  produced 
by  reactions  similar  to  those  employed  with  the  aliphatic  ketones  : 

(i)  By  the  oxidation  of  secondary  alcohols,  like  phenyl-methyl 
carbinol. 

(20)  From  the  di-secondary  and  secondary-tertiary  phenyl-ethylen  e 


AROMATIC   MONOKETONES  265 

glycols  and  ethylene  oxides  by  heating  with  dilute  acids  or  alone 
(C  1905,  II.  1628  ;  1907,  I.  1577)  :  

C6H5CH(OH).CH(OH)CH3 >  CaH5CH2.CO.CH3  < C6H6iH.O.CH.CH3. 

(zb)  From  the  iodo-hydrins  of  some  olenn-benzols  on  treating  with 
NO3Ag  or  HgO,  with  migration  of  the  phenyl  group  : 

C«H6\C(OH).CHI.CH3  >  CH3.CO.CH/C«H6 


(3)  When  sulphuric  acid  acts  upon  phenyl-acetylene  : 
C6H5C:CH  ---  >C6H5COCH3. 

Nuclear  Synthesis.  —  (4)  By  the  distillation  of  a  mixture  of  calcium 
salts  of  an  aromatic  and  a  fatty  acid  (C.  1910,  I.  1008). 

(5)  By  the  action  of  zinc  alkyls  on  acid  chlorides  (A.  118,  20). 

(6)  By    the    action    of    alkyl-magnesium    iodides    upon    aromatic 
nitriles  addition  products  are  obtained,  which,  on  decomposition  with 
mineral  acids,  give  aromatic  ketones  (C.  1902,  I.  299)  : 


C6H6C=N+CH,MgI  --  >  C«H*C  --  "  c«H*COCHs- 


Benzo-nitrile  oxide  CjHg.C        with  alkyl-magnesium  haloids  gives 

ketoximes  (B.  40,  1672). 

(7)  From  benzols  by  the  action  of  aliphatic  acid  chlorides  and  Al 
chloride  or  ferric  chloride.     Additive  compounds  of  these  chlorides 
and  the  acid  chlorides  are  first  formed,  e.g.  (CH3COC1)A1C13,  and  these 
thereupon  react  with  the  hydrocarbons  (B.  33,  815  ;   C.  1900,  II.  188  ; 
1901,  I.  1263). 

(8)  By   heating   aryl-glycidic   acids.     These   are   easily   obtained 
synthetically    by    condensing    aromatic    aldehydes    or   ketones   with 
a-chloro-propionic  ester  and  sodium  ethylate  (C.  1906,  I.  669)  : 

C6H5COCH3  -  *  C6H5(CH3)do.(!;£COOH  -  *  C,H6(CH3)CHCO.CH3. 

(9)  From  aldehydes  with  diazo-methane  (B.  40,  479). 

(10)  In  the  alkyl-phenyl  ketones  the  H  atoms  adjoining  the  car- 
boxyl  group  may  be  replaced  by  alkyls  by  the  action  of  sodium  amide 
and  halogen  alkyls  (C.  1909,  I.  647  ;   II.  600)  : 

C6H5COCH2CH,  -££-+  C6H6CO.C(C2H5)2CH3. 

(n)  By  decomposing  j3-ketone-car  boxy  lie  acids  —  e.g.  mono-  and 
dialkyl-benzoyl-acetic  acids  (B.  16,  2131)  —  with  alcoholic  potash. 

(12)  Acidulated  benzols  finally  result,  as  a  consequence  of  intra- 
molecular rearrangement,  upon  heating  the  alkyl  ethers  of  phenyl- 
olefin  alcohols,  which  are  prepared  by  the  distillation  of  ortho-ethers 
of  aceto-phenone.  In  this  way  the  acidyl  benzols  can  be  built  up  from 
aceto-phenone  (Claisen,  B.  29,  2931)  : 

C8H5CO.CH3->C,H5C(OCH3)2.CH3-^C6H5C(OCH3)  :  CH2~>CeH6COCH,.CH3 

Aceto-phenone  and  higher  ketones  are  found  in  the  so-called  heavy 
benzene  oil  of  coal-tar  (B.  36,  754). 

Properties  and  Behaviour.  —  The  mixed  aromatic-aliphatic  ketones 
are  colourless  liquids,  insoluble  in  water,  and  possess  an  odour  which 
is  not  disagreeable. 


266  ORGANIC   CHEMISTRY 

(i)  On  reduction  they  pass  into  secondary  alcohols  or  the  corre- 
sponding alkyl-benzols  (C.  1905,  I.  29). 

(20)  Chromic  acid  transforms  the  ketone  C6H5.COR  into  benzoic 
acid  and  the  alkyl,  which  is  further  oxidised. 

(26)  Potassium  permanganate  converts  them  into  a-ketone-carbo- 
xylic  acids  (B.  23,  R.  640  ;  24,  3543  ;  26,  R.  191). 

(3)  Acids  and  acid  amides,  with  the  same  number  of  carbon  atoms, 
strangely  enough,  are  formed  when  phenyl-alkyl  ketones  are  heated 
with  yellow  ammonium  sulphide  (/.  pr.  Ch.  2,  81,  74,  382)  : 

C6H5COCH2CH3  -  \  /~r>ATTj    • 

1  -  >  C6ii5Crl2Crl2CxUJN.rl2 

With  increasing  number  of  carbon  atoms  in  the  side  chain,  the 
yield  of  carboxylic  acids  decreases,  so  that  it  vanishes  in  phenyl-heptyl 
ketone. 

(4)  On  heating  benzene  ketones  with  sulphuric   acid,  the  acetyl 
group  splits  off,  -and  benzol-sulphonic  acid  results  (B.  19,  2623). 

(5)  Those  ketones  in  which  the  CO  group  is  attached  to  the  benzene 
nucleus  do  not  unite  with  alkaline  bisulphites. 

(6)  The  phenyl-alkyl  ketones  apparently  form  but  one  acetoxime 
with  hydroxylamine  ;   the  opposite  is  true  of  benzaldehyde. 

(7)  They  form  hydrazones  with  phenyl-hydrazin. 

(8)  With  phosphoric  and  arsenic  acids  the  aryl-methyl  ketones 
especially  form  crystalline  compounds,  some  of  which,  when  heated, 
regenerate    the    hydrocarbons   with    elimination   of    the   keto-group 
(B.  32,  1549  i   35,  2313). 

(9)  On  heating  with  sodium  amide  in  benzene  solution,  the  trialkyl- 
aceto-phenones  break  up  into  benzene  and  the  amides  of  the  corre- 
sponding trialkyl-acetic  acids  (C.  1909,  I.  912  ;  II.  600)  : 


C6H5CO.C(CH3)3          ->  C6H6+NH2CO.C(CH3)3. 

Aceto-phenone,  phenyl-methyl  ketone,  acetyl-benzol  C6H5.CO.CH3, 
m.p.  20°,  b.p.  202°,  crystallises  in  large  plates.  It  is  applied  as  an 
opiate  under  the  name  of  hypnone.  It  is  formed  (i)  from  phenyl- 
methyl  carbinol  ;  (2)  from  phenyl-acetylene  ;  (3)  by  distilling  benzoate 
of  calcium  with  calcium  acetate  ;  (4)  by  the  action  of  zinc  methyl 
upon  benzoyl  chloride  ;  (5)  from  benzene,  acetyl  chloride,  and  A1C13  ; 
(6)  from  benzaldehyde  and  diazo-methane  ;  (7)  from  benzoyl-aceto- 
acetic  ester  C6H5CO.CH(COCH3).COOC2H5  and  benzoyl-acetic  ester. 
The  methods  3  and  5  are  employed  in  its  preparation. 

Nascent  hydrogen  converts  it  readily  into  phenyl-methyl  carbinol. 
Chromic  acid  oxidises  it  to  benzoic  acid,  and  potassium  permanganate 
to  phenyl-glyoxylic  acid. 

Aceto-phenone,  like  acetone,  has  been  introduced  into  numerous 
nuclear-synthetic  reactions.  Some  of  the  simplest  of  these  will  be 
given.  It  may  be  condensed  to  dypnone  (q.v.)  and  to  [i,  3,  $\-triphenyl- 
benzol  (cp.  C.  1900,  II.  255),  two  bodies  bearing  the  same  relation  to 
aceto-phenone  that  mesityl  oxide  and  mesitylene  have  to  acetone. 

Aceto-phenone  also  condenses  in  the  most  varied  proportions  with 
benzaldehyde,  forming  benzal-aceto-phenone,  benzal-diaceto-phenone, 
and  dibenzal-triaceto-phenone  (B.  29,  1488).  It  yields  the  nitrile  of 
a-phenyl-lactic  acid  with  hydrocyanic  acid.  At  higher  temperatures 


ACETO-PHENONE 


267 


chlorine  enters  the  methyl  group ;  PC16  substitutes  the  ketone-oxygen- 
producing  aeeto-phenone  chloride  (A.  217,  105).  Amyl  nitrite  and 
sodium  ethylate  convert  aceto-phenone  into  iso-nitroso-aceto-phenone, 
which  will  be  described  under  Phenyl-glyoxal. 

With  ammonia,  aceto-phenone  reacts  like  the  higher  aliphatic 
ketones,  with  formation  of  aceto-phenone  ammonia  (C6H5(CH3)C)3N2, 
m.p.  115°  (C.  1907,  I.  809). 

Ortho-ethers  of  aceto-phenone,  like  aceto-phenone  ortho-ethyl  ether 
C6H5C(OC2H5)2CH3,  b.p.  107°  (17  mm.),  are  prepared  from  aceto- 
phenone  and  ortho-formic  ethers  (B.  40,  3908).  When  heated  under 
ordinary  pressure,  or  by  the  action  of  acid  chlorides  and  pyridin  (B.  31, 
1019),  they  lose  alcohol  and  pass  into  alkyl  ethers  of  phenyl-olefin 
alcohols.  They  yield  aniles  with  aniline.  Aceto  -  phenone  -  anile 
C6H6C  :  (NC6H5)CH3,  m.p.  41°,  b.p.  310°. 

Aceto-phenone-ethyl  mercaptol  C6H5C(SC2H5)2CH3  is  oxidised  by 
permanganate,  in  the  cold,  to  the  disulphone  CgH6C(SO2C2H5)2CH3, 
m.p.  120°  (B.  35,  2343). 

Aceto-phenone  oxime  C6H5.C  :  (N.OH).CH3,  m.p.  59°.  It  is  only 
known  in  one  modification  (B.  24,  3482).  By  the  action  of  concen- 
trated sulphuric  acid,  or  of  HC1  in  glacial  acetic  acid,  it  is  converted 
into  acetanilide  C6H5.NH.CO.CH3.  This  remarkable  intramolecular 
atomic  rearrangement  was  discovered  by  Beckmann  ("  Beckmann's 
Transposition/'  B.  20,  2580  ;  23,  2746). 

Other  ketoximes  behave  in  an  analogous  manner.  The  reaction 
has  been  applied  in  determining  the  point  of  double  union  in  the 
higher  olefin-monocar  boxy  lie  acids,  and  for  the  decomposition,  or 
rupture,  of  ring  ketones. 

Aceto-phenone-phenyl-hydrazone  melts  at  105°. 

Aceto-phenone  Homologues. — These  are  numerous,  and  can  be 
arranged  in  two  groups  :  (A)  ketones  whose  CO  group  is  attached  to 
the  benzene  ring — acidulated  benzols  ;  (B)  ketones  whose  CO  group  is 
not  in  immediate  union  with  the  benzene  ring — phenylated  fatty  ketones. 

(A)  Acidulated  benzols  have  been  made,  especially  by  the  general 
methods  4,  6,  7,  10,  n,  12. 

Benzoylated  paraffins  : 


Propio-phenone  . 
Butyro-phenone 
Valero-phenone  . 
Iso-valero-phenone     . 
Tert.  butyl-phenyl  ketone     . 
Caprono-phenone 
Iso-amyl-phenyl  ketone 
Diethyl-aceto-phenone 
Ethyl-dimethyl-aceto-phenone 
Hexyl-phenyl  ketone    . 
Propyl-dimethyl-aceto-phenone 
Triethyl-aceto-phenone 
Lauroyl-benzol  . 
Palmityl-benzol  . 


C6H5COCH2CH3 . 
C6H5CO(CH2)2CH3        . 
C6H5CO(CH<,)3CH3 
C6H5CO.CH2CH(CH3)2 
C6H5CO.CH(CH3)3 
C6H5CO(CH2)4CH3        . 
C6H5COCH2.CH2CH(CH3)2 
C6H5COCH(C2H5)2       . 
C6H5COC(CH3)2C2H5    . 
C6H5CO(CH2)5CH3       . 
C6H5COC(CH3)2C3H7   . 
C6H5COC(C2H5)3 
C6H5CO(CH2)10CH3      . 
C6H.CO(CH2)14CH3      . 


b.p. 

210°  ! 

M 

222° 

,, 

237° 

,, 

230° 

''n 

220°  2 

b.p-14 

133°  3 

b.p. 

240° 

b.p.10 

II2°4 

b-p-io 
m.p. 


145° 4 

47° £ 
59° 


Literature. — x  B.    26,    1427  ;     35,    1073. 
4  C.  1909,  I.  647.     5  B.  28,  R.  648. 


2  A.    310,    318.      3  B.    40,   1601 


268  ORGANIC   CHEMISTRY 

/CH 
Benzoyl-trimethylene  CflH5CO.CH<Q     ,  formed  on  heating  trimethy- 

lene-benzoyl-acetic    acid    to    200°,    boils   at    239°.     Its    oxime  melts 
at  88°. 

Benzoyl-tetramethylene  C8H6COCH<^2^>CH2,  from  the  chloride  of 

tetramethylene-carboxylic  acid,  boils  at  258°  (B.  25,  R.  372). 

Nuclear- acidulated   A  Iky  I -benzols,   Homobenzoylated   Paraffins.— 
p-Acetyl-toluol  is  produced  when  concentrated  nitric  acid  acts  upon 
cymene  (pp.  58),  and  acetyl-3,  4~(o)-xylol  is  formed  from  camphor  by 
the  action  of  concentrated  sulphuric  acid  (B.  26,  R.  415)  : 

p-Acetyl-toluol  CH3CO[4].C,,H4[i].CH3  boils  at  224° 
l-Acetyl-3, 4-(o)-xylol       ....       246° 


l-Acetyl-2, 4-(m)-xylol      .         . 

Acetyl-p-xylol       .... 

Acetyl-mesitylol    .... 
l-Acetyl-2,  4,  5,  6-durol  melts  at  73°  and 


247° 

224° 

235°  (B.  24,  3542) 

206°  (B.  29,  847). 


(B)  Phenylated  fatty  ketones  have  been  prepared  by  methods  2,  4, 
5,  6,  8,  and  n  (p.  264  seq.)  : 

Benzyl-propyl  ketone  C(,H5CH2.CO.CH2CH3,  b.p.  240°,  from  benzyl 
cyanide  with  propyl-magnesium  iodide,  etc.  (C.  1902,  I.  299). 

Benzyl-methyl-ethyl  ketone  C6H5CH2CH2COCH2CH3,  b.p.  257°, 
from  a-benzylidene-methyl-ethyl  ketone  by  reduction,  or  by  distilla- 
tion of  calcium  hydro-cinnamate  or  propionate  (B.  35,  971). 

Substituted  Aceto  -  phenones. —  Haloid  A  ceto  -  phenones.  —  Aceto- 
phenones  containing  halogens  in  the  methyl  group  will  be  discussed 
after  the  corresponding  ox3^gen  derivatives  :  benzoyl-carbinol  (q.v.), 
phenyl-glyoxal  (q.v.),  and  phenyl-glyoxylic  acid  (q.v.).  p-Haloid 
aceto-phenones,  like  C1.C6H4.CO.CH3,  have  been  obtained  from 
haloid  benzenes,  acetyl  chloride,  and  aluminium  chloride  (cp.  haloid 
thiophene  ketones)  (B.  24,  997,  3766)  : 

p-Chloraceto-phenone,  acetyl-p-chloro-benzene,  melts  at  20°  and 

boils  at  230°  (B.  18,  R.  502). 

p-Bromaceto-phenone,  acetyl-p-bromo-benzene,  melts  at  51°. 
p-Iodaceto-phenone,  acetyl-p-iodo-benzene,  melts  at  83°. 

Nitro-aceto-phenones. — The  meta-body  is  the  chief  product  (just  as 
in  the  case  of  benzaldehyde)  when  aceto-phenone  is  dissolved  in  fuming 
nitric  acid  ;  at  30°-40°  o-nitro-aceto-phenone  predominates  (B.  18, 
2238).  The  three  isomerides  can  be  prepared  from  the  three  nitro- 
benzoyl-aceto-acetic  esters  (see  these)  (A.  221,  323). 

p-Nitro-aceto-phenone  is  formed  when  concentrated  sulphuric  acid 
acts  upon  p-nitro-phenyl-propiolic  acid  (see  this),  through  the  rearrange- 
ment of  the  nitro-phenyl-acetylene,  formed  at  first,  by  water  (A.  212, 
160)  (see  method  of  formation  3). 

o-Nitro-aceto-phenone,  b.p.16 159°;  oxime,  m.p.  115°  (C.  1902,  I.  472) 
m-Nitro-aceto-phenone,  m.p.     81° ;      „          ,,    131°  (B.  37,  3542) 
p-Nitro-aceto-phenone,    ,,        80°. 

o-Nitro-aceto-phenone  oxime  is  also  produced  from  o-nitro-ethyl- 
benzol  NO2C6H4CH2CH3  with  amyl  nitrite  and  sodium  ethylate  (see 
Nitro-benzaldoximes,  and  C.  1900,  II.  458). 


ACETO-PHENONE  269 

m-Dinitro-aeeto-phenone,  m.p.  83°,  is  prepared  from  dinitro- 
benzoyl-aceto-acetic  ester  with  H2SO4  (/.  pr.  Ch.  2,  65,  290). 

o-Nitro-aceto-phenone,  on  gentle  reduction  with  zinc  dust  and 
sal  ammoniac  or  tin  and  acetic  acid,  is  converted  into  o-hydroxylamino- 


aceto-phenone  anhydride  or  o-methyl  anthranile 

iu°,  a  colourless  oil,  easily  volatilised  with  steam,  which  must  be 
regarded  as  analogous  to  anthranile  ;  like  the  latter,  it  forms  with 
sublimate  a  double  compound,  which,  on  further  reduction,  passes 
into  amido-aceto-phenone.  On  heating  at  ordinary  pressure  it  is  trans- 
posed into  indoxyl  or  converted  into  indigo  (see  Indigo  syntheses,  and 
B.  36,  1611). 

m-Hydroxylamino-,  azoxy-  and  azo-aceto-phenones,  see  B.  36, 
1618  ;  C.  1903,  II.  112. 

Amido-aeeto-phenonesC6H4(NH2).CO.CH3. 

o-,  m-  and  p-Amido-aceto-phenone  are  obtained  :  by  reducing 
o-nitro-aceto-phenone  (A.  221,  326) ;  the  o-amido-aceto-phenone  has 
also  been  prepared  from  o-amido-phenyl-propiolic  acid  by  boiling  in 
water  (B.  15,  2153)  ;  from  o-amido-phenyl-acetylene  C6H4(NH2)C  ;  CH 
by  the  action  of  sulphuric  acid  (B.  17,  964)  ;  by  boiling  o-amido-phenyl- 
propiolic  acid  with  water  (B.  15, 2153)  ;  and  a  slight  quantity  on  heating 
aniline  with  acetic  anhydride  (B.  18,  2688).  o- Amido-aceto-phenone  is 
a  thick  yellow  oil,  which  boils  at  242°-252°,  and  possesses  a  character- 
istic sweetish  odour,  m- Amido-aceto-phenone  melts  at  93°.  p-Amido- 
aceto-phenone  melts  at  106°  ;  its  oxime  melts  at  147°  (B.  20,  512).  A 
pine  splinter  dipped  into  the  aqueous  solution  of  o-amido-aceto-phenone 
hydrochloride  is  coloured  an  intense  orange-red. 

o-,  m-  and  p-Acetyl-amido-aceto-phenones  CH3CONHC6H4COCH3, 
m.p.  77°,  129°,  and  167°.  The  p-body  is  also  formed  from  diacet- 
anilide  by  transposition  on  heating  with  HC1  or  zinc  chloride  (C.  1903, 

i.  832). 

Hetero-ring  Formations  of  the  Aromatic  o-Amido-ketones. — (i)  Di- 

methyl-quinolin  is  produced  (B.  19, 1037)  when  o-amido-aceto-phenone 
is  digested  with  acetone  and  sodium  hydroxide. 

(2)  o-Acetyl-amido-aceto-phenone    is    condensed    by    NaHO    to 
a-methyl-y-oxy-  and  a-oxy-y-methyl-quinolin  (B.  32,  3228). 

(3)  and  (4)  Oily  nitro-compounds  are  formed  in  the  nitration  of 
phenyl-acetone    and    benzyl-acetone.      They    yield,    by    reduction, 
j8-methyl-dihydro-ketol  and  tetrahydro-quinaldin  (B.  14,  889),  as  the 
o-amido-bodies    (probably    the    o-amido-alcohols)    produced    at    first 
sustain  an  intramolecular  anhydride  formation  : 

c  H   (  WCO.CH.CH,        NaOH ^  £  ^   f  C(CH,)=CH         ^^ 

4\[2]NH2          CO.CH,  HN  C.CH3     <^umoUn 

C.H,,H,,O.CH, ^(C.H.{|;™H-) »C.H.(<yHCH'      <£«„, 

r  H  rvr  TH  ro  rw         ^  (c  H  /MCH"--CH'-cacHA  _  „  JCH2— CH2  Tetrahydro- 

(_6Hs.t/rl2.Crl2.LU.L-rl3 >   IC«H4<  I >  *-s"4  \ 

\          \[2]NH2  \NH-CHCH3         ***&*• 

(4)  AROMATIC  MONOCARBOXYLIC  ACIDS. 

The  aromatic  carboxylic  acids  result  upon  replacing  the  hydrogen 
in  benzene  or  its  homologues  by  the  carboxyl  group.  This  group  in 


270  ORGANIC  CHEMISTRY 

these  new  derivatives  is  directly  linked,  as  in  the  benzene-carboxylic 
acids,  to  the  benzene  ring,  or  it  replaces  the  hydrogen  of  an  alkyl 
side  chain  : 


C6H5.C02H 
Benzole 
acid 

CH3.C6H4CO2H 
Toluic  acids 

C6H4(C02H)2 
Phthalic  acids 

(CH3)2C6H3C02H 
Xylic  acids 

C6H3(C02H)3  .  . 
Benzene-  tricar- 
boxylic  acids 

C6H5CH2C02H 
Phenyl-  acetic  acid 
a-  Toluic  acid 

,     C6(C02H)6 
Mellitic  acid 

C6H6CH2CH2C02H 
Hydro-cinnamic  acid 
/S-Phenyl-propionic 
acid. 

Only  the  monocarboxylic  acids  will  be  now  discussed,  after  the 
monohydric  aromatic  alcohols. 

General  Methods  of  Formation. — (i)  While  the  aliphatic  mono- 
carboxylic acids  or  the  paraffin  carboxylic  acids  could  not  be  obtained 
by  the  oxidation  of  the  paraffins,  the  aromatic  acids  can  be  readily 
obtained  from  the  benzene  homologues  by  oxidising  the  side  chains 
to  carboxyl  groups.  The  importance  of  this  reaction  in  establishing 
constitution  has  been  previously  alluded  to  (p.  54).  The  most  suitable 
oxidants  are  chromic  acid,  dilute  nitric  acid,  potassium  permanganate, 
and  potassium  ferricyanide. 

(a)  Oxidation   with    Chromic    Acid. — Only   the   para-   and   meta- 
derivatives  (the  former  more  readily  than  the  latter)  of  benzenes,  carry- 
ing two  side  chains,  are  oxidised  to  acids  by  chromic  acid,  while  the 
ortho-  are  either  not  attacked  at  all,  or  are  completely  destroyed. 

In  substituted  alkyl-benzenes  the  alkyl  group  is  prevented  from 
being  oxidised  by  chromic  acid,  if  a  negative  group  occupying  the  o-posi- 
tion  with  reference  to  the  alkyl  group  is  present  (B.  15,  1021).  The 
oxidations  are  conducted  either  with  free  chromic  acid  in  glacial  acetic 
acid,  or  with  a  mixture  of  potassium  bichromate  (3  parts)  and  sulphuric 
acid  (3  parts),  diluted  with  2-3  volumes  of  water. 

(b)  Oxidation  with  Nitric  Acid. — When  oxidising  with  nitric  acid, 
use   acid  diluted  with   3   parts  of  water  and  boil  for  some  time,  in 
connection  with  a  return  condenser  (2-3  days) .     Konowaloff  contends 
that  phenyl-nitro-paraffins  are  first  produced  ;    these  then  are  further 
oxidised  to  carboxylic  acids.     To  remove  the  nitro-acids  which  are 
invariably  formed,  the  crude  product  is  digested  with  tin  and  concen- 
trated hydrochloric  acid  ;    this  converts  the  nitro-  into  amido-acids, 
which  dissolve  in  hydrochloric  acid. 

In  the  derivatives  with  two  different  alky  Is  the  higher  alkyl  is  usually 
attacked  first,  by  nitric  acid  or  chromic  acid  ;  sometimes  ketones  are 
present  in  the  intermediate  products  (see  Cymol,  p.  58). 

(c)  Potassium  permanganate  often  effects  the  oxidation  at  ordinary 
temperatures.     Ortho-di-derivatives  may  also  be  subjected  to  oxida- 
tion, without  the  complete  destruction .  of  the  benzene  nucleus  follow- 
ing as  a  consequence. 

(d)  Potassium  ferricyanide  oxidises  methyl  to  carboxyl,  if  the  nitro- 
group  occupies  the  ortho-position  relatively  to  the  methyl  group.     This 
does  not  occur  if  the  nitro-group  holds  the  meta-position  (B.  22,  R.  501). 

(2)  Oxidation  of  the  corresponding  aromatic  alcohols  and  alde- 
hydes. 

(3)  By  the  addition  of  hydrogen  to  the  unsaturated  monocarboxylic 
acids.     Cinnamic  acid  becomes  hydro-cinnamic  acid. 


AROMATIC   MONOCARBOXYLIC  ACIDS  271 

(4)  By  the  reduction  of  phenylated  oxy-fatty  acids,  haloid  aro- 
matic acids,  and  ketone-carboxylic  acids. 

(5)  From  the  phenyl-alkyl  ketones  by  heating  with  Am2S,  acids  and 
acid  amides  of  the  same  number  of  C  atoms  are  produced  : 

1.  C6H5.CH3  -  -^-  —  C6H5COOH 

2.  C6H6.CH2OH  -  -+  C6H5CHO >  C6H5COOH 

3.  C6H5.CH=CH.COOH  -  — *  C6H5CH2.CH2.COOH 

4.  C6H6.CH(OH).COOH  -  ->  C6H5CH2.COOH 
C6H5.CO.CO2H  -            4HI  -*  C6H5CH2.COOH 
C6H5.CHC1.COOH  -  --+  C6H5CH2COOH 

5.  C6H5.CO.CH2.CH3 ^^ >  C6H5CH2.CH2.COOH. 

Nuclear-synthetic  Reactions. — (6a)  Action  of  CO2  upon  aryl-mag- 
nesium  haloids ;  phenyl-magnesium  iodide  gives  rise  to  benzoic  acid, 
and  benzyl-magnesium  chloride  to  phenyl-acetic  acid. 

(6b)  Action  of  sodium  and  CO2  upon  monobromo-benzols  (Kekule"). 

(7)  A  similar  reaction  is  that  of  sodium  and  esters  of  chloro-carbonic 
acid  upon  phenols  and  bromo-hydrocarbons  (Wiirtz). 

(8)  Fusion  of  salts  of  the  sulphonic  acids  with  sodium  formate. 

(9)  Action  of  carbon  oxy-chloride  upon  benzols  in  the  presence  of 
Al  chloride,  acid  chlorides  being  obtained. 

(10)  Urea  chlorides,  in  the  presence  of  A1C13,  act  in  an  analogous 
manner  upon  the  benzols.     Acid  amides  are  the  first  products.     The 
urea  chlorides  can  be  replaced  (a)  by  cyanuric  acid,  or  (b)  by  nascent 
cyanic  acid  and  HC1  (B.  32,  1116)  ;  (c)  with  phenyl  cyanate  we  obtain 
anilides ;  (d)  with  phenyl-mustard  oil  we  get  thio-anilides  ( /.  pr.  Ch. 
2,  59,  572). 

(n)  By  the  action  of  benzene  and  aluminium  chloride  upon  ali- 
phatic lactones  or  olefin-carboxylic  acids  (C.  1908,  II.  noo). 
(12)  By  the  synthesis  of  the  acid  nitriles  : 

(a)  Upon  fusing  the  sulphonates  with  potassium  cyanide  ; 

(b)  By  action  of  potassium  cyanide  upon  the  phenyl-alkyl  chlorides ; 

(c)  When    the    bromo-nitro-benzols   are    heated   with    potassium 
cyanide  ; 

(d)  When   diazo-salts   are   treated   with   potassium    cyanide   and 
copper  sulphate  ; 

(e)  By  heating  the  iso-nitriles  alone. 

The  nitriles  are  changed  to  carboxylic  acids  when  they  are  heated 
with  mineral  acids,  or  alkalies. 
Nuclear  Syntheses  : 

6.  C6H5MgI+CO2  --  -»  C6H5COOMgI 

7.  C6H5Br+ClCO2C2H5+2Na  -  — »  C6H5COOC2H6+NaCl+NaBr 

8.  C6H5SO3Na+HCOONa  -  ~>  C6H5COONa-fHSO3Na 

9.  C6H6+COC12  -           A1'cl6  — >  C6H5COC1+HC1 
ioa.  C6H6+C1.CONH2 ^L—  ->  C6H5CONH2+HC1 

b.  C6H6+CO  :  NH  ±»9 >  C6H5CONH2 


272  ORGANIC   CHEMISTRY 

loc.  C6H6+CO  :  NC6H5  -    -^ >  C6H5CONHC6H6 

d.  C6H6+CS  :  NC6H5 ^ >  C6H5CSNHC6H5 

ii.  C6H6+CH3CH  :  CH.COOH  -^k+  C6H5(CH3)CH.CH2COOH 
I2fl.  C6H5S03K+CNK  -  ->  C6H5CN+S03K2 

b.  C6H6CH2C1+CNK-  ~>  C6H5CH2CN  +  KC1 

c.  C6H4BrNO2-fCNK-  — >  C6H4(N02)CN  +  KBr 

d.  C6H5N2C1+CNK  -  -*  C6H5CN+N2+KC1 

e.  C6H5.NC  -  ->  C6H5CN. 

(13)  By  the  oxidation  of  phenyl-pyro-racemic  acids  with  hydrogen 
peroxide  (A.  370,  368)  : 

C6H5CHO *  C6H5CH2.COCOOH >  C6H5CH2COOH. 

(14)  Action  of  benzyl  chloride  upon  sodium-aceto-acetic  ester,  and 
the  decomposition  of  the  ketonic  esters — e.g.  benzyl-aceto-acetic  ester 
— by  alkalies.  * 

(15)  The  decomposition  of  phenyl  substitution  products  of  the 
malonic  acid  series — e.g.  benzyl-malonic  acid — by  heat. 

(16)  Action  of  metallic  sodium  upon  the  acetates,  propionates,  etc., 
of  the  phenyl  carbinols  :  benzyl  acetate  yields  phenyl-propionic  benzyl 
ester,  while  j3-benzyl-phenyl-butyric  ester  is  obtained  from  benzyl  pro- 
pionate.     This   reaction   recalls   the   synthesis   of   aceto-acetic   ester 
(Vol.  I.),  inasmuch  as,  in  the  latter,  alcohol  is  split  off  under  the  in- 
fluence of  sodium,  while,  in  the  present  reaction,  acetic  acid  is  liberated  : 

C2H5OOCCHo|Hj  C6H5CH2OOC.CH2:H; 

CH3CO  lOGjHsi  C6H5CH2iOOCCH3; 

Aceto-acetic  ester  /5-Phenyl-propionic  benzyl  ester. 

Besides  these,  unsaturated  acids  are  formed  by  secondary  reactions, 
leading,  e.g.,  to  phenyl-acrylic  acid  and  phenyl-crotonic  acid  (A.  193, 
321  ;  204,  200) : 

COOCH2C6H6  COONa 

CH2CH2C6H5  H          -  CH  :  CHC6H5  +  C«H«CH3  + 

Occurrence,  Properties,  and  Behaviour. — The  aromatic  acids  occur 
naturally,  partly  in  a  free  state,  partly  in  many  resins  and  balsams, 
and  in  the  animal  organism  (see  Benzoic  acid).  They  arise  also  in  the 
decay  of  albuminoid  bodies  (see  Hydro-cinnamic  acid)  (B.  16,  2313). 

The  aromatic  acids  are  crystalline  solids,  which  generally  sublime 
undecomposed.  Most  of  them  dissolve  with  difficulty  in  water  ;  hence 
they  are  precipitated  from  their  salt-solutions  by  mineral  acids.  Elec- 
trolytic reduction  (B.  39,  2933  ;  41,4148),  or  sodium  amalgam,  or  zinc 
dust  will  reduce  some  to  aldehydes,  while  heating  with  concentrated 
hydro-iodic  acid,  or  phosphonium  iodide,  converts  them  into  hydro- 
carbons. When  heated  with  lime,  or  soda-lime,  their  carboxyl  groups 
are  eliminated  and  hydrocarbons  result  (cp.  methane,  Vol.  I.). 

From  the  polycarboxylic   acids  we  obtain,  as  intermediate   pro- 


BENZOIC  ACID  273 

ducts,  acids  having  fewer  carboxyl  groups — e.g.  phthalic  acid  first 
yields  benzoic  acid  and  then  benzene. 

The  hydrogen  of  the  benzene  nucleus  in  the  acids  can  sustain  sub- 
stitutions similar  to  those  observed  with  the  hydrocarbons  and  phenols 
by  the  halogens,  and  the  groups  NO2,  SO3H,  NH2,  OH,  etc.  In  other 
respects  they  are  very  similar  to  the  fatty  acids,  and  afford  correspond- 
ing derivatives  by  the  alterations  of  the  carboxyl  group. 

Benzoic  acid,  phenyl-formic  acid  C6H5.COOH,  m.p.  120°  and  b.p. 
250°,  occurs  free  in  some  resins,  especially  hi  gum  benzoin  (from  Styrax 
benzoin),  in  dragon's  blood  (from  Dcemonorops  Draco],  also  in  Peru 
and  tolu  balsams,  where  it  exists  in  the  form  of  its  benzyl  ester.  It  is 
found  as  hippuric  acid  in  the  urine  of  herbivorae. 

It  is  produced  by  the  general  methods  I  and  2  from  toluol  (B.  36, 
1798),  benzyl  alcohol,  and  benzaldehyde  upon  oxidation,  as  well  as 
from  all  hydrocarbons,  alcohols,  aldehydes,  ketones,  and  carboxylic 
acids,  and  their  derivatives,  which  are  obtainable  from  benzene  by  the 
replacement  of  one  hydrogen  atom  by  a  univalent  side  chain.  Benzoic 
acid  can  also  be  prepared  by  the  oxidation  of  pure  benzene ;  this  is 
very  probably  due  to  the  oxidation  of  diphenyl,  which  is  formed  at 
first  (A.  221,  234).  Toluol  can  also  be  changed  to  benzyl  chloride,  and 
this  can  then  be  oxidised  (see  "Preparation")  to  benzoic  acid ;  or  benzo- 
trichloride  may  be  heated  with  water,  concentrated  sulphuric  acid,  or 
anhydrous  oxalic  acid,  and  the  product  will  be  benzoic  acid.  It  can 
also  be  obtained,  by  the  nuclear-synthetic  reactions  6,  7,  8,  9,  10,  and 
12,  from  benzol,  bromo-benzol,  sodium-benzol  sulphonate,  and  from 
aniline  through  diazo-benzol  chloride  or  phenyl-carbylamine.  Finally, 
CO 2  can  be  added  to  benzol  by  means  of  aluminium  chloride,  and 
benzoic  acid  will  result. 

History. — Benzoic  acid  was  obtained  from  gum  benzoin  by  sub- 
limation, in  the  beginning  of  the  seventeenth  century.  In  1775  Scheele 
showed  how  the  acid  could  be  extracted  from  the  gum  with  lime-water, 
and  then  be  precipitated  from  the  solution  of  its  calcium  salt.  In  1832 
Liebig  and  Wohler,  in  the  course  of  their  classic  research  upon  the 
radicle  benzoyl,  determined  the  elementary  composition  of  the  acid 
and  illustrated  its  connection  with  benzaldehyde,  as  well  as  pointed  out 
the  simplest  transformation  products  of  the  acid.  This  investigation 
produced  such  a  profound  impression  upon  the  great  master,  Berzelius, 
that  he  proposed  as  a  substitute  for  the  name  benzoyl — the  name  of  the 
new  radicle  containing  more  than  two  elements — that  of  prom  or 
orthrin,  from  the  Greek  words,  irpwi,  the  beginning  of  day,  or  opOpos, 
morning  dawn,  because  a  new  day  was  now  breaking  for  organic  chem- 
istry. In  1834  Mitscherlich  distilled  benzoic  acid  with  lime  and  got 
benzene,  which  led  him  to  regard  the  acid  as  a  derivative  of  this  hydro- 
carbon. From  that  day,  and  especially  since  the  establishment  of  the 
benzene  theory  by  Aug.  Kekule,  benzoic  acid  has  been  serving  in  con- 
stantly increasing  amount  as  the  fundamental  material  for  the  pre- 
paration of  innumerable  products.  It  is  the  carbon  acid  which  has 
been  most  exhaustively  investigated.  The  study  of  its  derivatives  has 
been  greatly  facilitated  by  the  fact  that  the  great  crystallising  power  of 
the  acid  has  been  transferred  to  most  of  its  compounds  (Vol.  I.). 

Preparation. — Gum  benzoin  is  sublimed  or  the  resin  is  boiled  with 
milk  of  lime,  and  the  benzoic  acid  precipitated  with  hydrochloric  acid. 

VOL.  II.  T 


274  ORGANIC   CHEMISTRY 

A  more  advantageous  method  is  the  production  of  the  acid  from  hip- 
puric  acid.  To  accomplish  this,  boil  the  latter  with  concentrated  hydro- 
chloric acid.  It  is  also  produced  when  benzyl  chloride  is  boiled  with 
dilute  nitric  acid  (B.  10, 1275).  Benzoic  acid  results  from  phthalic  acid 
by  heating  its  calcium  salt  to  350°  with  calcium  hydroxide.  For  its 
preparation  by  hydrolysis  of  benzo-sulphonic  acids,  see  C.  1899,  1. 1173. 

Properties  and  Behaviour. — Benzoic  acid  crystallises  from  hot  water, 
in  which  it  is  very  soluble,  in  white,  shining  flakes.  It  sublimes 
readily,  and  is  carried  over  with  steam.  It  dissolves  with  difficulty  in 
cold  water  (i  part  in  600  parts  at  o°).  Its  vapours  possess  a  peculiar 
odour,  which  produces  coughing  and  sneezing.  The  officinal  benzoic 
acid  is  obtained  by  the  sublimation  of  Siam  gum  benzoin. 

The  acid  yields  benzene  and  carbon  dioxide  when  heated  with  lime. 
Benzoic  acid,  upon  reduction,  can  yield  tetra-  and  hexahydro-benzoic 
acids  (q.v.). 

Salts. — The  benzoates  are  mostly  quite  readily  soluble  in  water. 
Ferric  chloride  throws  out  a  reddish  precipitate  of  ferric  benzoate  from 
their  neutral  solutions. 

The  potassium  salt  2C7H5KO2+H2O  crystallises  in  concentrically 
grouped  needles.  The  calcium  salt  (C7H6O2)2Ca-f  3H2O  consists  of 
shining  prisms  or  needles.  The  silver  salt  C7H5AgO2  crystallises  from 
hot  water  in  bright  flakes.  It  dissolves  in  alcohol  with  great  difficulty 
(B.  35,  1094). 

Homologues  of  Benzoic  Acid. — These  compounds,  like  the  homo- 
logues  of  benzaldehyde  and  aceto-phenone,  can  be  arranged  in  two 
groups  :  alkyl-benzoic  acids,  in  which  the  CO2H  group  is  attached  to  the 
benzene  nucleus,  as  in  benzoic  acid  itself,  and  phenyl-fatty  acids,  in 
which  the  carboxyl  group  occurs  in  an  aliphatic  side  chain  of  an  alkyl- 
benzene.  The  first  group  or  class  is  naturally  more  nearly  related  to 
benzoic  acid  than  the  second  group. 

Alkyl-benzoic  acids. —  Toluic  acids  or  methyl-benzoic  acids  CH3.C6H4. 
CO2H  are  isomeric  with  a-toluic  acid  or  phenyl-acetic  acid.  They  are 
produced  when  the  three  xylols  are  boiled  for  some  time  with  dilute  nitric 
acid,  and  from  bromo-  and  iodo-toluol  by  the  nuclear-synthetic  methods 
6  and  7,  as  well  as  from  the  three  toluidins  according  to  method  I2c. 

o-Toluic  acid  can  also  be  obtained  by  the  reduction  of  phthalide 
with  hydriodic  acid  (B.  20,  R.  378),  as  well  as  by  rupturing  the  ring 
of  i,  3-naphthalene-disulphonic  acid,  i,  3-naphthalene  derivatives,  like 
i,  3-dioxy-naphthalene,  i,  3-naphthalene-disulphonic  acid,  i,  3-naph- 
thol-sulphonic  acid,  upon  fusing  them  with  caustic  alkali  (B.  29, 1611). 
p-Toluic  acid  is  formed  on  boiling  cymol  with  dilute  nitric  acid. 

o-Toluic  acid,  m.p.  102° 
m-Toluic  acid,    ,,     110°,  b.p.  263° 
p-Toluic  acid,    „     186°,   „     275°. 

For  derivatives  of  the  toluic  acids,  see  C.  1901,  II.  289. 

Ethyl-benzoic  acids  C2H5.C6H4.CO.OH. — The  three  isomerides  are 
known.  The  o-acid  results  in  the  reduction  of  o-aceto-phenone-car- 
boxylic  acid,  of  methyl  phthalide  (B.  29,  2533),  and  of  phthalic  acetic 

acid    CrH4J\o  with   hydriodic    acid    (B.    10,   2206),    and   in 


-Hj\o 
ICO 


HOMOLOGUES   OF   BENZOIC   ACID  275 

that  of  the  chloro-vinyl-benzoic  acids  with  sodium  amalgam  (B.  27, 
2761).  o-  m-,  and  p-Ethyl-benzoic  acids  melt  at  68°,  47°,  and  112° 
(B.  21,  2830  ;  A.  216,  218)  respectively. 

Dimethyl-benzole  acids  (CH3)2C6H3CO2H.  —  Mesitylenic  acid  is 
the  most  important  member  of  this  group.  It  is  formed  when  mesity- 
lene,  symmetrical  or  [i,  3,  5]-trimethyl-benzol  is  oxidised  with  dilute 
nitric  acid.  Iso-xylol  or  m-xylol  is  obtained  when  this  acid  is  distilled 
with  lime.  These  reactions  are  the  basis  of  the  evidence  that  iso-xylol 
and  its  oxidation  products,  m-toluic  acid  and  iso-phthalic  acid,  are  ni- 
di-substitution products  of  benzene.  Further  oxidation  of  mesitylene 
acid  leads  to  uvitinic  acid  and  trimesic  acid. 

i,  2 -Dimethyl-3 -benzole  acid,  a-hemellithic  acid,  m.p.  144°  (B.  19,  2518) 

i,  2-Dimethyl-4-benzoic  acid,  p-xylylic  acid,        .     „  163°  (B.  17,  2374) 

i,  3-Dimethyl-2-benzoic  acid,  .          .          .  „  98°  (B.  11,  21) 

i,  3-Dimethyl-4-benzoic  acid,  .          .          .          .      „  126°  (B.  12,  1968) 

i,  3-Dimethyl-5-benzoic  acid,  mesitylenic  acid,  .     ,,  166°  (A.  141,  144) 

i,  4-Dimethyl-2-benzoic  acid,  iso-xylylic  acid,     .      ,,  132°,  b.p.  268°  (A.  244,  54)- 

Propyl-benzoic  acids  C3H7.C6H4CO2H.  —  o-  and  p-n-Propyl  and 
p-iso-propyl-benzoic  acids  are  known.  p-Iso-propyl-benzoic  acid,  or 
cumic  acid,  the  oxidation  product  of  the  most  note.  Chromic  acid 
oxidises  cumic  acid  to  terephthalic  acid,  and  potassium  permanganate 
converts  it  into  p-oxy-iso-propyl-benzoic  acid  and  p-acetyl-benzoic  acid  : 

o,  n-Propyl-benzoic  acid   .         .  m.p.    58°  (B.  11,  1014) 
p,  n-Propyl-benzoic  acid  .         .      ,,     138°  (B.  21,  2231) 
o-Iso-propyl-benzoic  acid       .      ,,       51°  (A.  248,  63) 
Cuminic  acid,  p-Iso-propylb.    „  117°  (A.  219, 279 ;  B.  20,  860). 

Trimethyl-benzoie  acids. — Five  are  known.  Durylic  acid  is  ob- 
tained from  durol,  and  a-,  )3-,  and  y-iso-durylic  acids  from  iso-durol 
(B.  27,  3446),  upon  oxidation  with  dilute  nitric  acid.  j3-Iso-durylic 
acid  or  mesitylene-carboxylic  acid  can  also  be  formed  from  acetyl- 
mesitylene  (p.  268)  (B.  25,  503). 

i,  2,  3-Trimethyl-4-benzoic  acid,  Prehnitylic  acid,  melts  at  167° 
i,  2,  3-Trimethyl-5-benzoic  acid,  a-Iso-durylic  acid,  ,,  215° 
i,  2, 4-Trimethyl-5-benzoic  acid,  Durylic  acid,  ,,  150° 

i,  2,  4-Trimethyl-6-benzoic  acid,  y-Iso-durylic  acid,  ,,  127° 
i,  3,  5-Mesitylene-carboxylic  acid,  /Mso-durylic  acid,  „  152°. 

Tetramethyl-benzoic  acids. — Several  are  known  :  i,  2,  3,  4-tetra- 
methyl-^-benzoic  acid,  melting  at  165°,  is  the  oxidation  product  of 
pentamethyl-benzene  (B.  20,  3287)  ;  i,  2,  3,  $-tetramethyl-6-benzoic 
acid,  durol-carboxylic  acid  (B.  29,  2569)  ;  2,  3,  5,  6-tetramethyl~ 
benzoic  acid  melts  at  127°  (B.  29,  R.  233). 

Pentamethyl-benzoic  acid  (CH3)5.C6.CO2H,  melting  at  210°,  is  made 
according  to  method  9  (B.  22,  1221). 

Phenyl-fatty  acids. — The  most  important  representatives  of  this 
group  are  phenyl-acetic  acid  or  a-toluic  acid,  j8-phenyl-propionic  acid 
or  hydro-cinnamic  acid,  and  a-phenyl-propionic  acid  or  hydratropic  acid. 
The  synthesis  and  decomposition  of  the  phenyl-f  atty  acids  can  be  realised 
in  the  same  manner  as  the  synthesis  and  decompositions  of  the  fatty 
acids  (I.  251).  The  general  methods  of  formation  2,  3,  4,  5,  6,  n,  126, 


276  ORGANIC  CHEMISTRY 

13,  14,  15,  and  1 6  are  particularly  prominent  in  the  formation  of  the 
phenyl-fatty  acids. 

Phenyl-acetie  acid,  alpha-toluic  acid  C6H5.CH2.CO2H,  melts  at 
76°  and  boils  at  262°.  This  acid  is  formed  from  toluol  just  as  acetic 
acid  is  obtained  from  methane.  Toluol  is  converted  into  benzyl  chloride, 
and  this  into  benzyl  cyanide,  which  is  then  digested  with  sulphuric  acid 
(B.  19,  1950  ;  20, 592) ;  or  the  benzyl  chloride  is  converted  into  benzyl- 
magnesium  chloride  by  magnesium  in  ether  solution,  and  CO2  is  con- 
ducted through  (B.  35,  2523,  2694)  : 

r  TT  TTT         v  r  H  rn  n/ — *  C«H5CH2CN >  C6H5CH2CO2H 

C6H5CH3  -  _^  C6H5CHaMgCl >  C6H5CH2C02H  ' 

It  can  also  be  obtained  from  phenyl-chloracetic  acid  C6H5.CHC1. 
CO2H  (B.  14,  240),  from  phenyl-gly collie  acid  or  almond  acid  C6H5CH 
(OH).CO2H,  and  phenyl-glyoxylic  acid  C6H5.CO.CO2H,  by  reduction. 

It  is  produced  when  phenyl-malonic  acid  is  heated  (see  method  15), 
and  it  appears  in  the  decay  of  albuminates  (B.  12,  649).  It  may  be 
prepared,  furthermore,  from  bromo-benzene,  chloracetic  ester,  and 
copper  (B.  2,  738)  ;  by  heating  aceto-phenone  with  yellow  ammonium 
sulphide ;  and  by  oxidising  phenyl-pyro-racemic  acid  with  H2O2. 
Chromic  acid  oxidises  it  to  benzoic  acid.  Chlorine,  with  heat,  con- 
verts it  into  phenyl-chloracetic  acid,  while  in  the  cold  the  halogens 
replace  the  aromatic  hydrogen. 

Tolyl-aeetic  acids,  alpha-xylic   acids    c.H4<^?*  „    „.— The  three 

\L/rlj.L/O2ri 

isomeric  acids  have  been  obtained  from  the  three  xylene  bromides. 
The  ortho-acid  melts  at  89°,  the  meta-  at  61°,  and  the  para-  at  91°  (B.  20, 
2051  ;  24,  3965)- 

p-Xylyl-acetic  acid  (CH3)2[i,  4]C6H3CH2COOH,  m.p.  128°,  from 
aceto-p-xylol  and  Am2S  (C.  1897,  II,  411). 

Hydro-einnamie  acid,  jS-phenyl-propionic  acid  C6H5.CH2.CH2.CO2H, 
m.p.  47°  and  b.p.  280°,  is  isomeric  with  a-phenyl-propionic  acid,  the 
three  alpha-xylic  acids,  the  three  ethyl-benzoic  acids,  and  the  six 
dimethyl-benzoic  acids.  It  is  obtained  :  from  cinnamic  acid  C6H5CH  : 
CHCOOH  by  reduction,  e.g.  with  electrolytic  hydrogen  evolved  at  a 
Hg  cathode  (C.  1903,  II.  107),  or  with  sodium  amalgam  or  HI  (B.  30, 
1680)  ;  from  phenyl-ethyl-magnesium  bromide  C6H5CH2.CH2.MgBr 
and  CO 2  (C.  1904,  I.  1493)  ;  from  propio-phenone  with  yellow  Am2S  ; 
from  phenyl-ethyl  cyanide  (A.  156,  249)  ;  from  benzyl-aceto-acetic 
ester  (B.  10,  758)  and  benzyl-malonic  ester  (A.  204,  176)  ;  also  from 
benzyl-acetic  ester,  with  sodium  (A.  193,  300)  (see,  further,  methods 
5,  6,  14,  15,  and  16) ;  and  in  the  decay  of  albuminoid  substances  (B.  12, 
649).  Chromic  acid  oxidises  it  to  benzoic  acid. 

The  aliphatic  haloid  hydro-cinnamic  acids,  readily  obtained  by  the 
addition  of  haloid  acids  and  halogens  to  cinnamic  acid,  will  be  described 
after  phenyl-lactic  and  phenyl-gly  eerie  acids. 

Hydratropie  acid,  a-phenyl-propionic  acid  C6H5CH(CH3).CO2H, 
b.p.  265°,  is  an  oil,  volatile  in  aqueous  vapour.  It  results  from  the 
reduction  of  atropic  acid  or  a-phenyl-acrylic  acid  C6H5C(=CH2).CO2H, 
and  in  the  action  of  hydriodic  acid  upon  the  prussic  acid  addition 
product  of  aceto-phenone — the  nitrile  of  atro-lactinic  acid  (A.  250, 135). 

Higher  homologues  of  these  acids  are  usually  made  according  to 


HOMOLOGUES   OF   BENZOIC  ACID  277 

the  following  reactions  : — (i)  By  reduction  of  homologous  cinnamic 
acids  (q.v.),  which  can  be  readily  prepared  by  Perkins'  reaction  from 
the  aromatic  aldehydes.  (2)  By  the  reduction  of  homologous  almond 
acids,  obtained  from  homologous  phenyl-glyoxylic  acids.  The  latter 
result  upon  oxidising  homologous  acetyl-benzols  with  potassium 
permanganate.  (3)  From  the  alkyl-phenyl  ketones  with  yellow  Am2S. 
(4)  From  alkylised  benzyl  cyanides,  which  are  produced  by  the  action 
of  alkylogens  upon  sodium-benzyl  cyanide.  (5)  By  the  action  of 
benzene  and  aluminium  chloride  upon  aliphatic  lactones  and  olefm- 
carboxvlic  acids. 

y-Phenyl-butyric  acid  C6H5.CH2.CH2.CH2.COOH,  m.p.  517°,  is 
formed  by  the  reduction  of  phenyl-butyro-lactone  or  of  phenyl-crotonic 
acid  (C.  1899,  I.  792)  from  o>-bromo-propyl-benzol,  Mg,  and  CO2  (B.  43, 
1233)  ;  also  from  phenyl-propyl  ketone  with  Am2S  (/.  pr.  Ch.  2, 
80,  197). 

j3-Phenyl-butyric  acid  C6H5(CH3)CH.CH2.COOH,  m.p.  39°,  is  formed 
(i)  by  reduction  of  j8-methyl-cinnamic  acid  (B.  40,  1595)  ;  (2)  from 
crotonic  acid,  benzene,  and  A12C16  (C.  1908,  II.  1023)  ;  (3)  from  phenyl- 
iso-propyl  ketone  with  Am2S  ;  (4)  by  the  disintegration  of  the  addition 
product  of  CH3MgI  and  benzal-malonic  ester  (C.  1905,  II.  1023). 

a-Phenyl-iso-butyric  acid  C6H5C(CH3)2COOH,  m.p.  78°,  b.p.10 150°- 
155°,  from  benzene,  Al  bromide,  and  a-bromiso-butyrie  acid  (C.  1899, 
11.1047). 

j8-Phenyl-iso-butyric  acid,  benzyl-methyl-acetic  acid  C6H5CH2 
CH(CH3)COOH,  m.p.  37°,  b.p.  272°,  is  split  up  by  means  of  its  quinine 
salt  into  optically  active  components  (C.  1902,  I.  661). 

S-Phenyl-valerianie  acid  C6H5(CH2)4COOH,  m.p.  59°,  by  reduction 
of  phenyl-cumalin  with  HI  (B.  29,  1675,  R.  14). 

a-Phenyl-iso-valerianie  acid  (CH3)2CH.CH(C6H5)COOH,  m.p.  59°, 
and  a-methyl-jS-phenyl-butyric  acid  CH3CH(C6H5)CH(CH3)COOH,  m.p. 
132°,  from  iso-propylidene-acetic  acid  and  tiglinic  acid  with  benzene 
and  A12C16  (C.  1908,  II.  noo) .  a-Methyl-y-phenyl-butyrie  acidiC6H5CH0 
CH2CH(CH2)COOH,  m.p.  67°,  from  phenyl-iso-butyl  ketone  and 
Am2S  (/.  pr.  Ch.  2,  80,  198). 

(b)  DERIVATIVES  OF  THE  AROMATIC  MONOCARBOXYLIC  ACIDS. 

The  derivatives  of  benzoic  acid  and  its  homologues  arrange  them- 
selves into  two  groups.  The  first  group  comprises  those  compounds 
resulting  from  the  alteration  of  the  carboxylic  group  (see  Acetic  acid, 
Vol.  I.),  and  the  second  group  the  aromatic  substitution  products  with 
the  exception  of  the  phenol  monocarboxylic  acids.  The  first  group 
divides  itself  into  A,  the  benzoyl-compounds  ;  B,  the  benzenyl  com- 
pounds and  the  derivatives  of  ortho-benzoic  acid.  The  chemistry  of 
no  single  carboxylic  acid  has  been  so  fully  developed  as  that  of 
benzoic  acid. 

BENZOYL  COMPOUNDS. 

i.  ESTERS  OF  THE  MONOBASIC  AROMATIC  ACIDS  (Vol.  I.). — The 
benzoic  esters  of  the  alcohols  and  phenols  can  be  prepared  like  the  acetic 
esters.  Like  the  latter,  they  are  frequently  employed  in  determining  the 
number  of  alcoholic  hydroxyl  groups  present  in  a  compound.  They  are 
formed  (i)  by  the  action  of  hydrochloric  acid  upon  an  alcoholic  solution 


278  ORGANIC  CHEMISTRY 

of  benzole  acid.  In  the  substituted  benzoic  acids  the  following  rule  is 
found  : — Ortho-substituted  acids  take  a  longer  time  to  esterify  than 
m-  and  p-substituted  acids  (Z.  physik.  Ch.  24,  221).  In  the  diortho- 
substituted  acids,  like  mesit3dene-carboxylic  acid,  2,  6-dibromo-, 
2,  4,  6-tribromo-,  and  2,  4,  6-trinitro-benzoic  acid,  the  ester  formation 
is  usually  so  slow  on  boiling  with  alcohol  and  HC1  that  it  is  practically 
non-existent  (B.  28, 1468  ;  29, 1399,  2301  ;  33,  2026  ;  42,  317  ;  C.  1901, 
II.  1117).  But  the  ester  formation  is  easily  accomplished  by  heating 
these  acids  to  i8o°-20O°  with  alcohol,  even  without  a  catalyser 
(Z.  physik.  Ch.  66,  275).  The  esters  of  these  acids  are  also  obtained 
readily  (2)  from  the  silver  salts  with  halogen  alkyls,  or  the  alkali  salts 
with  dimethyl  sulphate  ;  (3)  by  treating  with  diazo-methane  (B.  31, 
501).  Furthermore,  the  esters  of  benzoic  acid  are  produced  (4)  by  the 
action  of  benzoyl  chloride  or  benzoic  anhydride  upon  alcohols,  alco- 
holates,  phenols,  and  phenolates.  In  carrying  out  the  second  reaction 
it  is  advisable  gradually  to  add  sodium  hydroxide,  and  shake  the 
alkaline,  aqueous  solution  of  the  alcohols  with  benzoyl  chloride  until 
there  is  a  permanent  alkaline  reaction  (Baumann,  B.  19,  3218).  In  this 
manner,  also,  the  benzoyl  ethers  of  the  poly-alcohols,  the  polyoxy- 
aldehydes — e.g.  of  the  glucoses — have  been  obtained,  and  nearly  all 
have  been  completely  benzoylated  (B.  22,  R.  668). 

Methyl-benzole  ester  boils  at  199°.  The  ethyl  ester  boils  at  213° ;  the 
n-propyl  ester  at  229°;  the  n-butyl  ester  at  247°.  Glyeol  dibenzoate 
melts  at  73°  (B.  23,  2498).  Glycerol  tribenzoate  melts  at  76°  (B.  24, 
779  ;  C.  1902, 1. 1224).  Erythrol  tetrabenzoate  melts  at  187°.  Mannitol 
hexabenzoate  melts  at  124°.  Glucose  pentabenzoate  melts  at  179°. 

Methylene  dibenzoate  CH2(OCOC6H5),  m.p.  96°,  by  heating  benzoyl 
chloride  with  trioxy-methylene  and  zinc  chloride,  an  intermediate  pro- 
duct being  C1.CH2OCOC6H5  (C.  1901,  II.  396,  682). 

Benzoyl-glyeollie  acid  C6H5CO.OCH2.CO2H  consists  of  large  prisms. 
It  results  when  nitrous  acid  acts  upon  hippuric  acid.  Phenyl-benzoic 
ester  melts  at  71°  and  boils  at  314°  (A.  210,  255  ;  B.  24,  3685).  The 
benzyl  ester  melts  at  20°  and  boils  at  323°  (B.  20,  647).  It  occurs  in 
Peru  balsam  (A.  152,  130).  For  the  benzoyl  compounds  of  the  homo- 
logous phenols,  see  Phenols. 

0-,  m-  and  p-Toluie  methyl  esters,  b.p.  213°  and  221°,  m.p.  34° 
(C.  1901,  II.  290). 

Phenyl-acetic  ethyl  ester  C6H5CH2COOC2H5,  b.p.  226°,  from  benzyl 
cyanide,  alcohol,  and  HC1  (A.  296,  361).  Phenyl  ester,  m.p.  38°,  b.p.15 
1 80°.  Phenyl-acetic  ester  adds  itself  to  aj3-unsaturated  ketones  and 
acid  esters  (B.  42,  4496)  With  ethyl  nitrate  and  potassium  ethylate 
it  gives  phenyl-nitro-acetic  ester  C6H5CH(NO2)COOR,  which  easily 
eliminates  the  carbox-ethyl  group  and  forms  phenyl-nitro-methane. 
With  ethyl  nitrite  and  K  ethylate,  iso-nitro-phenyl-acetic  ester  is 
formed  (B.  42,  1930).  jS-Phenyl-propionic  ethyl  ester,  b.p.  248°. 

2.  AROMATIC  ACID  HALOIDS  OR  HALOID  ANHYDRIDES  OF  THE 
AROMATIC  ACIDS. — The  methods  pursued  in  the  preparation  of  these 
bodies  are  similar  to  those  employed  for  the  corresponding  fatty 
derivatives. 

Benzoyl  chloride  C6H5.COC1,  melting  at  — 1°  and  boiling  at  198°, 
is  isomeric  with  the  chlorinated  benzaldehydes  C1.C6H4.CHO.  It  is  a 
liquid  with  penetrating  odour.  It  is  formed  from  benzoic  acid,  phos- 


BENZOYL  COMPOUNDS  279 

phorus  pentoxide,  and  hydrochloric  acid  (B.  2,  80) ;  from  benzaldehyde 
and  chlorine  ;  from  sodium  benzoate  and  phosphorus  oxy-chloride  ; 
and  from  benzoic  acid  and  phosphorus  pentachloride.  The  action  of 
phosgene  and  aluminium  chloride  or  oxalyl  chloride  (B.  41,  3566)  upon 
benzene  hydrocarbons,  and  of  anhydrous  oxalic  acid  upon  benzo- 
trichloride  (A.  226,  20),  are  only  applicable  in  the  preparation  of  the 
chlorides  of  benzene-carboxylic  acids. 

With  antimony  chloride,  benzoic  acid  combines  to  form  C6H5COOH. 
SbQ5,  m.p.  71°,  which,  on  heating,  yields  benzoyl  chloride  (B.  35, 
1117). 

The  history  of  benzoyl  chloride,  the  first-discovered  chloride  of  a 
carboxylic  acid,  was  given  in  connection  with  the  fatty  acid  chlorides 
(I.  257).  Benzoyl  chloride  is  readily  accessible  and  very  reactive  ;  it 
is  therefore  one  of  the  most  frequently  used  compounds  in  various 
reactions. 

o-,  m-,  and  p-Toluyl  chlorides  boil  at  212°,  220°,  and  95°  (10  mm.) 
respectively.  Phenyl-acetyl  chloride  C6H5.CH2COC1  boils  at  102° 
(17  mm.)  (B.  20,  1389). 

Benzoyl  bromide  C6H5.COBr,  melting  about  o°  and  boiling  at  218°, 
results  from  the  action  of  phosphorus  tribromide  upon  benzoic  acid 
(B.  14,  2473).  Benzoyl  iodide,  consisting  of  crystalline  flakes,  is  pro- 
duced when  potassium  iodide  or  magnesium  iodide  acts  upon  benzoyl 
chloride  (B.  3,  266  ;  C.  1909,  II.  1132).  Benzoyl  fluoride,  from  benzoyl 
chloride  and  AgF,  boils  at  145 °. 

So  far  as  concerns  properties,  benzoyl  azimide  or  benzoyl  nitride,  to 
be  treated  later  in  connection  with  benzoyl-hydrazin,  attaches  itself  to 
the  halogen  anhydrides  of  benzoic  acid. 

The  acid  chlorides  and  haloid  anhydrides  connect  the  mixed 
anhydrides  of  aromatic  acids  with  inorganic  acids. 

Benzoyl  nitrate  C6H5COONO2,  a  light  yellow  oil,  is  formed  by  the 
transformation  of  benzoyl  chloride  with  silver  nitrate  at  low  tempera- 
tures. On  heating,  it  decomposes  into  nitric  oxides  and  benzoic 
anhydride.  Water  decomposes  it  into  benzoic  and  nitric  acids.  It 
nitrifies  aromatic  substances  (B.  39,  3798). 

Benzoyl  nitrite  C6H5COONO,  an  unstable  oil,  from  silver  benzoate 
and  nit  rosy  1-chloride  (C.  1904,  II.  511). 

Benzoic-boric  anhydride  (C6H5COO)3B,  m.p.  145°,  by  heating 
benzoic  acid  with  aceto-boric  anhydride  (B.  36,  2224). 

Benzoic-arsenic  anhydride  (C6H5COO)3As,  m.p.  155°,  on  melting 
benzoic  acid  with  aceto-arsenic  anhydride  (C.  1906,  I.  21). 

3.  ACID  ANHYDRIDES  (I.  259). — Benzoic  anhydride  (C6H5.CO)2O, 
melting  at  42°  and  boiling  at  360°,  is  obtained  from  benzoyl  chloride 
and  sodium  benzoate  or  silver  benzoate  ;  from  benzoyl  chloride  and 
benzo-trichloride  upon  digesting  them  with  anhydrous  oxalic  acid  ; 
from  benzoyl  chloride  by  means  of  lead  nitrate  (B.  17,  1282)  or  sodium 
nitrite  (B.  24,  R.  371) ;  and  by  the  action  of  concentrated  sulphuric  acid 
upon  benzo-trichloride  (B.  12,  1495). 

Mixed  anhydrides  are  obtained  from  benzoic  acid  treated  with 
anhydrides  of  acid  chlorides,  pyridin  or  quinolin  (C.  1901,  I.  347  ; 
B.  42,  3483).  Aceto-benzoic  anhydride  C6H5.COOCOCH3,  m.p.  10°, 
b.p.17  I25°-I40°,  decomposes,  on  heating,  into  acetic  acid  and 
benzoic  acid. 


280  ORGANIC  CHEMISTRY 

Benzoic-earbonie  anhydride  (C6H6COO)  2CO,  an  oil,  from  benzoic 
acid,  COC12,  and  pyridin,  yields  CO2  even  at  ordinary  temperatures. 

o-  and  p-Toluic  anhydride,  m.p.  37°  and  95°.  Phenyl-aeetie  anhy- 
dride (C6H5CH2CO)2O,  m.p.  72°  (B.  20,  1391). 

4.  ACID  PEROXIDES.  —  BenzoyI  peroxide  (C6H5CO)2O2,  melts  at  103° 
and  deflagrates  when  heated.  It  is  formed  from  benzoyl  chloride  and 
barium  peroxide,  or  from  benzoyl  chloride,  hydrogen  peroxide,  and 
sodium  hydrate  (B.  27,  1511  ;  29,  1727  ;  30,  2003  ;  33,  1043).  On 
treating  an  ether  solution  of  benzoyl  peroxide  with  sodium  alcoholate, 
benzoic  ester  is  produced,  together  with  benzoyl-sodium-hydrogen 
peroxide  : 


(C6H6CO)2O2      a'-V  C6H6COOC2H5+C6H5COOONa  ; 

from  the  latter,  even  carbonic  acid  liberates. 

Benzoyl-hydrogen  peroxide  C6HsCOOOH,  m.p.  4i°-43°.  It  closely 
resembles  hydrogen  peroxide.  A  mixture  of  benzoyl-hydrogen  peroxide 
and  benzaldehyde  gives  first  two  molecules  benzoic  acid.  Probably 
it  is  also  formed  in  the  first  phase  during  the  auto-oxidation  of  benzalde- 
hyde in  air  ;  a  mixture  of  benzaldehyde  and  acetic  anhydride  forms, 
under  the  influence  of  atmospheric  oxygen,  benzoyl-aeetyl  peroxide 
C6H5COOOCOCH3,  m.p.  38°,  by  acetylation  of  the  benzoyl-hydrogen 
peroxide  first  formed  (B.  33,  1569  ;  C.  1902,  I.  930). 

5.  Tmo-  ACIDS  AND  BiTHio-AciDS.  —  Thio-benzoic  acid  C6H5COSH, 
m.p.  24°,  is  formed  by  the  interaction  of  benzoyl  chloride  and  alcoholic 
potassium  sulphide  ;    also,  besides  triphenyl  carbinol,  from  phenyl- 
magnesium   bromide   with   COS    (B.    36,    1010).     Thio-p-toluie   acid 
CH3C6H4COSH,  m.p.  44°. 

Benzoyl  sulphide,  thio-benzoic  sulphanhydride  (C6H5CO)2S,  m.p.  48°, 
from  two  molecules  benzoyl  chloride  with  one  molecule  sodium  sulphide 
(B.  40,  2862).  Benzoyl  disulphide  (C6H5CO)2S2,  m.p.  130°,  from  thio- 
benzoic  acid  on  oxidation  in  ether  solution  by  atmospheric  oxygen 
(A.  115,  27),  or  from  its  salts  on  oxidation  by  potassium  ferricyanide 
(B.  40,  2862).  Thio-benzamide  and  thio-anilide,  see  below. 

Dithio-benzoic  acid,  phenyl-carto-thio-acid  C6H5CSSH,  a  heavy 
purple  oil,  rather  unstable,  obtained  from  benzo-trichloride  with 
alcoholic  potassium  sulphide  (A.  140,  240)  ;  from  phenyl-magnesium 
bromide  and  CS2  (B.  39,  3219)  ;  as  well  as  by  the  action  of  hydrogen 
persulphide  and  zinc  chloride  upon  benzaldehyde  (C.  1909,  II.  1780). 
Methyl  ester,  b.p.  155°  ;  ethyl  ester,  b.p.  167°  ;  luminous  red  oils. 
The  lead  salt  consists  of  purple  flakes,  melting  at  204-5°.  The  alkali- 
salt  solution  gives,  by  oxidation  with  iodine,  thio-benzoyl  disulphide 
(C6H5CS)2S2,  m.p.  117°,  dark-red  needles.  Dithio-phenyl-aeetie  acid 
CeH5CH2CSSH,  a  reddish-yellow  oil,  from  benzyl-magnesium  chloride 
with  CS2.  Lead  salt,  m.p.  149°,  yellow  needles. 

Phenyl-thio-acetyl  disulphide  (C6H5CH2.CS)2S2,  m.p.  78°  (B.  39, 
3227). 

Phenyl-p-tolyl-keto-sulphone  C6H5CO.SO2C6H4CH3,  from  benzoyl 
chloride  and  sodium-toluol  sulphinate,  forms  a  hydrate  of  m.p  80° 
(C.  1899,  II.  719). 

6.  ACID  AMIDES.  —  The  methods  of  formation  and  the  behaviour  of 
the  acid  amides  have  been  sufficiently  considered  in  connection  with 
the  fatty  acid  amides.     Attention  was  also  called  to  the  fact  that  the 


BENZOYL  COMPOUNDS  281 

amides  of  the  carboxylic  acids  could  have  two  constitution  formulae. 
Thus,  benzamide  has  two  formulae  : 


I.  C8HSC<  ™«    and    II. 


The  imido-ethers  are  derived  from  the  second  formula  (see  Silver 
benzamide).  To  the  methods  mentioned  under  the  amides  of  the 
fatty  acids  must  be  added,  in  connection  with  the  amides  of  the 
benzol-carboxylic  acids,  their  formation  through  the  action  of  alumi- 
nium chloride  upon  aromatic  hydrocarbons  and  urea  chlorides. 

Benzamide  C6H5.CO.NH2,  melting  at  130°  and  boiling  at  288°, 
results  (i)  when  benzoyl  chloride  is  acted  upon  by  gaseous  or  aqueous 
ammonia,  or  by  ammonium  carbonate  (see  Tribenzamide)  ;  (2)  from 
benzoic  ester  and  ammonia  ;  (3)  by  heating  benzoic  acid  and  ammo- 
nium thio-cyanate  to  170°  (A.  244, 50) ;  (4)  by  saponification  of  benzo- 
nitrile  with  an  appropriate  amount  of  alcoholic  potash  (C.  1900, 1.  257)  ; 
(5)  from  urea  chloride,  benzene,  and  A1C13  (A.  244,  50).  It  crystallises 
in  pearly  flakes,  melts  at  130°,  and  boils  near  288°.  It  is  readily  soluble 
in  hot  water,  alcohol,  and  ether. 

Sodium  benzamide  C6HsCONHNa  or  C6H5C(:  NH)ONa  results  from 
the  action  of  metallic  sodium  upon  benzamide  dissolved  in  benzene 
(B.  23,  3038).  On  heating  with  acid  esters  it  forms  mixed  diacyl- 
imides  (B.  23,  3038  ;  C.  1900,  II.  190  ;  1903,  I.  157). 

Silver  benzamide  C6H5.CO.NHAg  or  C6H5.C(:  NH).O.Ag,  obtained 
by  precipitating  the  aqueous  solution  of  benzamide  and  silver  nitrate 
with  a  calculated  amount  of  sodium  hydroxide,  is  a  white  crystalline 
powder.  When  digested  with  ethyl  iodide  it  yields  benzimido-ethyl 
ether  (B.  23,  1550). 

Dibenzamide  (C6H5CO)2NH,  melting  at  148°,  is  obtained  from  benzo- 
nitrile  with  fuming  sulphuric  acid,  or  from  benzoyl  chloride  and  benzo- 
nitrile  with  aluminium  chloride.  When  distilled  under  a  pressure  of 
15  mm.  dibenzamide  breaks  down  into  benzo-nitrile  and  benzoic  acid 
(B.  21,  2389).  Sodium  dibenzamide  (C6H5CO)  2NNa  is  a  shining  white 
powder.  It  is  formed  when  sodium  acts  upon  dibenzamide  dissolved 
in  xylol. 

Tribenzamide  (C6H5CO)3N,  melting  at  202°,  results  in  the  action  of 
benzoyl  chloride  in  ethereal  solution  upon  sodium  dibenzamide,  and 
together  with  benzamide  and  dibenzamide  when  benzoyl  chloride  acts 
upon  ammonium  carbonate  (B.  25,  3120). 

Benzoyl-chlorimide  C6H5CONHC1  melts  at  113°.  Benzoyl-bromimide 
C6H5.CONHBr  melts  with  decomposition  at  170°.  Dibenzamide 
chloride  (C6H5CO2)2NC1,  m.p.  89°  (C.  1902,  II.  359).  Methyl-  and 
dimethyl-benzamide  C6H5CON(CH3)2  melt  at  78°  and  41°. 

N-methylol-benzamide  C6H5CO.NH.CH2OH,  m.p.  106°,  from  benz- 
amide and  formaldehyde,  under  the  influence  of  alkaline  condensing 
agents.  On  heating  alone,  or  in  aqueous  solution,  it  easily  dissolves 
into  its  components.  Chromic  acid  oxidises  it  to  formyl-benzamide 
C6H5CONHCHO,  m.p.  120°.  With  phenyl-hydrazin  the  latter  gives 
2, 5-diphenyl-triazol  (q.v)  (A.  343,  223).  Benzoyl-benzylamine  C6H5CO. 
NH.CH2C6H5,  m.p.  105°  (B.  26,  2273). 

We  get  benzanilide  C6H5.CO.NH.C6H5,  phenyl-benzamide,  on  mixing 
aniline  and  benzoyl  chloride.  It  can  also  be  made  by  the  action  of 


282  ORGANIC   CHEMISTRY 

aluminium  chloride  upon  benzene  and  carbanile,  and  upon  heating 
benzo-phenoxime  (C6H5)2C  :  N.OH  with  concentrated  sulphuric  acid, 
acetyl  chloride,  or  glacial  acetic  acid  containing  hydrochloric  acid,  to 
100°,  or  with  glacial  acetic  acid  alone  to  180°  (B.  20,  2581).  Sodium 
benzanilide,  see  C.  1900,  II.  190. 

When  benzanilide  is  boiled  with  sulphur  it  becomes  benzenyl-amido- 
thio-phenol  or  ju,-phenyl-benzo-thiazole.  o~,  m-,  and  p-Benzoyl-toluides 
C6H6CONH.CeH4CH8  melt  at  131°,  125°,  and  158°. 

Diphenyl-benzamide  C6H5CO.N(C6H5)2,  m.p.  177°,  results  from 
diphenyl-amine  and  benzoyl  chloride,  as  well  as  from  diphenyl-urea 
chloride  :  (i)  by  condensation  with  benzene  and  aluminium  chloride 
(B.  20,  2119)  ;  (2)  by  heating  with  benzoic  acid  in  pyridin  solution 
(B.  41,  636). 

Methylene-dibenzamide,  hipparaffin  CH2(NH.CO.C6H5)2,  m.p.  221°, 
is  obtained  in  the  oxidation  of  hippuric  acid  with  PbO2  and  dilute 
sulphuric  or  dilute  nitric  acid,  and  results  from  formaldehyde,  benzo- 
nitrile,  and  hydrochloric  acid  (B.  25,  311) ;  or  from  boiling  benzamide 
with  formaldehyde  and  dilute  sulphuric  acid  (A.  343,  226). 

Ethylidene-dibenzamide  CH3.CH(NHCOC6H5)2,  m.p.    204°  (B.    7, 

159). 

Ethylene  -  dibenzamide    C6H5CO.NH.CH2.CH2.NH.CO.C6H5,    m.p. 

249°,  when  heated  alone,  or  with  hydrochloric  acid,  yields  ethylene- 
benzenyl-amidine,  benzoic  acid  splitting  off  at  the  same  time  (B. 
21,  2334). 

Benzoyl-iso-cyanate,  carbonyl-benzamide  C6H5CON  :  CO,  m.p.  26°, 
b.p.10  88°,  from  silver  cyanate  and  benzoyl  chloride,  yields  dibenzoyl- 
urea  in  water,  and  benzoyl-urethane  C6H5CONH.CO2C2H5,  m.p.  m°, 
in  alcohol  (B.  36,  3218). 

Hippuric   acid,    benzoyl-gfycocoll   CHa/NH-cac6H6,  m.p.  187°,  de- 

\CO2H 

composes  at  240°  into  benzoic  acid,  benzo-nitrile,  and  prussic  acid.  It 
occurs  in  considerable  amount  in  the  urine  of  herbivorous  animals,  in 
that  of  the  cow  and  horse  ("TTTTOS,  horse,  and  ovpov,  urine),  and  in 
minute  quantities  in  that  of  man.  Benzoic  acid,  cinnamic  acid,  toluol, 
and  other  aromatic  substances,  when  taken  internally,  are  eliminated 
as  hippuric  acid.  It  can  be  obtained  artificially  (i)  by  heating  benz- 
amide with  monochloracetic  acid  ;  (2)  by  the  action  of  benzoyl  chloride 
or  silver  gly co-collide  (B.  15,  2740) ;  or  (3)  by  adding  sodium  hydroxide 
to  glycocoll,  and  shaking  with  benzoyl  chloride  (B.  19,  R.  307) ;  and 
(4)  by  heating  benzoic  anhydride  with  glycocoll  (B.  17,  1662). 

History. — Liebig,  in  1829,  recognised  that  hippuric  acid  was  a  dif- 
ferent body  from  benzoic  acid,  and,  to  indicate  its  origin,  named  it  hip- 
puric acid.  In  1839  he  established  its  constitution.  Dessaignes  (1846) 
showed  that,  upon  boiling  with  strong  alkalies  or  acids,  it  was  resolved 
into  glycocoll  and  benzoic  acid  (/.  pr.  Ch.  i,  37,  244).  In  1848 
Strecker  converted  the  acid  by  means  of  nitrous  acid  into  benzoyl- 
glycollic  acid  (A.  68,  54),  and  in  1853  Dessaignes  synthesised  hippuric 
acid  from  benzoyl  chloride  and  zinc  glyco-collide  (A.  87,  325). 

Hippuric  acid  crystallises  in  rhombic  prisms,  and  dissolves  in  600 
parts  cold,  and  readily  in  hot  water,  and  alcohol.  Boiling  acids,  or 
alkalies,  decompose  hippuric  acid  into  benzoic  acid  and  glycocoll. 

Compare  hipparaffin  (above),  benzoyl-glycollic  acid,  for  other  trans- 


BENZOYL   COMPOUNDS  283 

formations  of  hippuric  acid.     Hippuric  acid  condenses  with  benzalde- 
hyde,  sodium  acetate,  and  acetic  anhydride  to  benzoyl-amido-cinnamic 

anhydride  C8H5CH  .-  ^^^^  (A.  337,  265). 

Silver  salt  C9HsAgNO3.  The  ethyl  ester  melts  at  60°  (/.  pr.  Ch.  v, 
15,  247).  It  is  converted  by  PC15  into  hippuro-flavin  C1SH10O4N2, 
consisting  of  citron-yellow  crystals  (B.  21,  3321  ;  26,  2324  ;  A.  312,  81). 
Benzaldehyde  and  sodium  acetate  change  it  to  benzoyl-amido-cinnamic 
ester  (A.  275,  12).  The  phenyl  ester  melts  at  104°.  When  boiled  with 
POC13  it  passes  into  anhydro-hippuric  phenyl  ester,  melting  at  42° 
(B.  26,  2641). 

With  formic  acid  ester  and  sodium  ethylate,  hippuric  ethyl  ester 
condenses  to  formyl-hippuric  ester  C6H5CO.NH.CH(CHO)CO2C2H5, 
which  is  reduced  by  sodium  amalgam  to  benzoyl-serinic  ester  C6H5CO. 
NH.CH(CH2OH)C02C2H5,  m.p.  80°.  The  latter  is  split  up  by  H2SO4 
into  benzoic  acid  and  i-serin  ;  with  P2S5  it  passes  into  benzoyl-eystein 
ester  C6H5CONH.CH(CS2SH)C02C2H5,  m.p.  185°,  from  which,  by 
saponification  with  concentrated  HC1,  we  obtain  i-cyste'in,  or  its  oxida- 
tion product,  i-cystin  (cp.  Vol.  I.,  and  A.  337,  236). 

Hippuric  acid  nitrile  C6H5CONHCH2CN,  m.p.  144°,  from  amido- 
aceto-nitrile,  benzoyl  chloride,  and  NaHO  (B.  36,  1646).  Hippuryl- 
hydrazin  C6H5CO.NHCH2CO.NH.NH2,  m.p.  162°,  from  hippuric  ethyl 
ester  and  hydrazin  ;  cp.  hippuryl-phenyl-buzylene  and  hippurazide 
(B.  29,  R.  181). 

Benzoyl-alanin  C6H5CONH.CH(CH3)COOH,  m.p.  166°,  and  benzoyl- 
a-amido-iso-butyric  acid  C6H5CONHC(CH3)2COOH,  m.p.  198°,  on 
heating  with  acetic  anhydride,  readily  pass  into  anhydrides  resembling 

/^   TT  r*  _  TO— 

lactone  :  benzoyl-alanin  anhydride        5oZco/CH^CH3^  m-p-  39°>  and 


benzoyl-a-amido-iso-butyric  anhydride  ^/^01*3^'  m-P-  34°  (CP- 


the  similarly  constituted  acyl-anthranilic  acids).  Ammonia,  aniline, 
and  HC1  burst  the  lactone  ring,  with  formation  of  the  amides,  anilides, 
and  chlorides  of  the  corresponding  benzoyl-amido-acids.  With  a- 
amido-acids  they  similarly  combine  to  form  benzoylated  dipeptides, 
e.g.  benzoyl-alanyl-glycocoll  C6H5CONH.CH(CH3)CONHCH2COOH, 
Benzoyl-alanyl-alanin  C6H5CONH.CH(CH3)CONH.CH(CH3)COOH, 
etc.  (J.pr.  Ch.  2,81,49,473) 

Benzoyl-asparaginic  acid,  see  B.  43,  661. 

7.  ACID  HYDRAZIDES.  —  Benzoyl-hydrazin  C6H5CONHNH2,  m.p. 
112°,  from  benzoic  ester  and  hydrazin  hydrate,  or  by  heating  hydrazin 
benzoate  (B.  35,  3240)  ;  in  alkaline  solution  benzoyl-hydrazin  suffers 
an  auto-reduction,  leading  to  benzai-benzoyl-hydrazin  C6H5CONHN  : 
CHC6H5,  and  subsequently  benzalazin  (B.  33,  2561).  With  excess  of 
benzoic  ester  hydrazin  forms  dibenzoyl-hydrazin  (C6H5CO.NH)2,  m.p. 
238°,  also  generated  by  the  action  of  benzoyl  chloride  upon  alkaline 
hydrazin  solutions  (C.  1899,  I.  1240).  On  boiling  with  alcoholic  potash, 
it  yields  a  potassium  salt  (C6H5CO)2N2HK  ;  the  corresponding  silver 
salt  with  iodine  gives  azo-dibenzoyl  (C6H5CO)2N2,  m.p.  118°  (B.  33, 
1769).  Tri-  and  tetrabenzoyl-hydrazin,  m.p.  206°  and  238°,  are  ob- 
tained by  further  benzoylation  of  dibenzoyl-hydrazin  (C.  1904,  II.  97). 

Sym/benzoyl-phenyf-hydrazin,  m.p.  168°  (B.  19,  1203),  on  oxidation 


284  ORGANIC  CHEMISTRY 

with  mercuric  oxide  or  nitrous  acid  is  converted  into  benzoyl-azo- 
benzolC6H5CON2C6H5,  red  prisms,  melting  at  80°  (C.  1909,  II.  84)  ;  the 
latter  gives  with  HC1  an  addition  product  which  changes  into  o-chloro- 
phenyl-benzoyl-hydrazin  (B.  30,  319)  : 

CCH5CONH.NC1C6H5  ---  >  C6H5CONHNH[i]C6H4[2]Cl. 

Unsym.  benzoyl-phenyl-hydrazin,  m.p.  70°  (B.  26,  945,  R.  816). 

Dibenzoyl-phenyl-hydrazinC6H5.CO.N(C6H5).NHCOC6H5,  m.p.  177°. 

Benzal-benzoyl-hydrazin  C6H5CO.NHN.CHC6H4,  m.p.  203°,  from 
benzoyl-hydrazin  and  benzaldehyde,  or  from  benzalazin  with  benzoyl 
chloride  (C.  1900,  1.  334).  The  corresponding  silver  salt  C6H5CONAgN  : 
CHC6H5  passes  with  iodine  into  diphenyl-furo-diazol 


and   with    benzoyl   chloride   into    diphenyl-benzoyl-dihydro-furo-diazol 


Phenyl-acetic  hydrazide,  m.p.  116°. 

Hydro-cinnamic  hydrazide,  m.p.  103°. 

8.  ACIDYL  -  AZIDES.  —  Benzoyl  -  azide,     benzoyl     nitride,     azimide, 

,N 
C,H6CON<  ||,   m.p.   20°,  is  formed  when  sodium  nitrite,   and   acetic 

XN 

acid,  act  upon  benzoyl-hydrazin  (B.  23,  3023).  Its  odour  is  intensely 
like  that  of  benzoyl  chloride  ;  it  volatilises  in  part  with  aqueous  vapour 
without  decomposition,  and  explodes  with  slight  detonation  upon  the 
application  of  heat.  It  is  insoluble  in  water,  very  soluble  in  ether,  and 
rather  readily  soluble  in  alcohol.  It  gives  a  neutral  reaction.  It 
breaks  down,  on  boiling  with  alkalies,  into  benzoic  acid  and  potassium 
azo-imide  (B.  23,  3029).  On  heating  in  benzene  solution  it  is  clearly 
divided  up  into  N2  and  phenyl  iso-cyanate  : 

/N 
C6H5CON<  ||   -  >  [C6H5CON<]  -  >  C6H5N  :  C  :  O 

XN 

(B.  42,  2339). 

Heating  with  alcohol  and  water  leads  to  the  evolution  of  N2,  and 
the  formation  of  the  transformation  products  of  phenyl  iso-cyanate  : 
phenyl-urethane  C6H5NH.CO.OC2H5,  and  carbanilide  CO(NHC6H5)2. 
Boiling  with  acid  hydrazides  yields  acidylated  semi-  car  bazides  (B.  29, 
R.  981)  : 

C6H5CON3+C6H5CONHNH2  ==  N2+C6H5NHCONHNHCOC6H5 

and  p-bromo-benzazide,  m.p.  46°  (/.  pr.  Ch.  2,  58,  190).  Phenyl- 
acetic  azide  C6H5CH2CON3  and  hydro-einnamic  azide  C6H5CH2CH2 
CON3  with  alcohol  yield  the  urethanes  of  benzyl-amine  and  phenyl- 
ethyl-amine  (/.  pr.  Ch.  2,  64,  297).  The  azides  can  also  be  obtained 
by  the  action  of  salts  of  diazo-benzol  upon  the  acid  hydrazides. 

Hippurazide  C6H5CO.NH.CH2.CO.N3,  m.p.  98°,  results  when  sodium 
nitrite  and  acetic  acid  act  upon  hippuryl-hydrazin.  It  is  decomposed 
by  mineral  acids,  alkalies,  ammonia,  and  amines,  with  the  elimination 
of  hydr  azoic  acid.  When  boiled  with  alcohols,  and  with  water,  N2  is 
evolved,  and  there  result  hippenyl-urethane  C6H5CONHCH2NHCOOR 
and  dihippenyl-urea  (C6H6CONHCH2NH)2CO  (B.  29,  R.  183). 


BENZOYL  COMPOUNDS  285 

The  action  of  hippurazide  upon  glycocoll,  glycyl-glycin,  alanin,  etc. 
(Vol.  I.),  gives  the  benzoyl  derivatives  of  di-  and  poly-peptides,  like 
C6H5CONHCH2CONHCH2COOH,  C6H5CONHCH2CONHCH2CO.NH 
CH2COOH,  C8H5CONHCH2CONHCH2CONHCH2CONHCH2COOH 
(/.  pr.  Ch.  2,  70,  57). 

9.    NlTRILES     OF     THE     AROMATIC     MONOCARBOXYLIC    ACIDS. — The 

aromatic  nitriles  are  connected  by  numerous  reactions  with  the  prin- 
cipal classes  of  the  aromatic  derivatives.  They  are  produced,  like  the 
nitriles  of  the  fatty  acids,  (i)  from  the  corresponding  ammonium  salts  ; 
(2)  from  the  corresponding  acid  amides,  by  the  withdrawal  of  water 
with  P2Os,  PC16,  and  SOC12  (B.  26,  R.  401)  ;  (3)  by  action  of  bromine, 
and  caustic  alkali,  upon  the  primary  phenyl-alkyl-amines ;  (4)  from  the 
aldoximes  by  the  action  of  acetyl  chloride  or  acetic  anhydride.  There 
is  also  (5)  the  method  of  distilling  aromatic  monocarboxylic  acids,  with 
potassium  sulpho-cyanide,  or,  better,  with  lead  sulpho-cyanide  (B. 
17,  1766)  : 

2C6H5C02H+(CNS)2Pb  =  2C6H5CN+2C02+PbS+H2S. 

Nuclear  -  synthetic  Methods. — (6)  The  direct  replacement  of  the 
halogens  in  the  benzol  hydrocarbons  by  the  cyanogen  group  is  of 
exceptional  occurrence  —  e.g.  when  chloro-  and  bromo- benzol  are 
conducted  over  strongly  ignited  potassium  ferrocyanide,  or  when 
benzol  iodide  is  heated  to  300°  with  silver  cyanide,  the  product  being 
cyano-benzol. 

However,  the  phenyl-carbinol  chlorides — e.g.  C6H5CH2C1 — are  as 
readily  transposed,  as  the  alkylogens,  into  nitriles  of  the  phenyl-fatty 
acids  by  means  of  potassium  cyanide. 

The  nitriles  are  also  intimately  related  to  the  anilines,  sulphonic 
acids,  and  phenols.  Thus,  aniline  yields  (7)  phenyl-carbylamine, 
which,  upon  the  application  of  heat,  is  rearranged  into  the  isomeric 
nitrile.  They  are  also  produced  (8)  on  heating  the  diphenyl-thio-ureas 
with  zinc  dust ;  (9)  by  desulphurising  the  phenyl-mustard  oils  with 
copper  ;  (10)  by  distilling  the  formanilides  with  concentrated  hydro- 
chloric acid  or  with  zinc  dust  (B.  17,  73)  ;  (n)  by  decomposing  diazo- 
benzene  chloride  with  potassium  cyanide  and  copper  sulphate. 


(7) 

(8) 

C6H5NH,    (9) 


10 


(ii) 


C6H6NC 


(C6H5NH)2CS 


C6H6N  :  CS 


— C.H.NH, 
— S 


C6H6NH.CHO 


C6H5N:NC1 


KCN 


C6H5.C=N. 


— N, 


(12)  By  distilling  the  alkali-benzene  sulphonates  with  potassium  cya- 
nide or  yellow  prussiate  of  potash  ;  (13)  the  distillation  of  the  triphenyl 
phosphates  with  potassium  cyanide  or  ferrocyanide  ;  (14)  alkyl  benzyl- 
cyanides  are  formed  by  the  interaction  of  sodium-benzyl  cyanide  and 
alkylogens,  C6H5.CHNa.CN+C2H5I  =  C6H5CH(C2H5)CN ;  (15)  the 
hydrogen  atoms  of  the  benzols  are  directly  replaced  by  the  cyanogen 
group,  (a)  if  cyanogen  gas  be  conducted  into  the  boiling  hydrocarbon 


286  ORGANIC  CHEMISTRY 

mixed  with  aluminium  chloride  (B.  29,  R.  185) ;  (b)  in  the  action  of 
mercury  fulminate  C  :  NOHg  upon  benzene  and  anhydrous  AC13,  benzo- 
nitrile  (80  per  cent.)  is  formed,  while  hydrated  A1C13  leads  to  the  for- 
mation of  benzaldoxime  (B.  36,  10).  On  the  action  of  chlorine  and 
bromine  cyanide  upon  benzene  hydrocarbons  in  the  presence  of  Al 
chloride,  see  B.  33,  1052. 

Properties  and  Behaviour. — The  benzo-nitriles  are  indifferent,  agree- 
ably smelling  liquids,  or  solids  with  low  melting-points.  Their  reactions 
are  very  numerous,  but  it  may  be  mentioned  that  boiling  alkalies  or 
acids  convert  them  into  the  corresponding  aromatic  acids,  while  nascent 
hydrogen,  best  from  alcohol  and  sodium,  changes  them  to  primary 
amines.  They  yield  amide  iodides  with  hydriodic  acid. 

They  combine  with  alcohols  and  HC1  to  form  imido-ethers,  with 
anilines  to  amidines,  and  with  hydroxylamine  to  amidoximes. 

Benzo-nitrile,  cyano-benzol  C6H5.CN,  boiling  at  191°,  with  sp.  gr. 
1-023  (o°)»  is  isomeric  with  phenyl-carbylamine,  and  is  best  obtained 
from  benzene-sulphonic  acid  by  method  12,  or  from  benzoic  acid  by 
method  5.  It  is  an  oil  with  an  odour  resembling  that  of  oil  of  bitter 
almonds. 

When  it  is  dissolved  in  fuming  sulphuric  acid,  or  boiled  with  sodium, 
or  acted  upon  by  other  condensing  agents,  benzo-nitrile  polymerises 
to  cyano-phenin  C3N3(C6H5)3.  Upon  nitration  the  product  is  almost 
exclusively  m-nitro-benzo-nitrile.  For  other  transpositions,  see 
Benzo-imido-ethers  and  Thio-benzamide. 

Alphyl-cyanides :  o-,  m-,  and  p-Tolu-nitriles,  cyano-toluols  CH3. 
C6H4CN  boil  at  203°,  213°,  and  218°.  The  p-body  melts  at  29°. 
p-Xylo-nitrile  boils  at  231°  (B.  18,  1712).  1,  3-Xylo-4-nitrile  melts  at 
24°  and  boils  at  222°  (B.  21,  3082).  Cumo-nitrile  (CH3)2.CH[4]C6H4 
[i]CN  boils  at  244°. 

Nitriles  of  Phenyl-fatty  Acids. — Benzyl  cyanide,  phenyl-aceto-nitrile 
C6H3.CH2CN,  b.p.  232°,  with  specific  gravity  1-014  (IS°),  is  isomeric 
with  the  three  tolu-nitriles.  It  occurs  in  the  ethereal  oil  of  several 
cresses  (Trop&olum  majus  and  Lepidium  sativum)  (B.  7, 1293  ;  32,  2335). 
It  is  artificially  prepared  from  benzyl  chloride  with  potassium  cyanide. 
It  yields  toluic  acid  by  saponification  ;  by  reduction  /3-phenyl-ethyl- 
amine  is  the  product,  and  upon  nitration  it  is  chiefly  p-nitro-benzyl 
cyanide  which  results. 

As  in  aceto-acetic  ester  and  malonic  ester,  the  hydrogen  of  the  CH2 
group,  combined  with  the  negative  groups  C6H5  and  CN,  is  very  readily 
replaced.  Thus,  sodium  ethylate  produces  the  monosodium  deriva- 
tive, which  may  be  transposed  by  alkylogens  to  alkyl-benzyl  cyanides 
(see  method  14)  (B.  21,  1291,  R.  197  ;  22,  1238  ;  23,  2070).  Nitrous 
acid,  acting  upon  a  sodium  ethylate  solution  of  benzyl  cyanide,  pro- 
duces iso-nitroso-benzyl  cyanide  (see  Phenyl-glyoxalic  acid).  Sodium 
ethylate,  acting  upon  benzyl  cyanide  and  benzaldehyde,  produces 
a-phenyl-cinnamic  nitrile  C6H5.C(CN)  :  CH.C6H5  (B.  22,  R.  199).  It 
adds  itself  to  a,  jS-unsaturated  esters  and  ketones  like  Na-malonic 
ester. 

Methyl-benzyl  cyanides,  tolyl-aceto-nitriles  CH3.C6H4.CH2.CN.  The 
o-body  boils  at  244°,  the  m-body  at  241°,  while  the  p-compound 
melts  at  18°  and  boils  at  243°  (B.  18, 1281  ;  21,  1331). 

j3-Phenyl-propio-nitrile,    hydro-cinnamic    nitrile    C6H5CH2CH2CN, 


BENZENYL  COMPOUNDS  287 

b.p.  261°  (corr.)  occurs  in  the  ethereal  oil  of  spring-cress,  Nasturtium 
officinal*  (B.  7,  520  ;  26,  1971). 

a-Phenyl-propio-nitrile,  hydratropic  nitrite  C6H5CH(CH3)CN,  b.p. 
231°  (A.  250,  123,  137). 

In  addition  to  the  benzo-nitriles,  the  classes  of  bodies  10  to  31 
arrange  themselves  with  the  benzenyl  compounds. 

10.  Amido  -  haloids,  n.  1  mido  -  chlorides.  12.  Phenyl  -  hydrazide 
Imido-chlorides. 

Benzamide  chloride  C6H5CC12NH2  (?)  results  when  hydrochloric 
acid  gas  is  conducted  into  an  ether  solution  of  benzo-nitrile  (B.  10, 
1891)  ;  it  is  probably  the  first  product  resulting  from  the  action  of  PC15 
upon  benzamide,  which,  however,  is  partly  split  into  benzo-nitrile  and 
HC1,  while  another  part  unites  with  the  POC13  formed  to  form  phos- 
phuretted  compounds  like  C6H5CC12NHPOC12  and  C6H5CC1  :  NPOC12 
(C.  1909,  II.  814). 

Benzamide  bromide  C6H5CBr2NH2,  m.p.  70°  (A.  149,  307).  Benz- 
amide iodide  C6H5CI2NH2  melts  with  decomposition  (B.  25,  2536)  at 
140°.  It  is  produced  when  benzo-nitrile  is  poured  into  concentrated 
aqueous  hydriodic  acid. 

Dimettiyl-benzamide  chloride  C6H5.CC12.N(CH3)2,  m.p.  36°,  from 
the  amide  with  phosgene  or  PC15.  On  heating,  the  dialkylated  benz- 
amide chlorides  split  off  one  or  two  molecules  of  chloralkyl  and  decom- 
pose into  alkyl-benzimide  chlorides  and  benzo-nitrile,  the  latter  being 
partly  polymerised  to  cyaphenin  (B.  37,  2812)  : 


C6H5CC12N(CH3)2  J  C6H5CC1  :  NCH3          >>  C6H5CN. 

On  the  utilisation  of  this  reaction  for  the  breaking  up  of  cyclic 
secondary  bases,  see  Piperidin. 

Benzanilide  chloro-iodide  C6H5CC1I.NNC6H5,  m.p.  106°  with 
decomposition,  from  benzanilide-imido-chloride  and  HI  (C.  1905,  1.  442). 

Methyl-benzimido-ehloride  C6H5CC1  :  NCH3,  from  methyl-benzamide 
with  PC15. 

Benzanilide-imido-chloride  C6H5CC1  :  N.C6H5,  m.p.  40°  and  b.p.  310°, 
is  produced  when  PC15  acts  upon  benzanilide  (Wallach,  A.  184,  79),  or 
upon  benzo-phenone  oxime  (C6H5)2C=NC1.  Water  or  alcohol  will 
decompose  it  into  hydrochloric  acid  and  benzanilide.  For  other 
transpositions  of  benzanilide-imido-chloride,  compare  thio-  benz- 
anilide, etc. 

When  benzanilide-imido-chloride  acts  upon  sodium  aceto-acetic 
ester,  the  products  are  anil-benzyl  compounds,  /S-ketonic  acid  deriva- 
tives, which  change  to  phenyl-quinolin-carboxylic  acids  upon  the 
application  of  heat. 

Benzo-phenyl-hydrazide-imido-ehloride  C6H5CC1  :  N.NH.C6H§,  m.p. 
131°,  is  formed  when  alcohol  acts  upon  the  reaction  product  of  PC15 
and  sym.  benzoyl-phenyl-hydrazin  C6H5.CC1  :  N.N(C6H5)POC12  (B.  27, 
2122). 

Dibenzo-hydrazide  chloride  C6H6CC1  :  N.N  :  C1CC6H5,  m.p.  123°, 
from  sym.  dibenzoyl-hydrazin  and  PC15.  It  can  easily  be  transformed 
.into  heterocyclic  compounds  :  —  (i)  On  boiling  with  water  it  yields 
diphenyl-furo-diazol  ;  (2)  with  P2S5,  diphenyl-thio-diazol  ;  (3)  with 
ammonia  or  primary  amines,  diphenyl-pyrro-diazols  ;  (4)  with  hydroxyl- 


288  ORGANIC   CHEMISTRY 

amine,  N-oxy-diphenyl-pyrro-diazol ;      (5)   with    hydrazin,    diphenyl- 
dihydro-tetrazin  (/.  pr.  Ch.  2,  73,  277)  : 

Diphenyl-furo- 
Diphenyl-thio- 

^N— N\ 
\C1    Cl/ 


NH, 


__  r,^N.N\_  oDiphenyl-pyrro- 

6    sC\NH  /CC«H5          [bbj-diazol 


„     //N.N=\r  N-Oxy-c-diphenyl- 

6^\N(OH)/      8    6    pyrro-CbbJ-diazol 
NH2.NH,     r  M  r/N  -  N\r  N,  y-Dihydro- 

NH/  ^^6*15  c-diphenyl-tetrazin. 


13.  IMIDO-ETHERS  OF  THE  AROMATIC  ACIDS  (Vol.  I.)  —  Theimido-ethers 
(their  HC1  salts)  result  from  the  action  of  HC1  upon  a  mixture  of  a 
nitrile  with  an  alcohol  (Pinner,  B.  16,  1654;  21,  2650;  23,  2917). 
Their  methyl  sulphates  are  obtained  by  addition  of  dimethyl  sulphate 
to  primary  and  secondary  acid  amides. 

Water  decomposes  the  HC1  imido-ethers  into  acid  esters  and 
ammonium  chloride.  Benzalkyl-imido-chlorides,  with  sodium  alcohol- 
ates,  change  into  benzalkyl-imido-ethers.  The  latter  are  transposed 
into  tertiary  benzamides  by  the  action  of  alkyl  iodides  or  by  heat 
(C.  1903,  I.  833,  876)  : 

C8H5CON(CH3)2. 

Sodium  amalgam  in  acid  solution  reduces  benzimido-ether  to  benz- 
aldehyde  (B.  35,  3039).  With  ammonia  the  benzimido-ethers  yield 
benzamidin  (q.v.)  ;  with  hydroxylamine,  benzamidoxime  ;  with 
hydrazin,  benzenyl-hydrazidin  (q.v.).  The  following  bodies  should  be 
viewed  as  imido-ethers  of  aromatic  carboxylic  acids  : 


/o—  CH,  c—     »H        c 

C«H*-C\N-CH3  C'H5-C\N-CH,/('H'          C' 


jU-Phenyl-oxazolin.        yti-Phenyl-pentoxazolin.          /z-Phenyl-benzoxazol. 

Benzimido-methyl  ether  C6H5C(NH)OCH3,  b.p.^  96°,  and  benzimido- 
ethyl  ether  C6H5C(NH)OC2H5,  b.p.16  102°,  are  oils  precipitated  from 
their  chlorohydrates  by  soda  solution.  The  ethyl  ether  is  also 
obtained  from  silver  benzamide  with  ethyl  iodide.  Similarly,  silver 
dibenzamide  gives,  with  ethyl  iodide,  benzol-benzimido-ethyl  ether 
C6H5C(NCOC6H5)OC2H6,  m.p.  65°  (C.  1898,  I.  569).  n-Methyl-benz- 
imido-methyl  ether  C6H5C(NCH3)OCH3,  b.p.12  94°. 

14.  THI  AMIDES  OF  THE  AROMATIC  ACIDS.  —  Thio-benzamide  C6H5.CS 
NH2  or  C6H5C(SH)NH,  melting  at  116°,  results  on  conducting  hydrogen 
sulphide  into  an  alcoholic  solution  of  benzo-nitrile  mixed  with  ammonia 
(B.  23,  158),  and  when  benzyl-amine  is  heated  to  280°  with  sulphur 
(A.  259,  304).  Zinc  and  hydrochloric  acid  convert  it  into  benzyl- 

N—  S 
amine,  iodine  into  dibenzenyl-azo-sulphime  (q.v.)  CGH5G^        ^>C.C6H6 


N- 

(B.     25,     1588),     ethylene    bromide     into     /z-phenyl-thiazolin     (see 
below),  trimethylene  bromide  into  /x-phenyl-penthiazolin   (see  Imido- 


BENZENYL   COMPOUNDS  289 

ethers),   and  ethylene-diamine   into  benzenyl-ethylene-diamine   (g.v.) 

/NH—  CH2 
C6H5C/          |      (B.  25,2134).     Methyl-thio-benzamideC6H5CSNHCH3> 

m.p.  79°,  from  phenyl-magnesium  bromide  and  methyl^mustard  oil 
(B.  37,  877). 

Thio-benzanilide  C6H5.CSNH.C6H5,  melting  at  98°,  consists  of 
yellow  plates  or  prisms.  It  is  formed  (i)  when  H2S  acts  upon  benzenyl- 
phenyl-amidine  at  100°  ;  (2)  by  the  action  of  CS2  at  110°,  hydro- 
sulpho-cyanic  acid  being  simultaneously  produced  (A.  192,  29)  ;  (3) 
when  H2S  acts  upon  benzanilide  chloride  ;  (4)  when  P2S5  acts  upon 
benzamide  ;  (5)  from  the  interaction  of  phenyl-mustard  oil,  benzene, 
and  aluminium  chloride  (B.  25,  3525)  (/.  pr.  Ch.  2,  59,  572)  ;  (6)  from 
phenyl-mustard  oil  and  phenyl-magnesium  bromide  (B.  36,  587).  It 
is  changed  to  benzyl-amido-thio-phenol  by  heat  or  oxidation. 

Selenium  benzamide  C6H5CSeNH2,  m.p.  102°,  golden  needles,  from 
benzo-nitrile  and  SeH2.  Iodine  oxidises  it  to  dibenzenyl-azo-selenime 

C,H5C^  (B.  37,2550). 

NJN=U.C6H5 

15.  IMIDO-THIO-ETHERS  OF  THE  AROMATIC  CARBOXYLIC  ACIDS  are 
obtained  as  chlorohydrates  from  nitriles,  mercaptans,  and  hydrochloric 
acid  (compare  Imido-ethers)  .  The  following  compounds  must  be  con- 
sidered as  cyclic  imido-thio-ethers  of  benzoic  acid  : 

S—  CH2  S—  CH2X  s  [i] 


/z-Phenyl-thiazolin  ^u-Phenyl-penthiazolin        //-Phenyl-benzo-thiazol. 

Benzimido-thio-ethyl  ether  C6H5C(NH)S.C2H5  is  an  oil.  It  readily 
resolves  itself  into  benzo-nitrile  and  mercaptan  (A.  197,  348). 

By  heating  sodium  xanthogenates  with  benzalkyl-imido-chlorides  in 
benzene  solution  the  strongly  red-coloured  imido-xanthides  are  obtained: 
Benzo-phenyl-amido-ethyl  xanthide  C6H5C(NC6H5)SCSOC2H5,  m.p.  98°, 
garnet-red  prisms  (B.  35,  2470).  Benzimido-thio-phenyl  ether  C6H5 
C(NH)SC6H5,  m.p.  48°  (B.  36,  3465)- 

16.  AMIDINES  of  aromatic  monocarboxylic  acids  are  obtained  from 
nitriles,  imido-ethers,  imido-chlorides  and  thio-amides  by  means  of 
ammonia  and  ammonium  bases.  The  cyclic  amidins  correspond  to 
the  cyclic  imido-ethers  and  imido-thio-ethers  : 

/NH—  CH2  /NH—  CH2 


/i-Phenyl-glyoxalidin     m-Phenyl-tetrahydro-pynmidin  /j-Phenyl-benzimide-azol. 
Ethylene-benzamidin      Trimethylene-benzamidin 


Benzamidine,*  benzenyl-amidine  C8H6.C          ,  melting  at  75°-8o°, 

is  formed  from  its  hydrochloride  C7H8N2.HC1+2H2O,  consisting  of 
vitreous  crystals,  melting  at  72°,  which,  being  anhydrous,  become 
liquid  at  169°  (A.  265,  130). 

Silver  salt  C6H5.C(=NAg)NH2.  Benzamidine  is  a  stronger  base 
than  ammonia.  Hydroxylamine  converts  it,  by  an  exchange  of  the 
NH  group  for  the  N(OH)  group,  into  an  amidoxime.  Benzamidine 

*  Die  Imidodther  und  ihre  Derivate,  Pinner,  1892,  p.  152. 
VOL.  II.  U 


290 


ORGANIC  CHEMISTRY 


gives  with  diazo-benzol  :  benzamidine-diazo-benzol  (see  below)  ;  with 
benzaldehyde  :  benzal-benzamidine,  melting  at  175°  ;  with  phenyl-iso 
cyanide  :  benzenyl-diphenyl-diureUe  C6H5C(:  N.CONHC6H5).NHCO.NH. 
C6H5,  melting  at  172°  ;  with  phenyl-mustard  oil  :  benzamidin-phenyl- 
thio-urea  C6H5.C(:  NH).NH.CS.NH.C6H5,  melting  at  125°;  with  chloro- 
carbonic  ether:  benzamidine-ur  ethane  C6H5.C(:  NH).NHCO2C2H5, 
melting  at  58°  ;  heat  converts  it  into  diphenyl-oxy-cyanidin  ;  with 
phosgene  :  dibenzamidin-urea  CO(NH.C(:  NH.)C6H6)2,  melting  at  289°, 
and  diphenyl-oxy-cyanidin. 

The  action  of  nitrous  acid  upon  benzamidin  is  very  remarkable. 
The  product  is  benzenyl-dioxy-tetrazotic  acid  (see  below). 

Benzamidin  Hetero-ring  Formations.  —  Benzamidin  heated  alone 
becomes  cyano-phenin  ;  heated  with  acetic  anhydride  the  product  is 
diphenyl-methyl-cyanidin  ;  with  trimethylene  bromide  :  trimethylene- 
benzamidin,  or  ^-phenyl-tetrahydro-pyrimidin  ;  with  acetyl  acetone  : 
phenyl-dimethyl-pyrimidin  ;  with  aceto-acetic  ester  :  phenyl-methyl- 
oxy-pyrimidin  : 


/NH2 


Heat 


(CH3.CO)20 


Cyano-phenin 


Diphenyl-methyl- 
cyanidin     (B. 
25,  1624) 


BrCHa.CH,.CH,Br 


/NH— CH2\          Phenyl-tetra- 
C6H5.C4  ;>CH2     hydro-pyrimidin 

^N CH2/  (B.  26,  2122) 


(CH,CO),CH, 


CtL 


Phenyl-dimethyl- 


CH2.COa.C2H5 
CO.CH, 


\OH 


Phenyl-methyl- 
oxy-py  rimidin . 


Many  other  amidins  besides  benzamidin  are  known  ;  also  numerous 
alkyl,  phenyl,  and  benzyl  substitution  products  of  the  simple 
amidins.  As  may  be  gathered  from  the  description  of  benzamidin, 
the  amidins  are  unusually  reactive  bodies,  whose  investigation  has 
contributed  much  to  the  chemistry  of  the  nitrogen-carbon  ring 
systems. 

Phenyl-benzamidin  C6H5C(NH)NHC6H5,  m.p.  114°,  by  the  action 
of  sodium  upon  a  mixture  of  benzo-nitrile  and  aniline  (/.  pr.  Ch.  2, 
67,  445).  On  the  acidulation  of  phenyl-benzamidin  and  the  accom- 
panying transpositions,  see  C.  1903,  II.  830. 

Diphenyl-benzamidin  C6H5C(NC6H5)NHC6H5,  m.p.  144°,  is  a 
chromogen,  yielding  yellow  dyes  by  the  introduction  of  amido-groups 
(C.  1898,  II.  1049).  Trialkyl-benzamidin,  see  B.  37,  2678. 

17.  DIOXY-TETRAZOTIC  ACIDS.  —  Free  benzenyl-dioxy-tetrazotic  acid 

*?H  (?)    is    not    known.     Its    benzamidin    salt,    melting 


at  178°,  is  produced  when  nitrous  acid  acts  upon  benzamidin.  Sodium 
amalgam  reduces  the  potassium  salt  to  benzenyl-oxy-tetr  azotic  acid 
C7H6N4O+H2O,  melting  in  anhydrous  form  at  175°  with  explosion, 


BENZENYL  COMPOUNDS  291 

and  benzenyl-tetrazotic  acid  (Lessen,  A.  263,  73  ;  265,  129).  These 
bodies  belong  to  the  class  of  heterocyclic  tetrazols  or  pyrro-triazols. 

1  8.  HYDRAZIDINS  OR  AMIDRAZONES  of  aromatic  monocarboxylic 
acids.  —  Several  representatives  of  the  aliphatic  phenyl-hydrazidins  were 
discussed  in  connection  with  phenyl-hydrazin.  The  simple  aromatic 
hydrazidins  result  from  the  action  of  hydrazin  upon  the  imido-ethers. 
The  most  thoroughly  investigated  is  : 

Benzenyl-hydrazidin  C6H6.C<^NH*  or  C8H6.c<^H*  -     This  com- 

pound cannot  be  obtained  from  its  salts  in  a  pure  condition.  Its 
benzoyl  derivative  C6H5C(:  NH)NH.NH.CO.C6H5  melts  at  188°.  It 
slowly  parts  with  water,  even  at  120°,  changing  into  c-diphenyl-triazol, 
whereas  nitrous  acid  converts  it  into  dibenzenyl-isaoxime  or  diphenyl- 
furo-  (bbj-diazol. 

In  addition  to  benzenyl-hydrazidin,  produced  in  the  interaction  of 
hydrazin  and  benzimido-ether,  there  also  result  : 

Dibenzenyl-hydrazidin  C6H5.C(:  NH).NH.NH(NH  :)C.C6H5  or  C6H5 
C(NH2)  :  N—  N  :  (NH2)C  :  C6H5,  melting  at  202°,  and  diphenyl-dihydro- 
tetrazin  (q.v.).  Nitrous  acid  changes  benzenyl-hydrazidin  into  phenyl- 
tetrazotic  acid  (q.v.)  : 

r/NH.NH2  Benzenyl- 

(~        *  CeM5-C\NH  hydrazidin 

r  TT  r/OC2Hs  NH,NH,  r  H  r/NH2NH2\c  c  H     Dibenzenyl- 

\  -  >  C«H'-C\N  _  N/^6    '         hydrazidin 

/NHNH-x  Diphenyl-dihydro- 

>  ^•'••"•s'          __    /?"    *    $         tetrazin 


~/N.NH2          NOOH  r  „   r/"N—  NH  c-Phenyl-tetrazotic 

CeH5'C\NH2  CeH6-C\N=]fT  acid 


-Diphenyl-triazol 


N-NH          _  f  ~  -  . 

NH2COC6H6      \NOQH  r/N—  N  Dibenzenyl-isazoxime 

6    5     \O  _  C.C6H5  Diphenyl-furo^bb^-diazol. 

Diphenyl-dihydro-tetrazin  is  readity  rearranged  by  acids  into 
iso-diphenyl-dihydro-tetrazin.  It  oxidises  on  exposure  to  the  air  to 
diphenyl-  tetrazin  (Pinner,  B.  27,  3273  ;  28,  465  ;  A.  297,  221  ;  298,  i)  : 

/NH—  N\  /NH-NH\  O  /N=N\ 


19.    NlTRAZONES,    NlTROSAZONES    OR    PHENYL  -  AZOXIMES.  —  These 

derivatives  of  the  benzoic  acids  are  obtained  by  the  same  methods  as 
are  the  corresponding  aliphatic  derivatives. 

Benzenyl  -  nitrazone,       phenyl  -  nitro  -  formaldehydrazone, 

C6H5C\NNHC8H5  and  C'HfiC\N°NC8H5'  m'P'  IO2°'  1S  fOmied  fr°m  P116^1' 
nitro-methane,  or  from  nitro-methane  itself,  by  the  action  of  diazo- 
benzol.  It  is  best  obtained  from  benzaldehyde-phenyl-hydrazone  with 
amyl  nitrite  or  N2O4  (C.  1908,  II.  945)  ;  an  intermediate  product  is 
benzenyl-nitrosazone  C6H5C(NO)  :  NNHC6H5,  with  its  more  stable 

transposition  product,  phenyl-azo-benzaldoxime  C«H5C\N°NC  H  '  m'p> 
135°.  This  is  obtained  from  benzaldehyde-phenyl-hydrazone  with 
amyl  nitrite  and  pyridin.  Reduction  with  Am2S  converts  phenyl- 


292  ORGANIC  CHEMISTRY 

mtro-formaldehydrazone  first  into  phenyl  -  hydrazo  -  benzaldoxime 
C6HgC(NOH)NHNHC6H5,  and  this  is  oxidised  by  ferric  chloride  to 
phenyl-azo-benzaldoxime.  The  methyl  ester  of  phenyl-nitro-formalde- 
hydrazone  C6H6C(NOOCH3)  :  NNHC6H5,  m.p.  92°,  breaks  up,  on  boiling 
with  alcohol,  into  formaldehyde  and  phenyl-azo-benzaldoxime  (B.  34, 
2019  ;  35,  1091  ;  36,  62,  90).  m-Nitro-benzenyl-nitrosazone  NO2C6H4 
C(NO)  :  NNHC6H5,  m.p.  98°  with  decomposition,  is  transposed  by 
sodium  ethylate,  or  pyridin,  into  phenyl-azo-m-nitro-benzaldoxime 
NO2C6H4C(NOH).N  :  NC^,  m.p.  183°  with  decomposition.  The 
nitrosazones  easily  lose  nitric  oxide,  even  when  boiled  with  ether,  and 
the  residues  undergo  various  condensations  (B.  36,  92). 

20.    FORMAZYL  DERIVATIVES   OF  THE  AROMATIC   MONOCARBOXYLIC 


ACIDS.—  Formazyl-benzol  C6H5C=-*         m.p.  173°,  consists  of 

x'JN  -  JN  XT.v^giric* 

red  flakes  with  a  greenish  metallic  reflex.  It  is  produced  (i)  when  diazo- 
benzolin  alkaline  solution  (B.  27,  1690)  acts  upon  benzaldehyde-phenyl- 
hydrazone  ;  (2)  from  benzenyl-amidoxime  and  phenyl-hydrazin  (B.  27, 
I6o)  ;  (3)  when  phenyl-hydrazin  and  benzo-phenyl-hydrazide-imide 
chloride  interact.  The  hetero-ring  formations  of  the  formazyl  com- 
pounds have  been  described.  A  glacial  acetic  acid  solution  of  sulphuric 
acid  converts  formazyl-benzol  into  pheno-phenyl-triazin  (q.v.).  It 
yields  triphenyl-tetrazolium  hydroxide  upon  oxidation  : 

—  C,H6NH2  r/N=N—  [i]\~  TJ    Phene-phenyl- 

H<       triazin 


^N—  NC6H6  hydroxide. 


Guanazyl-  benzol    C6H5C2    NH,  orange-yellow   prisms, 

\.N  .  -NUjJtlg 

melting  at  199°.  It  is  formed  when  diazo-benzol  chloride  acts 
upon  benzal-amido-guanidin,  the  condensation  product  derived  from 
benzaldehyde  and  amido-guanidin.  Nitric  acid  oxidises  guanazyl- 
benzol  to  diphenyl-tetrazol  (B.  30,  444). 

21.  HYDROXAMIC  ACIDS,  THEIR  ETHERS  AND  ESTERS.  —  Under  benz- 
amide  mention  was  made  of  the  two  structural  formulae  which  were 
theoretically  possible  for  benzamide  :  the  benzamide  formula  and  the 
benzimido-acid  formula.  If  we  suppose,  in  these  formulae,  a  hydrogen 
atom  in  union  with  nitrogen  to  be  replaced  by  the  hydroxyl  group, 
we  arrive  at  the  two  formulae  theoretically  possible  for  a  hydroxamic 
acid  : 

r  TT  r/NH2        •    r  w  r-/NH  .  r  TT  r/NHOH       .    r 

C«H'-C\0  CeH'C\OH'  C'H6C\0  C6 

Benzamide  Benzo-hydroxamic  acid. 

The  amido-formula  is  preferred  for  the  amides  of  the  carboxylic 
acids  ;  the  imido-ethers  are  derived  from  the  imido-acid  formula.  The 
oximido-acid  formula  is,  however,  more  probable  for  the  benzo-hydrox- 
amic  acids.  Hydro  xime-acid  chlorides  correspond  to  the  imide 
chlorides,  and  amidoximes  to  the  amidines.  Although  hydroxamic 
acid,  and  its  homologues,  are  known  in  but  one  form  each,  many  ethereal 
derivatives  of  the  hydroxamic  acids  occur  in  several  similarly  consti- 
tuted modifications,  whose  observed  difference  can  in  no  satisfactory 


BENZENYL  COMPOUNDS  293 

way  be  attributed  to  structural  difference  (W.  Lessen,  A.  281,  169). 
Just  as  in  the  case  of  the  oximes,  so  here  the  isomeric  phenomena  of 
benzo-hydroxamic  acid  ethers  are  referred  to  the  stereo-chemistry  of 
nitrogen. 

a-  and  /2-Ethyl-benzo-hydroxamic  acids  differ  from  each  other  by 
the  following  space-formulas  (Werner,  B.  25,  33)  : 

C6H5.C—  OC2H5         Ethyl-syn-benzo-         C6H6.C—  OC2H5       Ethyl-anti-benzo- 

hydroxamic  acid  (a-)  N.OH  hydroxamic  acid  (ft-). 


Crystallographic  studies  have  shown  that  many  classes  of  amide-like 
derivatives  of  hydroxylamine  appear  in  polymorphous  modifications. 

Benzo-hydroxamie  aeid  C6H5.C(:  NOH).OH,  m.p.  124°,  and  dibenzo- 
hydroxamie  acid  or  benzoyl-benzo-hydroxamic  ester  C6H5C(:  NO. 
COC6H5)OH,  m.p.  161°,  are  produced  by  the  interaction  of  benzoyl 
chloride  and  hydroxylamine.  Benzo-hydroxamic  acid  is  also  formed 
by  oxidation  of  benzaldoxime  with  Caro's  acid  ;  from  phenyl-nitro- 
methane  C6H5CH2NO2  ;  by  isomerisation  by  means  of  alkali  ;  from 
benzaldehyde  by  transposition  with  benzol-sulphydroxamic  acid,  or 
with  mtro-hydroxylaminic  acid  (B.  34,  2023  ;  35,  51  ;  C.  1901,  II.  99, 
770  ;  1904,  I.  24).  If  silver  benzoate  is  made  to  act  upon  benzo- 
hydroximic  chloride,  an  isomer  of  dibenzo-hydroxamic  acid  is  first 
formed,  melting  at  95°,  and  this  easily  transposes  into  an  isomer  of 
higher  m.p.,  incidentally  splitting  off  benzoic  acid,  and  forming  a 
certain  quantity  of  diphenyl  -  furoxane.  A  few  substituted  benzo- 
hydroximic  chlorides  only  yield  the  corresponding  diphenyl-furoxanes 
(B.  32,  1654).  On  heating  benzo-hydroxamic  acid  with  thionyl  chloride 
in  benzene  solution,  we  get  phenyl  iso-cyanate,  with  intramolecular 
atomic  displacement  (C.  1907,  I.  633)  : 

C6H5C(:  NOH)OH+SOC12  =  C6H5N  :  C  :  O-j-SO2+2HCl. 

The  potassium  salt  of  the  dibenzo-hydroxamic  acid  is  decomposed 
by  water,  especially  on  heating,  into  potassium  benzoate,  s-diphenyl- 
urea,  and  CO2  : 

2C6H5C(  :  NOCOC6H5).OK+H20  =  2C6H5COOK+CO(NHC6H5)2+CO2. 

Other  acidyl  derivatives  of  benzo-hydroxamic  acid  behave  similarly  ; 
on  heating  with  ammonia  they  yield  monophenyl-urea  ;  with  alcohol, 
phenyl-ure  thane,  —  i.e.  transformation  products  of  phenyl  iso-cyanate 
(A.  309,  189). 

The  rearrangement  occurring  here  recalls  that  of  ketoximes  (Beck- 
mann,  p.  189)  to  alky  Used  acid  amides.  As  s-diphenyl-urea  can  be 
resolved  by  hydrochloric  acid  into  aniline  and  CO2,  it  is  possible,  aided 
by  these  reactions,  which  are  capable  of  greater  generalisation,  to 
change  benzoic  acid  to  aniline  —  that  is,  to  replace  the  CO2H  group  by 
the  NH2  group  (A.  175,  313  ;  compare  benzoyl  azide).  The  alkyl 
ethers  of  dihydroxamic  acid  are  known  in  two  modifications  : 
a-(syn)-methyf  ether,  m.p.  53°;  £-(anti)  -methyl  ether,  m.p.  55°; 
a-(syn)-ethyl  ether,  m.p.  58°  ;  jS-(anti)  -ethyl  ether,  m.p.  63°  (A.  205, 
281  ;  281,  235).  The  a-bodies  result  from  the  action  of  alkyl  iodides 
upon  the  silver  salts  ;  the  jS-compounds  through  the  action  of  benzoyl 
chloride  and  caustic  potash  upon  the  alkyl-hydroximic  acids. 

Benzo-hydroximie    acid    alkyl    ethers    or    alkyl-benzo-hydroximie 


294  ORGANIC  CHEMISTRY 

acids  C6H5C(:  NOH)OR'  are  obtained  from  benzimido-ethers  and 
hydroxylamine  hydro-chloride,  and  from  dibenzo-hydroxamic  acid 
alkyl  ethers  (A.  252,  211).  They  occur  in  two  modifications,  which 
can  be  distinguished  by  the  fact  that  the  a-  or  syn-modifications 
yield  on  treatment  with  PC15  (by  Beckmann's  transposition)  phenyl- 
carbamic  acid  ethers,  or  their  transposition  products  : 

C6H5COCH3  OCOCH3 

HO  tf  *  C6H5ttH 

whereas  the  j8-  or  anti-forms  become  phosphoric  ethers  of  the  alkyl- 
benzo-hydroximic  acids  (B.  29,  1146).  a- (syn) -Methyl  ether,  m.p.  64°, 
readily  changes  to  a  physical  isomeride,  also  belonging  to  the  syn- 
modification,  m.p.  101°  (B.  29,  1150).  jS-(anti) -Methyl  ether,  m.p. 
44° ;  a-(syn)-ethyl  ether,  m.p.  53° ;  and  jS-(anti) -ethyl  ether,  m.p.  68°. 

The  alkyl-benzo-hydroximic  acids  also  form  alkyl  and  acidyl  ethers. 
Tribenzoyl-hydroxylamine  C6H5.C(:  NOCOC6H5)O.COC6H5  is  produced 
in  three  forms  when  benzoyl  chloride  acts  upon  hydroxylamine  chloro- 
hydrate  :  a-modification,  m.p.  100°  ;  /^-modification,  m.p.  141°  ;  and 
the  y-modification,  m.p.  112°.  Hydrochloric  acid  changes  the  a-  and 
•/-modifications  into  the  j8-form  (A.  281,  276). 

Thio-benzo-hydroxamic  acid  C6H5C^        ,  an  unstable  oil,  is  formed 

by  the  action  of  hydroxylamine  upon  dithio-benzoic  acid.  The  di- 
benzoyl  compound  melts  at  92°  (C.  1909,  II.  1552). 

22.  HALOIDS  OF  BENZO-HYDROXAMIC  ACID. — The  free  chlorides,  as 
well  as  the  ethers  of  the  fluorides,  chlorides,  and  bromides,  are  known. 
The  free  chlorides  result  from  the  corresponding  benzaldoximes  upon 
treatment  with  chlorine  in  chloroform  solution.     The  ethers  are  pro- 
duced when  the  amidoxime  ethers  are  treated  with  haloid  acids  and 
an  alkaline  nitrite  ;    also  when  PC15  acts  upon  the  alkyl  ethers  of 
hydroxamic    acid    (A.    252,    217).     The   hydroximic    chlorides   with 
ammonia  yield  atnidoximes  ;  with  hydroxylamine,  hydroxam-oximes ; 
on  standing,  or,  rapidly,  on  heating,  they   are  decomposed  to  form 
azoximes  (q.v.)  and  nitriles  ;  with  sodium  carbonate  they  split  off  HC1 
and  yield  nitrile  oxides.     For  transposition  with  silver  salts;  see  B.  32, 

1975. 

Benzo-hydroximic  acid  chloride  C6H5C( :  NOH)C1,  melting  at  48°, 
from  benzaldoxime,  is  converted  by  ammonia  into  benzenyl-amidoxime 
(B.  27, 2193,  2846).  Benzenyl-methoxime  chloride  C6H5.C( :  NOCH3)C1, 
boils  at  225°.  Benzenyl-ethoxime  bromide  C6H5.C( :  NOC2H5)Br  boils 

at  239°  (B.  24,3454)- 

Benzenyl-hydroxylamine-acetic  acid  C6H5.C( :  NOCH2.CO2H).OH, 
melting  at  I35°-I38°,  is  formed  when  caustic  potash  acts  upon  ben- 
zenyl-nitroxime-acetic  acid  C6H5.C(  :  NO.CH2CO2H)ONO,  melting  at 
95°.  The  latter  is  produced  through  the  action  of  sulphuric  acid  and 
potassium  nitrite  upon  benzenyl-amidoxime-acetic  acid  (see  below). 
Benzenyl-fluor-,  chlor-,  and  bromoxime-acetic  acids  all  melt  at  135°. 
They  are  obtained  when  haloid  acids  and  an  alkaline  nitrite  are  allowed 
to  act  upon  benzenyl-amidoxime-acetic  acid  (B.  26, 1570). 

23.  BENZO-NITROLIC  ACID  C6H5C\^QH'  tight-yell°w  needles,  of  very 
bitter  taste,  m.p.  58°,  is  formed,  besides  benzaldoxime  peroxide,  by 
the  action  of  HNO2  upon   phenyl-iso-nitro-methane,  and,  in  small 


BENZENYL  COMPOUNDS  295 

quantity,  by  oxidation  of  benzo-nitrosolic  acid  with  KMnO4  (B.  39, 
2522).  It  is  much  more  unstable  than  the  paraffin-nitrolic  acids,  and 
easily  decomposes  on  standing,  doing  so  instantly  on  heating  with  HNO2 
and  diphenyl-furoxane  (q.v.),  with  intermediate  formation  of  benzo- 
nitrile  oxide.  In  alkalies  it  dissolves  with  an  orange  coloration.  The 
solutions  of  the  alkali  salts  decompose  spontaneously  into  alkali  nitrite 
and  tribenzo-nitrile  oxide. 


24.  BENZO-NITROSOLIC  ACID  C6Hs\Q     is  obtained  in  the  form  of 

its  dark-blue  salts,  by  the  action  of  aqueous  alkalies,  or  ammonia, 
upon  benzo-hydroxame  oxime,  with  intermediate  formation  of  the  very 

unstable  red  azo-compound  C6H5C^^      ^/CC6H5,  which  is  split  up, 

by  hydrolysis,  into  benzenyl-amidoxime  and  benzo-nitrosolic  acid. 
The  free  acid  is  not  stable  ;  liberated  from  its  salts,  it  decomposes 
into  HNO2  and  benzo-nitrile.  The  action  of  iodine  upon  the  silver 
salt  (pink  needles,  decomposing  at  94°)  produces  diphenyl-furoxane 
(B.  39,  1480). 

25.  NITRILE  OXIDES.  —  The  nitrile  oxides  contain  the  atomic  group 
.N 

—  C^  i   and  may  therefore  be  regarded  as  anhydrides  of  the  hydrox- 

amic  acids,  with  which  they  are  in  close  genetic  connection. 

^N 
Benzo-nitrile  oxide  C6H5C^  |    forms  a  mobile  oil,  of  a  penetrat- 

ing odour,  resembling  nitrile.  At  a  low  temperature  it  solidifies  in 
a  crystalline  mass,  melting  at  15°.  It  is  obtained  by  withdrawing 
HC1  from  benzo-hydroximic  chloride  by  means  of  sodium  carbonate 
(B.  40,  1667).  On  keeping,  it  quickly  polymerises  to  diphenyl-furoxane 

C6H5N^\06H5'  On  heatin&  in  xylcl  solution  it  partly  isomerises 
to  phenyl  iso-cyanate  (B.  42,  4207).  Concentrated  HC1  splits  it  up  into 
benzoic  acid  and  hydroxylamine,while  zinc  dust  and  glacial  acetic  acid 
reduce  it  to  benzo-nitrile.  With  methyl-magnesium  iodide  it  combines 
to  form  aceto-phenone  oxime  : 

C6H5C^   .EM?i.  C6H5C(  :  NOMgI)CH3  —  *™->  C6H5C(  :  NOH)CH3. 

A  trimeric  body  of  benzo-nitrile  oxide  is  formed  by  the  spontaneous 
decomposition  of  an  aqueous  solution  of  sodium  benzo-nitrolate,  with 
splitting  off  of  sodium  nitrite. 

/  /N\ 

Tribenzo-nitrile  oxide     C6H5C<  |       is  decomposed  at   130°,  with 

\  X0/3 

explosion  when  rapidly  heated.  In  its  transformations  it  resembles 
the  monomeric  compound.  Heating  in  toluol  solution  depolymerises 
it,  with  formation  of  phenyl  iso-cyanate  ;  with  aniline  ,  it  yields 
diphenyl-urea,  by  reduction,  benzo-nitrile.  Alcoholic  HC1  splits  it, 
partly  into  benzoic  acid  and  hydroxylamine,  and  partly  transforms  it 

intodibenzenyl-azoxime^  tt?'°'£\~-H5  (B.  42,  806). 

C'g.H.gC/—  —  IN  —  O 

26.  THE  AMIDOXIMES  are  produced  by  the  action  of  hydroxylamine 
upon  thio-amides,  nitriles,  imido-ethers,  and  amidines.  Ferric  chloride 
imparts  a  deep-red  colour  to  the  alcoholic  solution  of  the  amidoximes. 


296  ORGANIC  CHEMISTRY 

Benzenyl  -  amidoxime,  amide  of  benzo  -  hydroxamic  acid 
C6H6.C^[^H),  melts  at  79°.  It  gives  the  iso-nitrile  reaction  with 

chloroform  and  potassium  hydroxide.  Nitrous  acid  changes  it  to 
benzamide.  With  acids  and  caustic  alkalies  it  yields  salts  —  -e.g. 
C6H5.C(  :  N.OH)NH2.HC1  and  C6H5.C(NH2)  :  N.OK.  Alkyl  iodides 
convert  the  latter  into  amidoxime  ethers. 

Methyl  ether  C6H5(.NH2)  :  NOCH3  melts  at  57°  ;  the  ethyl  ether 
melts  at  67°  (A.  281,28o). 

Acetyl-benzenyl-amidoxime  C6H5.C(  :  NOCOCH3).NH2  melts  at 
16°  (B.  18,  1082).  Benzenyl-oximido-carbonic  ester  C6H4C(.NH2)  : 
NOCO2C2H5  melts  at  127°.  Benzenyl-oximido-glyeollic  acid  C6H5. 
C(.NH2)  :  NO.CH2.CO2H  melts  at  123°.  Benzenyl-amidoxime-butyric 
acid  C6H5C(NH2)  :  NOCH(C2H5)COOH  melts  at  82°  (B.  29,  2655). 

Hetero-ring  Formations  of  the  Amidoximes.  —  (i)  The  amidoximes 
condense  with  the  aldehydes  of  the  fatty  series  to  hydrazoximes.  The 
amidoxime  acid  derivatives,  alluded  to  above,  throw  off,  on  heating 
above  their  melting-points,  water  or  alcohol,  and  become  azoximes  : 

/NH2  +CH,CHO  r  TT   r/NH_  .  Benzenyl  hydraz- 

~  -CH.C  ,H.CH3      oxime_ethidene 


-H2O  r  TT    ~/N=^\  Ethenyl-benzenyl- 

.  C6H5.C^N_0  XC.CH3          azoxime 

r  IT  r/NH2  -C2H5OH     r  TT     /NH_.  Carbonyl-ben- 

CeH5-C\N.O.CH2.C02H~  '  CeH5'C\N—  0>(  zenyl-azoxime 

p  TT   r/NH2  —  H2O        r  TT   r/NH  —  CO^^          Benzenyl-amidoxime- 

U6ll5-C\N.O.CH2.C02H  ~  '  UeH5-C\N  -  O  -      'H2      glycollic  acid. 

There  is  a  distinction  between  the  amidoximes  and  the  oxy-amidins, 
which  have  the  same  tautomeric  fundamental  form  : 

_C/-NOH          d  /NHOH 

'\NH  - 


Oxy-amidins  are  produced  from  imido-chloride  with  j8-aryl-hydro- 
xylamines  (B.  34,  2620  ;  36,  18).  Benzenyl-phenyl-p-tolyl-oxy-amidin 
C6H5C(NC6H5)N(C7H7)OH,  m.p.  175°,  and  benzenyl-p-tolyl-phenyl-oxy- 
amidin  C6H5C(NC7H7)N(C6H5)OH,  m.p.  191°,  on  reduction  with  H2SO3, 
form  the  same  phenyl-tolyl-benzamidin. 

27.  HYDRAZIDOXIMES  result  from  benzo-hydroximic  chloride,  and 
hydrazin  hydrate,  in  alcoholic  solution.  Like  the  amidoximes,  they 
possess  an  amphoteric  character,  and  dissolve  in  acids  as  well  as  in 
alkalies.  The  latter  readily  decompose  them,  with  liberation  of  nitrogen. 

Benzenyl-hydrazidoxime   ceH4C^^H  ,  rn.p.   110°  with   decom- 

position, yields  N-oxy-c-phenyl-tetrazol  with  nitrous  acid.  With 
benzaldehyde  it  condenses  to  benzal-benzenyl-hydrazidoxime  C6H5C 
(  :  NOH)NH.N  :  CHC6H5,  m.p.  120°,  which,  with  acids,  is  easily 
anhydrated  into  ccj-diphenyl-triazol  (B.  42,  4199)  : 

/NOH  NOOH  „  TT  r,/N(OH).N 

'         N-Oxy-c-phenyl-tetrazol 

cfCl-Diphenyl-triazol. 


DERIVATIVES   OF   ORTHOBENZOIC  ACID  297 

28.  HYDROXAMOXIMES. — Benzo-hydroxamoxime,  benzenyl-oxy-ami- 
doxime  C6H5C(NOH)NHOH,  m.p.  115°  with  decomposition,  is  formed 
from    benzo-hydroximic    chloride    with    hydroxylamine ;  it    yields    a 
reddish-brown   copper   salt    (C7H^2O2)2Cu    (B.    31,   2126).     Alkalies 
convert  it  into  a  red  azo-body,  which  is  further  hydrolysed  to  benzenyl- 
amidoxime  and  the  salts  of  benzo-nitrosolic  acid  (B.  39,  1480). 

DERIVATIVES  OF  ORTHOBENZOIC  ACID. 

29.  Ethyl  -  orthobenzoie  ester,  ethyl  ortho-benzoate,  benzenyl  -  ethyl 
Ether  C6H5C(O.C2H5)3,  from  phenyl-chloroform  and  sodium  ethylate, 
boils  at  220°-225°,  or  from  phenyl-magnesium  bromide  and  ortho-car- 
bonic ester  (B.  38,  564). 

30.  Benzo-triehloride,  phenyl-chloroform,   benzoic    acid  trichloride, 
benzenyl  trichloride  C6H5CC13,  melting  at  — 22-5°  (B.  26,  1053),  boiling 
at    213°,   with  sp.   gravity   1-38    (i°4),  is  isomeric  with  the    chloro- 
benzal  chlorides,  dichloro-benzyl  chlorides,  and  the  trichloro-toluenes. 
Phenyl-chloroform  bears  the  same  relation  to  benzoic  acid  or  phenyl- 
formic  acid  that  methyl-chloroform  bears  to  acetic  acid  or  methyl 
formic  acid    (I.  256).     It   results   (i)   upon  conducting  chlorine  into 
boiling  toluol,  until  there  is  no  further  increase  in  weight  (A.  146, 
330)  ;    (2)   by  the  action  of   phosphorus  pentachloride  upon  benzyl 
chloride   (A.   139,  326).     It  changes  to  benzoic  acid  when  heated  to 
100°  with  water.     It  yields  benzoyl  chloride  and  benzoic  anhydride  on 
being  digested  with  anhydrous  oxalic  acid  (A.  226,  20).     It  readily 
condenses  to   triphenyl-methane   derivatives,  with   the   anilines   and 
phenols  (B.  15,  232  ;  A.  217,  223). 

Benzo-trifluoride  C6H5CF3,  b.p.  103°,  is  formed  besides  difluoro- 
chloro-toluol  C6H5CC1F2,  b.p.  143°,  from  benzo-trichloride  and  antimony 
trifluoride  (C.  1898,  II.  26). 

31.  Ortho-benzoie  acid  piperidide  C6H5C(N.C5H10)3,   m.p.   80°,  is 
produced  on  warming  benzo-trichloride  and  piperidin. 

The  benzamide  haloids  also  belong  to  the  derivatives  of  ortho- 
benzoie acid. 

(c)  SUBSTITUTED  AROMATIC  MONOCARBOXYLIC  ACIDS. 

Only  those  will  be  given  in  connection  with  the  monocarboxylic 
acids  in  which  the  substitution  has  occurred  with  the  hydrogen  atoms  of 
the  benzene  nucleus.  Certain  ortho-products  show  the  power,  by  water 
elimination,  of  yielding  inner  anhydrides  or  heterocyclic  compounds. 

See  above  for  the  behaviour  of  2,  6-substituted  car  boxy  lie  acids  in 
their  esterincation  with  alcohol  and  hydrochloric  acid. 

i.  Halogen  Benzoic  Acids  are  formed  : 

(1)  By  the  substitution  of  benzoic  acids  or  nitriles  ;  the  halogen 
atom  entering  first  prefers  the  meta-position  with  reference  to  car- 
boxyl. 

(2)  By  oxidising  p-  and  m-halogen  toluols  and  higher  homologues 
with  chromic  acid,  and  o-haloid  hydrocarbons  with  dilute  nitric  acid 
or  potassium  permanganate.     In  the  animal  organism  the  halogen 
toluols  are  transformed  with  the  corresponding  halogen-substituted 
hippuric  acids  (C.  1903,  I.  411). 


298  ORGANIC  CHEMISTRY 

(3)  From  the  amido-acids  by  means  of  (a)  the  diazo-sulphates,  or 
(b)  the  diazo-amido-acids  ;  both  classes,  when  boiled  with  haloid  acids, 
have  been  obtained  from  the  diazo-amido-benzoic  acids  (B.  15,  1197). 

(4)  By  the  action  of  phosphorus  pentachloride  upon  the  oxy-acids 
(compare  salicylic  acid). 

(5)  Nuclear  synthesis  :  heating  the  halogen  nitro-benzols  to  200°- 
230°  with  potassium  cyanide  and  alcohol,     In  (his  reaction  the  cyano- 
gen group  replaces  the  nitro-group  ;  it  does  not,  however,  take  the  same 
position  in  the  benzene  residue  (B.  8,  1418).     At  the  temperature  of 
the  reaction  the  nitrile  changes  to  the  acid.     m-Chloro-nitro-benzol 
yields    o-chloro-benzoic    acid  ;    and  p-chloro-nitro-benzol,    m-chloro- 
benzoic  acid. 

(6)  From  the  haloid  anilines  through  the  diazo-compounds,  etc. 
Properties  and  Behaviour.  —  In  the  following  tabulation  of  the  melt- 

ing-points of  the  monohaloid  benzoic  acids  it  will  be  observed  that  the 
ortho-bodies  melt  at  the  lowest  temperatures,  and  the  para-compounds 
at  the  highest.  The  melting-point  rises  with  the  atomic  mass  of  the 
substituting  halogen.  The  ortho-derivatives  are  fairly  readily  soluble 
in  water,  and  easily  yield  soluble  barium  salts,  whereby  they  can 
usually  be  quite  readily  separated  from  the  meta-  and  para-derivatives. 
When  they  are  fused"  with  caustic  potash,  oxy-benzoic  acids  result. 
With  NH3,  or  amines  and  copper,  o-chloro-benzoic  acid  is  transposed 
into  anthranilic  acid  and  n-alkyl-anthranilic  acids  (A.  355,  312). 

Fluoro-benzoie  acid  :  o-,  m.p.  120°  :  m-,  m.p.  124°  ;  p-,  m.p.  182° 

Chloro-benzoie  acid  :  o-,     „      137°  ;  m-,     „     153°  ;  p-,     ,,     240° 

Bromo-benzoie  acid  :  o-,     „     147°  :  m-,     „     155°  ;  p-,     ,,      251° 

lodo-benzoie  acid  :      o-,    ,,      162°  ;  m-,     „     187°  ;  p-,     „      265°. 

Numerous  poly-chloro-  and  poly-bromo-benzoic  acids  are  known. 
The  five  hydrogen  atoms  of  the  phenyl  of  benzoic  acid  can  be  replaced 
by  chlorine  or  bromine. 

2.  lodoso-  and  lodo-benzoic  Acids.  —  Upon  chlorinating  the  three 
iodo-benzoic  acids  in  chloroform,  three  iodo-chloro-benzoic  acids  are 
produced.  Sodium  hydroxide  changes  these  to  the  iodoso-benzoic  acids 
(B.  27,  2326).  o-Iodoso-benzoic  acid  C6H4(IO)CO2H  consists  of  bril- 
liant flakes,  which  explode  at  244°.  This  acid  is  also  produced  in  the 
oxidation  of  o-iodo-benzoic  acid  with  fuming  nitric  acid  (B.  28,  83),  and 
together  with  o-iodo-benzoic  acid  C6H4(IO2)CO2H,  exploding  at  230° 
with  violence,  when  o-iodo-benzoic  acid  is  oxidised  with  potassium  per- 


mangate.     The  formula  C6H4{£    _^>O  has  also  been  suggested  for 

the  o-iodoso-benzoic  acid,  as  it  yields,  like  laevulinic  acid,  when  heated 
with  acetic  anhydride,  an  acetyl  derivative  :  acetiodoso-benzoic  acid 

,  melting  at  166°  (B.  26,  1364). 


3.  Nitro-monoearboxylic  Acids.  —  Not  more  than  three  nitro-groups 
have  been  introduced  into  the  benzene  residue  of  an  aromatic  carboxylic 
acid. 

Nitro-benzoic  Acids.  —  (i)  Meta-nitro-benzoic  acid  is  the  principal 
product  in  the  nitration  of  benzoic  acid.  The  quantity  of  the  ortho-  (20 
per  cent.)  and  para-  (1-8  per  cent.)  acids  is  less  (A.  193,  202).  (2)  By 
oxidising  the  three  nitro-toluols  ;  the  ortho-  with  potassium  permangan- 


NITRO-MONOCARBOXYLIC  ACIDS  299 

ate  (B.  12,  443),  and  the  meta-  and  para-  with  a  chromic  acid  mixture 
(A.  155,  25).  o-  and  p-Nitro-benzoic  acids  are  also  produced  by  oxidis- 
ing o-  and  p-nitro-benzyl  chloride  with  potassium  permanganate  (B.  17, 
385),  as  well  as  by  oxidising  o-  and  p-nitro-cinnamic  acids.  (3)  By 
converting  the  three  isomeric  nitranilines  into  the  three  nitro-benzo- 
nitriles  (B.  28,  150).  The  nitration  of  o-benzo-nitrile  yields  m-nitro- 
benzo  -  nitrile  almost  exclusively.  o-Nitro-benzo-nitrile  has  been 
obtained  from  o-nitraniline  (B.  28,  151).  Nitro-acids  result  upon 
saponifying  the  nitro-nitriles  with  caustic  soda  : 

o-Nitro-benzoic  acid  melts  at  147°  ;  o-Nitro-benzo-nitrile  melts  at  109° 
m-Nitro-benzoic  acid  ,,  141°  ;  m-Nitro-benzo-nitrile  „  116° 
p-Nitro-benzoic  acid  ,,  238°  ;  p-Nitr  o-benzo-nitrile  „  147°. 

o-Nitro-benzoic  acid  possesses  a  sweet  taste,  and  dissolves  in  164 
parts  of  water  at  16°.  Its  nitration  produces  2,  6-,  2,  5-,  2,  4-dinitro- 
benzoic  acids,  and  styphnic  acid.  o-Nitro-benzoyi  chloride,  m.p.  25°, 
see  C.  1901,  I.  1227.  m-Nitro-benzoic  acid  dissolves  in  425  parts  of 
water  (16°).  Its  barium  salt  dissolves  with  difficulty.  Upon  nitration 
it  yields  2,  5-dinitro-benzoic  acid.  p-Nitro-benzoic  acid  (chloride, 
m.p.  75°  ;  anhydride,  m.p.  190°  ;  see  A.  314,  305),  called  also  nitro-dra- 
crylic  acid,  because  it  is  formed  in  the  action  of  nitric  acid  upon  dragon's 
blood  (A.  48,  344),  is  very  sparingly  soluble  in  water.  Nitration  con- 
verts it  into  2,  4-  and  3,  4-dinitro-benzoic  acids.  The  electrolysis  of 
its  warm  sulphuric  acid  solution  produces  p-amido-phenol-sulphonic 
acid  (B.  28,  R.  378  ;  compare  also  B.  28,  R.  126).  2,  4-,  3,  4-Dinitro- 
and  2,  4,  6-trinitro-benzoic  acids  are  obtained  by  the  oxidation  of  the 
corresponding  nitro-toluols.  The  dinitro-toluols  are  oxidised  by  a 
chromic  acid  mixture  (B.  27,  2209),  or  by  potassium  permanganate. 
Trinitro-toluol  is  oxidised  by  a  nitric-sulphuric  acid  mixture  at 

I50°-220°. 

2,  4-Dinitro-benzoic  acid  melts  at  179°  ;  the  2,  5-acid  melts  at  177°  ; 
2,  6-acid  at  202°  ;  the  3,  4-acid  at  165°  ;  the  3,  5-  or  ordinary  dinitro- 
benzoic  acid  melts  at  204°.  2,  4,  6-Trinitro-benzoic  acid  (NO2)3 
C6H2CO2H  melts  at  210°  with  the  elimination  of  CO2  (B.  27,  3154  ; 
28,  2564,  3065,  R.  125  ;  C.  1899,  H-  98)-  Chlorimido-m-nitro-benzoic 
methyl  ester  NO2[3]C6H4C  is  formed  from  benzoyl  chloramide 


and  diazo-methane  ;  it  occurs  in  two  stereo-isomeric  forms,  m.p. 
88°  and  84°  ;  gaseous  HC1  reduces  both  to  the  same  m-nitro-benz- 
imido-methyl  ester  NO2C6H4C(  :  NH)OCH3,  from  which  sodium  hypo- 
chlorite  restores  a  mixture  of  the  two  isomers  (C.  1908,  II.  1174). 

Nitro-haloid  benzoic  acids  (C.  1901,  II.  287  ;  1902,  II.  581).  — 
o,  o-Fluo-nitro-benzoic  acid  C6H3F(NO2)COOH,  melting  at  127°,  has 
been  prepared  by  oxidising  fluo-nitro-toluol.  In  contrast  with  the 
other  o,  o-di-substituted  benzoic  acids,  it  can  be  quite  readily  esterified 
(B.  29,  842).  1,  4,  6-Mononitro-chloro-benzoie  acid,  m.p.  165°,  and 
two  dinitro-chloro-benzoie  acids,  m.p.  238°  and  200°,  are  formed  by 
nitrifying  o-chloro-benzoic  acid  (C.  1900,  I.  742).  The  nitration  of 
m-bromo-benzoic  acid  yields  two  o-nitro-acids,  both  of  which  yield 
anthranilic  acid  upon  reduction  :  3-bromo-2-nitro-benzoic  acid,  melting 
at  250°,  and  3-bromo-6-nitro-benzoic  acid,  melting  at  139°  (compare 
equivalence  of  the  six  hydrogen  atoms  of  benzene).  The  halogen  atom 


300  ORGANIC  CHEMISTRY 

in  the  nitro-haloid  benzole  acids  is  reactive,  like  that  in  the  nitro- 
haloid  benzols  (B.  22,  3282). 

Nitro-phenyl-aeetie  acids  NO2.C6H4.CH2.CO2H  are  produced  by 
saponifying  the  nitro-benzyl-cyanides  with  caustic  alkali.  The  latter 
bodies  constitute  the  product  resulting  from  the  action  of  potassium 
cyanide  upon  the  nitro-benzyl  chlorides  (B.  16,  2064  ;  19,  2635). 
The  nitration  of  phenyl-acetic  acid  produces  chiefly  the  p-nitro- 
body,  with  little  of  the  o-nitro-acid  and  o,  p-dinitro-phenyl-acetic  acid, 
melting  at  166°.  The  latter  is  also  obtainable  from  2, 4-dinitro- 
phenyl-aceto-acetic  ester,  by  saponification  with  dilute  H2SO4  (B. 
42,  601). 

o-,  m-,  p-Nitro-phenyl-acetie  acid,  m.p.  141°,  120°,  152° 
o-,  m-,  p-Nitro-benzyl  cyanide  „      84°,    61°,  116°. 

Nitro-hydro-einnamie  acids  NO2C6H4CH2.CH2.CO2H.— p-Nitro-  and 
o-nitro-hydro-cinnamic  acids  result  from  the  nitration  of  hydro- 
cinnamic  acid.  Both,  in  turn,  yield  the  o,  p-dinitro-acid.  The  o-nitro- 
acid  is  also  prepared  from  o-nitro-p-amido-hydro-cinnamic  acid,  the 
first  reduction  product  of  the  o,  p-dinitro-acid,  as  well  as  from  o-nitro- 
benzyl-malonic  ester  (q.v.).  The  m-nitro-acid  is  obtained  from  p-acet- 
amido-m-nitro-hydro-cinnamic  acid  (B.  15,  846  ;  29,  635  ;  compare 
also  m-nitro-toluol). 

o-,  m-,  p-Nitro-hydro-einnamie  acid,  m.p.  115°,  118°,  163° 
o,  p-Dinitro-hydro-einnamie  acid,         „     123°  (B.  13,  1680). 

o-  and  p-Nitro-hydratropic  acids  NO2.C6H4.CH(CH3).CO2H,  m.p. 
no0  and  87°,  are  produced  upon  introducing  hydratropic  acid  into 
strongly  cooled  fuming  nitric  acid  (A.  227,  262). 

4.  Nitroso-monoearboxylie  Acids. — o-Nitroso-benzoie  acid  C6H4[i] 
NO[2]CO.OH,   melting  with   decomposition  at   210°.     It  consists  of 
colourless  crystals,  green  in  solution,  and  is  formed  from  anthranilic 
acid  by  oxidation  with  Caro's  acid  (B.  36,  3651),  and  from  o-nitro- 
benzaldehyde    by    transposition    under    illumination    in    indifferent 
solvents.     In  alcoholic  solutions  we  obtain  the  esters  :    methyl  ester, 
m.p.  153° ;  ethyl  ester,  m.p.  121°  (A.  371,  319).     o-Nitro-benzylidene- 
aniline    C6H4[i]NO2[2]CH  :  NC6H5,    in    light    gives    o-nitroso-benz- 
anfflde  C6H4(NO)CONHC6H5  (B.  35,  2715  ;   36,  4373).     In  connection 
with  these  modes  of  formation,  we  have  the  formation  of  o-nitroso- 
benzoic  acid  by  the  action  of  alcoholic  ammonia  on  o-nitro-mandelic 
nitrile  NO2[i]C6H4[2]CH(OH)CN,  with  elimination  of  HCN   (B.   39, 
2335).     o-Nitroso-benzoic  acid  is  also  produced  by  the  oxidation  of 
phenyl-oxy-indol.    4-Nitro-  and  2,  4-dinitro-o-nitroso-benzoie  acid  are 
transformation    products    of    2, 4-dinitro-    and    2, 4,  6-trinitro-benz- 
aldehyde  in  light.     0-,  m-,  and  p-nitroso-benzoic  acid,  and  their  esters, 
are  also  obtained  by  the  oxidation  of  the  corresponding  hydroxyl- 
amino-benzoic  acids,  which  result  from  nitro-benzoic  acids  by  reduc- 
tion (B.  37,  333). 

5.  Hydroxylamino  -  carboxylie    Acids. —  o  -  Hydroxylamino  -  benzoic 
acid  C6H4[2]NHOH[i]COOH,  brilliant  needles,  m.p.  142°  with  decom- 
position, obtained  by  reducing  o-nitro-benzoic  acid  with  zinc  dust  and 
sal  ammoniac.     It  has  the  general  properties  of  hydroxylamino-com- 
pounds  :   oxidising  agents  convert  it  into  o-nitroso-benzoic  acid,  with 


AROMATIC  AMIDO-MONOCARBOXYLIC  ACIDS         301 

which  it  condenses  in  alkaline  solutions  to  oo'-azoxy-benzoic  acid.  On 
warming  with  dilute  H2SO4  it  is  partly  transposed  into  5-oxy-anthra- 
nilic  acid  OH[5]C6H3[2]NH2[i]CO2H,  while  the  major  part  passes  into 
its  anhydride. 

Benzisoxazolone,  oxy-anthr  anile 

f[i]CO\  |[i]C(OH) 

'  C«H*  X2NH/(  U    C«H42ft  _ 


[2]N 

m.p.  112°  with  decomposition.  It  has  an  acid  character.  While 
the  alkali  salts,  on  account  of  their  very  difficult  breaking  up 
into  o-hydroxylamino-benzoic  salts,  must  be  regarded  as  probably 
derivatives  of  oxy-anthranile  (formula  II.),  the  alkyl-  and  acyl-benziso- 
oxazolones  obtained  from  them  are  reducible  to  formula  I.,  since,  on 
reduction,  they  easily  form  N-alkyl-  and  acyl-anthranilic  acids. 

N-Aeetyl-benzisoxazolone    ceH4{^?COCH  x/*0.    m-P-    118°,   is  also 

formed  by  condensation  of  o-nitroso-benzoic  acid  with  paraldehyde 
under  the  influence  of  light  (B.  42,  2297). 

6.  Aromatic  Amido-monoearboxylie  Acids.  —  These  are  obtained  by 
reducing  the  corresponding  nitro-benzoic  acids.  Like  glycocoll,  the 
amido-benzoic  acids  yield  crystalline  salts  both  with  acids  and  bases. 
They  do  not  combine  with  acetic  acid,  hence  are  precipitated  by  it 
from  their  alkali  salts. 

Like  glycocoll,  these  acids  can  be  considered  as  cyclic  ammonium 
salts  (Vol.  I.).  The  hydrogen  atoms  of  the  amido-group  are  replace- 
able by  alkyl  and  acidyl  residues.  Dimethylated  amido-acids  are 
produced  by  the  action  of  phosgene  and  aluminium  chloride  upon  the 
dimethyl-anilines.  Acetamido-benzoic  acids  are  formed  by  the  oxida- 
tion of  the  acetyl-toluidins. 

The  o-amido-acids  (of  which  o-amido-benzoic  acid  and  o-amido- 
phenyl-acetic  acid  are  closely  related  to  indigo,  and  o-amido-hydro- 
cinnamic  acid  to  quinolin)  form  hetero-rings,  and  yield  rather  remark- 
able ortho-condensation  products. 

Anthranilie  acid,  o-amido-benzoic  acid  C,H4  {^™Hor  C6H4  \  ' 

'  U2]NH2  ([2]NH3 

m.p.  145°,  sublimates  at  low  pressures  without  decomposition  (C. 
1903,  1.  922),  but  breaks  down,  upon  heating,  into  aniline  and  carbonic 
acid.  Its  aqueous  solution  has  a  sweet  taste;  many  of  its  organic 
solutions  have  a  blue  fluorescence  (B.  31,  1693)  It  was  first 
obtained  from  indigo  (q.v.)  by  the  action  of  caustic  potash  (Fritzsche, 
1841). 

The  oxidation  can  be  accelerated  by  the  addition  of  manganese 
dioxide  (A.  234,  146).  The  acid  results  from  the  reduction  of  o-nitro- 
benzoic  acid  and  the  two  m-bromo-o-nitro-benzoic  acids  with  tin  and 
hydrochloric  acid  ;  from  o-nitro-toluol  by  heating  with  concentrated 
potash  (C.  1900,  I.  1098),  and  from  anthranile,  acet-anthranilic  acid, 
and  isatoic  anhydride  by  splitting.  Cp.  o-chloro-benzoic  acid. 

Industrially,  it  is  obtained  from  phthalimide  by  treatment  with 
bromine  and  caustic  potash  (B.  24,  R.  966  ;  36,  218  ;  /.  pr.  Ch.  2, 
80,  i)  : 

C6H4(CO)2NK+BrOK+2KOH  =  C6H4(NH2)COOK+BrK-f  CO3K2. 


302  ORGANIC  CHEMISTRY 

It  is  also  obtained  from  phthalic  hydroxylamine  with  alkali  (C.  1902, 
II.  1439). 

Nitrous  acid  converts  anthranilic  acid,  in  aqueous  solution,  into 
salicylic  acid,  and  sodium,  in  amyl-alcohol  solution,  into  hexahydro- 
anthranilic  acid,  hexahydro-benzoic  acid  (q.v.),  and  n-pimelic  acid 
(Vol.  I.)  (B.  27,  2466). 

With  PC15  anthranilic  acid  forms  chlorides  :  COC1.C6H4NHPOC12, 
m.p.  62°,  and  (COC1.C6H4NH)2POC1,  m.p.  I48°-I53°  (B.  36,  1824). 

The  methyl  ester,  m.p.  25-5°,  b.p.  125°,  is  a  characteristic  con- 
stituent of  orange-blossom  oil  and  neroli  oil  (B.  32,  1512),  and  is  also 
found  in  the  oil  of  flowers  of  Tuber osa  (B.  36,  1465).  The  ethyl  ether 
boils  at  260°.  These  esters  are  also  obtained  direct  from  phthalimide, 
in  alcoholic  alkaline  solution,  with  alkali  hypochlorite  (C.  1903,  I.  745). 
Also  from  isatoic  anhydride,  with  sodium  alcoholate  and  water 
(B.  33,  28).  Its  amide,  from  isatoic  acid  and  ammonia,  melts  at  108° 

(B.18,R.273). 

Unsym.  phenyl-hydrazide,  m.p.  134°  (A.  301,  89). 

Anthranilic  nitrile,  o-amido-benzo-nitrile,  o-cyananiline  NH2[2]C6H4 
CN,  m.p.  49°,  b.p.  267°,  from  nitro-benzo-nitrile,  with  SnCl2  and 
HC1  (B.  42,  3711),  or  from  o-amido-benzaldoxime  by  splitting 
off  H2O  (B.  36,  804)  ;  on  heating  with  Am2S  it  yields  the 
thiamide  NH2C6H4CSNH2,  m.p.  122°;  with  HNO2,  y-amido-indazol 

C6H4{^H^)N  (C.  1903,  I.  1270  ;  B.  42,  3716). 

Formyl-anthranilic  aeid  CHO.NH[2]C6H4[i]CO2H,  melting  at  169°, 
is  produced  in  boiling  isatoic  acid  with  formic  acid.  It  condenses  on 

heating  to  keto-dihydro-quinazolone-benzoic  acid  c.H4{^J^eH4CC 

(B.  35,  3475). 

Aeetyl-anthranilie  acid  CH3CO.NH[2]C6H4[i]CO2H  results  from 
anthranilic  acid  treated  with  acetic  anhydride ;  from  o.-aceto- 
toluidin,  by  oxidation  with  KMnO4,  in  the  presence  of  magnesium 
sulphate  (B.  36,  1801),  and  from  the  oxidation  of  methyl-ketol  and  of 
quinaldin  (q.v.).  The  methyl  ester,  m.p.  61°,  and  the  amide,  m.p.  170°, 
have  been  obtained  from  anthranilic  acid  ester  and  amide.  Heating 
of  acetanthranilic  acid,  or  its  ester,  with  POC13  produces  the  so-called 
dianhydro-diacetanthranilic  acid  C18H14N204,  m.p.  250°.  By  heating 
with  acetic  anhydride  to  150°,  or,  by  itself,  to  2OO°-2io°,  acetanthra- 
nilic acid  is  partly  anhydrated  to  acetanthranile,  and  partly  condensed 

to  methyl-dihydro-quinazolone-benzoic  acid   C6H4{£^^**COOH  (B. 

35,  3470).  Benzoyl-anthranilie  acid  CfH»CONHC6H4COOH,  m.p.  183°, 
see  B.  26,  1304 ;  A.  324,  134.  Benzo-sulphone-anthranilic  aeid, 
C6H5SO2NHC6H4COOH,  m.p.  214° ;  chloride,  m.p.  155°  (A.  367,  104). 

rCH. 
Anthranile    c6H4j  |    No,    b.p.18  99°  (B.  42,   1647),  an  oil   of  a 

peculiar  odour,  volatile  in  water  vapour.  It  is  dealt  with  in  this  place 
because  it  behaves,  in  many  reactions,  like  an  anhydride  of  anthranilic 

(CO 
acid,     C6H4s  I       fi-lactame,    being    transformed    by    alkalies    into 

INK 

anthranilic  acid,  and  by  acetic  anhydride  into  acetanthranile.  These 
reactions,  however,  probably  take  place  with  an  intramolecular  atomic 


AROMATIC  AMIDO-MONOCARBOXYLIC  ACIDS         303 

displacement.  A  direct  conversion  of  anthranilic  acid  into  anthranile 
has  not  been  hitherto  accomplished.  The  modes  of  formation  of 
anthranile  are  as  follows  :  (i)  from  nitro-benzaldehyde  by  reduction 
with  tin  and  acetic  acid,  or  with  ferrous  sulphate  and  ammonia  ;  (2) 
from  acido-benzaldehyde  ;  (3)  from  o-nitroso-benzyl  alcohol,  on  boiling 
with  water  ;  (4)  from  amido-benzaldehyde  by  oxidation  with  Caro's  acid. 
These  reactions  lead  to  the  conclusion  that  anthranile  is  an  anhydride 
or  inner  ether  of  the  unstable  o-hydroxylamino-benzaldehyde 

C6H4<(  (see  B.  36,  3653),  whose  oxime  is  obtained  by  treating 

v.  JN  rKJjj 

it  with  hydroxylamine,  and  whose  nitroso-compound  results  from  the 
action  of  HNO2.  This  view  is  supported  by  the  easy  reduction  of 
anthranile  to  o-amido-benzaldehyde,  and  the  close  relation  to  anthrox- 

i  C—  COOH 
anic  acid  CaH4-   |  ^Q  (<?•*>•)  >  apparent  from  the  analogous  forma- 

tion and  especially  from  the  fact  of  its  passing  into  anthranile  on 
heating  with  water  to  150°  (/.  pr.  Ch.  2,  81,  254).  The  improbability 
of  the  /Mactame  formula  is  also  seen  by  a  comparison  with  dianthra- 
nilide,  which  must  be  taken  as  a  true  molecular  anhydride  of  anthranilic 
acid.  Anthranile  is  easily  obtained  from  the  dimercury  compound  of 
o-nitro-toluol  by  the  action  of  concentrated  HC1.  With  corrosive 
sublimate,  anthranile  forms  a  characteristic  double  compound  C7H5NO. 
HgCl2,  m.p.  178°.  With  chlorine,  it  combines  to  form  a  dichloride 

C6H4{  |      \o  m.p.   77°,  which,  on  heating  with  water,   passes   into 

(NCI/ 

B2-monochlor-anthranile,  m.p.  79°,  with  migration  of  a  chlorine  atom 
B.  42,  1701). 

Methyl-anthranile   C6H4CH^>O,     from     o-nitro-aceto-phenone, 


and    phenyl-anthranile    C6H4C6H5O,   from  o-nitro-  or  o-amido- 


benzo-phenone,  must  be  regarded  as  true  homologues  of  anthranile 
(B.  36,  819,  2042).  Anthranile  derivatives  are  probably  traceable 
in  the  compounds  produced  by  the  condensation  of  o-nitro-benzalde- 
hyde  with  phenols  and  tertiary  amines  in  the  presence  of  concentrated 
HC1  (B.  42,  1714). 

Acetyl-anthranile  C6H4{^°1°CH3  or  c6H4{^°OCHg,  m.p.  8i°,b.p.14 

147°,  from  anthranile  or  acetanthranilic  acid,  as  well  as  carbox-ethyl- 
anthranilic  acid,  with  acetic  anhydride.  It  must  therefore  be  regarded 
as  a  true  anhydride  of  acetanthranilic  acid.  With  NH3  it  yields 
o-acetamido-benzamide  ;  with  aniline  and  other  amine  bases  it  gives 

derivatives     of     methyl  -  dihydro  -  quinazolone     C6H4j  A 

' 


similar  behaviour  is  shown  by  benzoyl-anthranile  CJi«<  or 

WJN  =L/L>j-rijj 

C6H4-[<??r,r,  „  ,  m.p.  122°,  formed  from  benzoyl-anthranilic  acid  by 

Vi  .W  Ov_/V-xg  JuLc 

splitting  off  H2O  ;  from  anthranilic  acid,  benzoyl  chloride,  and  pyridin 
in  the  cold  ;  and  from  anthranile  after  several  hours'  heating  with 
benzoyl  chloride  (B.  35,  3480  ;  36,  2766).  The  very  smooth  formation 
of  acidyl-anthraniles  from  the  acidyl-anthranilic  acids,  as  well  as  the 


304  ORGANIC  CHEMISTRY 

close  relations  to  the  quinazolones,  indicate  the  first  formula  rather 
than  the  second.  This  is  corroborated  by  the  anhydride  formation 
of  those  acyl-anthranilic  acids,  like  benzol-sulphone-anthranilic  acid 
and  picryl-anthranilic  acid,  in  which  the  formation  of  compounds  of 

(CO.O 
the   formula  C6H41        I       *s    difficult,   or  is  impossible,   dimolecular 

anhydrides  being  formed  (see  Dianthranilides,  and  A.  367,  124).  The 
acyl-anthraniles  must  therefore  be  regarded  as  j3,  y-benzo-metoxazins, 
and  are  closely  related  to  the  anhydrides  obtained  from  benzoyl-a- 
amido-acids  ;  cp.  hippuric  acid,  benzoyl-alalin,  etc. 

DIMOLECULAR  ANHYDRIDES  OF  ANTHRANILIC  ACID  (A.  367,  101).  — 
While,  therefore,  anthranile  cannot  be  regarded  as  a  simple  anhy- 
dride of  anthranilic  acid,  dimolecular  true  anhydrides  of  anthranilic 
acid  are  known  :  anthranoyl-anthranilic  acid,  anthranoyl-anthranilic 
anhydride  (anthranoyl-anthranile),  and  dianthranilide,  which  can  all 
be  broken  up  to  obtain  anthranilic  acid. 

Anthranoyl-anthranilic  aeid  NH2[2]C6H4[i]COHN[2]C6H4[i]COOH, 
m.p.  203°,  is  formed  (i)  by  reduction  of  o-nitro-benzoyl-anthranilic 
acid  ;  (2)  by  condensation  of  anthranilic  acid  with  isatoic  anhydride  ; 
and  hence  (3)  as  an  intermediate  product  in  the  industrial  preparation 
of  anthranilic  acid  from  phthalimide,  sodium  hypochlorite,  and  sodium 
hydrate  (/.  pr.  Ch.  2,  80,  i).  On  heating  above  the  melting-point, 
or,  more  easily,  by  the  action  of  thionyl  chloride,  it  liberates  water  and 
passes  into  anthranoyl-anthranilic-acid-0-anhydride,  anthranoyl-anthra- 

nile C6H4{^°C  H  NH  ,  ni.p.  162°,  yellow  needles,  easily  polymerised 
on  heating.  Its  benzol-sulphone  compound  C6H4/^T°'° 

tJN  =U.Ugil4JNxl.olJ2v>e-cl5, 

m.p.  223°,  is  formed  by  the  action  of  benzol-sulpho-chloride  upon 
anthranile  (B.  40,  997).  By  repeatedly  treating  anthranoyl-anthranilic 
acid  with  nitro-benzoyl  chloride,  and  then  reducing,  anhydrides  of 
anthranilic  acid  are  obtained,  which  have  a  polypeptide  character,  e.g. 
NH2C6H4CO.NHC6H4CO.NHC6H4COOH,  etc.  (A.  351,  267). 

Dianthranilide  c6H4{^]]^^^}c6H4,  m.p.  about  330°,  colourless 

needles,  is  obtained  from  its  monoacetyl  compound,  the  product  of 
the  action  of  concentrated  H2S04  and  glacial  acetic  acid  upon  dibenzol- 
sulphone-dianthranilide,  on  boiling  with  NaHO.  It  has  the  character 
of  a  weak  dibasic  acid,  and  yields  a  disodium  salt,  which,  on  methylation 
with  dimethyl  sulphate,  passes  into  N,  N-dimethyl-dianthranilide 

N(CH3).CO 


Boiling  with  concentrated  alkali  breaks  up  the  dianthranilide  into 
two  molecules  of  anthranilic  acid. 


Dibenzol-sulphone-  dianthranilide  c6H4c6H4,  m.p. 

264°,   is  formed  by  heating  benzol-sulpho-anthranilic  chloride  with 
pyridin. 

Carboxyl-anthranilie  dimethyl  ester  and  diethyl  ester,  isatoic  dialkyl 
ester  C6H4(NHCOOCH3)COOCH3,  m.p.  61°,  b.p.12  166°,  and  m.p.  44°, 
b.p.10  174°,  are  obtained  from  phthalimide  chloride,  or  bromide, 
C6H4(CO)2BrN,  by  the  action  of  sodium  alcoholates  ;  further  action 
converts  them  into  the  acid  isatoic  esters  :  earboxy-methyl  and  carboxy- 


AROMATIC  AMIDO-MONOCARBOXYLIC  ACIDS         305 

ethyl-anthranilic  acid  C6H4(NHCO2C2H5)COOH,  m.p.  181°  and  126°, 
also  obtained  from  anthranilic  acid  with  chloroformic  esters,  and  from 
isatoic  anhydride  by  heating  with  alcohols.  Treatment  with  acetyl 

fCO.O 
chloride    converts    them    into    isatoic    anhydride    C6Hj        I     ,    m.p. 

HNH.CO 

233°-240°.  It  was  first  obtained  by  oxidising  a  glacial  acetic  acid 
solution  of  indigo  with  chromic  acid  (H.  Kolbe,  1885),  and,  later,  from 
anthranile  and  anthranilic  acid  by  the  action  of  chloro-carbonic  esters 
(B.  22,  1672).  Also  by  conducting  phosgene  into  sodium-anthranilate 
solution. 

It  is  very  sparingly  soluble  in  water.     Digested  with  alkalies  or 

alkaline  earths,  it  forms  unstable  salts  of  the  formula  Ct 


from  which  CO2  regenerates  isatoic  anhydride.  With  excess  of  alkali, 
salts  of  isatoic  acid  are  first  formed,  and  these,  digested  with  alkalies, 
or,  instantly,  on  adding  acids  and  CO2,  are  broken  up  into  CO2  and 
anthranilic  acid  ;  free  isatoic  acid  can  therefore  not  be  obtained  (B.  32, 
2159  ;  33,  21  ;  /.  pr.  Ch.  2,  79,  281).  Ammonia,  hydrazin,  phenyl- 
hydrazin,  and  hydroxylamine  change  it  into  the  corresponding  amide 
derivatives  of  anthranilic  acid  (B.  19,  R.  65  ;  26,  R.  585). 

Isatoic  anhydride  forms  an  important  intermediate  product  in  the 
industrial  preparation  of  anthranilic  acid  from  phthalimide,  sodium 
hypochlorite,  and  NaHO,  and  can  be  isolated  if  an  excess  of  NaHO  is 
avoided.  The  processes  involved  are  represented  by  the  following 
system  of  formulae  (/.  pr.  Ch.  2,  80,  i)  : 

r  „   /COONa  ClONa        r  w    f  /%       -NaCl 

C*McONH2  l 


r  „    fCO. 
C«H*\N= 


CO.O  NaOH  f  COONa  _.cot>  r  COONa 

CONa  "  C«H*\NHCOONa~ 


Kynuric  acid,  oxalyl-anthranilic  acid,  carbostyrilic  acid  CO2H. 
CONH[2]C6H4[i]CO2H-j-H2O,  becomes  anhydrous  at  100°,  and  melts 
at  180°  with  decomposition.  It  is  formed  from  the  quinolin  deriva- 
tives —  kynurin  (q.v.),  kynurenic  acid  (q.v.),  a-phenyl-quinolin  (q.v.), 
carbostyrile  (q.v.),  aceto-tetrahydro-quinolin,  and  indoxylic  acid  (q.v.)  — 
by  oxidation.  It  is  prepared  synthetically  by  heating  anthranilic  acid 
with  oxalic  acid  to  130°  (B.  17,  401  ;  R.  no).  Its  monoethyl  ester  CO2. 
C2H5CO.NH[2]C6H4[i]CO2H  is  formed  in  the  oxidation  of  the  ester  of 
indoxylic  acid  (B.  15,  778).  It  melts  at  180°. 

Oxalyl-anthranilic  acid  nitrile,  o-cyano-anilic  acid  CO2H.CONH 
[2]C6H4[i]CN,  m.p.  126°.  The  methyl"  ester,  m.p.  139°,  has  been  ob- 
tained by  condensing  o-amido-benzo-nitrile  with  oxalic  ester.  Dilute 
acids  transpose  the  nitrile  into  the  isomeric  4-keto-dihydro-quinazolin- 

/CO.NH 

2-carboxylic  acid  C6H4<        I  (B.  42,  3710). 

XN=CCOOH  v 

Dicyanamino  -  benzoyl    C6H4{^I]CO>^       (Anschiitz)   melts    with 

U  [2jN  =C.CN 

decomposition.      It   results    from    cyanogen   and   o  -  amido  -  benzoic 
acid  in   aqueous  solution  (B.  11,  1086).     Ethoxy-cyanamino-benzoyl 

f[i]CO.N 

C6H4-!  melting  at  173°,  is  formed   from  cyanogen  and 

i[2]NH.C.OC2H6 

VOL.  II.  X 


306  ORGANIC  CHEMISTRY 

anthranilic  acid  in  alcoholic  solution  (B.  11,  1986).     Ammonia  changes 

( [i]CO.N 
it  to  o-benzo-glyco-eyamidin,  benzoylene-guanidin  C6HJ  y 

[  [2JNH.C  :  NH2 
which   CH3I,   in  strong   alkaline   solution,   converts   into   a-o-benzo- 

r[i]co N 

creatinin  C6HJ  ||  (B.  13, 977). 

1[2]N(CH3)— C:NH2   V 

Methyl-anthranilic  acid  CH3NH[2]C6H4[i]COOH,  m.p.  182°,  from 
anthranilic  acid  with  soda  and  methyl  iodide  or  dimethyl  sulphate  in 
methyl  alcoholic,  or  aqueous,  solution  ;  also  from  o-chloro-benzoic  acid 
with  methyl-amine  and  copper  (C.  1903,  II.  1099).  Methyl  ester  CH3 
NHC6H4COOCH3,  b.p.13  129°  (C.  1902,  II.  1257).  The  acid  is  converted 
into  indoxyl  (and  indigo)  by  heating  with  NH2Na,  alkali,  or  amalgams 
of  alkaline  earth  metals  ;  this  conversion  is  even  more  direct  in  the 
case  of  the  acyl-methyl-anthranilic  acids :  formyl-methyl-anthranilie 
acid  CHON(CH3)C6H4COOH,  m.p.  169°,  and  formyl-ethyl-anthra- 
nilic  acid,  m.p.  119°,  obtained  from  methyl-  and  ethyl-quinolinium  salts 
by  oxidation  with  permanganates  (B.  36,  1806  ;  C.  1903,  I.  745). 

Nitroso-methyl-anthranilic  acid  NO.N(CH3)C6H4COOH,  m.p.  127°, 
from  methyl-anthranilic  acid  with  HNO2  or  oxidation  of  nitroso- 
methyl-o-toluidin  with  MnO4K  (B.  34,  1644).  Hydrochloric  acid 
transposes  it  into  5-nitroso-methyl-anthranilic  acid  NO[5]C6H3[2] 
NHCH3[i]COOH,  which,  on  boiling  with  soda  solution,  splits  off  methyl- 
amine,  and  passes  into  5-nitroso-salicylic  acid  (B.  42,  2745).  On  fur- 
ther methylation,  methyl-anthranilic  acid  passes  into  dimethyl-anthra- 
nilic  acid  (CH3)2N[2]C6H4[i]COOH,  m.p.  70°,  from  which  anthranilic 

betain,  o-benzo-beta'in  C6H4/^CH3)3\O,  m.p.  227°,  is  generated.     The 

t  UL) / 

latter,  on  heating  to  240°,  transposes  into  dimethyl-anthranilic  methyl 
ester,  b.p.1]L  131°  (B.  37,  411  ;  cp.  m-  and  p-amido-benzoic  acid,  and 
anilido-acetic  acid  ;  also  Betain,  Vol.  I.). 

Ethyl-anthranilic  acid,  m.p.  153°,  see  B.  39,  3236.  Diethyl-an- 
thranilic  acid,  m.p.  121°,  M.  25, 487. 

Aryl-anthranilic  acids  are  formed  by  heating  o-chloro-benzoic  acid 
with  aromatic  amines,  in  the  presence  of  copper  (A.  355,  312).  On 
heating  alone,  they  split  off  CO2,  and  pass  into  diphenyl-amines  ;  and 
on  heating  with  concentrated  SO4H 2,  into  acridone.  Phenyl-anthranilic 
acid  C6H5NHC6H4COOH,  m.p.  181°,  is  also  obtained  by  de-amidating 
amido-phenyl-anthranilic  acid.  Diphenyl-anthranilic  acid  (C6H5)2 
NC6H4COOH,  m.p.  208°,  from  phenyl-anthranilic  acid,  iodo-benzol, 
and  copper.  On  heating,  it  decomposes  into  CO2  and  triphenyl-amine 
(B.  40,  2448).  Picryl-anthranilic  acid  (NO3)3C6H2NHC6H4COOH, 
m.p.  272°  (A.  367, 118).  Diphenyl-amine-o,  o'-,  -o,  m'-  and  o,  p'-diearb- 
oxylic  acid  CO2HC6H4NHC6H4CO2H,  m.p.  295°,  296°,  and  290°  with 
decomposition,  from  o-chloro-benzoic  acid  with  o-,  m-,  and  p-amido- 
benzoic  acid  (A.  355,  352).  Sym.  diphenyl-p-phenylene-diamine-o,  o'- 
dicarboxylic  acid  CO2H[i]C6H4[2]NH[i]C6H4[4]NH[2]C6H4[i]CO2H, 
m.p.  288°  with  decomposition,  from  p-dibromo-benzol,  anthranilic  acid, 
and  copper  (C.  1906,  II.  932). 

Formaldehyde  condenses  with  anthranilic  acid  in  various  molecular 
ratios,  according  to  the  conditions. 

Methylene-dianthranilie  acid,  formaldehyde-dianthranilic  acid  CH2 


AROMATIC  AMIDO-MONOCARBOXYLIC  ACIDS         307 

(NH[2]C6H4COOH)2,  m.p.  158°  with  decomposition,  from  2  molecules 
anthranilic  acid  and  I  molecule  formaldehyde  solution,  is  transposed  by 
methyl-alcoholic  HC1  into  p2-diamido-diphenyl-methane-diearboxylie 
acid  CH2[C6H3(NH2)COOH]2  ;  by  acetylation  with  acetic  anhydride 
and  sodium  acetate,  we  obtain  methylehe-diaeeto-anthranilie  acid  CH2 
[N(COCH3)C6H4COOH]2.  Potassium  cyanide  splits  up  formaldehyde- 
dianthranilic  acid  into  anthranilic  acid  and  anthranilido-aceto-nitrile 
(A.  324,  1  1  8).  By  the  condensation  of  equimolecular  quantities  of  for- 
maldehyde and  anthranilic  acid,  and  its  N-mono-substitution  products 
(CO2HC6H4NHR),  we  obtain  compounds  insoluble  in  alkalies,  the  so- 
called  formalities,  which  may  be  used  for  characterising,  and  isolating, 
substituted  anthranilic  acids,  since  they  are  easily  dissolved  into  their 
components  on  heating  with  acids  or  alkalies.  Anthranilic  formalide 

,  m.p.  i45°-i48°  with  decomposition  ;  phenyl-anthranilic 


By   treating   with    KCN    or   alkaline    bisulphite,    the    formalides 
are  split  up,  with  formation  of  salts  of  cu-cyano-methyl-anthranilic 

acids     c«H4<l2CN'     and     w  "  sulPho  "  methyl  -  anthranilic     acids 


With  excess  Qf  formaldehyde>  anthranilic  acid 

combines,  on  heating,  to  form  anthranilic  diformalide  ;  it  forms  a 
heavy  yellow  oil  insoluble  in  alkali,  combining  with  I  molecule  KCN 
to  a  mononitrile  C8H4<f  NjjCH,.CN)  .CH2^  m  0^  and  with  2  moiecuies 

\O(_)  -  O 

KCN  to  anthranilido-diaceto-nitrile  C6H4<(^^CN)2,  m.p.  i68°-i7i° 

with  decomposition  (B.  42,  3534;  C.  1910,  1.  309).  Methylene-anthra- 
nilic  acid  CO2HC6H4N  :  CH2,  m.p.  about  210°  (B.  41,  1565). 

Anthranilido-acetic  acid,  phenyl-glycin-o-carboxylic  acid  COOH[2] 
C6H4NHCH2COOH,  m.p.  215°  with  decomposition,  has  acquired  great 
technical  importance  on  account  of  its  transformation  into  indoxyl 
and  indigo.  It  is  formed  :  (i)  from  chloracetic  acid  and  anthra- 
nilic acid,  in  neutral  solution  ;  with  excess  of  chloracetic  acid  we  obtain 
anthranilido-diacetic  acid  COOHC6H4N(CH2COOH)2,  m.p.  212°  with 
decomposition  (B.  33,  3182)  ;  (2)  from  anthranilic  acid  on  heating 
with  multivalent  alcohols,  like  glycerine,  mannite,  etc.  (C.  1900,  II. 
549)  ;  (3)  by  saponification  of  anthranilido-aceto-nitrile  COOH[2]C6H4 
NHCH2CN,  m.p.  181°  with  decomposition,  which  is  obtained  from 
anthranilic  acid,  formaldehyde,  and  KCN,  or  by  splitting  up  formalde- 
hyde-dianthranilic  acid,  or  anthranilic  formalide  with  KCN  (A.  324, 
118  ;  /.  pr.  Ch.  2,  63,  392  ;  B.  39,  989)  ;  (4)  from  o-chloro-benzoic 
acid,  by  heating  with  glycocoll  in  the  presence  of  alkaline  carbonate 
and  copper  (C.  1903,  II.  81,  610).  On  heating  with  caustic  alkalies,  or 
acetic  anhydride  and  sodium  acetate,  the  acid  passes  into  indoxyl  and 
its  derivatives,  which  are  easily  converted  into  indigo  : 

/NHCH,CO,H  _  „  /NH 

\  COOH  -*  2C'HM 


The  esters  :  dimethyl  ester,  m.p.  97°  ;    diethyl  ester,  m.p.  75°,  are 
condensed  by  means  of  sodium  ethylate  to  indoxylic  acid  esters.     The 


5o8  ORGANIC  CHEMISTRY 

condensation  of  anthranilido-acetic  acid,  and  its  esters,  is  facilitated  by 
introducing  acyl,  or  alkyl,  groups  into  N-position. 

Aeetanthranilido-aeetic  acid  COOHC6H4N(COCH3)CH2COOH,  m.p. 
214°  with  decomposition  ;  diethyl  ester,  m.p.  64°.  Methyl-anthranilido- 
acetie  acid  COOHC6H4N(CH3)CH2COOH,  m.p.  189°  with  decomposi- 
tion (B.  35,  1683  ;  C.  1903,  I.  305).  Phenyl-anthranilido-acetic  acid 
COOHC6H4N(C6H5)CH2COOH,  m.p.  166°  ;  its  nitrile  is  formed  from 
phenyl-anthranilic  formalide  with  KCN  (C.  1910,  I.  309). 

p-Sulpho-anthranilic  acid  SO8H[4]NH2[2]CeH8COOH  is  formed 
from  o-nitro-toluol-sulphonic  acid  with  NaHO,  in  a  manner  analogous 
to  the  formation  of  anthranilic  acid  from  o-nitro-toluol  (C.  1903,  1.  371). 

3,  5-Dibromo-anthranilic  acid  from  o-nitro-toluol  with  bromine  (M. 
28,  987)  .  Of  the  six  possible  isomeric  diehloro-anthranilie  acids,  five  are 
known  (  B.  42,  3533  ;  C.  1910,  1.  310).  Tetraehloro-anthranilic  acid  C14C6 
[2]NH2[i]CO2H,  m.p.  182°,  from  tetrachloro-phthalic  anhydride  (B.  42, 
3549).  5-Nitro-anthranilic  acid  NO2[5]NH2[2]C6H3CO2H,  m.p.  269°,  is 
obtained  from  its  aceto-compound,  m.p.  221°,  which  results  from  the 
oxidation  of  nitro-aceto-toluide  with  (MnO4)Ca  (B.  36,  1801)  ;  besides 
the  isomeric  acid  NO2[4]NH2[2]C6H3CO2H,  it  is  formed  from  4-nitro- 
phthalimide  with  KOBr  (C.  1902,  II.  359).  In  the  same  way,  3-  and 
6-nitro-anthranilic  acids,  m.p.  203°  and  180°  with  decomposition,  are 
formed  from  3-hitro-phthalimide  with  KOBr.  Dinitro-anthranilic 
acid  (NO2)2[3,  5]NH2[2]C6H2COOH,  m.p.  265°,  from  dinitro-chloro- 
benzoic  acid  with  NH3  (C.  1901,  II.  545). 

Hetero-ring  Formations  of  Anthranilic  Acid  and  its  Derivatives.  — 
It  is  evident  from  the  formation  of  acidyl  anthraniles,  isatoic  anhydride, 
indoxyl,  and  other  substances  mentioned  above,  that  anthranilic  acid 
and  its  derivatives  are  very  prone  to  the  formation  of  heterocyclic 
ring  systems,  and  "  ortho-condensation."  (Compare  o-amido-benzyl 
alcohol,  o-amido-benzaldehyde,  and  o-amido-aceto-phenone.) 

Acetyl-anthranilic  acid  and  phenol  condense,  on  heating,  to  acri- 
done,  which  also  results  in  digesting  phenyl-anthranilic  acid  with  con- 
centrated sulphuric  acid  (B.  25,  2740).  Anthranilic  acid  condenses 
with  aceto-phenone  and  aceto-acetic  ester  to  quinolin  derivatives 
(B.  27,  1396)  : 

—  H20 


]COOH  '  CH2.C02C2H5 


+ 


Co.CH3 


[i]COOH     CH3  -2H20  /C(OH)  =CH          a-Phenyl-y-oxy- 

O]NH2     +CO.C6H6  4\N=C.C6H5         quinolin. 


o-Benzoylene-urea  is  formed  on  heating  anthranilic  acid  and  anthra- 
nil-amide  with  urea.  It  also  results  upon  heating  carboxethyl-o- 
amido-benzamide  (B.  2,  416  ;  22,  R.  196),  as  well  as  by  the  action  of 
mineral  acids  upon  uramido-benzoic  acid  (B.  27,  976).  Keto-dihydro- 
quinazolins  are  produced  on  heating  formyl-,  acetyl-,  and  benzoyl-o- 
amido-benzamide.  The  jS-methyl  compound  is  formed  in  the  action 
of  acetamide  upon  anthranilic  acid,  and  ammonia  upon  ethyl-acet- 
amido-benzoic  ester  (B.  20,  R.  630  ;  22,  R.  196  ;  27,  R.  516  ;  C.  1903, 
I.  174,  1270).  a-Phenyl-j3-keto-dihydro-quinazolin  results  from  heat- 
ing anthranilic-acid  ester  with  benzimido-ethyl  ester  (C.  1906,  II.  1124). 


AROMATIC  AMIDO-MONOCARBOXYLIC  ACIDS         309 

The  condensation  products  of  o-amido-benzoic  acid  and  cyanogen  gas 
have  been  described  and  formulated  : 


CaH4{ 


[i]COOH 

_[2]NH.CO.NH2  \       c  H  /CO— NHo-Benzoylene-urea 

H    f[i]CONH2  —  0,11.0)"*'     6    4\NH— CODiketo-tetrahydro-quinazolin 

6    4 1[2]NH.COOC2HS  ~ 


TT  /[i]C02C2H5        NH\r  r  „  -2c,H«or  „  /CO.N  a-Phenyl-tf-keto- 

C6lH[2]NH2       +C2H50/  6    4lNH.CC8H6  dihydro-quinazolin. 

Nitrous  acid  converts  anthranil-amide  directly  into  benzazimide, 
whereas  the  o-diazo-benzoic  ester  first  resulting  from  anthranilic  ester 
must  be  treated  with  ammonia  to  effect  this  change.  Similarly,  an- 
thranilic thio-amide  gives  rise  to  thio-benzazimide  (B.  42,  3719). 

o-Diazo-amido-benzol-carboxylie  ester,  m.p.  76°,  on  boiling  with 
alcohol,  gives  a-phenyl-pheno-J3-triazone  or  benzazanile  (B.  21,  1538, 
R.  57i  ;  /•  pr-  Ch.  2,  64,  70)  : 


m-  and  p-Amido-benzoic  acid  melt  at  173°  and  186°  respectively. 
Their  aceto-compounds,  melting  at  250°  and  256°,  result  when  m-  and 
p-aceto-toluide  are  oxidised  by  permanganates  (B.  36,  1801)  ;  p-amino- 
benzo-nitrile,  m.p.  86°  (see  C.  1903,  II.  113).  m-Amino-benzo-nitrile, 
m.p.  53°  (see  C.  1904,  II.  100).  m-  and  p-Methyl-amido-benzoie  acid 
CH3NHC6H4CO2H,  m.p.  127°  and  161°,  are  produced  by  methylating 
the  amido-acids  with  dimethyl  sulphate  (B.  43,  210  ;  42,  3744)'.  The 
p-methyl-amido-benzoic  acid  is  obtained,  by  nuclear  synthesis,  from 
the  magnesium-iodide  compound  of  methyl-aniline  C6H5N(CH3)MgI, 
by  the  action  of  CO2  and  transposition  of  the  first  product,  a  carbamin- 
ate  C6H5N(CH3)COOMgI,  by  heating,  in  a  process  akin  to  the  synthesis 
of  salicylic  acid.  From  N-methyl-  and  ethyl-o-toluidin,  in  a  similar 
manner,  p-methyl-amido-  and  p-ethyl-amido-m-methyl-benzoie  acids 
are  generated,  melting  at  201°  and  170°  respectively.  Dimethyl- 
aniline  and  diethyl-aniline  react  similarly  with  CH3MgI  and  CO2, 
forming  p-dimethyl-  and  p-diethyl-amido-benzoic  acid,  m.p.  236°  and 
193°  (B.  42,  4488,  4815). 

By  methylation  with  ICH3  and  KOH,  m-  and  p-amido-benzoic 
acids,  like  anthranilic  acid,  yield  compounds  resembling  betain 

C6H4/^^:H3^3No,  which,  on  heating,  isomerise  to  m-  and  p-dimethyl- 

amido-benzoic  ester  (B.  37,  414).  p-Amido-benzoic-diethyl-amino- 
ethyl  ester  NH2[4]C6H4[i]COOCH2CH2N(C2H5)2-f-2H2O,  m.p.  51°, 
melting  at  61°  when  anhydrous,  results  from  the  interaction  of 
p  -  nitro-benzoyl  chloride  and  ethylene  chloro-hydrin,  followed  by 
reduction  and  transformation  with  diethyl-amine.  Its  monochloro- 
hydrate,  m.p.  156°,  is  used  as  a  local  anaesthetic  under  the  name  of 
Novocain  (A.  371,  125). 

Chrysanisic   acid,  3,  5-dinitro-4-amido-benzoie  acid 


3io  ORGANIC  CHEMISTRY 

C6H2CO2H,  melting  at  259°,  consists  of  golden-yellow  flakes,  and  is 
produced  when  3,  5-dinitro-4-methoxy-benzoic  acid  is  heated  with 
aqueous  ammonia. 

Diamido-benzoic  acids  (NH2)2C6H3CO2H  are  prepared  by  reducing 
the  dinitro-  and  the  nitro-amido-benzoic  acids.  2,  4-Diamido-benzoie 
acid  (NH2)2[2,  4]C6H3COOH  is  obtained  from  its  diaceto-compound 
(B.  36,  1803).  The  acids  break  down  in  dry  distillation  into  carbon 
dioxide  and  phenylene-diamines.  Like  the  o-phenylene-diamines,  the 
diamido-benzoic  acids,  containing  two  amido-groups  in  the  ortho- 
position  with  reference  to  each  other,  readily  yield  heterocyclic  deriva- 
tives —  e.g.  nitrous  acid  converts  3,  4-diamido-benzoic  acid  into  3,  4- 
azimido-benzoic  acid  (B.  15,  1880).  Them,  p-  and  the  p,  m-amido-ur- 
amido-benzoic  acids  yield  two  different  uramido-azimido-benzoic  acids, 
which  afford  the  same  azimido-benzoic  acid  by  saponification  (B.  29, 
R.  586).  The  2,  3-diamido-benzoic  acid  forms  characteristic  com- 
pounds, with  many  varieties  of  sugar. 

3,  4,  5-Triamido-benzoie  acid  (NH2)3.C6H2.CO2H,  from  chrysanisic 
acid  by  reduction,  breaks  down,  when  heated,  into  CO2  and  i,  2,  3-tri- 
amido-benzol  (A.  163,  12).  2,  3,  5-Triamido-benzoic  acid  (B.  15,  2199), 
from  dinitro-anthranilic  acid  (C.  1902,  II.  1293). 

Many  amido-acids,  derived  from  alkyl-benzoic  acids,  are  known  ; 
also  haloid  amido-acids,  nitro-amido-acids,  etc. 

Amido-phenyl-fatty  acids  are  obtained  from  the  nitro-phenyl-fatty 
acids.  Certain  o-amido-phenyl-fatty  acids  are  particularly  note- 
worthy because  of  their  tendency  to  form  inner  anhydrides  :  y-  or  8- 
lactames  (I.  359),  which  is  so  great  that  the  corresponding  free  o-amido- 
acids  are  not  capable  of  existing  —  e.g.  o-amido-phenyl-acetic  acid  and 
o-amido-phenyl-hydro-cinnamic  acid. 

m-  and  p-Amido-phenyl-acetic  acids  melt  at  149°  and  200°. 

m-  and  p-Amido-hydro-cinnamic  acids     ,,       84°    ,,     131°. 

4-  Amido-^-nitro-hydro-cinnamic  acid,  from  p-acetamido-hydro- 
cinnamic  acid,  melts  at  145°. 

p-  Amido-hydratropic  acid,  melting  at  128°. 

y-  and  S-Lactames  of  the  o-Amido-phenyl-fatty  Acids.—  Oxindol, 

the  lactame  of  o-amido-phenyl-acetic  acid,  c«H4/r          '      '  melting  at 


120°,  is  obtained  by  the  reduction  of  o-nitro-phenyl-acetic  acid  with 
tin  and  hydrochloric  acid,  and  from  dioxindol  with  sodium  amalgam. 
If  heated  to  150°  with  baryta  water  it  is  converted  into  the 
barium  salt  of  o-amido-phenyl-acetic  acid,  from  which  oxindol  is 
separated  by  acids  (B.  16,  1704).  Nitrous  acid  converts  it  into  isat- 
oxime  (q.v.). 

Oxindol     boiled     with     acetic     anhydride    yields     aceto-oxindol, 

-00         '  melting  at  126°.     It  dissolves  to  aceto-o-amido- 

phenyl-acetie  acid3  CH3.CO.NH.C6H4.CH2.CO2H,  melting  at  142°. 
Heated  with  alkalies  or  acids  it  breaks  down  into  oxindol  and  acetic  acid. 
p-Amido-oxindol  NH2.C8H6NO,  melting  about  200°,  is  formed  by 
the  reduction  of  2,  4-dinitro-phenyl-acetic  acid  with  tin  and  hydro- 
chloric acid.  If  ammonium  sulphide  be  used  as  the  reducing  agent, 
the  product  will  be  ^-amido-2-nitro-phenyl-acetic  acid,  melting  at  185° 
(B.  14,  824)  ;  compare  o-nitro-phenyl-iso-nitroso-acetic  acid. 


6H4/ 


DIAZO-BENZOIC  ACIDS  311 

Atroxindol,  lactame  of  o-amido-hydratropic  acid, 

melts  at  119°. 

Hydrocarbo-styrile,  lactame  of  amido-hydro-cinnamic  acid,  melting  at 
163°,  is  formed  by  the  reduction  of  o-nitro-hydro-cinnamic  acid  with  tin 
and  hydrochloric  acid  (Glaser  and  Buchanan,  1869)  (B.  15,  2103)  ;  by 
heating  hydrocarbo-styrile-carboxylic  acid,  resulting  from  the  reduction 
of  o-nitro-benzyl-malonic  acid  (B.  29,  667)  ;  and  from  hydrindone 
oxime  by  Beckmann's  transposition  (B.  29,  667). 

Hydrocarbo-styrile  has  the  same  relation  to  quinolin  that  oxindol 
bears  to  indol  : 


oa  Hydrocarbo-styrile     C.H4  Quinolin. 

p-Amido-hydroearbo-styrile  NH2C9H8NO,  m.p.  211°,  is  formed, 
together  with  4-amido-2-nitro-hydro-cinnamic  acid,  melting  at  139°, 
from  2,  4-dinitro-hydro-cinnamic  acid. 

7.  Diazo-benzoic  Acids  are  produced  from  the  mineral  acid  salts  of 
the  amido-benzoic  acids  with  nitrous  acid,  just  as  the  ordinary  diazo- 
bodies  are  obtained  from  the  aniline  salts.     Nitrous  acid  converts  the 
amide  of  o-amido-benzoic  acid  into  benzazimide.    The  free  diazo- 
benzoic  acids  are   very  unstable.     The   diazide  of   anthranilic   acid 

C6H4/^^  DS)>O  consists  of  white,  glistening  needles.      It  is  obtained 

L[2]N2  / 

when  the  chloride  is  acted  upon  with  silver  oxide  (B.  29,  1535). 

8.  Diazo-amido-benzoic   Acids  are   formed  when  nitrous  acid  is 
conducted  into   the   alcoholic   solution   of   the   amido-benzoic   acids. 
Diazo-m-amido-benzoic    acid    CO2H[i]C6H4[3]N=N-NH[3']C6H4[i'] 
CO2H  is  an  orange-red  powder.     Hydrofluoric  acid  converts  it  into 
m-fluoro-benzoic  acid. 

N\ 

9.  Diazo  -  imido  -  benzoie     Acids     ||  )>N.c6H4co2H     result     when 

w 

ammonia  acts  upon  the  perbromides  of  diazo-benzoic  acids,  or  when 
hydrazin-benzoic  acids  are  treated  with  nitrous  acid.  The  o-body 
melts  at  about  70°  ;  the  meta-  at  160°  ;  and  the  p-compound  at  185° 
(B.  9,  1658). 

/N.C6H4CO2H 

10.  Azoxy-benzoic  Acids  o<  |  are  formed  in  the  reduction 

XN.C6H4CO2H 

of  the  nitro-benzoic  acids  with  alcoholic  potash.  The  o-derivative  is 
also  produced  when  n-oxy-indol-carboxylic  acid  (q.v.)  is  oxidised  with 
alkaline  potassium  permanganate  (B.  17,  1904  ;  24,  R.  666;  29,  656). 

N.C6H4.CO2H 

11.  Azo-benzoic  Acids    |  '    .     These  result  from  the  action 

N.C6H4.CO2H 

of  sodium  amalgam  upon  the  nitro-benzoic  acids  ;  or  from  the  action 
of  zinc  dust  and  NaHO  in  alcoholic  solution  upon  the  same  ;  or  from 
the  action  of  highly  concentrated  NaHO  upon  nitro-benzaldehydes 
(B.  34,  4132  ;  C.  1904,  1.  722).  o-,  m-,  and  p-Azo-benzoic  acid  decom- 
pose on  melting.  By  the  distillation  of  the  calcium  salts,  azo-phenylene, 
or  phenazin,  is  formed. 

Azo-benzol-o-monocarboxylic  acid  C6H5N2[i]C6H4[2]COOH,  m.p. 
92°,  and  its  homologues,  result  from  the  condensation  of  o-nitro- 
benzoic  acid  with  primary  anilines  (C.  1909,  I.  69).  PC15  converts 


312  ORGANIC   CHEMISTRY 

them  into  y-oxy-fi-phenyl-indazols  (q.v.)  (C.  1907,  I.  469).  Azo-benzol- 
m-monoearboxylic  acid,  m.p.  171°.  Azo-benzol-p-monocarboxylic  acid 
C6H5N2C6H4[4]COOH,  m.p.  238°,  is  obtained  from  p-amido-azo-benzol, 
by  way  of  the  cyanide,  and  from  benzol-azo-p-toluol  by  oxidation  with 
chromic  acid  (A.  303,  385). 

o-Tolyl-azo-benzoic  acid  CH3[2]C6H4N  :  NC6H4[2]COOH,  m.p.  148°, 
from  o-nitro-toluol  by  the  action  of  finely  divided  metals  and  alkaline 
hydrate  (C.  1903,  II.  973).  m-  and  p-Benzaldehyde-azo-m-  and 
-p-benzoie  acid  CHOC6H4N2CgH4COOH  is  formed  from  m-  and  p-azoxy- 
benzaldehyde  by  transposition  with  concentrated  H2SO4  (B.  36, 
3469,  3801). 

12.  Hydrazin-benzoie  Acids. — The  symmetrical  hydrazo-benzoic 
acids  result  when  the  azo-benzoic  acids  are  reduced  with  sodium 
amalgam,  or  with  ferrous  sulphate  and  sodium  hydroxide.  o-Hydrazo- 
benzoic  acid  melts  at  205°.  m-Hydrazo-benzoic  acid  CO2H[3]C6H4 
[i]NH.NH[i']C6H4[3']CO2H.  These  two  acids,  .  when  boiled  with 
hydrochloric  acid,  rearrange  themselves  to  diamido-diphenyl-dicar- 
boxylic  acids  (q.v.).  The  rearrangement  of  the  m-acid  into  p-diamido- 
diphenic  acid  is  of  importance  for  the  proof  of  the  constitution  of 
diphenic  acid  (q.v.),  and  consequently  that  of  phenanthrene. 
p-Hydrazo-benzol-carboxylie  acid  C6H5NHNHC6H4[4]COOH,  m.p.  193°, 
on  transposition  gives  benzidin,  with  liberation  of  CO2  (A.  303,  384). 

o-,  m-  and  p-Hydrazin-benzoie  acids  NH2.NH.C6H4.CO2H  result 
when  the  hydrochlorides  or  nitrates  of  diazo-benzoic  acids  are  reduced. 

o-Cyano-phenyl-hydrazin  NH2NH[2]C6H4CN,  m.p.  153°,  from 
o-diazo-benzo-nitrile  by  reduction,  seems  also  to  be  formed  by  the 

reduction  of  the  pheno-j8-triazone  oxime  C6H4|^(NOH)-^H  (B.  36,  805). 

o-,  m-,  p-Benzoie-thionyl-hydrazone  SO  :  NNHC6H4COOH,  m.p. 
155°,  231°,  258°  (B.  27,  2555).  Benzylidene-o-hydrazin-benzoic  acid 
C6H5CH  :  NNH.C6H4COOH,  m.p.  224°,  is  reduced  by  sodium  amalgam 
to  o-benzyl-hydrazin-benzoic  acid  C6H5CH2NHNHC6H4COOH,  m.p. 
134°  with  decomposition.  On  heating  alone,  or,  better,  with  POC13  in 
an  open  vessel,  o-hydrazin-benzoic  acid  yields  an  inner  anhydride, 

o-hydrazin-benzoie  lactazame  C6H4^NH/NH,  m.p.  242°  with  decom- 
position; while,  on  heating  with  POCL  under  pressure,  chlorindazol 
CCK 

>NH  is  formed  (B.  35,  2315). 


(CC 
6H4j    I 


13.  Phosphine  -  benzoic    Acids.  —  Trimethyl-phospho-p-benzo-beta'in 

r  [i]CO \ 

C6H4«c  r4-ip/cH  )  /°  *s  obtained  from  p-tolyl-trimethyl-phosphonium 
chloride  by  oxidation  with  alkaline  permanganate  ;  similarly,  the 
trimethyl  -  phospho  -  tolu  -  betain  is  formed  from  trimethyl  -  xylyl  - 
phosphonium  chloride  (B.  31,  2919). 

14.  Sulpho-benzoie  Acids. — On  conducting  the  vapours  of  SO3  into 
benzoic  acid,  we  obtain  as  chief  product  m-sulpho-benzoic  acid,  and  in 
smaller  amount  p-sulpho-benzoic  acid  (A.  178,  279). 

The  three  isomerides  can  be  obtained  by  oxidising  the  three  toluol- 
sulphonic  acids  with  an  alkaline  solution  of  potassium  permanganate. 

If  the  toluol  sulphamides,  instead  of  the  free  acids,  be  subjected  to 
similar  oxidation,  the  m-  and  p-toluol  sulphamides  yield  m-  and  p-  sulph- 


SULPHO-BENZOIC  ACIDS  313 

amine-benzoic  acids  ;  whereas  the  o-toluol  sulphamide  changes  to 
benzole  sulphinide,  or  anhydro-sulphamine-benzoic  acid,  called 
saccharin  (B.  12,  469),  from  which,  by  saponification  with  HC1,  the 
o-sulpho-benzoic  acid  is  obtained  (B.  33,  3485).  o-  and  p-sulpho- 
benzoic  acid  are  formed  together  on  boiling  potassium-m-nitro-benzol 
sulphonate  with  an  aqueous  solution  of  KI  ;  as  in  the  formation  of 
chloro-benzoic  acids  from  halogen  nitro-benzols  with  KCN,  the  entering 
cyanogen  group  does  not  take  the  place  of  the  expelled  nitro-group 
(C.  1905,  II.  230). 

o-Sulpho-benzoic  acid  SO3H[2]C6H4CO2H+3H2O,  m.p.  141°  (anhy- 
drous) behaves  somewhat  like  phthalic  acid  (q.v.).  It  forms,  for 
instance,  phthale'ins  (q.v.)  (C.  1898,  II.  717,  1105),  an  anhydride,  and 
an  imide.  By  the  action  of  PC15  two  dichlorides  are  obtained,  m.p. 
40°  and  79°,  the  more  stable  one  with  the  higher  melting-point  being 

probably   represented   by   the    formula  C6H4<        ri,   and    the    other 

V.  v3v-/2^-'-l 

by    the    formula    C6H4/      2\D.      On    boiling    with    alcohols    they 

yield  ester-sulphonic  acids  SO3HC6H4COOR  ;  with  sodium  ethylate, 
o-sulpho-benzoic-diethyl  ester,  b.p.22  212°  ;  with  ammonia,  the  sym. 
chloride  (m.p.  79°)  gives  benzoyl  sulphinide,  while  the  unsym. 
unstable  chloride  gives  chiefly  o-eyano-benzol-sulphonic  acid  CN[i] 
C6H4[2]SO3H,  m.p.  279°  (chloride,  m.p.  67-5°),  which  has  also  been 
obtained  from  o-aniline-sulphonic  acid  by  way  of  the  diazo-compound 
(B.  28,  R.  751).  With  aniline  the  chlorides  form  o-sulpho-benzoic 

anile  C6H4<^°2)>NC6H5,  m.p.  190°,  sym.  dianilide  C6H4(CONHC6H5) 
S02NHC6H5,  m.p.  195°,  and  unsym.  dianilide  C6H/^NHC«H6)8 

- 


m.p.  270°-28o°  with  decomposition  ;  while,  with  POC13,  the  two  last  give 
the  dianile  c6H/^:  NC6H5^NC6H5,  m.p.  189°. 

\oCj2   -  r- 

On  reduction  the  unstable  chloride  gives  sulpho-benzide,  and  the 
stable  chloride  gives  thio-salicylic  acid  SH.C6H4COOH.  Condensation 
with  benzene  and  A12C16  gives  mainly  the  sym.  product  C6H5COC6 
H4SO2C6H5.  The  unsym.  triphenyl-methane  derivative  is  also  obtained, 

(C6H5)2C.C6H4SO26  (B.  31,  1648  ;  C.  1906,  II.  329).  p-Nitro-  and 
p-bromo-o-sulpho-benzoic  acids,  with  PC15,  also  give  two  isomeric 
dichlorides  each,  which  are  transformed  in  a  similar  manner  (C.  1904, 
I.  274,  369). 

o-Sulpho-benzoic  anhydride,  m.p.  118°,  from  the  acid  with  acetyl 
chloride.  With  benzene  and  Al  chloride  it  yields  benzo-phenone-o- 
sulphonic  acid  C6H5CO.C6H4SO3H  (B.  33,  3486)  ;  the  isomeric  phenyl- 
sulphone-o-benzoic  acid  C6H5.SO2.C6H4COOH,  m.p.  268°,  is  formed 
from  phenyl-o-tolyl  sulphone  by  oxidation  (C.  1901,  I.  692). 

o-Sulpho-chloride-benzoie  methyl  ester  SO2C1.C6H4COOCH3,  m.p. 
65°,  from  o-benzo-sulphinic-acid  ester  SO2H.C6H4COOCH3,  m.p.  99°, 
treated  with  chlorine.  This  ester  is  prepared  from  anthranilic  acid 
ester  by  diazotating,  and  replacing  the  diazo-group  by  the  sulphinic 
residue  (C.  1901,  II.  961). 

o  -  Sulphamido  -  benzoic  acid  NH2SO2[2]C6H4[i]COOH  melts  at 
I53°-I55°,  with  transition  into  the  sulphinide,  Methyl  and  ethyl 


3i4  ORGANIC  CHEMISTRY 

ester,  m.p.  119°  and  84°  respectively  (C.  1899,  I.  1093).  The  acid  is 
formed  by  the  oxidation  of  o-toluol-sulphamide  with  red  prussiate  of 
potash  (B.  19,  R.  689),  and  from  its  inner  anhydride  with  warm  alkaline 
hydrate.  On  fusing  sulpho-benzoic  acid  with  ammonium  sulpho- 
cyanide  the  isomeric  o-benzamido-sulphonic  acid  is  formed,  C6H4 
(CONH2)SO3H,  m.p.  194°,  which,  with  potassium  hypobromite,  yields 
o-sulphanilic  acid  (B.  29,  R.  102). 

o  -  Anhydro  -  sulphamine  -  benzole       aeid,       benzoic       sulphinide 

Je  >  /NH>  called  saccharin,  melts  at  220°.     It  was  discovered 


in  1879  by  Ira  Remsen  and  C.  Fahlberg.  Its  preparation  is  given 
above.  This  compound  is  now  made  technically  in  very  large  quanti- 
ties. It  is  used  for  sweetening  purposes.  It  is  500  times  sweeter  than 
cane  sugar.  It  dissolves  with  difficulty  in  cold  water,  and,  like  succin- 
imide  and  phthalimide,  behaves  like  a  strong  acid,  forming  imide  salts. 

The  sodium  salt  ceH4^Hso  /NNa  is  very  readily  soluble  in  water,  and 
is  400  times  sweeter  than  cane  sugar.  It  is  readily  transposed  by  such 
haloid  derivatives  as  benzyl  chloride  and  acetyl  chloride  to  N-deriva- 
tives  of  saccharin  (B.  25,  1737  ;  29,  1048). 

o-  Sulpho-benzoic  anile  C6H4^^2^>N.C6H5,  melting  at  190°,  results 

from  the  action  of  aniline  upon  the  chlorides  of  sulpho-benzoic  acid 
(B.  29,  R.  353).  Phosphorus  pentachloride  converts  saccharin  into 

pseudo-saccharin  chloride  W^j^J^N,  melting  at  149°  (B.  29,  2995). 
At  7o°-75°  o-cyano-benzol-sulpho-chloride  is  formed  (B.  29,  2295  ; 
C.  1906,  I.  1609).  With  phenols  and  amido-phenols  saccharin  con- 
denses to  dyes  of  the  phthalein  type,  called  sacchareins  (C.  1897,  II.  847  ; 
1899,  I.  718). 

All  sulpho-acids  containing  the  sulpho-group  in  the  o-position  with 
reference  to  the  carboxyl  group  of  an  alkyl-benzoic  acid  are  capable 
of  forming  sulphinides  or  sulpho-carbonimides  (B.  25,  1737). 

On  esters  and  ester  acids  from  o-  and  p-sulpho-benzoic  acid,  see 
M.  23,  1093. 

3,  5-Disulpho-benzoic  acid  is  formed  by  heating  benzoic  acid  with 
fuming  sulphuric  acid  containing  70  per  cent.  SO3  to  250°  in  a  pressure 
tube  (B.  35,  2305).  2,  4-Disulpho-benzoie  acid,  from  2,  4-toluol- 
disulphonic  acid  (B.  14,  1205). 

Diphenyl-sulphone-o-monoearboxylic  acid  C6H5SO2[2]C6H4[i]COOH, 
m.p.  144°,  is  formed  by  oxidation  of  phenyl-o-tolyl-sulphone  and 
phenyl-thio-salicylic  acid  with  KMnO4,  or  by  heating  the  potassium 
salts  of  o-chloro-benzoic  acid  and  benzol-sulphinic  acid  in  aqueous  or 
amyl-alcoholic  solution,  in  the  presence  of  copper.  On  heating  with 
concentrated  H2SO4  the  acid  passes  into  benzo-phenone-sulphone 

(B.  38,  729  ;  C.  1905,  I.  1394)- 


(d)    MONOHYDRIC    OXY-PHENYL-PARAFFIN    ALCOHOLS    AND   THEIR 

OXIDATION  PRODUCTS. 

i.  Monohydrie  Oxy-phenyl-paraffin  Alcohols,  or  Phenol  Alcohols. 

—  These  alcohols  contain,  in  addition  to  the  alcoholic  hydroxyl,  other 
hydroxyl  groups  joined  to  the  benzene  nucleus,  which  impart  to  them 


MONOHYDRIC  OXY-PHENYL-PARAFFIN   ALCOHOLS    315 

the  character  of  phenols.  Some  of  the  alcohols  of  this  group  are 
simple  transposition  products  of  long-known  plant-substances.  Special 
interest  attaches  to  a  number  of  mono-  and  dioxy-phenyl-ethyl-amines 
on  account  of  their  strong  physiological  action,  and  their  occurrence 
in  animals  and  plants  ;  cp.  p-oxy-phenyl-ethyl-amine  and  hordenin. 

Formation. — Some  of  the  methods  described  under  the  benzyl 
alcohols  also  lead  to  phenol  alcohols  : 

(1)  The  reduction  of  corresponding  aldehydes  and  ketones. 

(2)  The  treatment  of  aldehydes  with  caustic  alkali. 

(3)  The  action  of  sodium  amalgam  upon  amides  (B.  24,  175). 

(4)  They  are  linked  to  the  benzyl  alcohols  through  the  amido- 
phenyl-paraffin  alcohols,  which  nitrous  acid  converts  into  oxy-phenyl- 
paraffin  alcohols. 

(5)  Nuclear  Synthesis. — Methylene  chlorides  (B.  13,  435)  or  form- 
aldehyde and  sodium  hydroxide  (B.  27,  2411  ;   35,  3844  ;   40,  2524  ; 
J.  pr.  Ch.  2,  50,  225)  change  phenols  into  phenyl  alcohols.     Phenols 
with  so-called  "  negative  "  substituents  (NO2,  Cl,  CHO,  COOH)  con- 
dense with  formaldehyde  and  HC1  to  oxy-benzyl  chlorides,  in  which  the 
chlorine  atom  is  very  easily  replaced  by  OH  or  OR  (B.  34,  2455  ;   C. 
1902,  II.  894)  ;    (6)  by  the  action  of  alkyl-magnesium  haloids  upon 
phenol-carboxylic  ester.     Closely  related  to  formation  (5)  of  the  phenyl 
alcohols  is  the   nuclear-synthetic  formation  of  acylated  oxy-benzyl- 
amines  by  the  condensation  of  phenols  with  N-methylol-acyl-amides 
RCONHCH2OH  (A.  343,  215). 

Monoxy-benzyl  Alcohols  HOC6H4.CH2OH.— The  three  theoretically 
possible  isomerides  have  been  prepared.  They  result  when  the  corre- 
sponding aldehydes  are  reduced  with  sodium  amalgam.  Saligenin,  or 
o-oxy-benzyl  alcohol,  is  the  best-known  member  of  the  group  : 

o-Oxy-benzyl  alcohol .        .        .  m.p.    82° 
m-Oxy-benzyl  alcohol .        .  67° 

p-Oxy-benzyl  alcohol  „    110°. 

Saligenin,  or  o-oxy-benzyl  alcohol,  was  first  obtained  in  the  decom- 
position of  the  glucoside  salicin  (q.v.)  by  means  of  emulsin,  ptyalin,  or 
dilute  acids  (Piria,  1845  ;  A.  56,  37)  : 

C6HuO5.O.C6H4.CHaOH+HaO  -  HO.C6H4CH2OH+C6H12O6. 

Saligenin  has  also  been  prepared  by  the  usual  methods,  from  salicyl- 
aldehyde,  salicyl-amide,  o-amido-benzyl  alcohol,  and  phenol.  It  is 
soluble  in  hot  water,  alcohol,  and  ether.  Ferric  chloride  produces 
a  deep-blue  colour  in  its  solutions.  Acids  resinify  it,  forming  salinetin 
(farivr),  resin).  Ethers  and  substitution  products  of  saligenin  are 
known.  These  have  been  made  in  part  from  the  corresponding 
salicyl  derivatives. 

o-Oxy-benzyl-amine,  salicyl-amine,  melts  at  121°  (B.  23,  2744). 
o-Oxy-benzyl-aniline,  m.p.  108°,  is  also  obtained  by  combining  anhydro- 
formaldehy de-aniline  with  phenol  (C.  1900,  II.  457 ;  A.  315, 138).  The 
O-acetyl  compounds  of  o-oxy-benzyl-amines  and  -anilines  are  unstable, 
and  transpose  spontaneously  into  the  isomeric  N-acetyl  compounds 
(A.  332,  159).  Steric  resistances  are  encountered  in  the  acetylation 
pf  substituted  o-oxy-benzyl-anilines  (B.  32,  2057). 


3i6  ORGANIC   CHEMISTRY 

Anisyl  alcohol,  p-methoxy-benzyl  alcohol  CH3O[4]C6H4[i].CH2.OH, 
is  obtained  from  anisic  aldehyde  by  alcoholic  potassium  hydroxide. 
It  melts  at  45°,  and  boils  at  259°.  It  forms  anisic  aldehyde  when 
oxidised. 

p-Homo-saligenin  CH3[5]C6H3[2](OH)CH2.OH  melts  at  105°,  from 
p-cresol  by  method  5  (B.  42,  2539). 

p-Thymotin  alcohol  CH3[2]C3H7[5]C6H2[4]OH[i]CH2OH,  m.p.  120° 
(B.  27,  2412). 

o-Oxy-phenyl-ethyl  alcohol  HO[2]C6H4[i]CH2CH2OH,  b.p.  169°,  is 

( [i]CH  :  CH 
formed  by  the  splitting  up  of  cumarone  C6H4<  I     (q*v.)  with 

l[2]0 

alcoholic  potash,  besides  oxy-phenyl-acetic  acid;  the  bromide  of  the 
alcohol,  on  treatment  with  NaHO,  gives  the  cyclic  phenol-alcohol  ether, 

the  so-called  hydro-cumarone  C6HJ  '    I  2,  m.p.  188°,  also  formed 

l[2]0 ! 

from  cumarone  by  reduction  with  Na  and  alcohol,  and  from  bromo- 
methyl-o-bromo-phenyl  ether  BrC6H4OCH2.CH2Br  by  condensation 
with  sodium.  o-Oxy-phenyl-ethyl-amine  HO[2]C6H4[i]CH2CH2NH2, 
with  a  chlorohydrate  of  m.p.  153°,  is  formed  from  the  hydrazide  of 
melilotic  acid  by  disintegration.  The  quaternary  iodo-methylate  of 
the  base,  obtainable  by  the  action  of  ICH3,  melts  at  218°.  On  heating 
with  NaHO  it  splits  off  trimethyl-amine  and  yields  hydro-cumarone 
(B.  38,  2067).  p-Oxy-phenyl-ethyl-amine  HQ[4]C8H4[i]CH2CH1NHf, 
m.p.  162°,  increases  the  blood-pressure,  like  the  closely  related  adrena- 
lin (q.v.).  It  is  formed  from  tyrosin  (q.v.),  an  important  product  of 
the  decomposition  of  albumin,  by  further  decomposition,  or  by  heating 
with  rejection  of  CO2.  Synthetically,  the  p-oxy-phenyl-ethyl-amine 
is  obtained  by  reduction  of  oxy -benzyl  cyanide,  or  from  the  anisylidene- 
nitro-methane  CH3O[4]C6H4[i]CH  :  CHNO2  by  reduction  and  saponifi- 
cation  with  HI  (B.  42,  4778).  By  methylation  of  p-methoxy-phenyl- 
ethyl-amine  and  saponification  of  the  methoxyl  group  with  HI,  we 
obtain  p-oxy-phenyl-dimethyl-ethyl-amine,  hordenin  HO[4]C6H4[i]CH2 
CH2N(CH3)2,  m.p.  117°,  an  alkaloid  forming  the  effective  ingredient  of 
barley  seeds  (B.  43,  306). 

p-Oxy-phenyl-iso-propyl-amine  HOC6H4CH2.CH(NH2)CH3,  m.p. 
126°,  by  reduction  of  p-oxy-phenyl-acetoxime  (B.  43,  192). 

o-Oxy-phenyl-ethyl-carbinol  HO[2]C6H4CH(OH)C2H5,  b.p.0.25  125°- 
130°*  by  reduction  of  o-oxy-phenyl-ethyl  ketone,  and  synthetically 
from  tetra-acetyl-helicin  with  zinc  ethyl  (C.  1902,  II.  214 ;  B.  36, 

2575). 

o-Oxy-phenyl-diethyl-carbinol  HO[2]C6H4C(OH)(C2H5)2,  m.p.  57°, 
from  salicylic  ester,  with  C2H5MgI.  It  easily  splits  off  water,  and 
passes  into  olefm-phenol  (C.  1903,  I.  1222). 

o-Chloro-p-oxy-benzyl  alcohol  and  p-chloro-o-oxy-benzyl  alcohol 
C1C6H3(OH)CH2OH ;  also  o-nitro-p-oxy-  and  p-nitro-o-oxy-benzyl 
alcohol,  are  produced  in  the  form  of  their  easily  saponified  haloid  esters 
(see  Pseudo-phenol  haloids)  from  chloro-  and  nitro-phenols  with  form- 
aldehyde and  halogen  hydride.  The  p-amido-saligenin  NH2[4]C6H3 
[2]OH[i]CH2OH,  formed  by  reduction  of  p-nitro-o-oxy-benzyl  alcohol, 
is  used  as  a  photographic  developer,  under  the  name  "  edinol  "  (B.  34, 
2455  ;  C.  1902,  II.  394,  1439). 


PSEUDO-PHENOL  ALCOHOL  HALOIDS  317 

PSEUDO-PHENOL  HALOIDS,  METHYLENE-QUINONES,  QUINOLS. 

Pseudo-phenol  Alcohol  Haloids. — A  peculiar  behaviour  is  shown  by 
certain  halogen-hydrogen  esters  of  phenol  alcohols,  especially  those 
o-  and  p-oxy-benzyl  bromides  and  chlorides  in  which  nuclear  H  atoms 
are  replaced  by  chlorine  or  bromine.  Such  products  are  obtained  (i) 
by  the  action  of  HBr  upon  the  corresponding  phenol  alcohols  ;  (2)  from 
vinyl  phenols  by  adding  HBr  or  Br2  ;  (3)  by  suitable  bromination  of 
o-  and  p-alkyl  phenols,  e.g.  : 

o-Oxy-mesityl  chloride  C6H2[3,  5](CH3)2[2,  i](OH)CH2Cl,  m.p.  58°. 
o-Oxy-iso-duryl  chloride  C6H[3,  5,  6](CH3)3[2,  i](OH)CH2Cl,  m.p.  100°. 
m-Bromo-o-oxy-benzyl  bromide  C6H3[3]Br[2,i](OH)CH2Br,  m.p.  98°. 
m,m-Dibromo  -  o  -  oxy  -  benzyl  bromide  C6H2[3,  5]Br2[2,  i](OH)CH2Br, 
m.p.  117°.  Tribromo-o-oxy-benzyl  bromide  C6HBr3[2,  i](OH)CH2Br, 
m.p.  134°.  Tetrabromo-o-oxy-benzyl  bromide  C6Br4[2,  i](OH)CH2Br, 
m.p.  156°.  Dibromo-o-oxy-mesityl  bromide  C6Br2(CH3)2[2,  i](OH) 
CH2Br,  m.p.  150°.  Bromo-o-oxy-iso-duryl  bromide  C6Br(CH3)3[2,  i] 
(OH)CH2Br,  m.p.  112°.  m,  m-Dibromo-p-oxy-benzyl  bromide  C6H2Br2 
[4,  i](OH)CH2Br,  m.p.  150°.  Dibromo-p-oxy-pseudo-cumyl  bromide 
C6Br2(CH3)2[4,  i](OH)CH2Br,  m.p.  126°.  Dibromo-p-oxy-mesityl 
bromide,  m.p.  147°.  Tetrachloro-p-oxy-benzyl  bromide  C6C14[4,  i] 
(OH)CH2Br,  m.p.  160°,  and  chloride,  m.p.  146°.  Penta-,  hexa,-  and 
heptabromo-p-ethyl-phenol  C6HBr3[4,  i](OH)CHBr*CH2Br,  C6HBr3 
[4,  i](OH)CHBr*CHBr2  and  C6Br4[4,  i](OH)CHBr*CHBr2,  Tetra- 
bromo-iso-eugenol  C6HBr2[3]OCH3[4,  i](OH)CHBr*CHBrCH3.  Hepta- 
bromo-p-iso-propyl-phenol  C6Br4[2,  i](OH)CBr*(CHBr2)CH3,m.p.  183°, 
etc. 

These  substances  are  insoluble  in  alkalies,  and  show  an  abnormal 
mobility  of  one  aliphatically  linked  Br  atom.  This  Br  atom,  on  treat- 
ing with  water,  alcohol,  glacial  acetic  acid,  amines,  potassium  cyanide, 
or  sulpho-hydrate,  is  easily  exchanged  for  the  residues  OH,  OA1K, 
OCOCH3,  NHR,  CN,  SH  ;  with  phenols,  and  tertiary  amines  of  the 
dimethyl-aniline  type,  they  transpose  very  easily,  without  condensing 
agents,  into  diphenyl-methane  derivatives.  A  reactivity  similar  to 
that  of  the  pseudo-phenol  alcohols  is  possessed  by  the  corresponding 
sulpho-cyanides,  acetates,  and  nitro-bodies,  such  as  C6Br2(CH3)2[4,  i] 
(OH)CH2NO2  (B.  34,  4264  ;  cp.  also  the  analogous  behaviour  of  pro- 
penyl-phenyl  dibromides).  To  explain  the  behaviour  of  these  sub- 
stances, called  "  pseudo-phenols  "  on  account  of  their  insolubility  in 
alkalies,  it  is  assumed  that,  in  consequence  of  hitherto  unexplained 
influences,  the  CH2Br  (or  CHBr)  group  so  closely  approaches  the 
para-  or  ortho-hydroxyl  that,  in  most  reactions,  there  is  a  splitting 
off  of  HBr  in  the  first  instance,  leading  to  the  formation  of  highly 
reactive  "methylene-quinones"  or  "  quinone-methanes  "  (B.  36,  2336), 
which  react  further  with  addition  of  the  agents  ;  or  the  pseudo- 
phenol  bromides  are  regarded  as  quinone-like  substances,  corre- 
sponding to  the  scheme  : 

BrCH2<_  . 

CH2  . 


H' 

Pseudo-phenol  bromides         Methylene-quinones  Phenol  alcohols. 


3i8  ORGANIC  CHEMISTRY 

In  their  other  chemical  properties  the  pseudo-phenols  correspond 
exactly  to  the  phenols,  being  easily  converted  into  O-acetyl  compounds 
and  urethanes. 

Methylene-quinones. — The  methylene-quinones,  assumed  above  as 
intermediate  products,  may  be  obtained  from  the  o-  and  p-pseudo- 
phenol  bromides  by  treatment  with  sodium  acetate  solution,  or  dilute 
alkaline  hydroxide.  The  o-methylene-quinones  are  formed  much 
more  easily  than  the  para-bodies,  the  latter  easily  passing  into  poly- 
merised products,  and,  partly,  into  condensation  products  soluble  in 
alkalies,  e.g.  derivatives  of  p2-dioxy-diphenyl-methane. 

From  the  pseudo-bromides  of  p-ethyl-phenol,  iso-eugenol,  and 
p-iso-propyl-phenol,  on  the  other  hand,  derivatives  of  p-ethylidene- 
p-propylidene  and  p-iso-propylidene-quinone  can  be  isolated.  The 
methylene-quinones  are  yellow  substances,  easily  polymerised  and 
bleached,  by  light  or  by  acids.  The  chemical  behaviour  of  the  o-  and 
p-methylene-quinones  shows  a  remarkable  difference.  The  para-bodies 
are  highly  reactive,  easily  combining  with  water,  alcohols,  acetic  acid, 
and  H  haloids  to  form  the  corresponding  phenol-alcohol  derivatives  ; 
whereas  the  o-methylene-quinones  are  quite  indifferent,  so  that  they 
can  hardly  be  regarded  as  intermediate  products  in  the  transformations 
of  the  o-pseudo-phenol  haloids. 

o-Iso-durylene-quinone  CH2 :  [i]C6H(CH3)3[2]  :  O,  m.p.  129°.  Tetra- 
bromo-o-methylene-quinone  CH2 :  [i]C6Br  [2]  :  O,  m.p.  ca.  130°.  Bromo- 
o-iso-durylene-quinone  CH2 :  [i]C6Br(CH3)3[2] :  O,  m.p.  155°.  Dibromo- 
dimethyl-o-methylene-quinone  CH2  :  [i]C6Br2(CH3)3|>]  :  O,  m.p.  168°. 
Hexabromo-p-ethylidene-quinone  CHBr2CH  :  [i]C6Br  [4] :  O.  Tribromo- 
methoxy-p-propylidene-quinone  CH3CHBrCH  :  [i]C6HBr2(OCH3)[4]  :O. 
Heptabromo-p-iso-propylidene-quinone  CH3(CHBr2)C  :  [i]C6Br4[4]  :  O, 
m.p.  185°.  Cp.  also  the  much  more  stable  methylene-quinones  of  the 
di-  and  triphenyl-methane  series,  e.g.  diphenyl-methylene-quinone  and 
quino-diphenyl-m ethane,  the  dyestuffs  of  the  benzo-phenone  and  tri- 
phenyl-carbinol  group,  such  as  auramin,  rosaniline,  rosolic  acid,  etc., 
must  be  regarded  as  derivatives  of  methylene-quinone. 

Literature. — See  Auwers,  A.  301,  203  ;  334,  264  ;  344,  93  ;  B.  32, 
2978  ;  34,  4256 ;  36,  1878 ;  38,  3302 ;  39,  3160 ;  Zincke,  A.  320,  145 ; 
322,  174 ;  329,  i  ;  349,  67  ;  350,  269  ;  353,  357. 

Quinols. — Related  to  the  pseudo-phenols  and  methylene-quinones 
is  the  species  of  compounds  known  as  quinols,  which  are  also  related  to 
the  quinones  proper. 

(1)  Quinols  were  first  obtained  from  para-alkylated  bromine-  or 
chlorine-substituted  phenols,  by  oxidation  with  nitric  acid  or  nitrogen 
oxides,  the  so-called  nitro-ketones,  or  quinitrols,  being  intermediate 
products  : 

NOaH        CH3\H Cl  Acetate      CH8\H Cl    .  n 

~»  NO/ir-cT :  (          — »  HO/-R— cT  •  ° 

Dichloro-p-cresol  Dichloro-tolu-quinitrol  Dichloro-tolu-quinol. 

Caro's  acid  also  oxidises  the  non-substituted  p-alkyl-phenols,  like 
p-cresol,  2,  4-xylenol,  in  small  quantities,  to  quinol  (B.  36,  2028). 

(2)  The  simplest  representatives  of  this  series  were  obtained  from 
p-alkyl-phenyl-hydroxylamines   by   transposition    with    H2SO4 ;    the 


QUINOLS  319 

imine-quinols,  obtained  as  intermediate  products,  become  quinols,  by 
splitting  off  NH3  : 

NHOH  —  *       /~          "  :  NH 


HOH     H 

p-Tolyl-hydroxylamine  Imino-tolu-quinol  Tolu-quinol. 

Similarly,  the  p-alkyl-phenyl-hydroxylamines,  heated  with  alcoholic 
H2SO4,  give  imino-quinol  ether  and  quinol  ether  : 


:  NH  _*  :  O 


m-Xylyl-/3-hydroxylamine     Imino-xylo-quinol-ethyl        Xylo-  quinol-  ethyl  ether. 

ether 

(3)  Small  amounts  of  quinols  are  also  obtained  from  quinones,  by 
the  action  of  magnesium-methyl  iodide. 

The  quinols  are  colourless  substances,  soluble  in  alkalies,  and  subject 
to  acidulation  ;  they  are  easily  reduced  to  p-alkyl-phenols,  from  which 
they  may  be  partly  recovered  by  oxidation. 

On  the  plan  of  the  a,  j8-olefin-ketones,  the  simplest  quinols  combine 
with  two  molecules  of  hydroxylamine  to  form  j3-hydroxylamine-oximes 
(cp.  Vol.  I.).  With  phenyl-hydrazin,  various  substances  are  formed  — 
according  to  the  conditions,  phenyl-hydrazino-compounds,  diphenyl- 
hydrazones  of  diketo-oxy-tetrahydro-benzols,  or  azo-compounds  with 
rejection  of  H2O. 

With  alkyl-magnesium  haloids  the  quinols  yield  diquinols  by  method 
3  (above)  : 

CH3\  Br      Br  c.H,Mgl       CH3\  Br      Br  /C2H5 

OH/  Br      Br    :  °  *    OH/  Br      Br  \OH 

Tetrabromo-tolu-quinol          Tetrabromo-methyl-ethyl-diquinol. 

The  quinols  have  a  characteristic  tendency  towards  intramolecular 
atomic  displacements.  We  may  mention  the  migration  of  the  para- 
alkyl  group  brought  about  by  sulphuric  acid,  with  formation  of  hydro- 
quinones  : 

CH3\  H  CH3  H   CH3 

HO>H-Hr  :  °  -  —  HQ  CH3    H  QH 

2.,  4-Dimethyl-quinol  p-Xylo-hydroquirione. 

In  the  quinol  ethers  this  transposition  takes  two  directions,  resorcin 
ethers  being  formed  with  migration  of  the  alkoxyl  group,  besides  hydro- 
quinone  ethers,  on  heating  with  alcoholic  H2SO4. 

On  heating  with  concentrated  H2SO4,  the  halogen-substituted 
methyl-quinols  split  off  formaldehyde,  and  pass  into  p2-dioxy-diphenyl- 
methanes.  An  analogous  behaviour  is  shown  by  the  isomeric  p-oxy- 
benzyl  alcohols  and  their  derivatives,  the  pseudo-phenol  bromides, 
intermediate  products  being  probably  the  methylene-quinones  (A.  356, 
124).  Tetrabromo-ethyl-quinol,  on  being  treated  with  concentrated 
H2SO4,  gives  tribromo-ethyl-quinone  (A.  341,  262). 

In  the  halogen-substituted  quinols  the  halogen  atom,  occupying 
the  o-position  with  reference  to  the  quinol  group,  may  be  replaced  by 
OH,  NHC6H5,  etc.  (cp.  chloranile). 

Instead  of  the  expected  quinol,  nitro-chloro-p-cresol  yields  nitro- 
chloro-tolu-quinone  on  heating  with  HNO3,  the  quinol  undergoing  trans- 


320  ORGANIC  CHEMISTRY 

position  to  hydroquinone,  and  oxidation.  Nitro-bromo-  and  nitro- 
dibromo-p-cresol  behave  similarly  (A.  341,  310).  The  atomic  dis- 
placement may  also  take  other  directions,  according  to  the  structure 
of  the  quinols  (cp.  B.  35,  443). 

p-Tolu-quinol  CH3(OH)[4]C6H4  :  O,  m.p.  75°,  from  p-tolyl-hydro- 
xylamine  with  dilute  sulphuric  acid,  and,  in  small  quantities,  from 
p-cresol  with  Caro's  acid. 

2,  4-Dimethyl-qmnol  CH3(OH)[4]C6H3[2](CH3)  :  O,  m.p.  73°,  from 
m-xylyl-j8-hydroxylamine,  with  cold  dilute  H2SO4,  yields,  on  heating 
with  acids  or  alkalies,  or  on  illumination,  p-xylo-hydroquinone.  2, 4-Di- 
methyl-quinol-ethyl  ether  CH3(OC2H5)L4JC6H3|2](CH3)  :  O,  b.p.12  94°. 
Imino-2,4-dimethyl-quinol-ethyl  ether  CH3(OC2H5)[4]C6H3[2](CH3)  : 
NH,  b.p.n  98°,  from  m-xylyl-jS-hydroxylamine  with  alcoholic  H2SO4. 
Mesityl-quinol  CH3(OH)[4]C6H2[2,  6](CH3)2 :  O,  m.p.  46°,  from  mesityl- 
hydroxylamine,  is  transposed  into  cumo-hydroquinone.  2,  4,  5-Tri- 
methyl-quinol,  m.p.  116°,  from  pseudo-cumenol  with  Caro's  acid,  and- 
from  p-xylo-quinone  with  CH3MgI  (B.  36,  2038).  Di-,  tri-,  and  tetra- 
chloro-tolu-quinols,  m.p.  123°,  90°,  and  166°,  from  di-,  tri-,  and  tetra- 
chloro-p-cresol,  with  HNO3,  either  direct,  or  by  way  of  the  quiriitrols 
(method  i). 

Di-,  tri-,  and  tetrabromo-tolu-quinol,  m.p.  134°,  128°,  and  205°.  On 
treating  with  alcoholic  HC1,  two  bromine  atoms  are  replaced  by  chlorine 
in  the  tetrabromo-tolu-quinol,  and  one  Br  atom  in  the  tribromo-tolu- 
quinol,  forming  respectively  :  dibromo-dichloro-tolu-quinol,  m.p.  162°, 
and  dibromo-ehloro-tolu-quinol,  m.p.  135°.  Tetrabromo-ethyl-quinol 
C2H5(OH)[4]C6Br4 :  O,  m.p.  140°.  Tetrabromo-methyl-ethyl-diquinol 
CH3(OH)[i]C6Br4[4](OH)C2H5,  m.p.  191°,  and  tetrabromo-diethyl- 
quinol  C2H5(OH)[i]C6Br4[4](OH)C2H5,  m.p.  180°,  are  formed  from 
tetrabromo-ethyl-quinol  with  methyl-  and  ethyl-magnesium  iodide  re- 
spectively. 

The  pseudo-phenol  bromides  also  are  oxidised  by  HNO3  to  quinols, 
which,  on  treatment  with  alkalies  or  silver  oxide,  yield  oxides  with 
rejection  of  HBr. 

Br      Br  CH2Br\  Br      Br  CH2\  Br      Br 

Pentabromo-p-cresol  Pentabromo-tolu-quinol      Pentabromo-tolu-quinol 

oxide. 

These  oxides  add  HBr  and  acetyl  bromide,  with  formation  of  hydro- 
quinone derivatives  : 

HBr  R  rH  ^  Br      Br  ^ 

CH2\  Br      Br      Q f  2^~ fiT 

V+'    K^       ?,  \     CH8COBr       ?    p 

Tetrabromo-tolu-  iir 

quinol  oxide. 

Literature. — Cp.  Auwers,  B.  35,  425,  443 ;  Bamberger,  B.  33,  3600 ; 
35,  1424,  3886 ;  36,  1625 ;  40,  1890,  2236 ;  Zincke,  B.  34,  253 ;  A.  328, 
261 ;  343,  100  ;  341,  309. 

Dioxy-benzyl  alcohols  are  not  known  in  a  free  condition,  but  deriva- 
tives of  2,  5-dioxy-  and  of  3,  4-dioxy-benzyl  alcohol  have  been  obtained 
in  the  reduction  of  certain  aldehyde  ethers  with  sodium  amalgam. 
Di-methyl-gentisin  alcohol  (CH3O)2[2,  5]C6H3[i]CH2.OH  boils  at  278°. 


PHENOL-ALDEHYDES  321 

Vanillyl  alcohol  CH3O[3]HO[4]C6H3[i]CH2.OH,  from  vanillin, 
melts  at  115°. 

Piperonyl  alcohol  CH8/°^\  c6H3[i]CH2.OH,  from  piperonal,  melts 

\O[4J  J 

at  51°.    Homo-piperonyl  alcohol  CHa/O[3^\c8H3CH2CHaOH,  b.p.10 156°, 
see  B.  41,  2752.     o-Dioxy-benzyl-amine  melts  at  168°  (B.  27, 1799). 

(2)  AROMATIC  OXY-MONO-ALDEHYDES,  PHENOL-ALDEHYDES. 

The  phenol-aldehydes  are  obtained  (i)  by  oxidising  the  phenol  alco- 
hols with  chromic  acid  ;  (2)  by  an  important  nuclear-synthetic  method, 
consisting  in  letting  chloroform  and  an  alkaline  hydroxide  act  upon 
phenols  (reaction  of  Reimer) ,  when  the  chloroform  enters  the  o-  and  p- 
position  with  reference  to  the  phenol-hydroxyl,  and  is  then  converted 
into  the  aldehyde  group  (B.  9, 1268)  : 

C,H5.OH+CHC13+4KOH  =  C,H4/°^O+3KC1  + 3HaO. 

On  treating  o-  and  p-alkylated  phenols  with  chloroform  and  alkali, 
some  chlorinated  products  of  a  ketone  type,  insoluble  in  alkalies,  are 
produced  besides  the  phenol-aldehydes,  e.g. 

rw    H H  CH3\H H    , 

'Ha~ IT  *  CHC12/"H H" 

These  substances  should  be  regarded  as  derivatives  of  keto-dihydro- 
benzol,  and  are  dealt  with  in  that  connection. 

(3)  A  nuclear  synthesis  of  phenol-aldehydes  is  also  brought  about 
by  the  action  of  prussic  acid  and  gaseous  HC1  upon  the  phenols,  or  their 
ethers,  with  or  without  Al  chloride  ;  aldimines  are  first  formed,  and 
these  are  easily  converted  into  aldehydes  (Gattermann,  A.  357,  313)  : 

C6H5OH  HNC(HC1U  HN  :  CH.C6H4OH  -       — >  OCH.C6H4OH. 

By  similar  reactions,  oximes  of  phenol-aldehydes  are  produced  (30) 
from  multivalent  phenols,  mercury  fulminate,  and  HC1 ;  and  phenyl- 
imines  of  aldehydes  (36)  from  multivalent  phenols,  formanilide,  and 
POC18 : 


C  H  fOID  /  C6H3(OH)2CH  :  NOH 

^s^MvU^iJz  \       rwM-rHri 

— ->    C6H3(OH)2CH  :  NC6H6 

Behaviour. — All  the  phenol-aldehydes  show  the  same  reactions  of 
the  aldehyde  group  as  the  benzaldehydes.  Oxidising  agents  convert 
them  with  difficulty  into  phenol-carboxylic  acids  ;  this  is  most  easily 
accomplished  by  fusion  with  caustic  alkalies.  They  reduce  an  am- 
moniacal  silver  solution,  but  not  the  Fehling  solution.  On  oxidation 
with  dilute  alkaline  H2O2  solution  the  o-  and  p-phenol-aldehydes  split 
off  the  aldehyde  group  and  easily  pass  into  pyro-catechin  and  hydro- 
quinone  (C.  1910,  I.  634).  They  dissolve  in  alkalies,  forming  salts — 
e.g.  C6H4(CHO).ONa  ;  the  alkyl  iodides  convert  the  latter  into  alkyl 
ethers. 

(a)  Monoxy-benzaldehydes  HO.C6H4.CHO.  —  Three  are  possible 
according  to  theory  ;  all  of  them  are  known.  Anisic  aldehyde,  the 
VOL.  II.  Y 


322  ORGANIC   CHEMISTRY 

methyl  ether  of  p-oxy-benzaldehyde,  has  been  known  for  the  longest 
period. 

Salicylic  aldehyde,  o-oxy-benzaldehyde,  formerly  called  salicylous 
or  spiroylous  acid,  boils  at  196°.  Its  sp.  gravity  equals  1-172  (15°). 
It  occurs  in  the  volatile  oils  of  the  different  varieties  of  Spircea- — e.g. 
Spircea  ulmaria.  It  is  obtained  by  the  oxidation  of  saligenin  and  salicin 
(Piria,  1839)  and  by  the  decomposition  of  helicin,  an  oxidation  product 
of  salicin  (q.v.).  Also  by  reduction  of  sodium  salicylate  with  sodium 
amalgam  in  the  presence  of  free  boric  acid  (B.  41,  4147,  4148).  It  is 
most  readily  prepared  (together  with  p-oxy-benzaldehyde)  by  the 
action  of  chloroform  and  caustic  potash  upon  phenol.  It  is  separated 
from  the  p-body  by  distillation  in  steam,  in  which  salicylic  aldehyde 
is  very  volatile.  It  is  rather  easily  soluble  in  water  ;  the  solution  is 
coloured  a  deep  violet  by  ferric  chloride  (compare  saligenin  and  sali- 
cylic acid).  In  alkalies  it  dissolves  with  an  intense  yellow  coloration, 
in  contrast  with  p-oxy-benzaldehyde  (B.  39,  3087)).  Like  all  ortho- 
oxy-aldehydes,  it  colours  the  skin  an  intense  yellow.  Sodium  amalgam 
transforms  it  into  saligenin  ;  oxidising  agents  change  it  to  salicylic 
acid. 

Potassium  -  salicylic  aldehyde  C6H4(OK)CHO-fH2O  consists  of 
yellow  plates.  The  methyl  ether  C6H4(O.CH3).CHO  melts  at  35°  and 
boils  at  238°  ;  the  ethyl  ether  boils  at  248°.  The  aceto-derivative  CH3. 
CO.O.C6H4.CHO  melts  at  37°  and  boils  at  253°.  Glucose  derivative, 
see  Helicin.  o-Aldehydo-phenoxy-acetic  acid  CO2H.CH2O[2]C6H4[i] 
CHO,  melting  at  132°,  splits  off  water  and  becomes  cumarilic  acid 
(q.v.).  Salicyl-aldoxime  melts  at  57° ;  cp.  B.  22,  3320.  o-Anisaldoxime 
CH3O.[2]C6H4[i]CH  :  N(OH),  m.p.  92°  (B.  23, 2741) ;  alsoobtained  from 
anisol,  mercury  fulminate,  and  hydrated  A1C13  besides  p-anisaldoxime 
(B.  23,  2741 ;  36,  648).  Salieyl-hydramide  (C7H6O)3N2,  m.p.  167° 
(C.  1899,  II.  827 ;  1900, 1. 123).  Salicyl-hydrazone  HO.C6H4CH  :  NNH2, 
m.p.  96°.  o-Oxy-benzalazin  HOC6H4CH  :  N.N  :  CHC6H4OH,  m.p.  213° 
(B.  31,  2806).  Phenyl-hydrazone,  m.p.  142°,  b.p.28  234°,  decomposes 
on  distillation  partly  into  aniline  and  salicylic  acid  nitrile  C6H4(OH) 
CN  (B.  36,  580).  Nitro-salicyl-aldehyde,  see  B.  22,  2339. 

m-Oxy-benzaldehyde,  m.p.  104°,  b.p.  240°,  results  from  the  reduction 
of  m-oxy-benzoic  acid  with  sodium  amalgam  (B.  14,  969)  and  from 
m-nitro-benzaldehyde  (B.  15,  2045).  Its  oxime  melts  at  87°.  Its 
phenyl-hydrazone  melts  at  130°  (B.  24,  826).  See  B.  18,  2572,  for  the 
nitro-m-methoxy-benzaldehydes. 

p-Oxy-benzaldehyde  is  formed  from  phenol,  chloroform,  and  caustic 
alkali,  together  with  salicylic  aldehyde.  It  melts  at  116°,  and  sub- 
limes. Its  aldoxime  melts  at  65°  ;  its  hydrazone  at  178°.  Consult 
B.  29,  2302,  2355,  for  the  haloid  p-oxy-benzaldehydes.  Its  methyl 
ether,  readily  accessible,  is  the  so-called  : 

Anisic  aldehyde,  p-methoxy-benzaldehyde  CH3O[4]C6H4[i]CHO,  b.p. 
248°,  with  sp.  gr.  1-128  (15°).  It  results  in  oxidising  anethol  (q.v.), 
present  in  various  essential  oils  (anise,  fennel,  tarragon,  etc.),  with  dilute 
nitric  acid  or  a  chromic  acid  mixture  (C.  1900,  I.  255). 

p-Anisaldoxime,  m.p.  61°,  from  anisol,  mercury  fulminate,  and 
hydrated  A1C13,  besides  o-anisaldoxime  and  p-anisic  nitrile.  p-Ethoxy- 
benzaldoxime  (C2H5O)[4]C6H4CH  :  NOH,  obtained  in  two  forms,  melt- 
ing at  118°  and  157°  respectively,  from  phenetol,  mercury  fulminate, 


MONOXY-BENZALDEHYDES  323 

and  A1C13  (B.  36,  648,  650).     Anisal  chloride  CH3O.C6H4.CHC12,  m.p. 
20°  (B.  41,  2331). 

Homologous  monoxy-benzaldehydes  have  been  prepared  from 
various  phenols  by  Reimer's  method,  and  also  by  Gattermann's 
method  : 

M.p.       B.p. 

o-Homo-salicyl-aldehyde        .     CH3[3]CeH3[2]OH[i]CHO  .         .       17°      208°  * 
a-m-Homo-salicyl-aldehyde    .     CH3[4]C6H3[2]OH[i]CHO  .         .       59°      220° 2 
/3-m-Homo-salicyl-aldehyde    .     CH3[6]C6H3[2]OH[i]CHO  .         .      31°      229° 2 
p-Homo-salicyl-aldehyde        .     CH3[5]C6H3[2]OH[i]CHO  .         .       56°       217° 
o-Homo-p-oxy-benzaldehyde .     CH3[5]C6H3[4]OH[i]CHO  .         .     115° 3 
p-Homo-p-oxy-benzaldehyde .     CH3[2]C6H3[4]OH[i]CHO  .         .     110° 
Trimethyl-salicyl-aldehyde     .     (CH3)3[3,  5,  6]C6H[2]OH[i]CHO.     105° « 
p-Thymotin-aldehyde     .         .     CH[2]C3H7[5]C6H2[4]OH[i]CHO      133° 5 
p-Carvacrotin-aldehyde          .     CH[5]C3H7[2]C6H2[4]OH[i]CHO      liquid • 
P-Iso-butyl-salicyl-aldehyde   .     C5Hu[4]C6H3[2]OH[i]CHO         .        „        252°.' 

Literature. — *  B.  £4,3667;  2  C.  1906,  I.  1012;  5  B.  24,3667;  4  B.  18,2656; 
32,  3598  ;  5  B.  16,  2097  ;  31,  1767  ;  •  B.  19,  14  ;  7  B.  28,  R.  468. 

p-Oxy-mesitylene-aldehyde  (CH3)2[3,5](OH)[4]C6H2CHO,m.p.  114°, 
from  mesitol  by  oxidation  with  ethyl  nitrite;  oxime,  m.p.  169°  (A.  311, 

363). 

The  o-oxy-benzaldehydes  are  more  readily  soluble  in  water  and 
more  sparingly  soluble  in  chloroform  than  the  p-oxy-benzaldehydes. 
The  o-bodies  are  volatile  in  steam,  form  sparingly  soluble  sodium 
bisulphite  derivatives,  and  are  coloured  yellow  by  ammonia  (B.  11, 770). 

The  phenyl-hydrazones  of  homo-salicyl-aldehydes  and  other  salicyl- 
aldehydes  with  alkylated  nucleus  are,  strangely  enough,  insoluble  in 
alkalies  (B.  35,  4099). 

p  -  Methoxy  -  phenyl  -  acetaldehyde  CH3O[4]C6H4CH2CHO.  The 
oxime  of  this  aldehyde  is  obtained  by  the  reduction  of  anisylidene- 
nitro-methane  CH3OC6H4CH  :  CHNO2  (C.  1902,  II.  449). 

p-Methoxy-hydratropa-aldehyde  CH3O[4]C6H4CH(CH3)CHO,  b.p. 
256°,  from  anethol  CH3OC6H4CH  :  CHCH3  by  oxidation  with  HgO  and 
iodine,  with  migration  of  the  aromatic  residue  (C.  1902,  I.  1056). 

(b)  Dioxy-benzaldehydes. — Some  of  the  dioxy-benzaldehydes  which 
have  been  prepared  by  the  chloroform-potash  reaction  are  ethereal 
derivatives  of  proto-catechuic  aldehyde,  and  are  characterised  by  an 
agreeable  odour.  This  is  especially  true  of  vanillin  and  piperonal,  or 
heliotropine.  Both  substances  are  prepared  on  a  technical  scale  : 

r[i]CHO                          /-[ijCHO  r[i]CHO 

C.H.]  [3]OH  C9H3]  [3]OCH3  C8H3]  [3]O\CH 

'  [4]OH                             U4]OH  U4]O/ 

Proto-catechuic  aldehyde            Vanillin  Piperonal. 

Proto-catechuic  aldehyde,  [3, 4]-dioxy-benzaldehyde,  m.p.  153° 
(B.  26,  R.  701),  was  first  obtained  from  piperonal  (Fittig  and  Remsen, 
1871)  ;  also  from  vanillin,  iso-vanillin,  and  opianic  acid  by  heating  with 
hydrochloric  acid,  and  by  the  action  of  H2O2  upon  m-  and  p-oxy-benz- 
aldehyde  (C.  1904,  II.  1631).  It  is  prepared  in  the  nuclear-synthetic 
way  from  pyro-catechin  by  the  chloroform  reaction.  It  dissolves 
readily  in  water.  Ferric  chloride  colours  its  aqueous  solution  a  deep 
iqreen.  It  reduces  ammoniacal  silver  solutions.  Molten  caustic  potash 


324  ORGANIC   CHEMISTRY 

converts  proto-catechuic  aldehyde  into  proto-catechuic  acid.  Its 
phenyl-hydrazone  exists  in  two  modifications  :  a-  (stable),  melting  at 
176°,  and  )3-  (unstable),  melting  at  I2i°-i28°.  Its  oxime  melts  at  150° 
(B.  29,  R.  670).  Proto-catechuic-aldehyde-carboxylate  (CO)O2  :  C6H3 
CHO,  m.p.  124°,  b.p.13  162°. 

Vanillin,  m-methoxy-p-oxy-benzaldehyde,  m.p.  80°,  sublimes  readily, 
and  is  the  active  constituent  of  the  vanilla  bean  pod  (  Vanilla  plani- 
folia),  which  contains  about  2  per  cent,  of  it  (B.  9,  1287).  Vanillin 
also  occurs  in  the  orchid  Nigritella  suaveolens  (B.  27,  3049).  It  was 
first  prepared  artificially  from  the  glucoside  coniferine  by  its  oxidation 
with  chromic  acid  (Tiemann  and  Haarmann,  1874  ;  B.  7,  613).  Gly co- 
vanillin  was  obtained  as  an  intermediate  product  in  the  oxidation 
of  coniferine  ;  acids  or  emulsin  split  it  up  into  glucoses  and  vanillin 
(B.  18, 1595, 1657).  Vanillin  is  also  produced  by  oxidising  eugenol  (q.v.) 
(B.  9,  273).  In  the  nuclear-synthetic  way  it  has  also  been  formed, 
together  with  m-methoxyl-salicylic  aldehyde,  boiling  at  266°,  from 
guaiacol,  chloroform,  and  caustic  potash  (B.  14,  2023  ;  C.  1910, 1.  1881). 
Industrially,  it  is  obtained  on  a  large  scale  by  the  oxidation  of  iso- 
eugenol,  obtained  by  the  transposition  of  eugenol,  contained  in  abund- 
ance in  carnation  oil.  It  is  advantageous  to  protect  the  free  hydroxyl 
from  oxidation  by  the  temporary  introduction  of  an  acid  residue 
(CH3CO,  C6H5SO2,  etc.)  : 

f  [i]CHa.CH  :  CH2  t  [i]CH  :  CH.CH3  t  [ijCHO 

C6H3|  [3]OCH3  >  C6H3|  [3]OCH3  >  C.EU  [3]OCH3 

l[4]OH  U4JOH  U4JOH 

Eugenol  Iso-eugenol  Vanillin. 

Heated  with  HC1,  vanillin  splits  up  into  proto-catechu-aldehyde 
and  CH3C.  It  behaves  as  a  p-oxy-benzaldehyde  and,  when  fused  with 
KHO,  it  passes  into  proto-catechuic  acid — two  facts  which  determine 
its  constitution.  By  sodium  amalgam,  vanillin  is  converted  into 
vanillyl  alcohol,  and  into  hydra-vanilloiin,  which  corresponds  to  hydro- 
benzoin. 

Vanillin-oxime  melts  at  117°  (B.  24,  3654). 

Trithio-vanillin  [C6H3(OH)(OCH3)CSH]3  melts  at  236°  (B.  29,  143). 

Iso-vanillin,  p-methoxy-m-oxy-benzaldehyde,  melting  at  116°,  smells, 
when  heated,  like  vanilla  and  anise  oil.  It  is  obtained  by  oxidising 
hesperitinic  acid,  or  by  heating  opianic  acid  with  hydrochloric  acid. 

Methyl-vanillin  (CH3O)2C6H3CHO,  m.p.  42°,  b.p.  283°  (B.  11, 662). 

Piperonal,  proto-catechuic  aldehyde-methylene  ether,  heliotr  opine 
(CH2O2)C6H3CHO,  melting  at  37°  and  boiling  at  263°,  was  obtained  by 
the  oxidation  of  piperic  acid  (q.v.).  It  is  also  formed  by  treating 
proto-catechuic  aldehyde  with  alkali  and  methylene  iodide.  Industri- 
ally, it  is  obtained  from  safrol  (q.v.)  as  vanillin  is  obtained  from  eugenol. 
Its  odour  is  pleasant,  like  that  of  heliotrope.  Piperonylic  acid  results 
from  its  oxidation,  and  piperonyl  alcohol  from  its  reduction.  On  heat- 
ing with  dilute  mineral  acids  to  190°,  under  pressure,  it  breaks  up  into 
proto-catechuic  aldehyde  and  formaldehyde  or  methyl  alcohol  (C.  1905, 
II.  1060).  Its  oxime  melts  at  110°.  Its  phenyl-hydrazone  melts  at  100°. 
PC15  converts  it  into  piperonal  chloride  (CH2O2)C6H3CHC12,  and  di- 
chloro-piperonal  chloride  (CC12O2).CCH3CHC12,  which  is  changed  by  cold 
water  into  the  carboxylate  of  proto-catechuic  aldehyde  chloride  (CO)O2 : 


DIOXY-BENZALDEHYDES  325 

CeH3CHCl2,  m.p.  97°,  b.p.15  178°,  also  obtained  direct  from  piperonal 
with  thionyl  chloride  at  220°,  or  by  heating  with  chloride  of  sulphur 
(B.  42,  417).  Bromo-piperonal  (CH2O2).C6H2Br.CHO  (B.  24,  2592). 
o-Nitro-piperonal  yields  bidioxy-methylene  indigo  (B.  24,  617). 

Homo-piperonal  (CH2)O2  :  C6H3CH2CHO,  m.p.  69°,  b.p.10  144°, 
is  formed  by  the  oxidation  of  safrol  (q.v.)  with  ozone  (B.  41,  2751).  Its 
oxime,  m.p.  120°,  is  formed  from  piperonylidene-nitro-methane  by 
reduction  with  Al  amalgam  (C.  1902,  II.  449). 

Concerning  nitro-proto-catechuic  aldehyde,  nitro-vanillin,  ammo- 
vanillin,  and  derivatives,  see  C.  1902,  II.  31 ;  B.  36,  2930. 

The  following  bodies  have  been  prepared  from  resorcin  and  hydro- 
quinone  by  the  action  of  chloroform  and  caustic  alkali,  just  as  proto- 
catechuic  aldehyde  was  made  from  pyro-catechin  : 

£-Resorcyl-aldehyde  (HO)2[2,  4]C6H3[i]CHO  melts  at  135°. 
Orcyl-aldehyde    (HO)2[2 ,4]C6H2[5,  i](CH3)CHO,    m.p.     180°, 

from  hydroquinone  with  chloroform  and  alkali. 
Gentisin-aldehyde  (HO)2[2,  5]C6H3[i]CHO  melts  at  99°. 

Dioxy-aldehydes  are  also  produced  in  dilute  solutions  when  much 
chloroform  and  caustic  potash  are  used.  The  monomethyl  ethers  of 
resorcin  and  hydroquinone,  like  guaiacol,  each  yield,  upon  treatment 
with  chloroform  and  potash,  two  aldehydes :  one,  comparable  in 
deportment  with  salicyl-aldehyde,  contains  the  aldehyde  group  in  the 
o-position  with  reference  to  phenol-hydroxyl ;  while  the  other  contains 
the  aldehyde  group  in  the  p-position,  referred  to  the  free  phenol-hydro- 
xyl (B.  14,  2024). 

Gentisin-aldehyde  is  also  produced  by  oxidation  of  salicyl-aldehyde 
with  potassium  persulphate  in  alkaline  solution  (C.  1907,  II.  901).  The 
anile  of  resorcyl-aldehyde  C6H2[2,  4](OH)2CH  :  NC6H5,  m.p.  126°,  is 
also  obtained  from  resorcin  with  formanilide  and  POC13,  and  the  oxime 
C6H3(OH)2CH  :  NOH  with  mercury  fulminate  and  HC1. 

(c)  Tri-  and  Tetra-oxy-benzaldehydes. — From  pyrogallol,  phloro- 
glucin,  and  oxy-hydroquinone  the  corresponding  aldehydes  have  been 
obtained  with  HCN  and  HC1  :  Pyrogallol-aldehyde,  gallic  aldehyde 
(HO)3[2, 3, 4]C6H2CHO,  m.p.  161°.  Phloro-glucin-aldehyde  (HO)3 
[2,  4,  6]C6H2.CHO,  decomposed  on  melting.  Oxy-hydroquinone-alde- 
hyde  (HO)3[2,  4,  5]C6H2.CHO,  m.p.  223°  (B.  32,  278).  The  oximes 
and  aniles  of  these  aldehydes  have  also  been  obtained  synthetically 
by  methods  3#  and  36.  Alky!  ethers  of  these  bodies  have  been  formed 
by  oxidising  aromatic  plant  derivatives,  containing  unsaturated  ali- 
phatic side  chains  (B.  16,  2112  ;  17,  1086  ;  24,  3818  ;  41,  1918). 

Glyco-syringa-aldehyde,  an  oxidation  product  of  syringine  (q.v.), 
when  treated  with  emulsin  yields  4-oxy-3,  5-dimethoxy-benzaldehyde, 
syringa-aldehyde  (B.  22,  R.  107). 

2, 4, 5-Trimethoxy-benzaldehyde,  asaryl-aldehyde,  m.p.  114°,  is 
obtained  by  oxidising  asarone  (propenyl-trimethoxy-benzol) ,  and  from 
oxy-hydroquinone-trimethyl  ether,  with  HCN,  HC1,  and  A1C13  (B.  32, 
289  ;  39,  1211). 

(3)  PHENOL  KETONES. 

They  have  been  obtained  (i)  from  amido-ketones  (B.  18,  2691)  ; 
(2)  from  aromatic  jS-ketone-carboxylic  acids  (B.  25,  1308)  ;  (3)  by  the 


326  ORGANIC   CHEMISTRY 

breaking  up  of  C-alkylated  benzo-tetronic  acids  with  concentrated 
alkalies  (A.  379,  333)  ;  (4)  from  the  dibromides  of  the  propenyl-phenols 
and  their  ethers  :  (a)  by  transforming  into  bromo-hydrins  and  ethylene 
oxides,  and  transposing  the  latter  with  acids  or  by  heating  alone 
(B.  38,  3464)  :  _ 

CHBr.CHBrCHg  _H,p  CH(OH).CHBrCH3jcp_H  in.O.tH.CHg  _  CH2.CO.CH3 
C6H4OCH3  ^C^OCHg  ""'"C^OCHa  ">CflH4OCH3 


(b)  by  transforming  into  ethyl  bromo-hydrins  and  a-ethoxy-propenyl- 
phenols  by  sodium  ethylate,  and  saponifying  the  latter  : 

CHBr.CHBrCH3     C2H8ONa       CH(OC2H6).CHBr.CH3     caHtONa 

C6H4OCH3  >  C6H4OCH3 

C(OC2H5)  :  CHCH3  _    CO.CH2.CH8 
CeH4OCH3  C6H4OCH3     ' 

To  these  must  be  added  the  methods  of  nuclear  synthesis  consist- 
ing in  the  introduction  of  acid  radicles  into  phenols,  and  phenol-alkyl 
ethers  ;  (5)  condensation  of  phenols  with  glacial  acetic  acid,  and  other 
aliphatic  acids,  with  the  aid  of  zinc  chloride  or  tin  tetrachloride  (B.  14, 
1566  ;  23,  R.  43  ;  24,  R.  770),  or,  better,  by  phosphorus  oxy-chloride 
(B.  27,  1983)  ;  (6)  from  phenols  with  acid  chlorides  and,  preferably,  the 
addition  of  zinc  chloride  (B.  22,  R.  746  ;  C.  1904,  I.  1597)  ;  (7)  from 
phenol-alkyl  ethers  or  phenols  and  acid  chlorides  in  the  presence  of 
A1C13  (B.  36,  3890  ;  C.  1898,  I.  1223)  ;  excess  of  A1C13  saponifies  the 
resulting  phenol  ethers  to  oxy-ketones.  Starting  from  the  thio-phenol 
ethers,  thio-phenol  mono-ketones  are  obtained  by  this  method  (C.  1908, 

II.  1659) 

o-Oxy-aceto-phenone,  b.p.  213°,  is  formed  by  method  2.  p-Oxy- 
aceto-phenone,  m.p.  107°,  is  produced  by  method  i.  p-Aeetyl-anisol, 
p-methoxy-aceto-phenone,  m.p.  38°  and  b.p.  258°,  is  formed  by  method 
3.  Propionyl-phenol  HOC6H4COC2H5,  m.p.  148°,  is  produced  by 
method  4. 

Aceto-pyro-eatechol  (HO)2[3,  4]C6H3[i]CO.CH3,  melts  at  116°  (B. 
27,  1989).  Aceto-vanillonHO[4](CH3O)[3]C6H3[i]COCH3,  m.p.  115°, 
is  produced  in  the  oxidation  of  aceto-eugenol,  and,  synthetically, 
from  guaiacol  by  method  7,  or  by  condensation  of  benzoyl-vanillin 
with  CH3MgI,  oxidation,  and  rejection  of  the  benzoyl  group  (B. 
24,  2855,  2869).  Aeeto-veratron  (CH3O)2C6H3.CO.CH3,  m.p.  48° 
(B.  27,  1989).  Aeeto-piperone  (CH2O2)[3,  4]C6H3[i]CO.CH3,  m.p.  87°, 
results  on  oxidising  proto-cotoin  with  potassium  permanganate  (B.  24, 
2989  ;  25,  1127  ;  26,  2348). 

Resaceto-phenone  (HO)2[2,  4]C6H3[i]CO.CH3,  m.p.  142°,  is  pro- 
duced by  method  5,  and  from  jS-methyl-umbelliferone  upon  fusion 
with  caustic  potash  (B.  16,  2123).  Its  p-methyl  ether,  paeonol  CH3O[4] 
(HO)[2]C6H3.CO.CH3,  m.p.  45°,  occurs  in  the  root-bark  of  Pceonia 
Moutan,  a  ranunculus  from  Japan  (B.  25,  1292).  When  resorcin- 
diethyl  ether  is  acetylated  with  the  aid  of  aluminium  chloride  the 
products  are  1,  2,  4-resaeeto-phenone-diethyl  ether,  m.p.  69°,  and  an 
isomeric  resaceto-phenone  with  the  melting-point  178°  (B.  29,  R.  386). 
Consult  B.  29,  R.  674,  for  haloid  resaceto-phenones. 

Orc-aeeto  -  phenone  -  dimethyl     ether    CH3[i]C6H2[3,  5](OCH3)2[4] 


PHENOL-MONOCARBOXYLIC   ACIDS  327 

COCH3,  m.p.  89°,  and  isorc-aceto-phenone-dimethyl  ether  CH3[i]C6H2 
[3»  5](OCH3)2[2]COCH3,  m.p.  48°,  from  orcin-dimethyl  ether  by  method 
7  (B.  41,  793). 

Quina-aceto-phenone  (HO)2[2, 5]C6H3[i]CO.CH3,  m.p.  202°,  is 
produced  by  method  2.  Valero-hydroquinone  (HO)2[2, 5]C6H3.CO. 
C4H9,  m.p.  115°.  Its  quin-hydrone  results  when  sunlight  acts  upon 
benzo-quinone  and  valeric  aldehyde  (B.  24,  1344). 

Gall-aceto-phenone  (HO)3[2, 3, 4]C6H2[i]CO.CH3,  m.p.  168°,  is 
formed  by  method  3  (B.  27,  2737  ;  43,  1016). 

Anis-acetone,  p-methoxy-phenyl-acetone  CH30[4]C6H4CH2COCH3, 
b.p.  26i°-265°,  is  found  in  aniseed  oil  (?)  (C.  1902,  II.  1256). 

o-Acetyl-thio-phenol  HS[2]C6H4[i]COCH3,  b.p.  about  124°,  from 
o-amido-aceto-phenone  by  way  of  the  diazo-compound  ;  yields  thio- 
indigo  during  oxidation  in  alkaline  solution,  as  well  as  the  dithio- 
compound. 

(4)  PHENOL-MONOCARBOXYLIC  ACIDS. 

The  aromatic  oxy-acids,  containing  hydroxyl  united  to  the  benzene 
nucleus,  combine  the  character  of  acids  and  phenols,  hence  are  desig- 
nated phenol  acids.  Should  the  hydroxyl  groups  enter  the  aliphatic 
side  chains,  we  would  obtain  aromatic  alcohol  acids,  showing  in  their 
behaviour  very  great  similarity  to  the  oxy-fatty  acids. 

Formation. — A.  From  substituted  carboxylic  acids,  as  in  the  case  of 
the  phenols  :  (i)  Through  the  conversion  of  the  amido-acids,  by  means 
of  nitrous  acid,  into  diazo-compounds,  and  then  boiling  the  latter  with 
water.  (2)  By  fusing  the  sulpho-benzoic  acids  and  halogen-benzoic 
acids  with  alkalies.  (3)  By  oxidation  of  the  benzoic  acids,  in  the  form 
of  Am  salts,  with  H2O2,  o-,  m-,  and  p-oxy-benzoic  acids  being  formed 
together  (C.  1907,  II.  2046). 

B.  From  compounds  in  which  the  phenol-hydro xyl  is  already  present : 
(4)  By  fusing  homologous  phenols  with  alkalies,  when  the  methyl  group, 
linked  to  the  nucleus,  will  be  oxidised  to  the  carboxyl  group.     (5)  By 
oxidising  the  sulphuric  or  phosphoric  acid  esters  of  homologous  phenols, 
and  then  saponifying  the  resulting  phenol-carboxylic  esters.     (6)  By 
fusing  the  phenol-aldehydes,  difficult  to  oxidise,  with  alkalies.     (7)  By 
converting   the    phenol-aldoximes   into   oxy-acid   nitriles,    and   then 
saponifying  the  latter. 

C.  Nuclear  Synthesis. — (8)  By  the  action  of  carbon  dioxide  upon 
the  dry  sodium  salts  of  the  phenols,  at  elevated  temperatures,  when 
the  carbonic  acid  generally  enters  the  ortho-position  with  reference 
to  the  hydroxyl  group.     This  reaction  will  be  more  exhaustively  dis- 
cussed in  connection  with  salicylic  acid. 

(9)  By  boiling  the  phenols  with  carbon  tetrachloride  and  caustic 
potash  (B.  10,  2185)  : 

C6H5.OH+CC14+5KOH   =  C6H4</°**     +4KC1+3H20. 

Nl^L>2*»- 

The  carboxyl  usually  occupies  the  p-position  to  the  phenol-hydroxyl. 

This  reaction  is  perfectly  analogous  to  that  of  the  formation  of 
oxaldehydes  by  means  of  chloroform  and  caustic  alkali.  The  action 
of  carbon  tetrachloride  upon  p-alkylated  phenols  in  the  presence 
of  A1C13  yields  derivatives  in  both  cases  of  keto-dihydro-benzol 


328  ORGANIC  CHEMISTRY 


\  H  H  .  o  from  whicn  the  phenols  are  regenerated  on  reduction 
CC13/  H  H 

(B.  41,  897). 

(10)  When  urea  chloride,  phenyl  iso-cyanate,  and  phenyl-mustard 
oil,  together  with  aluminium  chloride,  act  upon  phenol  ethers  (or  thio- 
phenol  ethers)  in  carbon  disulphide  solution  (A.  244,  61  ;  B.  27,  1733), 
the  products  are  amides,  anilides,  and  thio-anilides  of  alkyl-oxy-acids. 

Behaviour.  —  They  are  monobasic  acids.  The  hydrogen  of  the 
carboxyl  group  is  alone  replaced  by  metals  when  they  are  acted  upon 
with  alkaline  carbonates. 

Their  hydroxyl  hydrogen  can  also  be  replaced  by  alkalies,  forming 


basic  salts  —  e.g.  C8H4<\rO^r  •     Carbon  dioxide,  however,  will  convert 

the  latter  into  neutral  salts.  The  ether  esters  manifest  a  like  deport- 
ment, inasmuch  as  it  is  only  the  alkyl  ester  which  is  eliminated,  with 
the  production  of  a  salt  of  an  alkyl-ether  acid  : 

/O.CH3  /O.CHjj 

C6H4<  +KOH  =  C6H4<  +CH3.OH. 

XC02.CH3  XC02K 

The  o-oxy-acids,  unlike  the  m-  and  p-derivatives,  volatilise  in 
aqueous  vapour,  are  coloured  violet  by  ferric  chloride,  and  dissolve 
in  chloroform.  The  m-oxy-acids  are  coloured  reddish  brown  when 
heated  with  concentrated  sulphuric  acid,  with  the  formation  of  oxy- 
anthraquinones  (B.  18,  2142).  They  are  usually  more  stable  than 
the  o-  and  p-acids.  Boiling  concentrated  hydrochloric  acid  decom- 
poses the  p-acids  into  carbon  dioxide  and  phenols.  All  the  oxy-acids 
decompose  into  carbon  dioxide  and  phenols  when  distilled  with  lime. 

A.  Monoxy-monoearboxylie  Acids.  —  Salicylic  acid  or  o-oxy-benzoic 
acid  is  by  far  the  most  important  representative  of  this  class.  It  is 
extensively  applied  both  in  therapeutics  and  in  the  colour  industry. 

Monoxy-benzoic  Acids.  —  The  three  isomerides  theoretically  possible 
are  known. 

Salicylic  acid,  o-oxy-benzoic  acid  HO[2]C6H4[i]CO2H,  melting  at 
155°,  occurs  in  a  free  condition  in  the  buds  of  Spircza  ulmaria,  as  the 
methyl  ester  in  oil  of  Gaultheria  procumbens  (oil  of  evergreen),  a 
species  of  Ericaceae.  It  is  produced,  by  the  general  methods  of  forma- 
tion, (i)  from  anthranilic  acid;  (2)  from  o-sulpho-,o-chloro-,and  o-bromo- 
benzoic  acids  ;  (3)  from  o-cresol  ;  (4)  from  saligenin  and  salicyl-alde- 
hyde  ;  (5)  from  phenolates  with  CO2  ;  and  (6)  with  carbon  tetrachloride. 

It  is  also  formed  upon  fusing  cumarin  (q.v.)  and  indigo  (q.v.)  with 
caustic  potash,  and  in  the  distillation  of  copper  benzoate. 

Technical  Preparation.  —  Two  methods  of  bringing  sodium  phenolate 
and  CO  2  in  reaction  are  applicable  for  this  purpose  : 

(a)  Sodium  phenoxide  is  heated  in  a  current  of  carbon  dioxide  at 
i8o°-220°,  when  the  latter  is  absorbed.  Half  of  the  phenol  distils 
over,  and  the  residue  consists  of  disodium  salicylate  (H.  Kolbe)  : 

CO  Na 
2C6H5ONa+COa  =  C6H4  +C6H5OH. 


The  behaviour  of  potassium  phenolate  in  this  reaction  is  remark- 
able. At  150°  dipotassium  salicylate  is  produced.  At  a  more  elevated 
temperature,  however,  there  is  formed  with  the  dipotassium  salicylate 


MONOXY-MQNOCARBOXYLIC   ACIDS  329 

its  isomeride,  dipotassium  para-oxy-benzoate.  The  latter  is  more 
abundant  in  proportion  to  the  increased  temperature,  until  at  220° 
it  is  the  sole  product.  The  primary  alkali  salicylates,  when  heated, 
show  the  following  behaviour. 

Monosodium  salicylate  at  220°  yields  disodium  salicylate,  phenol, 


Primary  potassium  salicylate  at  220°  yields  phenol,  dipotassium 
para-oxy-benzoate,  and  CO2. 

Primary  sodium  para-oxy-benzoate  at  280°  yields  phenol,  CO2, 
and  disodium  salicylate  (/.  pr.  Ch.  2,  16,  425). 

(b)  Sodium  phenoxide  is  saturated  under  pressure,  in  closed  vessels, 
with  carbon  dioxide,  when  it  is  converted  into  sodium  pheno-carbonate 
C6H5.O.CO2Na.  This  is  transformed,  under  pressure,  at  a  temperature  of 
I20°-i3o°,  into  phenol-sodium-o-carboxylic  acid  NaO[2]C6H4[i]COOH 
(R.'.Schmitt,  German  patent  29,939)  .  This  can  be  combined  in  one  process 
by  letting  CO2  act,  under  pressure,  upon  sodium  phenate  at  120°- 
140°  (German  patent  38,742).  The  second  method  gives  a  complete 
transformation  of  the  phenol  employed.  This  difference  is  probably 
due  to  the  fact  that,  in  Kolbe's  method,  the  phenol-sodium-o-carboxylic 
acid  first  formed  at  the  high  temperature  forms  disodium  salicylate 
and  free  phenol  with  the  sodium  phenate  (B.  38,  1375  ;  39,  14  ; 

A.  351,  313). 

History.  —  Piria  first  obtained  salicylic  acid  in  1838,  when  he 
oxidised  its  aldehyde  with  molten  caustic  potash  (A.  30,  165).  In 
1843  Cahours  proved  that  evergreen  oil  consisted  almost  entirely  of 
methyl-salicylic  ester  (A.  53,  332).  Gerland,  in  1853,  showed  that 
anthranilic  acid,  as  suspected  by  A.  W.  Hofmann,  could  be  converted 
by  nitrous  acid  into  salicylic  acid  (A.  86,  147).  In  1860  H.  Kolbe 
and  Lautemann  prepared  it  synthetically  from  phenol,  sodium,  and 
carbonic  acid  (A.  115,  201).  It  was  Kolbe  who  first  correctly  inter- 
preted salicylic  acid  to  be  a  monobasic  oxy-acid,  and,  in  1874,  dis- 
covered' that  the  acid  could  readily  be  formed  upon  conducting  carbon 
dioxide  over  dry  heated  sodium  phenate.  It  was  in  this  way  that  he 
ascertained  the  conditions  necessary  for  the  production  of  the  acid 
upon  a  commercial  scale. 

Properties  and  Behaviour.  —  Salicylic  'acid  crystallises  from  alcohol 
in  colourless  prisms  ;  from  hot  water  in  long  needles.  It  has  a  sweet 
acid  taste.  It  dissolves  in  400  parts  of  water  at  15°,  and  in  12  parts  at 
100°  ;  it  is  very  soluble  in  chloroform.  When  it  is  heated  alone,  salol, 
or.  phenyl-salicylic  ester,  and  xanthone  (q.v.)  are  produced  (A.  269,  323). 
Sodium  in  amyl-alcohol  solution  reduces  it  to  normal  pimelic  acid. 
In  this  reaction  the  ring  is  ruptured,  and  cyclo-hexanone-carboxylic 
acid  appears  as  an  intermediate  product  (B.  27,  331)- 

Its  aqueous  solution  acquires  a  violet  coloration  upon  the  addition 
of  ferric  chloride  (C.  1908,  II.  1511).  It  is  a  powerful  antiseptic,  arrests 
decay  and  fermentation  (Kolbe,  /.  pr.  Ch.  2,  10,  9),  and  is  applied 
therapeutically  both  as  the  free  acid  and  in  the  form  of  its  sodium  salt 
(in  rheumatoid  arthritis). 

Salicylates.—  Sodium  salicylate  HO.C6H4CO2Na  is  a  crystalline 
powder,  with  an  unpleasant  sweet  taste.  Basic  calcium  salicylate 


330  ORGANIC   CHEMISTRY 

(OC6H4CO2)Ca+H2O  dissolves  with  great  difficulty,  and  is  precipi- 
tated upon  boiling  salicylic  acid  with  lime  water.  It  serves  for  the 
separation  of  salicylic  acid  from  m-  and  p-oxy-benzoic  acids. 

Esters,  Ethers,  and  Ether  Esters.— Methyl  ester  HO.C6H4.CO2CH3, 
boiling  at  224°,  with  sp.  gr.  1-197  (o°),  is  the  chief  ingredient  of  ever- 
green oil  (from  Gaultheria  procumbens).  It  occurs  in  many  different 
plants  in  the  form  of  a  glucoside  (B.  29,  R.  511  ;  C.  1899,  II.  881). 

When  the  methyl  ester  is  digested  with  an  alcoholic  solution  of 
potassium  hydroxide  and  methyl  iodide,  we  get  the  dimethyl  ester 

C8H4.<^co  £H  ,  boiling  at  245°.  Boiled  with  potassium  hydroxide, 
it  is  saponified,  yielding  methyl  alcohol  and  methyl-salicylic  acid 
C6H4/  •  3,  melting  at  98°.  It  decomposes  into  carbon  dioxide  and 

\\s\JnJLJi 

anisol  when  heated  to  200°. 

The  chloride  CH3O[2]C6H4COC1,  b.p.17  145°,  is  obtained  from  the 
acid  with  thionyl  chloride  (C.  1902,  II.  216). 

Phenol-salicylic  ester,  salol  HO.C6H4.CO2.C6H5,  melting  at  43°  and 
boiling  at  172°  (12  mm.),  results  on  heating  salicylic  acid  alone  to  200°- 
220°,  with  the  elimination  of  water  and  carbon  dioxide  ;  from  salicylic 
acid,  phenol,  and  POC13  ;  from  poly-salicylide  on  heating  with  phenol, 
or  when  phosgene  acts  upon  the  sodium  salts  of  salicylic  acid  and 
phenol.  It  is  applied  as  an  antiseptic.  It  changes  to  xanthone,  or 
diphenylene-ketone  oxide,  when  it  is  heated.  When  sodium  salol 
C6H4(ONa).CO2.CH2H5  (from  salol  and  sodium)  is  heated  to  28o°-3OO°, 
it  changes  to  the  isomeric  sodium  salt  of  phenyl-salicylie  acid  C6H4 
(O.C6H5).CO2H,  which  melts  at  113°,  and  is  not  coloured  by  ferric 
chloride.  This  acid  is  also  obtained  by  heating  o-chloro-benzoic  acid 
with  alkaline  phenolates,  in  the  presence  of  copper  (B.  38,  2111). 
Phenyl-salicylic-aeid-phenyl  ester  C6H5O[2]C6H4[i]COOC6H5,  m.p.  100°, 
is  formed  by  heating  phenyl-carboxylate  (C6H50)  2CO  with  sodium  car- 
boxylate,  CO2,  and  phenol  (C.  1903,  I.  1362). 

Aeetyl-salieylic  acid  CH3CO.O.C6H4COOH,  m.p.  135°,  is  used  as  an 
anti-neuralgic,  under  the  name  aspirin.  The  anhydride,  m.p.  85°,  is 
formed  from  the  acid  with  SOC12  or  COC12  in  pyridin  solution  (C.  1908, 
II.  996). 

Carbo-methoxy-salicylie  acid  CH3OCO.O[2]C6H4[i]COOH,  m.p. 
135°  with  decomposition,  from  salicylic  acid,  chloro-carbonic  ester,  and 
dimethyl-aniline  (B.  42,  218). 

Salieyi-acetie  acid  C6H4(OCH2COOH)COOH,  m.p.  190°,  is  prepared  by 
oxidising  aldehydo-phenoxy-acetic  acid,  and  from  the  sodium  salts  of 
several  acid  derivatives  of  salicylic  acid  with  chloracetic  ester  and  sub- 
sequent saponincation.  The  esters  of  the  acids  are  condensed  by  sodium 
to  keto-cumarane-carboxylic  esters  (B.  33,  1398  ;  C.  1900,  II.  461). 

Salicyl  chloride  HO.C6H4COC1  is  not  known.  It  is  true  that  PC15 
acts  very  energetically  upon  salicylic  acid,  but  the  resulting  phosphor- 
oxy-chloride  is  transposed  by  the  phenol-hydroxyl,  with  evolution  of 
hydrochloric  acid  : 

C.H.{ g 
and  there  results  : 


MONOXY-MONOCARBOXYLIC   ACIDS  331 

o-  Chloro-earbonyl-phenyl-ortho-phosphorie-acid  dichloride,  melting 
at  1 68°  (n  mm.).  If  the  PC15  continues  to  act,  this  compound  will 
exchange  an  oxygen  atom  for  two  chlorine  atoms,  and  o-triehloro- 
methyl-phenyl-ortho-phosphorie-acid  dichloride  (Cl2PO)O[2]C6H4[i] 
CC13,  boiling  at  178°  (n  mm.),  will  be  formed.  When  this  is  heated 
with  PC15  in  a  sealed  tube  to  180°,  there  results  : 

o-Chloro-benzo- trichloride  Cl[2]C6H4[i]CCl3,  melting  at  30°  and 
boiling  at  130°  (n  mm.)  (A.  239,  314).  m-  and  p-Oxy-benzoic  acids, 
as  well  as  m-  and  p-cresotinic  acids,  behave  similarly. 

If,  however,  the  hydrogen  atom  of  the  phenol-hydroxyl  is  replaced  by 
the  carbo-methoxyl  or  acetyl  group,  then  PC15  produces  the  chlorides  : 

Methyl-salicyl  chloride  CH3O[2]C6H4[i]COCl,  boiling  at  254°; 
acetyl-salieyl  chloride  CH3CO2[2]C6H4[i]COCl,  melting  at  43°  and 
boiling  at  135°  (12  mm.) ;  also  earbo-methoxy-salicylie  chloride  CH3 
OCOO[2]C6H4[i]COCl,  b.p.  io7°-iio°. 

When  halogen  atoms,  nitro-groups,  or  methyl  groups  are  introduced 
into  salicylic  acid,  and  then  occupy  the  o-position  with  reference  to 
the  phenol-hydroxyl,  the  latter  will  be  protected  by  them  from  the 
attack  of  the  phosphorus  oxy-chloride.  Consequently,  in  the  action 
of  PC15  free  oxy-chlorides  will  be  produced  : 

o-Cresotinic  chloride  HO[2]C(JH3[3]CH3[i]COCl,  melting  at  28°; 
3-ehloro-salicyl  chloride,  melting  at  63° ;  [3, 5]-dichloro-salicyl 
chloride,  melting  at  79° ;  and  [3, 5]-dichloro-nitro-salieyl  chloride, 
melting  at  70°  (B.  30,  221)  ;  also  the  3,  5-dibromo-  and  3,  5-di-iodo- 
chlorides  (A.  346,  300). 

The  influence  of  substituents  in  the  vicinity  of  the  phenol-hydroxyl 
group  is  manifested  in  other  ways,  as  in  that  of  the  esterification  of 
[2,  6]-substituted  benzoic  acids  with  alcohol  and  hydrochloric  acid. 

Salicylo-phosphoric  chloride  c6H4^^o_>pci,  melting  at  30°  and 

boiling  at  167°  (i i  mm.),  is  readily  formed  when  PC13  acts  upon  salicylic 
acid  at  70°  (A.  239,  301).  All  substituted  salicylic  acids  react  similarly 
(B.  30,  221). 

Salicylo-salieylie  acid  HO[2]C6H4[i]COO[2]C?H4[i]COOH,  m.p. 
148°,  is  formed  by  careful  treatment  of  salicylic  acid  and  its  salts  with 
SOC12,  PC13,  COC12,  etc.  It  is  used  in  medicine  under  the  name 
diplosal  (C.  1909,  II.  1285). 

Salicylides. — An  intramolecular  anhydride  of  salicylic  acid  of  the 

/CO 

formula  C6H4/  |  is  unknown,  but  several  polymers  of  this  hypo- 
thetical simplest  salicylide  have  been  prepared  : 

Di-salicylide  C6H4<(^^)>  C6H4,  needles,  m.p.  201°,  produced  by  con- 
ducting phosgene  into  a  pyridin  solution  of  salicylic  acid  (B.  34,  2951). 
O  .  CfiH,  COO  CfiH,  CO 

Tetra-salicylide  |  i    ,  m.p.  260°,  and  poly-salicylide 

CO.C6H4O.CO.C6H40 

(CjJE^OjJj.,  m.p.  322°-325°,  are  produced  when  POC13  acts  upon 
salicylic  acid  in  xylol  solution.  The  two  compounds  are  separated 
by  means  of  boiling  chloroform,  with  which  the  tetra-salicylide  forms 
a  compound,  salicylide  chloroform  (C7H4O2)4.2CHC13,  crystallising  in 
beautiful  quadratic  octahedra,  which  contain  33  per  cent,  of  chloroform, 


332  ORGANIC  CHEMISTRY 

loosely  combined  as  chloroform  of  crystallisation.  This  body  has  been 
used  technically  in  the  preparation  of  pure  chloroform  (Anschiitz, 
A.  273,  94).  o-Cresotinic  acid  and  the  o-haloid-salicylic  acids  behave 
similarly  (B.  35,  3644).  Concerning  later  molecular-weight  determina- 
tions of  tetra-salicylide,  see  A.  367,  164. 

Salicyl-amide  HO.C6H4.CONH2  melts  at  138°  (B.  24,  138).  If 
phosgene  is  allowed  to  act  upon  a  pyridin  solution  of  salicyl-amide, 
we  obtain  salicylic  nitrile  (see  below)  and  earbonyl-salicyl-amide 

C6H4/       |    §  m.p.  227°,  which  is  more  easily  obtained  from  chloro- 

carbonic  ester  with  salicyl-amide  in  pyridin  (B.  35,  3647).  The  O-acyl- 
salicylic  amides  are  unstable,  and,  on  fusing,  or  heating  with  pyridin, 
they  easily  pass  into  the  isomeric  N-acyl  compounds  : 

AcOC6H4CONH2 >  HOC6H4CONHAc. 

Under  certain  conditions  this  migration  of  the  acyl  residue  is 
reversible  (B.  40,  3506).  Bromine  and  alkali  transpose  salicyl-amide 
into  carbonyl-amido-phenol,  which  is  further  brominated  to  dibromo- 
carbonyl-amido-phenol  (C.  1900,  I.  255). 

Salicyl-anilide  C6H4(OH)CONHC6H5  changes,  when  heated  in  dry 

condition,  to   acridone    C.H4<^^>C6H4.       It   is   very   probable   that 

it  is  at  first  rearranged  into  phenyl-anthranilic  acid  (B.  29,  1189). 
Salicylo-nitrile  HO.C6H4.CN,  m.p.  98°,  is  obtained  from  salicyl-aldoxime 
and  acetic  anhydride  (B.  26,  2621  ;  27,  R.  134  ;  31,  3087). 

Salicylic-acid  hydrazide  HO.C6H4CONH.NH2,  m.p.  147°,  gives  with 
HNO2  salicylic-acid  azide  HO.C6H4.CON3,  m.p.  27°,  crystals  of  a  pene- 
trating odour.  Salieyl-uric  acid  HO.C6H4CO.NHCH2COOH,  m.p.  170°, 
occurs  in  urine  after  taking  salicylic  acid  (A.  97,  250)  ;  synthetically, 
it  is  prepared  from  salicylic-acid  azide  or  carbo-methyoxy-salicylic-acid 
chloride  and  glycocoll  (B.  42,  219). 

Thio-salicylic  acid,  and  its  derivatives,  have  lately  acquired  great 
industrial  importance  on  account  of  their  easy  conversion  into  indigoid 
sulphur  dyes ;  see  Thio-indigo,  and  A.  351,  390. 

Thio-salicylie  acid  HS[2]C6H4[i]COOH,  m.p.  164°  (?),  is  formed 
(i)  from  diazotised  anthranilic  acid  by  transposition  with  potassium 
xanthogenate  or  sulpho-cyanate,  or  alkali  polysulphides,  and  reduction 
of  the  resulting  compounds :  CO2HC6H4S.C.SOC2H5,  CO2HC6H4SCN, 
(C02HC6H4)2S2 ;  (2)  from  chloro-benzoic  acid  by  heating  with  alkaline 
sulpho-hydrates  or  alkaline  sulphides  with  addition  of  powdered  copper 
(German  patent  189,200) ;  (3)  by  reduction  from  the  unstable  o-sulpho- 
benzoic  dichloride.  By  oxidation,  it  is  easily  converted  into  dithio- 
salicylic  acid  S2(C6H4COOH)2,  m.p.  289°  (B.  31, 1665). 

Methyl-thio-salicylic  acid  CH3SC6H4COOH,  m.p.  169°,  is  formed 
by  the  action  of  dimethyl  sulphate  or  methyl  iodide  upon  alkaline 
solutions  of  thio-salicylic  acid,  di-thio-salicylic  acid,  o-rhodano-benzoic 
acid,  etc.  On  melting  with  alkalies,  with  addition  of  a  condensing  agent 
like  disodium  cyanamide,  sodium-lead,  etc.,  it  passes  into  thio-indoxyl 
(German  patent  200,200). 

Aeetylene-bis-thio-salicylie  acid  CO2HC6H4S.CH  :  CH.SC6H4COOH, 
formed  by  the  action  of  acetylene  dichloride  upon  the  alkali  salts  of 
thio-salicylic  acid.  With  an  acid  condenser  it  gives  thio-indigo. 


MONOXY-MONOCARBOXYLIC   ACIDS  333 

Phenyl-thio-glyeol-o-carboxylic  acid  HOCO[i]C6H4[2]S.CH2COOH, 
m.p.  213°,  is  obtained  (i)  from  thio-salicylic  acid  and  monochloracetic 
acid  ;  (2)  by  the  action  of  thio-glycollic  acid  upon  o-diazo-benzoic  acid. 
Its  nitrile,  m.p.  140°,  is  formed  from  o-amido-thio-phenol  by  transposi- 
tion with  monochloracetic  acid,  and  replacement  of  the  amido-group 
by  the  cyanogen  group,  through  the  diazo-compound  (A.  351,  412). 
On  heating  with  alkali,  the  phenyl-thio-glycol-o-carboxylic  acid  and 
its  nitrile  pass  into  thio-indoxyl-carboxylic  acid,  which  is  easily  con- 
verted into  thio-indigo  by  splitting  off  CO2  and  oxidation  : 

C0\_          CO  \ 


JCOOH  (C(OH)^ 

C'HMS.CH,COOH  "      •  C«H*  IS  -  ^C'C° 

Phenyl  -  thio  -  salicylic  acid  C6H5SC6H4COOH,  m.p.  167°,  from 
o-  chloro-benzoic  acid,  sodium  thio-phenol,  and  copper.  Gives  thiox- 
anthone  on  warming  with  concentrated  H2SO4  and  acetic  anhydride 
(A.  263,  2  ;  B.  37,  4526  ;  C.  1905,  I.  1394).  Thio-salicylie-phenyl 
ester  HSC6H4CO2C6H5,  m.p.  91°,  from  thio-salicylic  acid,  phenol,  and 
POC13  (B.  42,  1134). 

Diphenyl  -  sulphide  -  o,  o  -  diearboxylic  acid  S(C6H4COOH)2,  m.p. 
230°,  by  heating  thio-salicylic  acid  with  o-chloro-benzoic  acid  and 
copper  (B.  43,  588). 

Substituted  Salicylic  Acids.  —  The  5-derivatives  of  the  mono-sub- 
stitution products  are  the  most  readily  prepared.  3-Derivatives  are 
formed  simultaneously.  Of  the  di-substituted  salicylic  acids,  the  3,  5- 
derivatives  are  most  easily  made.  In  them  the  substituents  enter  the 
o  p-position,  referred  to  phenol-hydroxyl.  5-Chloro-,  5-bromo-,  5-iodo-, 
and  5-nitro-salieylie  acids  melt  at  172°,  164°,  196°,  and  228°  respectively. 

5-Nitroso-salieylic  acid,  m.p.  156°  with  decomposition,  blue-green 
crystals,  from  5-nitroso-methyl-anthranilic  acid  on  boiling  with  NaHO. 
It  may  be  regarded  as  possible  quinone-oxime-carboxylic  acid  (B.  42, 
2757). 

3-Chloro-,  3-bromo-,  3-iodo-,  and  3-nitro-salicylic  acids  melt  at 
178°,  220°,  193°,  and  144°  respectively  (B.  33,  3240). 

3-Nitro-salicylic  acid  is  prepared  synthetically  from  nitro-malone- 
aldehyde  and  aceto-acetic  ester  (C.  1900,  II.  560). 

3,  5-Diehloro-,  3,  5-dibromo-,  3,  5-di-iodo-,  and  3,  5-dinitroso- 
salicylic  acids  melt  at  214°,  223°,  220°-23O°  with  decomposition,  and 
at  173°  respectively.  An  anhydride,  melting  at  187°  (B.  30,  223),  has 
been  prepared  by  the  action  of  the  chloride  of  3,  5-dichloro-salicylic 
acid  upon  the  silver  salt  (B.  30,  223  ;  A.  346,  307).  For  other  halogen- 
substituted  salicylic  acids,  see  B.  38,  3294. 

3-Amido-salieylic  acid  NH2[3]C6H3[2](OH)COOH,  see  /.  pr.  Ch.  2, 
61,  532.  5-Amido-salicylie  acid  NH2[5]C6H3[2](OH)COOH  is  formed 
by  reduction  of  benzol-azo-salicylic  acid  C6H5N2C6H3(OH)COOH  (C. 
1906,  II.  1058). 

By  diazotising,  and  successive  combination  with  a-naphthyl-amine 
and  with  a-naphthol-sulphonic  acid,  diamond  black  is  obtained  ;  by 
reduction  of  the  diazo-compound,  hydrazin-salieylic  acid  NH2NHC6H3 
(OH)COOH,  m.p.  148°  (B.  32,  81  ;  C.  1900,  I.  205).  5-Diethyl-glyeo- 
coll  -  amido  -  salicylic  methyl  ester  (C2H5)  2NCH2CO.NH.C6H3(OH) 
COOCH3  is  recommended  as  a  local  anaesthetic,  and  called  nirvanin. 
Sulpho-salieylic  acid  (SO3H)C6H3(OH)COOH,  and  nitro-sulpho-salicylic 


334  ORGANIC  CHEMISTRY 

aeid,  see  B.  33, 3238 ;  /.  pr.  Ch.  2,  61,  545.     Amido-sulpho-salieylie  acid 

is  formed  from  nitro-salicylic  acid  with  Na  bisulphite  (C.  1901,  II.  716). 

m-Oxy-benzoic  acid  HO[i]C6H4[i]CO2H,  m.p.  200°,  sublimes  with- 
out decomposition.  p-Oxy-benzoie  acid  HO[4]C6H4[i]CO2H  melts, 
when  anhydrous,  at  210°  with  partial  decomposition  into  carbon  dioxide 
and  phenol.  Its  methyl  ester  melts  at  131°  and  boils  at  270°-28o° 
(B.  27,  R.  570).  The  two  acids  are  obtained  from  their  corresponding 
amido-  and  haloid  benzoic  acids  by  methods  I  and  2.  See  above  for 
the  production  of  p-oxy-benzoic  acid,  together  with  salicylic  acid,  by 
methods  8  and  9.  p-Oxy-benzoic  acid  is  also  obtained  from  many 
resins  by  fusing  them  with  caustic  potash.  For  the  behaviour  of  m- 
and  p-oxy-benzoic  acids  with  PC15,  consult  above.  Compare  A.  261, 
236,  for  the  action  of  chlorine  upon  the  three  oxy-benzoic  acids. 

m-Oxy-p-amido-  and  m-amido-p-oxy-benzoic  methyl  ester,  m.p. 
121°  and  in0,  are  known  as  local  anaesthetics,  under  the  names 
orthoform  and  new  orthoform  (A.  311,  26). 

Anisic  acid,  p-methoxy-benzoic  acid  CH3O[4]C6H4[i]CO2H,  m.p. 
185°  and  b.p.  280°,  is,  like  benzoic  and  salicylic  acids,  one  of  the  acids 
which  has  been  long  known.  It  is  isomeric  with  methyl-salicylic  ester 
and  the  other  monomethyl  derivatives  of  the  oxy-benzoic  acids  in 
general,  as  well  as  with  the  oxy-phenyl-acetic  acids.  Anisic  acid  is 
easily  obtained,  hence  numerous  transposition  products  of  it  are  known. 
It  is  prepared  by  oxidising  anethol,  the  chief  ingredient  of  anise  oil,  and 
other  ethereal  oils  containing  anethol  (q.v.),  with  dilute  nitric  acid,  or 
with  a  chromic  acid  mixture.  Synthetically,  it  is  obtained  from 
p-bromo-anisol,  Mg,  and  CO2  (C.  1903,  I.  636). 

Nitrile,  m.p.  60°,  b.p.  257°,  from  p-nitro-benzo-nitrile  with  sodium 
methylate.  Also  from  anisamide  with  PC15,  and  from  anisol,  BrCN, 
and  A1C13  (B.  33, 1056  ;  36,  648  ;  C.  1900, 1.  130). 

History. — Cahours  (1839)  discovered  anisic  acid  when  he  oxidised 
anise  oil  (A.  41,  66).  Kolbe  at  first  considered  it  methoxy-benzoic  acid, 
because  when  it  was  distilled  with  caustic  baryta  it  broke  down  into 
CO  2  and  anisol.  Saytzew  (1863)  found  that  when  anisic  acid  was 
heated  with  hydriodic  acid  it  yielded  an  acid  different  from  salicylic 
acid,  yet  isomeric  with  the  latter  (A.  127, 129).  This  was  subsequently 
found  to  be  p-oxy-benzoic  acid.  In  1867  Ladenburg  showed  that 
anisic  acid  could  be  prepared  by  saponifying  the  dimethyl  ether  ester 
of  p-oxy-benzoic  acid  (A.  141,  241). 

Oxy-toluic  Acids  or  Cresotinic  Acids  CH3.C6H3(OH).CO2H.— The 
ten  possible  isomerides  are  known  (B.  16,  1966).  They  are  isomeric 
with  the  three  oxy-methyl-benzoic  acids,  or  benzyl-alcohol-carboxylic 
acids,  and  phenyl-glycollic  acid,  or  almond  acid.  They  have  been  pre- 
pared from  the  toluic  acids  by  methods  i  and  2,  from  the  oxy-aldehydes 
by  method  6,  and  from  the  cresols  by  methods  8  and  9. 

Homo-salicylic  acids :  Methyl- m-oxy-benzoic  acids  : 

CH3[3]C6H3[2,  i](OH)COOH,  m.p.  163°.  CH3[2]C6H3[3,  i](OH)COOH,  m.p.  183°. 

CH3[4]C6H3[2,  i](OH)COOH,     „    177°.  CH3[4]C6H3[3,  i](OH)COOH,     „    206°.' 

CH3[5]C6H3[2,  i](OH)COOH,     „     151°.  CH3[5]C6H3[3,  i](OH)COOH,     „    208°. 

CH3[6]C6H3[2,  i](OH)COOH,     „     168°.  CH3[6]C6H3[3,  i](OH)COOH,     „     184°. 

Methyl-p-oxy-benzoic  acids : 
CH3[2]C6H3[4,  i](OH)COOH,  m.p.  177°.     CH3[3]CaH3[4,  i](OH)COOH,  m.p.  172°. 


MONOXY-MONOCARBOXYLIC   ACIDS  335 

Those  isomerides,  containing  the  hydroxyl  group  in  the  ortho-posi- 
tion with  reference  to  carboxyl,  are  coloured  violet  by  ferric  chloride, 
just  like  salicylic  acid.  They  dissolve  easily  in  cold  chloroform  and  are 
volatile  with  steam.  See  above  for  their  behaviour  towards  PC15,  PC13, 
POC13,  etc.  3-Methyl-homo-salicylic  acid  yields  an  o-homo-salicylic 
or  o-cresotide*  chloroform  (A.  273,  88)  similar  to  salicylide  chloroform. 
5-Methyl-m-oxy-benzoic  acid,  prepared  synthetically  by  the  action  of 
baryta  water  upon  acetone-oxalic  ester  (B.  22, 3271),  yields  by  nitration 
nitrococcic  acid  or  2,  4,  6-trinitro-m-oxy-m-toluic  acid,  melting  at  180°, 
which  is  also  formed  when  carminic  acid,  the  dye  of  red  cochineal,  is 
oxidised  (B.  26,  2648).  The  6-methyl-m-oxy-benzoic  acid  is  best  ob- 
tained by  heating  /3-naphthol-6,  8-disulphonic  acid  with  50  per  cent. 
NaHO  to  26o°-28o°  (A.  350,  253).  When  the  three  isomeric  creso- 
tinic  acids,  or,  better,  their  dibromo-substitution  products,  are  reduced 
with  sodium  and  amyl  alcohol,  the  ring  is  ruptured  and  a-,  j8-,  and 
y-methyl-pimelic  acids  are  produced  (A.  295,  173). 

o-  and  p-Oxy-mesitylenic  acids  HO.C6H2(CH3)2CO2H  melt  at  179° 
and  223°  (A.  206,  197;  311,  372).  The  former  is  obtained  by  nuclear 
synthesis,  through  condensation  of  a-methyl-jS-ethyl-acrolein  with 
malonic  ester,  and  treatment  of  the  product  with  sodium  alcoholate 
(A.  358,  71)  : 

CH3  CH3 

CH— CH2    .  ROCO  -H,0  CH— C=COH 


Similarly,  we  obtain  from  citral  (q.v.)  and  malonic  ester  3-iso- 
amenyl-4-methyl-salicylic  acid,  m.p.  167°. 

The  trimethyl-oxy-benzoic  acids  (B.  21,  884),  as  well  as  ethyl- 
methyl-oxy-benzoie  acids  (A.  195, 284),  are  also  known.  The  correspond- 
ing iso-propyl-oxy-benzoic  acids — thymo-  and  iso-oxy-eumic  acids, 
melting  at  142°  and  94°  (B.  19,  3307) — result  upon  fusing  carvacrol  and 
thymol  with  caustic  potash. 

Different  isomeric  p-methyl-iso-propyl-oxy-benzoic  acids  (CH3) 
(C3H7)C6H2(OH)COOH  :  thymotic  and  earva-erotinic  acids  have  been 
made  by  introducing  the  CO2  group  into  thymol  and  carvacrol.  See 
B.  28,  2795,  for  the  derivatives  of  thymotic  acid. 

The  oxy-phenyl-fatty  acids  attach  themselves  to  the  alkyl-substituted 
oxy-benzoic  acids.  They  are  produced  (i)  by  diazotising  the  corre- 
sponding amido-phenyl-fatty  acids,  and  then  decomposing  the  diazo- 
derivatives  with  boiling  water ;  (2)  by  saponifying  the  oxy-benzyl 
cyanides. 

The  o-oxy-acids,  in  which  the  phenol-hydroxyl  group  occupies  the 
y-  or  8-position  with  reference  to  the  carboxyl  group,  are,  in  contrast  to 
the  corresponding  o-amido-fatty  acids,  capable  of  existing,  but  when 
heated  they  part  with  water  and  yield  y-  and  S-lactones  (Vol.  I.). 

The  oxy-phenyl-aeetie  acids  HO.C?H4.CH2.CO2H  are  isomeric  with 
the  ten  oxy-toluic  acids  (see  these) ,  with  the  three  oxy-methyl-benzoic 
acids,  and  with  the  mandelic  acids.  o-Oxy-phenyl-acetic  acid,  bearing 
close  relationship  to  oxindol  and  isatin  (q.v.),  is  also  obtained  from 
o-oxy-mandelic  acid  by  reduction  with  hydriodic  acid.  Ferric  chloride 
colours  it  violet.  It  passes  into  its  lactone  (see  below)  when  it  is 
heated.  p-Oxy-phcnyl-acetic  acid  occurs  in  urine,  and  arises  from  the 


336  ORGANIC  CHEMISTRY 

decomposition  of  albuminous  bodies  as  well  as  in  that  of  sinalbin, 
occurring  in  the  seeds  of  white  mustard  (B.  22,  2137). 

o-,  m-,  and  p-Oxy-phenyl-acetic  acids  melt  at  137°,  129°,  and  148°. 
m-  and  p-Oxy-phenyl-aeeto-nitrile  melt  at  52°  and  69°  (B.  22, 2139). 

5,  2-Nitro-oxy-phenyl-acetic  acid,  m.p.  149°,  is  obtained,  syntheti- 
cally, by  condensation  of  nitro-malonic  aldehyde  and  levulinic  acid 
(C.  1900,  II.  560). 

Oxy-phenyl-propionic  acids. — Four  of  the  six  theoretically  possible 
acids  are  known. 

Phloretic    acid,     p  -  oxy  -  hydratropic    acid    HO[4]C.H4[i]CH<^;°«H. 

melting  at  129°,  is  formed,  together  with  phloro-glucin,  when  phloretin 
(the  phloro-glucin  ester  of  phloretic  acid)  is  digested  with  potassium 
hydroxide.  It  has  been  prepared  synthetically  from  p-amido-hydro- 
cinnamic  acid.  Ferric  chloride  colours  its  solution  green.  Baryta 
decomposes  it  into  ethyl-phenol ;  fusion  with  potassium  hydroxide 
produces  para-oxy-benzoic  acid. 

Phloretin,  monophloretic  phloro-glucin  ester  (HO)2C6H3O.CO. 
CH(CH3).C6H4OH,  melts  at  254°  (B.  27, 1631,  2686).  See  Phlorizin. 

Hydro-cumarie  acids  or  j3-phenol-propionie  acids  HO.C6H4.CH2. 
CH2.CO2H  result  when  the  corresponding  cumaric  acids,  the  oxy- 
cinnamic  acids,  or  j3-oxy-phenyl-acrylic  acids  are  reduced  with  sodium 
amalgam. 

o-Hydro-eumaric  acid  or  melilotic  acid,  melting  at  81°,  occurs  free 
and  in  combination  with  cumarin,  the  lactone  of  o-oxy-cinnamic  acid, 
in  the  yellow  melilot  (Melilotus  officinalis).  It  is  produced  by  the 
action  of  sodium  amalgam  upon  cumarin.  Ferric  chloride  imparts  a 
bluish  colour  to  the  solution.  When  distilled,  it  passes  into  its  lactone 
— hydro-cumarin.  It  yields  salicylic  acid  when  it  is  fused  with  caustic 
potash. 

m-  and  p-Hydro-eumaric  acids  melt  at  111°  and  128°.  p-Hydro- 
cumaric  acid  is  also  produced  in  the  decomposition  of  tyrosine. 

y-  and  S-Lactones  of  o-oxy-phenyl-fatty  acids  are  produced  when 
these  acids  are  distilled.  They  correspond  to  the  y-  and  8-lactames 
described  above. 

o-Oxy-phenyl-acetie    acid    lactone    c6H4/[l]CH2tCTO  melts   at    49° 

l[2]0 1 

and  boils  at  236°  (B.  17,  975). 

Hydro-cumarin,   j3  -  o  -  Oxy  -  phenyl  -  propionic   acid    lactone 

C6H4{Cl]CH2'CH2(f0,  melts  at  25°  and  boils  at  272°.     When  boiled  with 

water  it  regenerates  the  acid  from  which  it  was  produced  by 
distillation. 

B.  Dioxy-monocarboxylic  Acids  are  obtained  by  the  same  methods 
which  were  used  in  the  preparation  of  the  aromatic  monocarboxylic 
acids.  The  car  boxy  1  group  is  more  readily  introduced  into  the  dioxy- 
benzols  than  into  the  monoxy-benzols.  This  occurs  upon  heating  the 
bodies  with  a  solution  of  ammonium  or  sodium  carbonate  to  100°  or 
130°  (B.  18,  3202;  19,  2318;  A.  351,  313).  The  dioxy-benzoic  acids 
break  down,  when  heated,  into  carbon  dioxide  and  dioxy-benzols. 

Dioxy-benzoic  Acids. — The  six  possible  isomerides  are  known.  The 
most  important  member  of  this  class  is  : 


DIOXY-MONOCARBOXYLIC  ACIDS  337 

Proto  -  catechuic  acid,  3,  4-dioxy-benzoic  acid  (HO)2[3,  4]C6H3 
[i]CO2H-j-H2O,  in  yellow  needles,  melts,  when  anhydrous,  at  190°,  and 
decomposes  into  pyro-catechin  and  carbonic  acid.  It  occurs  in  the  fruit 
of  Illicinm  religiosum.  It  has  been  obtained  from  many  tri-deriva- 
tives  of  benzene,  containing  substituents  in  the  3,  4-position  with 
reference  to  a  side  chain,  by  fusing  them  with  caustic  potash  —  e.g.  from 
the  corresponding  bromo-  and  iodo-p-oxy-benzoic  acids,  bromanisic 
acid,  p-  and  m-cresol-sulphonic  acid,  sulpho-p-  and  sulpho-m-oxy- 
benzoic  acids,  from  eugenol,  piperic  acid  (compare  also  piperonylic 
acid),  etc.,  as  well  as  from  various  resins  (benzoin,  asafcetida,  myrrh, 
and,  particularly,  kino)  on  fusion  with  potassium  or  sodium  hydroxide. 
The  latter  resin  readily  yields  large  quantities  of  the  acid  (A.  177,  188). 
Compare  further  phloro-glucin  ethers  of  pyro-catechuic  acid.  It  is  also 
produced  by  the  action  of  bromine  upon  quinic  acid  in  aqueous  solution. 

The  two  possible  pyro-catechuic  monocarboxylic  acids  are  produced 
when  pyro-catechin  is  heated  to  140°  with  a  solution  of  ammonium 
carbonate. 

Ferric  chloride  colours  the  solution  green  ;  after  the  addition  of  a 
very  dilute  soda  solution  it  becomes  blue,  later  red  (all  derivatives  con- 
taining the  proto-catechuic  residue  (OH)2C6H3.C  (B.  14,  958)  react 
similarly).  Ferrous  salts  colour  its  salt-solutions  violet.  It  reduces 
an  ammoniacal  silver  solution,  but  not  an  alkaline  copper  solution. 
Diproto-eatechuie  acid  C14H10O7,  is  a  tannic  acid  which  results  on  boil- 
ing proto-catechuic  acid  with  aqueous  arsenic  acid.  It  is  very  similar 
to  common  tannic  acid,  but  is  coloured  green  by  ferric  oxide.  It  forms 
a  compound  with  p-oxy-benzoic  acid  by  the  union  of  equimolecular 
quantities  (A.  134,  276  ;"  280,  18). 

See  Naphthalene  ring  formations  for  the  conversion  of  substituted 
proto-catechuic  acids,  by  oxidation  with  nitric  acid,  into  derivatives 
of  /?-naphtha-quinone. 

The  phenol  ethers  of  proto-catechuic  acid  are  : 

f[i]C02H                   f[i]C02H  f[i]CO,H                   f[i]C02H 

C6HJ[3]OCH3  C6H3][3]OH  C6HJ  [3]OCH3  C6H3J  [3]O\  QH 

[4]OH                       lC4]OCH3  l[4]OCH3                    l[4]0/ 

Vanillic  acid  Iso-vanillic  acid  Veratric  acid  Piperonylic  acid. 

These  alkyl-and  alkylene-ether  acids  are  formed  when  proto-catechuic 
acid  is  treated  with  CH3I,  CH2I2,  and  CH2Br.CH2Br  and  caustic  potash, 
as  well  as  by  oxidising  the  corresponding  ethers  of  proto-catechuic 
aldehyde.  The  proto-catechuic  acid  can  be  regained  from  them  upon 
heating  with  hydrochloric  acid  to  150°,  when  the  dimethyl-ether  acid 
will  yield  at  first  the  two  monomethyl-ether  acids;  whereas  the 
methylene  ether,  piperonylic  acid,  separates  carbon  in  addition  to 
proto-catechuic  acid  : 


C02H.C6H3<(°)>CH2 


The  alkyl-ether  acids  break  down  into  carbon  dioxide  and  alkyl- 
pyro-catechuic  ethers  when  they  are  heated  with  lime  or  baryta. 

Vanillic  acid,  m-methyl-proto-cateckuic  acid,  melting  at  211°,  sublimes. 
It  is  obtained  by  the  energetic  oxidation  of  its  aldehyde,  vanillin,  also 
from  coniferin,  as  well  as  by  the  decomposition  of  aceto-vanillic  acid, 
VOL.  II.  Z 


338  ORGANIC   CHEMISTRY 

melting  at  142°,  the  oxidation  product  of  aceto-eugenol,  aceto-ferulic 
acid,  and  aceto-homo-vanillic  acid,  when  they  are  treated  with  potassium 
permanganate.  Its  nitrite  melts  at  87°  (B.  24,  3654). 

Iso-vanillie  acid,  p-methyl-proto-catechuic  acid,  melts  at  250°,  and  was 
first  obtained  from  hemi-pinic  acid  (see  this),  or  4,  5-dimethoxy-o- 
phthalic  acid  upon  heating  with  hydrochloric  acid. 

Veratric  acid,  3,  ^-dimethoxy-benzoic  acid,  melting  at  179-5°,  occurs, 
together  with  veratrin  (see  the  alkaloids),  in  the  sabadilla  seeds  (from 
Veratrum  Sabadilla). 

Diethyl-proto-catechuic  acid  melts  at  149°. 

Piperonylie  acid,  methylene-proto-catechuic  acid,  melting  at  228°,  is 
also  formed  by  oxidising  a-homo-piperonylic  acid,  obtained  from  safrol, 
as  well  as  from  piperonal  and  proto-catechuic  acid  (see  this) .  It  breaks 
down  when  heated  with  hydrochloric  acid  (see  above).  By  the  action 
of  PC15,  and  subsequent  treatment  with  cold  water,  it  can  be 
converted  into  the  carboxylate  of  proto-catechuic  acid,  and  into  the 
latter  itself  by  saponification  (C.  1908,  I.  1689).  Its  nitrite  melts  at 
95°  (B.  24,  3656). 

Ethytene-proto-catechuic  acid  melts  at  133°. 

The  phtoro-gtucin  ethers  of  proto-catechuic  acid  are  probably  certain 
vegetable  substances  which,  upon  fusion  with  caustic  potash,  break 
down  into  phloro-glucin  and  proto-catechuic  acid.  They  are  also 
related  to  theflavones  (q.v.) ,  belonging  to  the  pyrone  group.  They  are  : 

Luteolin  C15H10O6  (B.  29,  R.  647,  848),  occurs  in  Reseda  tuteola  and 
crystallises  in  yellow  needles.  Ferric  chloride  colours  it  green. 

Catechin,  from  catechu,  and  Maclurin  or  moringa  tannic  acid 
C13H10O6-f  H2O,  from  yellow  wood,  Morus  tinctoria,  are  generally 
included  among  the  tannic  acids.  Proteaic  acid  C9H1004  appears  to 
be  a  homologue  of  proto-catechuic  acid.  It  is  present  in  Protea  mellifera 
(B.  29,  R.  415). 

Pyro  -  catechin  -  o  -  earboxylie  acid,  2,  3-dioxy-benzoic  acid  (HO)  2 
C6H3CO2H+2H2O,  melts  at  199°  when  anhydrous.  It  readily  breaks 
down  into  CO2  and  pyro-catechin,  from  which  it  is  formed,  together 
with  proto-catechuic  acid,  by  the  action  of  ammonium  carbonate  (A.  220, 
116).  It  also  results  when  3-iodo-salicylic  acid  is  fused  with  caustic 
potash. 

Resoreinol-monocarboxylie  Acids. — There  are  three.  Sym.  dioxy- 
benzoic  acid  results  on  heating  sym.  disulpho-benzoic  acid  with  caustic 
potash,  and  the  other  two  acids  are  produced  when  resorcinol  is  treated 
with  ammonium  dicarbonate  or  potassium  dicarbonate  solution  (B.  18, 
1985;  13,2379). 

The  a-compound  is  not  coloured  by  ferric  chloride  ;  whereas  the 
/3-body  is  coloured  a  dark  red,  and  the  y-modification  blue- violet,  by 
the  same  reagent. 

a-Resorcylie  acid,  3,  $-dioxy-benzoic  acid  (HO)2C6H3CO2H-f 
iJH20,  melts  at  233°.  It  yields  anthrachrysone  (q.v.)  when  it  is 
heated  with  sulphuric  acid. 

j8-Resorcylic  acid,  2, 4-dioxy-benzoic  acid-\-^H.2O,  melts  in  the 
anhydrous  state  at  213°.  See  B.  28,  R.  1051  ;  29,  R.  30,  for  the  ethers 
and  esters  of  the  acid. 

It  is  converted  in  glacial  acetic  acid  solution  by  chlorine  into 
hexachloro-m-diketo-hexene  (B.  25,  2687).  The  nitrite  melts  at  175°. 


DIOXY-MONOCARBOXYLIC  ACIDS  339 

y-Resorcylie  acid,  2,  6-dioxy-benzoic  acid,  melts  at  i48°-i67°,  and 
breaks  down  into  CO2  and  resorcinol. 

Gentisinic  acid,  hydroquinone-earboxylic  acid,  2,  5-dioxy-benzoic 
acid,  melts  at  200°,  and  at  215°  breaks  down  into  carbon  dioxide  and 
hydroquinone.  It  was  first  prepared  from  gentisin,  a  xanthone  deriva- 
tive, together  with  phloro-glucin,  on  fusing  it  with  caustic  potash.  It 
is  obtained  from  5-bromo-,  5-iodo-  and  5-amido-salicylic  acids  ;  also 
from  hydroquinone  and  from  gentisinic  aldehyde  (B.  14,  1988).  It  is 
most  easily  obtained  by  oxidation  of  salicylic  acid  with  potassium 
persulphate  in  alkaline  solution  (A.  340,  213).  Ferric  chloride  colours 
it  a  deep  blue  and  is  decomposed  into  CO2  and  quinone  (B.  18,  3499). 

The  Dioxy-toluic  Acids  (HO)2C6H2(CH3)CO2H  are  isomeric  with 
the  dioxy-phenyl-acetic  acids.  The  most  important  of  the  known 
acids  of  this  class  is  orsellinic  acid,  2,  6-dioxy-p-toluic  acid,  which 
melts  at  176°  and  breaks  down  into  CO2  and  orcin.  It  is  obtained 
from  orsellic  acid  upon  boiling  the  latter  with  water,  or  from  erythrin 
with  baryta  water.  It  is  coloured  violet  by  ferric  chloride. 

Orsellic  acid,  diorsellinic  acid  or  lecanoric  acid  C16H14O7,  melting 
at  153°,  is  an  ether-like  anhydride  of  orsellinic  acid  (HO)2.C6H2(CH)3. 
CO.OC6H2(OH)(CH3)CO2H  (?).  It  is  found  in  different  mosses  of  the 
varieties  Roccella  and  Lecanora.  Boiling  water  converts  it  into 
orsellinic  acid. 

Erythrin  C20H22O10+iJH2O,  erythrinic  acid,  is  an  ether  derivative 
of  diorsellinic  acid  and  erythrite.  It  occurs  in  the  lichen  Roccella 
fuciformis,  which  is  applied  in  the  manufacture  of  archil,  and  is  extracted 
from  it  by  means  of  milk  of  lime.  When  it  is  boiled  with  water  it 
breaks  up  into  orsellinic  acid  and  — 

Piero-erythrin  C12H16O7-f-H2O,  which,  boiled  with  baryta  water, 
yields  erythrite,  orcin,  and  carbon  dioxide  : 

Erythrin  C20H22010+H20   =  (HO)2C6H2(CH3)CO2H+CiaH16O7 

C12H1607+H20     =  (HO)2C,H3CH3+C02+C4H6(OH)4  Erythrite. 

Everninie  acid  C9H10O4=(HO)2C6H(CH3)2CO2H  (?)  is  produced, 
together  with  orsellinic  acid,  on  boiling  evernic  acid  (from  Evernia 
prunastris)  with  baryta.  It  melts  at  157°,  and  is  coloured  violet  by 
ferric  chloride. 

Dioxy-durylic  acid,  pseudo-cumene-hydroquinone-carboxylic  acid 
(HO)2[2,  5]C6[3,  4,  6](CH3)3CO2H,  melts  at  210°  when  rapidly  heated, 
and  results  from  the  reduction  of  durylic  acid  quinone,  pseudo-cumene* 
quinone-carboxylic  acid  O2[2,  5]C6[3,  4,  6](CH3)3CO2H,  which  decom- 
poses at  130°,  and  is  obtained  by  the  action  of  ferric  chloride  upon  a 
hydrochloric  acid  solution  of  diamido-phenylic  acid  (A.  237,  n). 

Dioxy-phenyl-fatty  Acids.  —  Certain  dioxy-phenyl-acetic  acids  and 
dioxy-phenyl-propionic  acids  in  this  group  are  interesting. 

a-Homo-proto-eateehuic  acid  and  its  ether  acids  have  their  side 
groups  occupying  the  same  positions  as  those  of  proto-catechuic  acid 
and  its  ether  acids  : 

CH2.C02H  (i)  CH2.C02H  (i)  [i]CHa.CO,H 


C6H3OH              (3)  C8H3o.CH3          (3)  C8H3    [3]O\rH 

OH          (4)                 [OH          (4)  l[4]o/     ' 

a-Homo  -proto-catechuic  a-Homo-vanillic  acid,  a-Homo-piperonylic 

acid,  m.p.  127°                             m.p.  142°  acid,  m.p.  127°. 


340  ORGANIC  CHEMISTRY 

The  aceto-a-homo-vanillic  acid  and  a-homopiperonylic  acid  result  in 
the  moderated  oxidation  of  aceto-eugenol  (q.v.)  and  safrol  (q.v.)  with 
KMnO4.  The  former  melts  at  140°,  and  is  converted  by  caustic  soda 
into  a-homo-vanillic  acid,  which  hydrochloric  acid,  at  180°,  changes  to 
a-homo-proto-catechuic  acid  (B.  10,  207  ;  24,  2882). 

a-Homo-vanillic  acid  and  a-homo-piperonylic  acid  have  also  been 
obtained  from  the  condensation  products  of  vanillin  and  piperonal 
with  hippuric  acid,  by  transformation  into  the  corresponding  pyro- 
racemic  acids  and  oxidation  with  H2O2  (A.  370,  372).  a-Homo-proto- 
catechuic  acid  is  best  prepared  from  the  cyano-hydrin  of  methyl- 
vanillin  by  boiling  with  HI  (B.  42,  2949). 

Homo-veratric  acid  (CH3O)2[3,  4]C6H3[i]CH2COOH,  m.p.  99°. 

2,  5-Dioxy-phenyl-aeetie  acid,  homo  gentisinic  acid,  m.p.  147°,  is 
found  in  human  urine  during  alcaptonuria.  It  crystallises  with 
one  molecule  H2O,  and  has  been  synthesised  from  the  corresponding 
dimethoxy-phenyl-aceto-nitrile,  and  from  2,  5-dioxy-mandelic  acid  by 
boiling  with  HI  (C.  1907,  II.  901). 

Sym.  dioxy-phenyl-acetie  acid  (H0)2[3,  5]C6H3[i]CH2.CO2H+H2O 
melts  at  54°. 

The  tri ethyl  ester,  obtained  from  the  dicarboxylic  acid  derived 
from  this  acid,  is  produced  by  the  condensation  of  acetone-dicarboxylic 
ester  with  sodium.  It  melts  at  98°,  and  yields  dioxy-phenyl-acetic  acid 
upon  saponification.  It  yields  orcin  when  its  silver  salt  is  heated. 

Hydro-caffeie  acid,  or  J3-3,4-dioxy-phenyl-propionic  acid,  corresponds, 
like  a-homo-proto-catechuic  acid,  in  the  same  arrangement  of  the  substi- 
tuting groups,  to  proto-catechuic  acid  : 


[i]CHsCHj,CO,H  C  [i]CH2CHaCO,H  ( [i]CH,CH2CO2H 

,-i  [3]OCH8  C.HJ  [3]OH 

l[4]OCH,  l[4]OH  U4JOCH,  U4]O' 


C,H,^[3]OCH,  QH8U3]OCH3  C,H,^  [3]OH  QH3 


Hydro-caffeic  dimethyl-  Hydro -ferulic  acid,          Hydro -iso-ferulic  acid,      Hydro-caffeic  methylene- 

ether  acid,  m.p.  96°  m.p.  89°  m.p.  164°  ether  acid,  m.p.  81°. 

Hydro-caffeic  acid  itself,  and  its  ether  acids,  are  formed  from  the 
corresponding  [3,  4]-dioxy-cinnamic  or  caffeic  acid,  and  their  deriva- 
tives— ferulic  and  iso-ferulic  acids — by  reduction  with  sodium  amalgam 
(B.  11,  650  ;  13,  758).  The  methylene-ether  acid  is  also  produced  by 
oxidising  jS-hydro-piperic  acid  (q.v.)  (B.  20,  421).  Ferric  chloride 
colours  hydro-caff eic  acid  the  same  as  it  does  proto-catechuic  acid. 

Hydro-umbellie  acid,  /3-2,  ^-dioxy-phenyl-propionic  acid  (HO)2 
[2,  4]C6H3.CH2.CH2.CO2H,  decomposes  at  110°.  It  is  obtained  from 
umbelliferone,  the  8-lactone  of  [2,  4]-dioxy-cinnamic  acid,  by  the  action 
of  sodium  amalgam.  Ferric  chloride  colours  it  green. 

Hydroquinone-propionic  acid  (HO)2[2,  5]C6H3CH2CH2CO2H  ;  its 
lactone  melts  at  163°  ;  obtained  by  oxidation  of  o-hydro-cumaric 
acid  with  potassium  persulphate  in  alkaline  solution  (C.  1907,  II. 
901). 

Trioxy-benzoie  acids  (HO)3C6H2CO2H.  Three  of  the  six  possible 
isomerides  are  known.  The  most  important  is — 

Gallic  acid  (HO)3[3,4,5]C6H2CO2H+H2O.  It  melts  and  decom- 
poses about  220°  into  CO2  and  pyrogallol.  It  occurs,  free,  in  tea,  in 
the  fruit  of  Ccesalpina  coriaria  (Divi-divi),  in  mangoes,  and  in  various 
other  plants.  It  is  obtained  from  the  ordinary  tannic  acid  (tannin) 
by  boiling  it  with  dilute  acids.  It  is  prepared  artificially  from  bromo- 


DIOXY-MONOCARBOXYLIC   ACIDS  341 

o-m-dioxy-benzoic  acid  and  bromo-proto-catechuic  acid  when  fused 
with  potassium  hydroxide. 

Gallic  acid  crystallises  in  fine,  silky  needles.  It  dissolves  with 
difficulty  in  cold  water,  but  readily  in  hot  water,  alcohol,  and  ether. 
It  has  a  faintly  acid,  astringent  taste.  It  reduces  both  gold  and  silver 
salts  (hence  its  application  in  photography).  Ferric  chloride  throws 
down  a  blackish-blue  precipitate  in  its  solutions. 

The  solutions  of  its  alkali  salts  absorb  oxygen  when  exposed  to  the 
air,  and,  in  consequence,  become  brown  in  colour. 

Rufigallic  acid,  a  derivative  of  anthracene  (q.v.),  is  obtained  by 
heating  gallic  acid  with  sulphuric  acid. 

Oxidising  agents,  such  as  arsenic  acid  and  iodine,  convert  gallic 
into  ellagic  acid,  probably  a  dilactone  of  a  hexaoxy-diphenyl-dicar- 

boxylic  acid  £°'^°2*'°     (M.  29,  263).     It  is  easily  obtained  in  the 

\_) C«/gXi(  v_/ Jij  2'^-'^"' 

oxidation  of  tannin  with  H2O2  besides  the  so-called  luteic  acid,  the 
monolactone^'^*^®^*,  __,  corresponding  to  ellagic  acid.  On  dis- 

O — C6rl  (vJ-tl)  z(^(J2ti 

tillation  with  zinc  dust,  ellagic  acid  yields  fluorene  (q.v.). 

In  alkaline  solution  gallic  acid  is  converted  into  gallo flavin  (q.v.),  a 
yellow  dye  of  the  xanthone  group.  Hydrochloric  acid  and  potassium 
chlorate  decompose  the  acid  into  iso-trichloro-glyceric  acid  or  trichloro- 
pyro-racemic  acid  (Vol.  I.). 

Basic  bismuth  gallate  (HO)3C6H2CO2Bi(OH)2,  under  the  name 
dermatol,  is  applied  as  an  odourless  drying  antiseptic. 

Basic  bismuth  oxy-iodide  gallate  (HO)3C6H2CO2Bi(OH)I  is  used  as 
a  substitute  for  iodoform  under  the  name  of  Airol. 

Ethyl-gallic  ester  (HO)3C6H2CO2C2H5  melts  at  141°  when  anhydrous. 
Trimethyl-  and  triethyl-gallie-ether  acids  (R'O)3C6H2  CO2H  melt  at 
168°  and  112°.  The  trimethyl-ether  acid,  heated  with  HC1,  yields 
3,  5-dimethyl-gallo-etheric  acid  HO[4](CH3O)2[3,  5]C6H2COOH,  m.p. 
202°,  identical  with  syringa  acid  and  also  obtained  from  sinapinic  acid 
or  oxy-dimethoxy-cinnamic  acid  by  oxidation.  4-Methyl-gallo-etheric 
acid,  m.p.  240°,  from  gallic  acid  with  dimethyl  sulphate  (B.  36, 
215,  660). 

Methylene-methyl-gallie-ether  acid,  myristicinic  acid  (CH3O)(CH2O2). 
C6H2C02H  melts  at  I30°-I35°  (B.  24,  3821)  when  it  is  anhydrous. 
Triacetyl-gallie  acid  melts  with  decomposition  at  170°.  Gallic-acid 
anilide,  gallanol,  has  been  used  in  medicine.  This  is  true  also  of 
dibromo-gallic  acid,  or  gallo-bromol,  melting  at  140°. 

Pyrogallol-earboxylic  acid  (HO)3[2, 3, 4]  -C6H2CO2H-f-JH2O  is 
prepared  by  heating  pyrogallol  with  potassium  bicarbonate  (B.  18, 
3205).  It  decomposes  at  I95°-20O°,  but  sublimes  without  decom- 
position in  a  current  of  carbon  dioxide.  Ferric  chloride  colours  it 
violet.  Triethyl-pyrogallol-carboxylie  acid  C6H2(O.C2H5)3.CO2H  melts 
at  105°.  It  results  in  the  oxidation  of  triethyl-daphnetic  acid  (q.v.). 

Phloro-glucin-earboxylie  acid  (HO)3[2, 4,  6]C6H2CO2H+H2O  decom- 
poses even  at  100°,  also  when  boiled  with  water,  into  carbon  dioxide 
and  phloro-glucin,  from  which  it  is  obtained  by  boiling  with  a  potassium 
carbonate  solution  (B.  18, 1323) .  For  ethers  of  phloro-glucin-carboxylic 
acid,  see  C.  1903,  I.  966. 

An  oxy-hydroquinone-earboxylie  acid  (OH)8[i,  2,  4]C6H2COOH,  m.p. 


342  ORGANIC   CHEMISTRY 

2i7°-2i8°   with    decomposition,    is    formed    from    oxy-hydroquinone 
on  boiling  with  bicarbonate  solution  and  passing  CO2  (B.  34,  2840). 

Triethyl-oxy-hydroquinone-ether  acid  (C2H5O)3[2,  4,  5]C6H2CO2H, 
m.p.  134°,  results  upon  treating  a-  or  /3-aesculetine-triethyl-ether  acid 
with  potassium  permanganate  (B.  16,  2113).  Trimethyl-oxy-hydro- 
quinone-ether  acid,  asaronic  acid,  m.p.  144°,  is  formed  by  the  oxidation 
of  the  synthetic  asaryl-aldehyde  (B.  12,  290). 

Iridic  acid,  a-homo-dimethyl-gallic-ether  acid  (CH3O)2(HO)[3, 4,  5] 
C6H2CH2CO2H,  m.p.  118°,  is  produced,  along  with  formic  acid  and 
iretol,  when  irigenin  is  decomposed  with  baryta  water  (B.  26,  2015). 

Trimethyl-homogallie  acid,  methyl-iridic  acid  (CH3O)3[3,  4,  5]C6H2. 
CH2COOH,  m.p.  120°,  is  formed  by  the  oxidation  of  elemicin  (q.v.), 
and,  synthetically,  from  trimethyl-gallic  aldehyde  (B.  41,  3662). 

Addendum  :  Tannic  Acids. — The  tannins,  or  tannic  acids,  are  sub- 
stances widely  disseminated  in  the  vegetable  kingdom.  They  are 
soluble  in  water,  possess  an  acid,  astringent  taste,  are  coloured  dark 
blue  or  green  (ink)  by  ferrous  salts,  precipitate  gelatine,  and  enter 
into  combination  (leather)  with  animal  hides.  Hence  they  are 
employed  in  the  manufacture  of  leather,  and  for  the  preparation  of 
ink.  They  are  precipitated  from  their  aqueous  solutions  by  neutral 
acetate  of  lead. 

Some  tannic  acids  appear  to  be  glucosides  of  gallic  acid — i.e.  ethereal 
compounds  of  the  same  with  various  sugars  or  of  their  dehydration 
products.  They  decompose  into  gallic  acid  and  grape  sugar  upon 
boiling  with  dilute  acids.  Others  contain  phloro-glucin  instead  of 
grape  sugar.  On  fusing  with  KHO  the  tannic  acids  mostly  form  proto- 
catechuic  acid  and  phloro-glucin.  For  the  constitution  of  the  tannic 
acids,  still  somewhat  obscure,  see  C.  1899,  I.  559. 

Gallo-tannic  acid,  tannin,  occurs  in  large  quantity  (upward  of  50 
per  cent.),  in  gall-nuts  (pathological  concretions  upon  different  oak 
species,  Quercus  infectoria,  produced  by  the  sting  of  insects)  ;  it  also 
occurs  in  sumach  (Rhus  coriaria),  in  tea,  and  in  other  plants. 

Tannin  is  best  obtained  from  gall-nuts.  The  latter  are  finely 
divided,  and  extracted  with  ether  and  alcohol.  The  solution  separates 
into  two  layers,  the  lower  of  which  is  aqueous,  and  contains  tannin 
chiefly,  and  this  is  obtained  by  evaporation.  For  further  purification 
the  solution,  in  amyl  alcohol  and  ether,  is  fractionally  precipitated  with 
benzine  (B.  31,  3169). 

Pure  tannic  acid  is  a  colourless,  shining,  amorphous  mass,  very 
soluble  in  water,  slightly  in  alcohol,  and  almost  insoluble  in  ether. 
Many  salts — e.g.  sodium  chloride — precipitate  it  from  its  aqueous 
solutions,  and  it  can  also  be  removed  from  the  latter  by  shaking  with 
acetic  ether.  It  reacts  acid,  and  is  coloured  dark  blue  by  ferric  chloride 
(ink)  ;  gelatine  precipitates  it.  Quantitative  methods  of  estimating 
tannin  are  based  on  this  behaviour.  Ordinary  tannin  is  optically 
active,  its  coefficient  of  rotation  being  about  +60°,  but  it  is  not  uniform, 
since  a  more  strongly  marked  constituent  can  be  separated  out,  with  a 
coefficient  of  about  76°.  Tannin  appears  to  consist  of  a  mixture  of 
inactive  digallic  acid  (HO)3C6H2CO.OC6H2(OH)2COOH  and  its  reduc- 
tion product,  the  optically  active  leuco-tannin  (HO)3C6H2CH(OH). 
OC6H2(OH)2COOH,  but  this  is  contradicted  by  the  very  slight  electric 
conductivity  of  tannin,  and  its  apparently  very  high  molecular  weight 


TANNIC  ACIDS  343 

(B.  43,  628).  Dilute  acids  and  alkalies  split  it  up  neatly  into  gallic 
acid,  which  is  oxidised  to  ellagic  acid  and  luteic  acid  by  boiling  in 
H2O2.  Distillation  with  zinc  dust  produces  diphenyl-methane. 

Digallic  acid  (see  above)  crystallises  with  2H2O,  melts  anhydrous 
at  268°  to  270°  with  decomposition,  and  can  be  obtained  from  tannin 
by  way  of  the  carbethoxy-derivative.  The  acid  behaves  like  tannin 
towards  glue,  FeQ3,  hydrolysis,  and  oxidation  with  H2O2.  Its  penta- 
acetate,  m.p.  211°  to  214°,  yields,  on  reduction  with  zinc  dust  and 
glacial  acetic  acid,  hexa-aeetyl-leueo-tannin,  m.p.  154°,  which  has  also 
been  isolated  from  the  acetylation  products  of  tannin. 

We  must  distinguish  the  digallic  acid  obtained  from  tannin  from  the 
digallic  acids  C14H10O9  obtained  artificially  from  gallic  acid  with  POC13, 
or  arsenic  acid.  These  were  formerly  believed  to  be  identical  with 
tannin,  but  they  are  distinguished  from  the  latter  by  their  much 
greater  electrical  conductivity  and  by  their  inability  to  become 
coagulated  with  arsenic  acid  (B.  31,  3167). 

The  penta-acetate  C14O5(C2H3O)5O9,  heated  to  210°,  decomposes 
with  formation  of  pyrogallol. 

Gallyl-gallic  acid  C14H10O9,  a  keto-tannic  acid,  forms  an  oxime  and 
phenyl-hydrazone.  See  B.  22,  R.  754  ;  23,  R.  24. 

The  other  tannic  acids  found  in  plants  have  been  but  little  investi- 
gated ;  but  we  may  mention — 

Kino-tannin,  which  constitutes  the  chief  ingredient  of  kino,  the 
dried  juice  of  Pterocarpus  erinaceus  and  Coccoloba  uvifera.  Its  solu- 
tion is  coloured  green  by  ferric  salts.  It  yields  phloro-glucin  on  fusion 
with  potassium  hydroxide. 

Catechu-tannin  occurs  in  catechin,  the  extract  of  Mimosa  catechu. 
Ferric  salts  colour  it  a  dirty  green.  Catechin  or  catechinic  acid  C21H20O9 
+5H2O  is  also  present  in  catechu.  It  crystallises  in  shining  needles. 

Moringa-tannin  C13H10O6-(-H2O,  Maclurin,  is  found  in  yellow  wood 
(Morus  tinctoria),  from  which  it  may  be  extracted  (along  with  morin) 
with  hot  water.  When  the  solution  cools  morin  separates  out  ; 
maclurin  is  precipitated  from  the  concentrated  liquid  by  hydrochloric 
acid,  in  the  form  of  a  yellow  crystalline  powder,  soluble  in  water  and 
alcohol.  Ferric  salts  impart  a  greenish-black  colour  to  its  solutions. 
When  fused  with  caustic  potash  it  yields  proto-catechuic  acid  and 
phloro-glucin.  It  forms  pentacidyl  derivatives  (C.  1897,  466). 

Morin  C13H8O6-f  2H2O  decomposes  into  phloro-glucin  and  resorcin. 
Nitric  acid  oxidises  it  to  jS-resorcylic  acid.  Consult  B.  29,  R.  646,  for 
its  constitution. 

The  tannin  of  coffee  C30H18O16  occurs  in  coffee  beans  and  Paraguay 
tea.  Gelatine  does  not  precipitate  its  solutions.  Ferric  chloride  gives 
them  a  green  colour.  It  decomposes  into  caffeiic  acid  and  sugar  when 
boiled  with  potassium  hydroxide.  Proto-catechuic  acid  is  produced 
when  it  is  fused  with  potassium  hydroxide. 

The  tannin  of  oak  is  found  in  the  bark  (together  with  gallic  acid, 
ellagic  acid,  quercite).  It  has  the  formula  C19H16O10,  and  is  a  red 
powder,  not  very  soluble  in  cold  water,  but  more  readily  in  acetic  ether. 
Ferric  chloride  colours  its  solution  dark  blue.  Boiling,  dilute  sulphuric 
acid  converts  it  into  the  so-called  oak-red  (phlobaphene),  C38H26O17(?). 

The  tannin  found  in  the  quinine  barks  is  combined  with  the  quinia- 
alkaloids.  It  closely  resembles  ordinary  tannic  acid,  but  is  coloured 


344  ORGANIC  CHEMISTRY 

green  by  ferric  salts.  When  boiled  with  dilute  acids  it  breaks  up  into 
sugar  and  quina-red,  an  amorphous  brown  substance,  yielding  proto- 
catechuic  acid  and  acetic  acid  on  fusion  with  potassium  hydroxide. 

(e)  Polyhydric  Aromatic   Alcohols,  in   which   only   one   Hydroxyl  is 
present  in  each  Side  Chain,  and  their  Oxidation  Products. 

(i)  Di-  AND  TRIHYDRIC  AROMATIC  ALCOHOLS. 

Xylylene  Alcohols  C6H4(CH2OH)2.— The  three  isomerides  are 
obtained  from  the  three  corresponding  xylylene  chlorides  or  bromides 
by  boiling  with  a  soda  solution.  The  ortho-  (i,  2),  called  phthalyl 
alcohol,  is  obtained  also  from  phthalic  acid  chloride  by  reduction  in 
glacial  acetic  acid  with  a  large  excess  of  sodium  amalgam  (B.  12,  646). 

M.p.  M.p.  M.p. 

1,  2-Phthalyl  alcohol,    62° ;  dichloride,    55° ;  dibromide,    95°. 

1,  3-Xylylene  alcohol,    46° ;  dichloride,    34° ;  dibromide,    77°. 

1,  4-Xylylene  alcohol,  112° ;  dichloride,  100° ;  dibromide,  143°. 

The  three  chlorides  are  formed  when  the  xylols  are  heated  to  150° 
with  PC15  (B.  19,  R.  24).  The  bromides  are  produced  when  bromine 
acts  upon  boiling  xylols  (B.  18,  1281),  or  upon  the  latter  in  sunlight 
(B.  18,  1278). 

o-Xylylene  oxide,  phthalane  C6H4(CH2)2O,  b.p.  192°,  a  colourless 
oil,  smelling  intensely  of  oil  of  bitter  almonds,  is  formed  by  heating 
o-xylylene  bromide  with  caustic  alkali  (B.  40,  965). 

Tetrachloro-xylylene  oxide  C6C14(CH2)2O,  m.p.  218°  (A.  238,  331). 

Xylylene  sulpho-hydrates  C6H4(CH2.SH)2,  i,  2-,  m.p.  46°;  i,  3-,  oil, 
boiling  at  157° ;  1,4-,  m.p.  47°,  from  the  xylylene  bromides  with  alcoholic 
KSH.  The  i,  2-xylylene  sulpho-hydrate  unites  with  aldehydes  and 
ketones  with  elimination  of  water  to  cyclic  mercapfals  and  mercaptols 

C6H4<^  c /C<(    ,  from  which  cyclic  sulphones  are  formed  by  oxidation 

\  O  /  NXV 

(B.  33,  729  ;  34,  1772  ;  35,  1388). 

o-Xylylene  sulphide  C6H4(CH2)2S,  an  oil  smelling  like  mercaptan, 
from  o-xylylene  bromide  with  concentrated  K2S  solution  besides  di- 
xylylene  disulphide  [C6H4(CH2)2S]2,  m.p.  234°,  which  is  more  easily 
obtained  from  o-xylylene  bromide  and  C6H4(CH2.SNa)2.  Xylylene 
sulphide  gives  by  oxidation  o-xylylene  sulphone  C6H4(CH2)2SO2,  m.p. 
152°,  and  its  polymeride  a  disulphone  [C6H4'(CH2)2SO2]2.  Dixylylene 
disulphide  forms  with  Br  a  stable  dibromide  (C6H4(CH2)2SBr)2,  m.p. 
in0  (B.  36,  18). 

o-Xylylene-diamine  CgH4[i,  2](CH2NH2)2  is  a  liquid.  It  results 
when  potassium  phthalimide  acts  upon  o-xylylene  bromide  (B.  21,  578), 
as  well  as  by  the  reduction  of  phthalazin.  Upon  heating,  its  chloride 
yields  : 

o-Xylylenimine,  dihydro-iso-indol  C6H4(CH2)2NH,  boiling  at  213°, 

also  obtained  by  the  reduction  of  chloro-phthalazin  c.H4<f  9?? ;  S,  which 

has  given  rise  to  a  large  number  of  derivatives  (B.  33,  2808). 

Xylylene  bromide,  treated  with  ammonia,  gives  bis-xylylene-am- 
monium  bromide  C6H4(CH2)2C6H4,  which  on  further  treatment  with 
ammonium  passes  into  bis-xylylene-diamine  [C6H4(CH2)2NH]2,  m.p.  80°, 


DI-   AND  TRIHYDRIC  AROMATIC  ALCOHOLS         345 

b.p.12  I3O°-I35°.  Xylylene  bromide  also  reacts  easily  with  primary, 
secondary,  and  tertiary  amines.  Primary  aliphatic  or  aromatic  amines 
mostly  yield  n-alkyl-  or  n-aryl-xylylene-imines  ;  but  in  aromatic  amines, 
containing  substituents  in  ortho-position  towards  the  NH2  group,  the 
closing  of  the  ring  encounters  steric  hindrance,  and  di-aryl-xylylene-di- 
amines  are  formed.  Secondary  amines  mostly  form  cyclic  xylylene- 
ammonium  bromides  C6H4(CH2)2N(RR1)Br,  and  tertiary  amines  form 
xylylene-di-ammonium  bromides  ;  their  behaviour  towards  xylylene 
bromide  may  be  advantageously  employed  in  testing  alkaloids  (B.  40, 
852  ;  C.  1899,  1.1246). 

Like  the  tertiary  amines,  tri-ethyl  phosphine  combines  with  o-xyly- 
lene  bromide  to  form  o-xylylene-di-triethyl-phosphonium  bromide  (B. 
33,  606).  m-  and  p-Xylylene  bromide  never  yield  cyclic  derivatives 
with  amines,  but  derivatives  of  the  corresponding  diamines  C6H4 
(CH2NH2)2  (B.  36,  1672). 

Pseudo-cumenyl-glycol,  CH3[i]C6H3[2,  4](CH2OH)8,  melts  at  77°  (B.  19,  867). 
Mesitylene-glycol,  CH3[i]C6H3[3,  5](CH2OH)2,  boils  at  190°  (20  mm.). 
co2-Diamiao-mesitylene,  CH3.C8H3(CH2NH2)2,  boils  at  268°  (B.  25,  3017). 

Mesitylene-glycerin,  mesicerine  C6H3[i,  3,  5](CH2OH)3  is  a  thick 
liquid  (B.  16,  2509). 

o-Di-a-oxy-ethyl-benzol  C6H4[i,  2][CH(OH)CH3]2  a  yellow  oil,  from 
o-phthalic  aldehyde  with  CH3MgI  ;  on  boiling  with  dilute  HC1  it 
passes  into  the  corresponding  oxide,  1,  3-dimethyl-phthalane  C6H4 
[CH(CH3)]20,  b.p.50  122°  (B.  41,  986). 

p-Di-a-ox-ethyl-benzol  C6H4[CH(OH)CH3]2,  liquid,  from  p-diacetyl- 
benzol  (B.  27,  2527). 

a,  a-Dimethyl-,  di-ethyl,  and  di-iso-propyl-o-xylyiene  alcohol 
HOCH2.C8H4CR2OH,  m.p.  64°,  82°,  and  108°  respectively,  are  formed 
by  the  action  of  alkyl-magnesium  compounds  upon  phthalide.  They 
easily  pass,  by  splitting  off  water,  into  the  corresponding  oxides,  called 
phthalanes  (B.  40,  3060). 

Oxy-m-xylenols  are  often  formed,  besides  the  univalent  phenol 
alcohols,  by  the  action  of  formaldehyde  and  NaHO  upon  phenols 
(B.  40,  2530)  ,  e.g.  2,  6-dimethylol  -  p  -  eresol,  oxy  -  mesitylene  -  glycol 
HO[i]C6H2[4]CH3[2,  6](CH2OH)2,  m.p.  i30°-5,  from  p-cresol  (B.  42, 

2539)- 

As  might  have  been  expected,  nine  classes  of  oxidation  products  are 
derivable  from  the  bivalent  aromatic  alcohols  with  hydroxyls  in  two 
side  chains,  as  in  the  case  of  the  aliphatic  glycols. 

(2)  ALDEHYDE  ALCOHOLS. 

In  this  connection  mention  may  be  made  of  hydro-phthalide 
C6H4<^  CH2/OH>  t*16  reduction  product  of  phthalide.  It  is  a  syrup, 

soluble  in  water.     Dimethyl-hydro-phthalide  CeH./^^^No,  the 


_ 

reduction  product  of  dimethyl-phthalide,  melts  at  89°  (A.  248,  61). 

Phenol-aldehyde  alcohols  are  formed  synthetically  from  phenol- 
aldehydes,  with  formaldehyde  and  HC1.  o-Oxy-aldehydo-p-benzyl 
alcohol  HO[i]CHO[2]C6H3[4]CH2OH,  m.p.  108°,  from  salicyl-aldehyde 
(B.  34,  2455). 


346  ORGANIC   CHEMISTRY 

(3)  AROMATIC  DI-ALDEHYDES. 

Phthalie  Acid  Aldehydes  C6H4(CHO)2  corresponding  to  the  three 
phthalic  acids  are  obtained,  like  benzaldehyde  from  benzal  chloride, 
by  heating  the  xylylol  tetrachlorides  with  water  or  potassium  oxalate. 
They  are  also  obtained  in  the  form  of  their  tetra-acetates  C6H4[CH 
(OCOCH3)2]2  by  the  oxidation  of  the  three  xylols,  dissolved  in  a  mix- 
ture of  acetic  anhydride  and  concentrated  H2SO4,  by  means  of  chromic 
acid.  The  o-phthalic  aldehyde,  treated  with  ammonia,  and  then 
acidulated,  gives  a  dark-violet  coloration  (A.  311,  353). 

o-Xylylol   tetrachloride,    or,    better,    o-xylylol   tetrabromide    and 

hydrazin,  yield  phthalazin  C6H4/^  \  S  (B-  28>  l83°)- 

WUlrl  '.  JM 

o-Phthalic  aldehyde,        m.p.    56° ;  dioxime  (see  below). 
Iso-phthalic  aldehyde,     ,,       89° ;  dioxime,  m.p.  180°  (A.  347,  109). 
Terephthalie  aldehyde,    „     116° ;  dioxime,    ,,     200°  (B.  16,  2995). 

The  o-,  m-,  and  p-xylylol  tetraehlorides  C6H4(CHC12)2,  corresponding 
to  the  aldehydes,  are  prepared  by  heating  the  three  xylols  with  PC15  to 
I5o°-i90°.  " 

The  o-body  melts  at  89°  and  boils  at  273°.  The  m-body  boils  at 
273°,  and  the  p-compound  melts  at  93°. 

o-,  m-,  and  p-Xylylene  tetrabromide  C6H4(CHBr2)2,  m.p.  116°,  107°, 
and  169°,  from  the  three  xylols  by  the  action  of  bromine  with  heat 
(A.  347,  107). 

Hetero-ring  formations  of  o-phthalic  aldehyde  :  (i)  With  concen- 
trated alkalies  it  forms  phthalide;  (2)  with  acetone  and  benzo-phenone 
it  condenses  to  fi-acetyl-  and  fi-benzoyl-hydrindone  ;  (3)  with  phenyl- 
hydrazin  chloride  it  forms  phenyl-phthalazonium  chloride  ;  (4)  with 
hydroxylamine  it  forms  phthalimidoxime  : 


r  „  f  [i]CHO 

CsH4MCH0- 


CH,COCH,  r  ^j    f  v^j..L2  \/~TJ  mm     /2) 


C,HSNHNH 


i~>   C6H 


rCH=N 


2NH,OH 


Mesitylene-trialdehyde  C6H3(CHO)3,  m.p.  98° ;  its  hexa-acetate  is 
obtained  from  mesitylene  with  chromic  acid  and  acetic  anhydride 
(C.  1908,  I.  1623). 

Oxy-dialdehydes  are  produced  together  with,  and  from,  the  oxy- 
monaldehydes  by  means  of  Reimer's  reaction. 

Thymo-dialdehyde  HO.C6H(CH3)(C3H7)(CHO)2  melts  at  79°  (B.  16, 
2104). 

Resorcin-dialdehyde  (HO) 2.C6H2(CHO)2  melts  at  127°  (B.  10,  2212). 

a-  and  j3-0rcin-dialdehydes  (HO)2C6H(CH3)(CHO)2  melt  at  118° 
and  168°  (B.  12,  1003). 

a-  and  £-Oxy-iso-phthal-aldehyde  (HO)[4]C6H3(CHO)2  and  HO[2] 
C6H3(CHO)2  melt  at  108°  and  88°  (B.  15,  2022). 


ALCOHOL-CARBOXYL1C  ACIDS  347 

Oxy-uvitinic  aldehyde  HO(CH3)[i,  4]C6H2[2,  6](CHO)2,  m.p.  133°, 
colourless  needles,  by  oxidation  of  oxy-mesitylene-glycol  (B.  42,  2545). 

(4)  Di-  and  Triketones. — Only  one  acidyl  group  can  be  introduced 
into  benzene,  even  by  means  of  the  aluminium  chloride  synthesis. 

p-Diaeetyl-benzol  C6H4[i,  4](COCH3)2,  m.p.  114°,  is  formed  by  the 
action  of  dilute  sulphuric  acid  upon  terephthalyl-dimalonic  ester 
(B.  27, 2527).  Diethyl-terephthalyl  C6H4(COC2H5)2  (B.  19, 1850).  Tri- 
acetyl-benzol  C6H3[i,  3,  5](COCH3)3,  m.p.  163°,  is  formed  by  the  ben- 
zene ring  formation  from  formyl  acetone.  In  the  benzene  homologues 
containing  methyl  groups  in  the  meta-positions  it  is  an  easy  matter, 
aided  by  A12C16,  to  introduce  acetyl  residues  between  every  two  such 
methyl  groups.  Thus,  mesitylene,  durol,  andiso-durol  have  given  : 

Diaeetyl-mesitylene  C6H(CH3)3(COCH3)2,  m.p.  46°  and  b.p.  310°; 
diacetyl-durol,  m.p.  178°  and  b.p.  323°-326°,  and  diacetyl-iso-durol, 
m.p.  121°  and  b.p  3i2°-3i7°  (B.  28,  3213  ;  29,  1413). 

Diaeeto-resorcin  (CH3CO)2[i,  5]C6H2[2, 4](OH)2,  m.p.  183°,  from 
resorcin,  acetyl  chloride,  and  ZnCl2  (C.  1905,  I.  814). 

Triaeeto-phloro-gluein  (CH3CO)3C6(OH)3,  m.p.  156°,  is  more  prob- 
ably to  be  regarded  as  a  derivative  of  triketo-hexamethylene  (B.  42, 
2736). 

(5)  ALCOHOL-CARBOXYLIC  ACIDS. 

Oxy-methyl-benzoie  Acids,  Carbinol-benzoic  Acids. — There  are  three 
possible  isomerides,  and  all  of  them  have  been  prepared.  They  are 
isomeric  with  almond  acid  and  the  oxy-toluic  acids.  o-Oxy-methyl- 
benzoic  acid  passes  quite  readily  into  the  corresponding  y-lactone, 
phthalide. 

Phthalide  and  meconin  are  the  first  lactones  with  which  organic 
chemistry  was  enriched. 

o  -  Oxy  -  methyl  -  benzoic    acid,    benzyl  -  alcohol  -  o-  carboxylic    acid 

C6H4/[J    '   *    „,  melts  at  120°,  loses  water  and  becomes  phthalide,  from 

v»  (_2jUri2Oxi 

which  it  is  obtained  by  dissolving  in  caustic  alkali  and  then  precipitat- 
ing with  mineral  acids  ;  also  from  o-chloro-methyl-benzoic  acid  with 
moist  silver  oxide. 

Phthalide,  o-oxy-methyl-benzoic  acid  lactone  C6H4/|^     No,  melt- 

U  [2jCH2/ 

ing  at  83°  and  boiling  at  290°,  was  first  made  from  o-phthalic  acid.  It 
is  formed  (i)  by  heating  o-oxy-methyl-benzoic  acid  or  by  allowing  it  to 
stand  in  contact  with  water  (B.  25,  524)  ;  (2)  by  the  reduction  of  phtha- 
lide chloride  with  zinc  and  hydrochloric  acid  (B.  10,  1445)  ;  (3)  by  the 
reduction  of  phthalic  anhydride  in  acetic  acid  solution  with  zinc  dust 
(B.  17,  2178)  ;  (4)  by  the  action  of  bromine  vapour  upon  ortho-toluic 
acid  at  130°-! 40°  ;  (5)  from  xylylene  dichloride  upon  boiling  with 
water  and  lead  nitrate  ;  (6)  by  decomposing  nitroso-phthalimidin  ob- 
tained from  phthalimide  with  caustic  potash  (A.  247,  291)  ;  (7)  by 
treating  o-cyano-benzyl  chloride  in  glacial  acetic  acid  with  hydro- 
chloric acid  at  100°  (B.  25,  3021)  ;  or  (8)  from  phthalide-carboxylic 
acid  by  heating  (B.  31,  374). 

It  is  reduced  to  ortho-toluic  acid  on  boiling  with  hydriodic  acid. 
Potassium  permanganate  oxidises  it  to  phthalic  acid.  See  also  Phthal- 
aldehydic  acid,  Phthalic  acid,  and  co-Cyan-o-toluic  acid.  Phenyl- 
hydrazin  adds  itself  to  phthalide  (B.  26, 1273  ;  33,  766). 


348  ORGANIC  CHEMISTRY 

Numerous  derivatives  have  been  obtained  from  o-oxy-methyl-ben- 
zoic  acid,  some  of  which,  like  the  acid  itself,  change  over  to  heterocyclic 
compounds. 

o-Chloro-methyl-benzoic  acid  Cl.CH2[2]C6H4[i]COOH,  m.p.  131°, 
form  phthalide  chloride  with  water,  HC1  being  liberated  ;  its  ethyl 
ester,  b.p.12  141°,  from  phthalide  chloride  and  alcohol  (Anschiitz). 

It  boils  at  141°  (12  mm.),  and  also,  without  decomposition,  at  245° 
(760  mm.). 

o-Chloro-methyl-benzoyl  chloride,  phthalide  chloride  C1CH2[2]C6H4. 
COO,  boiling  at  135°  (12  mm.),  results  when  PC15  acts  upon  phthalide 
at  55°-6o° ;  gives  anthranol  with  benzene  and  A1C13( Anschiitz). 

o-Chloro-methyl-benzamide  C1CH2[2]C6H4.CONH2  melts  with  de- 
composition at  190°  (see  Pseudo-phthalimidine) .  It  is  produced  on 
conducting  dry  ammonia  into  an  ethereal  solution  of  phthalide  chloride, 
and  by  the  action  of  sulphuric  acid  upon  its  nitrile. 

o-Chloro-methyl-benzanilide    C1.CH2[2]C6H4CONHC6H5    melts    at 

o-Chloro-methyl-benzo-nitrile,  o-cyano-benzyl  chloride  C1.CH2[2] 
C6H4CN,  melting  at  252°,  is  formed  upon  conducting  chlorine  into  boil- 
ing o-tolu-nitrile  (p.  286)  (B.  20,  2222).  The  corresponding  o-cyano- 
benzyl  alcohol  is  known  only  in  its  ethers  (B.  25,  3018). 

Phthalide  yields  the  base  phthalimidin  C6H4/W£°  \NH,  when  it 

is  heated  in  an  atmosphere  of  ammonia.  It  can  also  be  very  readily 
obtained  by  reducing  phthalimide  with  tin  and  hydrochloric  acid 
(A.  247, 291)  ;  from  o-cyano-benzyl-amine  with  HC1,  and  from  phthalide 
chloride  by  heating  in  a  current  of  ammonia.  It  melts  at  150°  and 
boils  at  337°. 

Nitroso-phthalimidin  C8H6ON.NO  melts  at  156°.     Pseudo-phthal- 

is  an  oil.      In  contact  with   water  it  is 


6H3  /  f I. 

L  [2] 


j]CH2— >0 

resolved  into  phthalide  and  ammonia.  Its  hydrochloride  is  formed 
when  o-chloro-methyl-benzamide  is  heated  to  i3o°-i4O°,  also  from 
phthalide  chloride  with  alcoholic  ammonia. 

Phthalide    anile,  phenyl-phthalimidin  C6H4{  W£°  ^>NC6H5)  melting 

at  160°,  results  on  heating  phthalide  and  aniline  to  2OO°-22O°,  upon 
reducing  phthalanile  with  tin  and  hydrochloric  acid,  and  by  distilling 
o-chloro-methyl-benzanilide  under  diminished  pressure  (Anschiitz). 
o-Cyano-benzyl-amine  NH2.CH2[2]C6H4CN  is  a  colourless  oil,  which 
becomes  crystalline.  It  is  formed  when  o-cyano-benzyl  chloride  acts 
upon  potassium  phthalimide  (B.  20,  2233  ',  31,  2738). 

o-Diethyl-benzyl-amine-carboxylic  acid  (C2H5)  2NCH2C6H4COOH, 
m.p.  105°  (A.  300,  163).  o-Cyano-benzyl-methylamine  CNC6H4CH2. 
NHCH3,  m.p.  105°;  o-cyano-benzyl-aniline  CNC6H4CH2.NHC6H5, 
m.p.  125°  (/.  pr.  Ch.  2,  80,  102). 

Thio-phthalide  C6H4/W^  /s  melts  at  60°  (A.  257,  298),  and— 

LljZJU-rlg 

Seleno-phthalide  ^^{r^cn  X*86  melts  at  58°  (B-  24»  2596 ; 
A  247,  299). 

Thio  -  phthalimidin   CtH^^!__>Ss  or    o-cyano-benzyl-mercaptan 


ALCOHOL-CARBOXYLIC  ACIDS  349 

C6H4(CN)CH2SH,  m.p.  62°,  from  o-eyano-benzyl-rhodanide  C6H4(CN) 
CH2SCN,  m.p.  86°,  with  sulphuric  acid,  and  from  o-cyano-benzyl 
chloride  with  potassium  sulpho-hydrate.  With  excess  of  the  latter  we 

obtain    a    dithio-phthalide     C6H4/™*\S,     m.p.    68°,    which    easily 

\Oo    / 

splits  off  SH2,  and  passes  into  a  stilbene  derivative  (B.  31,  2646). 
Phthalides,  substituted  in  the  benzene  nucleus,  are  also  known  ;  they 
have  been  mostly  obtained  from  substituted  o-phthalic  acids.  Mention 
may  be  made  of  : 

p-Kitro-phthalide     NOaC8H3  (W<^  \o,    m.p.    135°.     It    is    pro- 

U[2jCH2/ 

duced  when  chromic  acid  and  glacial  acetic  acid  act  upon  o-nitro- 
naphthalene  (A.  202,  219). 

p-Oxy-phthalide    HO.C6H3/W^a\o,    m.p.    222°    (A.    233,   235), 

\i  [ijGHg' 

is  obtained  from  p-oxy-o-phthalic  acid. 

Meconin,  5,  6-dimethoxy-phthalide  (CH3O)2[5,6]C8Ha^W^  ^>O,  m.p. 

102°,  is  the  lactone  of  meconinic  acid,  which  is  only  stable  in  the 
form  of  its  salts.  Its  name  is  derived  from  the  Greek  word  /XTJKWV, 
signifying  poppy. 

Meconin  occurs  already  formed  in  opium,  in  which  Couerbe  dis- 
covered it  in  1832,  and  is  obtained  on  boiling  narcotin  with  water 
(Wohler,  and  Liebig,  1832).  It  may  be  formed  from  opianic  acid, 
the  corresponding  aldehyde  acid,  just  tike  phthalide  from  phthal- 
aldehydic  acid,  by  reduction  with  sodium  amalgam  and  precipitation 
with  acids.  It  was  the  first  lactone  known  to  chemistry  : 


Phthalide         Phthalic  aldehyde  acid  Meconin  Opianic  acid. 

Synthetically,  meconin  has  been  prepared  from  the  condensation 
product  of  chloral  with  2,  3-dimethoxy-benzoic  ester,  of  dimethoxy- 

trichloro-methyl-phthalide     (CH3O)ac8H3<^°~      "No.       This    yields, 

\CH(CCl3)/ 

with  alkali,  an  acid  which,  on  heating,  yields  meconin  (A.  301, 
359)- 

i/r-Meconin,  3,  4-dimethoxy-phthalide   (CH3O)a[3, 

m.p.  132°.  It  is  made  from  hemi-pinimide,  just  as  phthalide  is  formed 
from  phthalimide  (B.  20,  884). 

o  -  a  -  Oxy  -  ethyl  -  benzoic     acid     lactone,     a  -  methyl  -  phthalide 

C6H4/y|  CH/O>  boils  at  275°.     It  is  formed.  in  the  reduction  of  aceto- 

phenone-o-carboxylic  acid  with  sodium  amalgam,  and  by  the  action  of 
CH3MgI  upon  o-phthalic  aldehyde  acid  (B.  38,  3981).  Hydro-iodic  acid 
and  phosphorus  reduce  it  to  o-ethyl-benzoic  acid  (B.  29,  2533). 

a-Ethyl-phthalide,  m.p.  12°,  b.p.  291°,  is  obtained  in  a  similar  manner 
(B.  32,  960). 

Dimethyl-phthalide,    o  -  j8  -  oxy  -  iso  -  propyl  -  benzoie    acid    lactone 

,  m.p.  67°  and  b.p.  270°,  was  made  by  the  action  of 


zinc  dust  and  methyl  iodide  upon  phthalic  anhydride  (A.  248,  57). 


350  ORGANIC   CHEMISTRY 

Similarly,  diethyl-,  dipropyl-,  and  di-iso-propyl-phthalides  have  been 
obtained,  melting  at  54°,  76°,  and  84°  respectively  (C.  1909,  II.  525). 

o-j3-0xy-ethyl-proto-catechuic  acid  lactone  C6H2(OH)2«(  f        '/,„   is 

l»L2jC±l2.Crlj 

closely  related  to  several  alkaloids  such  as  corydalin,  berberin,  etc. 

m-Oxy-methyl-benzoic  acid  is  only  known  in  the  form  of  its  alcohol 
anhydride  O[CH2[3]C6H4COOH]2,  m.p.  180°,  which  is  formed  from 
m-cyano-benzyl  chloride  C1.CH2[3]C6H4CN,  m.p.  67°  and  b.p.  259°, 
the  reaction  product  of  chlorine  upon  m-tolu-nitrile.  co-Chloro-m- 
toluic  acid  melts  at  135°,  and  m-benzyl-amine-carboxylic  acid  NH2CH2 
[3]C6H4CO2H  melts  at  216°.  m-Cyano-benzyl-amine  NH2CH2[3] 
C6H4CN,  see  B.  34,  3367. 

p-Oxy-methyl-benzoie  acid  HO.CH2[4]C6H4CO2H,  m.p.  181°,  is 
obtained  (i)  from  p-carbinol-bromide-benzoic  acid  Br  CH2[4]C6H4. 
CO2H  (A.  162,  342) ;  (2)  by  the  action  of  concentrated  sodium  hydroxide 
upon  tereph thai-aldehyde  (A.  231,  372). 

p-Cyano-benzyl  alcohol  HOCH2[4]C6H4CN,  m.p.  133°,  is  prepared 
from  p-cyano-benzyl  chloride,  m.p.  79°  and  b.p.  263°,  by  the  action 
of  potassium  carbonate.  p-Chloro-methyl-benzamide  CH2C1[4]C6H4 
CONH2,  m.p.  173°.  p-Chloro-methyl-benzoic  acid  CH2C1[4]C6H4CO2H, 
m.p.  199°  (B.  24,  2416). 

Benzyl-amine-p-carboxylic  acid,  yellow  scales,  and  diethyl-benzyl- 
amine-p-carboxylic  acid,  m.p.  150°,  see  B.  23,  1060  ;  A.  310,  207  ; 
p-cyano-benzyl-amine,  see  B.  34,  3368. 

p-Chloro-methyl-salieylie  acid  ClCH2[4]C6H3[i]OH[2]COOH,  m.p. 
163°,  from  salicylic  acid  with  formaldehyde  and  HC1  (C.  1901,  I.  1394). 

m-  and  p  -  Oxy  -  iso  -  propyl  -  benzoic  acids  (CH3) 2C(OH) .C6H4.CO2H, 
melting  at  123°  and  155°,  result  when  m-cymol  (A.  275,  159)  and 
p-cymol,  from  cumic  acid,  are  oxidised  with  potassium  permanganate. 
The  3-amido-4-oxy-iso-propyl-benzoic  acid,  derived  from  the  p-acid, 
changes  under  the  influence  of  carboxylic  anhydrides  into  cumazonic 
acids  (q.v.). 

(6)  ALDEHYDE  ACIDS. 

o-Phthal-aldehydic  acid  and  5, 6-dimethoxy-o-phthal-aldehydic 
acid,  or  opianic  acid,  are  the  most  important  representatives  of  this 
class.  In  the  ph  thai-aldehyde  acids  the  aldehyde  group  occupies  the 
y-position  with  reference  to  the  carboxyl  group.  Like  the  aliphatic 
y-ketonic  acids  (the  laevulinic  acids,  Vol.  I.),  the  ph  thai-aldehyde  acids 
form  monoacetyl  derivatives,  whose  existence  and  deportment  argue 
more  strongly  for  the  y-oxy-lactone  formula  (Liebermann,  B.  19,  765, 
2288)  than  the  carboxylic  acid  formula  of  such  acids  : 

CH,C02H      or  CH2.CO>0  ^wo^  M  CtH,(WC00 


IMCHOH 

Laevulinic  acid  o-Phthal-aldehydic  acid. 

Opianic  acid  forms  two  series  of  esters.  Their  difference  is  due  to 
the  fact  that  the  one  series  represents  carboxylic  esters,  while  the 
other  series  consists  of  y-oxy-lactone  esters. 

The  behaviour  of  the  oxime  anhydrides  of  phthal-aldehydic  acid 
and  opianic  acid  is  worthy  of  note.  They  change  to  the  corresponding 


ALDEHYDE   ACIDS  351 

phthalimides  with  an  appreciable  evolution  of  heat,  when  they  are 
gently  heated.  The  phthal-aldehydoxime-anhydridic  acid  first  changes 
to  o-cyano-benzoic  acid,  which  yields  phthalimide  upon  fusion.  The 
determination  of  the  heat  of  combustion  of  opian-oximic  acid  anhydride 
and  hemi-pinimide  has  shown  that  in  the  conversion  of  the  former  into 
the  latter  the  quantity  of  heat  set  free  (52-6  Cal.  for  the  gram-molecule) 
was  tenfold  greater  than  the  molecular  rearrangement-energy  of  allo- 
cinnamic  into  cinnamic  acid,  and  eight  times  that  observed  in  the 
conversion  of  malei'c  into  fumaric  acid  (B.  25,  89). 

o-Phthal-aldehydic  acid  (formulae  above),  melting  at  97°,  is  formed 
(i)  upon  heating  bromo-phthalide  (see  below)  with  water  ;  (2)  by  heat- 
ing co-pentachlor-o-xylol,  and  (3)  o-cyano-benzal  chloride  with  hydro- 
chloric acid  (B.  30,  3197).  Hydrazin  converts  the  acid  into  phthal- 

azone    (q.v.)    C6H4/[l]C     ~1jfH  ,    melting    at    183°;     phenyl-hydrazin 

U[2]CH=N 

changes  it  to  phenyl-phthalazone,  melting  at  105°  (B.  26,  531),  and 
hydroxylamine,  in  aqueous  solution,  into  benzaldoxime-o-carboxylic 
acid,  melting  at  120°  ;  while  in  alcoholic  solution  the  product  is  benzal- 
doxime-o-carbonic  anhydride,  benzo-ortho-oxazinone,  melting  at  145°. 
The  latter  at  145°  rearranges  itself  with  evolution  of  much  heat  into 
o-cyano-benzoic  acid,  which  at  more  elevated  temperatures  becomes 
phthalimide  (B.  26,  3264)  : 


C  H  r  _*c  H       [I]CO°H->C  H  /[I]C°\NH 

C8H4^C«H«-"C6H4->C8H41 


Benzaldoxime-o-car-      Benzaldoxime-o-      o-Cyano-benzoic      o-Phthalimide. 
boxylic  acid  carboxylic  acid  acid 

anhydride 

With  benzoyl-hydrazin  and  j3-phenyl-hydroxylamine  also  phthal- 
aldehydic  acid  and  opianic  acid  first  form  aldehyde  derivatives  (B. 
34,  1017). 

Methoxy-phthalide,  phthal-aldehydic  methyl  ether,  melting  at  44°  ; 
ethoxy-phthalide,  melting  at  66°  ;  and  amido-phthalide,  amide  of  phthal- 
aldehydic  acid,  are  produced  by  the  action  of  methyl  and  ethyl  alcohol, 
and  of  ammonia  upon  bromo-phthalide,  or  the  bromide  of  phthal- 
aldehydic  acid,  melting  at  85°,  produced  when  bromine  vapour  acts 
upon  phthalide  at  140°.  Aceto-phthal-aldehydic  acid,  acetoxy-phthalide, 
is  formed  by  the  interaction  of  acetic  anhydride  and  phthal-aldehydic 
acid. 


Diphthalide  ether  c6H4>ooq<c6H4l  melting  at  221°, 

is  formed  from  o-phthal-aldehydic  acid  and  bromo-phthalide.  In 
accordance  with  the  double  formulation  of  phthal-aldehydic  acid  (see 
above)  two  views  may  be  held  in  regard  to  its  various  derivatives  : 

J  [i]COOCH3  f  [i]CONH,  /  [i]COBr  /  [i]COOCOCH3 

'•H4l[2]CHO  L'H4t[2]CHO  C'HH[2]CHO         C'HH[2]CHO 

Hi]co>0  i[i]co>0  r[i]co>0          |[i]co>0 

M[2]CH  —  OCH,  «H*tt2]CH—  NH,      C'H4\[2]CHBr         Cf    M  [2]CH  —  OCOCH, 

Methoxy-phthalide  Amido-phthalide         Bromo-phthalide  Acetoxy-phthalide. 

The  theory  that  acetoxy-phthalide  and  the  diphthalide  ethers  are 
anhydrides  of  carboxylic  acids  is  very  improbable.  Phthal-aldehydic 
acid  and  opianic  acid  react  especially  readily,  even  in  the  cold,  with 


352  ORGANIC   CHEMISTRY 

amines.  Water  is  eliminated.  The  resulting  bodies  dissolve  in  part 
very  easily  in  soda,  and  in  part  with  difficulty,  hence  are  in  part  derived 
from  the  amido-phthalide  and  partly  from  the  imido-aldehydic  acid 
formula  (B.  29,  174,  2030). 

ci]co>o  rciicooH 

[2JCH-NHR  C«H<  \  [2]CH  =NR. 


r 

\ 


Phthal-aldehyde  Chlorides.  —  Pentaehloride  of  o-phthal-aldehydic  acid, 

n-pentachlor-o-xylol  CHC12[2]C6H  CC13,  melting  at  53°,  results  when  PC1B 
acts  upon  o-xylol  at  140°.  o-Cyano-benzal  chloride,  nitrile  of  o-phthal- 
aldehyde  chloride  acid,  CHC12[2]C6H4CN,  boiling  at  260°,  is  formed 
by  the  action  of  chlorine  upon  boiling  o-cyano-toluol  (B.  20,  3197). 

Nor-opianic  acid,  5,  6-dioxy-phthal-aldehydic  acid  (HO)2C6H4(CHO) 
COOH,  melting  at  171°,  is  obtained  from  opianic  acid,  together  with 
iso-vanillin  and  carbon  dioxide,  upon  heating  with  hydriodic  acid.  It 
is  coloured  bluish-green  by  ferric  chloride. 

Opianic  acid,  5,  6-dimethoxy-phthal-aldehydic  acid  (CH3O)2[5,  6] 
CgH2[2]CHO.CO2H,  melting  at  150°,  is  produced  on  oxidising  narcotin 
with  dilute  sulphuric  acid  and  MnQ2  (1842,  Wohler  and  Liebig,  A.  44, 
126).  Meconin  is  formed  in  its  reduction.  When  it  is  evaporated 
with  caustic  potash  it  changes  in  part  to  meconin  and  partly  to  hemi- 
pinic  acid,  just  as  benzaldehyde  yields  benzyl  alcohol  and  benzoic 
acid.  It  is  oxidised  to  hemi-pinic  acid.  Upon  heating  with  hydro- 
chloric acid  there  results  at  first  :  5-Methoxy-6-oxy-phthal-aldehydie 
acid,  methyl-nor-opianic  acid  (CH3O)[5](HO)[6]C6H2(CHO)CO2H,  melt- 
ing at  154°  (B.  30,  691),  while  under  more  intense  heat  iso-vanillin 
and  CO  2  are  the  products.  Concentrated  sulphuric  acid  converts 
opianic  acid  into  rufiopin  (q.v.),  a  tetra-oxy-anthraquinone  derivative. 

Opianic  acid  behaves  toward  hydrazin,  phenyl-hydrazin,  and 
hydroxylamine  just  like  phthal-aldehydic  acid.  Dimethoxy-phthal- 
azone,  opiazone,  melts  at  162°,  when  it  is  anhydrous  (B.  27,  1418). 
Phenyl-opiazone  melts  at  175°  (B.  19,  2518).  Opianoximic  acid,  melt- 
ing at  82°,  becomes,  on  boiling  its  aqueous  solution,  the  anhydride  of 
opianoximic  acid,  melting  at  114°.  When  this  is  heated  alone,  or 
when  its  alcoholic  solution  is  boiled,  hemi-pinimide  results  as  a  conse- 
quence of  rearrangement  (B.  24,  3264). 

Esters.  —  Opianic  acid  forms  two  series  of  alkyl  esters,  corresponding 
to  the  carboxylic  and  to  the  y-oxy-lactone  formulas  of  the  acid.  The 
one  series,  the  true  carboxylic  esters,  are  stable  in  the  presence  of  water. 
They  are  formed  by  the  action  of  alkyl  iodides  upon  the  silver  salt  or  of 
alcohols  upon  the  chloride  of  opianic  acid,  and  by  esterifying  opianic 
acid  with  diazo-methane. 

They  manifest  the  typical  aldehyde  reactions  (B.  29,  R.  507).  The 
second  series,  the  y-oxy-lactones  or  ^-esters,  are  formed  on  boiling 
opianic  acid  with  alcohols  :  Methyl-  opianic  ester  (CH3O)2C6H2(CHO) 
CO2CH3,  melts  at  82°  and  boils  at  233°  (51  mm.).  The  ethyl  ester  melts 

at  64°.     i/r-Methyl-opianie  ester   (C^O)iC^\S^>9         m.p.   103°, 

and  b.p.  238°  (52  mm.).  The  0-ethyl  ester  melts  at  92°  (B.  25,  R.  907  ; 
26,  R.  700). 

Acetyl-opianic  acid  melts  at  120°  (B.  19,  2288).  [3]-Nitro-opianic 
acid,  m.p.  166°,  has  an  abnormally  low  affinity  constant  in  aqueous 


KETONE-CARBOXYLIC  ACIDS  353 

solution,  and  therefore  probably  corresponds  to  the  oxy-lactone  from 
(B.  36, 1541) ;  methyl  ester,  m.p.  78° ;  j/f-methyl  ester,  m.p.  182°  (C.  1904, 

I.  163). 

It  yields  by  reduction  dimethoxy-anthranilo-carboxylic  acid,  azo- 

opianie  acid  (CH3O)2C6H(COOH)/^~\o,  which  upon  treatment  with 
acetone  and  sodium  hydroxide  condenses  to  acetonil-nitro-meeonin 
(CH30)2C6H(N02){™(CH2CC  CH3)^>o,  m.p.  175°,  and  opian-indigo  (B.  36, 

2208). 

Pseudo-opianie  acid  (CH3O)2[3,  4]C6H2[2](CHO)C02H,  m.p.  121°,  is 
formed  from  berberal,  an  oxidation  product  of  the  alkaloid  berberin 
(q.v.),  when  it  is  boiled  with  dilute  sulphuric  acid.  Amido-ethyl- 
piperonyl-carboxylic  anhydride  (B.  24,  R.  158)  is  formed  simultaneously. 
The  oxime,  melting  at  124°,  is  rearranged  upon  heating  into  hemipin- 
imide  (B.  24,  3266). 

m-Aldehydo-benzoie  acid,  iso-phthal-aldehydic  acid  CHO[3]C6H^ 
CO2H,  melts  at  165°.  m-Cyano-benzaldehyde  melts  at  80°.  m-Cyano- 
benzal  chloride  boils  at  274°  (B.  24,  2416).  p-Aldehydo-benzoic  acid, 
terephthal-aldehydie  acid  CHO[4]C6H4CO2H  melts  at  285°.  p-Cyano- 
benzaldehyde  melts  at  97°.  p-Cyano-benzal  chloride  boils  at  275° 
(B.  24,  2422). 

Mono-  and  dioxy-aldehydo-acids  have  been  obtained  from  mono- 
and  dioxy-carboxylic  acids  by  means  of  chloroform  and  caustic  alkali 
(B.  12,  1334  ;  16,  2182).  Similarly,  anthranilic  acid,  with  chloroform 
and  alkali,  yields  an  aldehydo-o-amido-benzoic  acid  (C.  1900,  I.  812). 

(7)  KETONE-CARBOXYLIC  ACIDS. 

o-Aceto-phenone-carboxylic  acid  is  the  most  important  of  the 
aromatic  monocarboxylic  acids  with  keto-  and  carboxyl-groups  in 
different  side  chains.  In  it  the  y-position  imparts  to  the  keto- 
and  carboxyl-groups  reactions  similar  to  those  manifested  by  o-phthal- 
aldehydic  acid.  Hence,  in  addition  to  the  carboxylic  acid  formula 
we  must  also  consider  the  y-oxy-lactone  formula  for  o-aceto-phenone- 
carboxylic  acid.  Its  acetyl  compound  must  be  viewed  as  acetyl- 
y-oxy-lactone  : 

CH   r[i]COOH  CH  /[i]CO>0         CH   f[2]CO>0 

4  \  [2]COCH3  4  \  [2]C(OH)CH3  4  \  [2]C(OCOCH3)CH3. 

o-Aeeto-phenone-carboxylie  acid,  o-aceto-benzoic  acid,  m.p.  115°,  is 
isomeric  with  benzoyl-acetic  acid  (q.v.)  and  tolyl-glyoxylic  acid  (q.v.). 
It  has  a  sweet  taste,  and  is  formed  on  boiling  benzoyl-aceto-o-carboxylic 
acid  with  water  (B.  26,  705  ;  29,  2533).  The  acetyl  compound  melts 
at  70°  (B.  14,  921).  Hydrazin  converts  it  into  methyl-phthalazone, 
m.p.  220°  and  b.p.  247°  (B.  26,  705).  With  phenyl-hydrazin  it  yields 
methyl-n-phenyl-phthalazone,  melting  at  102°  (B.  18,  803).  Its  ethyl 
ester  and  hydroxylamine  form  an  oxime  anhydride,  m.p.  158°  (B. 
16,  1995). 

Various  homologous  o-acidyl-benzoic  acids  have  been  obtained  by 

digesting  their  anhydrides,  the  alkylidene-phthalides,  with  potassium 

hydroxide.     These  anhydrides  are  produced  in  the  condensation  of 

phthalic  anhydride  and  fatty  acids,  when  water  and  carbon  dioxide 

VOL.  II.  2  A 


354  ORGANIC   CHEMISTRY 

are  eliminated.  o-Butyro-phenone-carboxylic  acid  and  o-iso-valero- 
phenone-carboxylie  acid  melt  at  89°  and  88°  (B.  29,  1437  ;  32,  959). 

p-Aceto-phenone-carboxylic  acid  melts  at  200°.  It  results  from  the 
oxidation  of  p-j8-oxy-iso-propyl-benzoic  acid  (A.  219,  260).  p-Cyan- 
aceto-phenone,  m.p.  60°,  is  made  from  p-amido-aceto  -  phenone 
(B.  20,  2955). 

Methyl-benzyl-ketone-o-carboxylic  acid  COOH[2]C6H4CH2COCH3, 
m.p.  119°,  is  formed  from  methyl-iso-cumarin  (q.v.)  by  boiling  with 
alkalies  (B.  32,  965). 

Benzyl-acetone-o-carboxylie  acid  COOH[2]C6H4[i]CH2.CH2.COCH3, 
m.p.  114°,  see  B.  40,  189. 

Polycarboxylie  Acids.  —  Three  varieties  are  to  be  distinguished  in 
each  group  of  these  acids  :  those  in  which  all  the  carboxyl  groups  are 
directly  joined  to  the  benzene  nucleus  ;  those  in  which  these  groups 
are  in  part  joined  to  the  nucleus  and  are  in  part  present  in  the  side 
chains  ;  and,  lastly,  those  in  which  all  of  the  carboxyl  groups  are 
contained  in  the  side  chains,  e.g.  : 

c  w  /COOH         r  „  rcH2co2H          r  w  /cH2co2H 


Phthalic  acids  Homo-phthalic  acids     Phenylene-diacetic  acids. 

(8)    DlCARBOXYLIC  AdDS 

(a)  Phthalic  acids  are  the  final  oxidation  products  of  all  benzene 
derivatives  in  which  two  hydrogen  atoms  of  the  benzene  nucleus  have 
been  replaced  by  side  chains.  Hence  they  are  of  importance  in  deter- 
mining the  position  of  these  two  side  groups  in  the  benzene  nucleus. 
Their  hydrogen  addition  products,  the  hydro-phthalic  acids,  are  also 
very  important  compounds  from  a  theoretical  standpoint.  Again, 
o-phthalic  acid  is  distinguished  from  the  m-  and  p-bodies  by  its  ability 
to  form  an  anhydride  and  other  cyclic  derivatives.  In  addition  to 
the  dicarboxyl  formula,  the  y-dioxy-lactone  formula  has  been  taken 
into  consideration  for  this  acid.  It  is  applied  technically  in  the  manu- 
facture of  phthalein-dye  substances,  which  are  of  great  value.  The 
phthalic  acids  bear  the  same  relation  to  the  phthalyl  alcohols,  the 
phthal-aldehydes,  oxy-methyl-benzoic  acids,  and  phthal-aldehydic 
acids,  that  oxalic  acid  bears  to  ethylene-glycol,  glyoxal,  glycollic  acid, 
and  glyoxalic  acid  : 

CH2OH        CHO       COOH        COOH       COOH 

CH2OH  CHO  CH2OH  CHO  COOH 

Glycol  Glyoxal  Glycollic  acid    Glyoxalic  acid       Oxalic  acid. 

r  TT  /CH2OH      r  TT  /CHO       r  M  /COOH       r  w  /COOH      r  „  /COOH 
C°MCHOH      C6  C6l  C«  ^ 


Phthalyl-  Phthal-  Oxy-methyl-      Phthal-aldehyde        Phthalic 

alcohols  aldehydes         benzoic  acids  acids.  acids. 

Phthalic    acid,    benzene  -  o  -  dicarboxylic    acid     C6H4/]^ 

it  1  2jOvJ  \~)  xi 

(A-  269»  I55)'  melts'  when  raPidly  heated,  at  213°, 


decomposing  at  the  same  time  into  the  anhydride  and  water.  It  is 
obtained  by  oxidising  naphthalene  and  tetrachloro-naphthalene  with 
nitric-acid  permanganates  (B.  36,  1805),  or  best  with  concentrated 


DICARBOXYLIC  ACIDS  355 

H2SO4  and  mercuric  sulphate  (German  patent  91,202).  It  is  manu- 
factured on  a  large  scale.  It  is  formed  from  the  naphthalene  together 
with  benzoic  acid  on  heating  with  NaHO  and  copper  oxide  to  240°- 
260°  (C.  1903,  I.  857). 

It  also  results  on  oxidising  o-xylol  and  o-toluic  acid  with  potassium 
permanganate,  alizarin  and  purpurin  with  nitric  acid,  or  with  manganese 
dioxide  and  sulphuric  acid  ;  and,  in  slight  amount,  in  the  oxidation  of 
benzene  and  benzoic  acid.  It  cannot  be  prepared  by  using  chromic 
acid  as  an  oxidising  agent,  since  the  latter  burns  it  at  once  to  carbon 
dioxide.  It  can  be  synthetically  obtained  from  o-nitro-benzoic  acid 
by  converting  the  latter  into  o-cyano-benzoic  acid,  and  then  boiling 
this  with  alkalies. 

History.  —  Laurent  first  obtained  the  acid,  in  1836,  by  oxidising 
naphthalene  tetrachloride.  He  considered  it  a  naphthalene  deriva- 
tive, and  named  it  naphthalinic  acid  (A.  19,  38).  After  Marignac  had 
deduced  the  correct  formula,  C8H6O4  (A.  38,  13),  and  demonstrated 
that  the  acid  was  not  a  derivative  of  naphthalene,  Laurent  gave  it  the 
name  phthalic  acid  (A.  41,  107). 

When  heated  with  excess  of  calcium  hydroxide  it  yields  benzene 
and  2CO2.  Only  iCO2  is  split  off,  and  calcium  benzoate  produced,  if 
its  lime  salt  be  heated  to  33O°-35o°  with  one  molecule  of  Ca(OH)2. 

Sodium  amalgam  converts  phthalic  acid  into  di-,  tetra-,  and  hexa- 
hydrophthalic  acids. 

Esters.  —  As  the  investigation  of  phthalyl  chloride  seemed  to  assign 
a  lactone  formula  to  this  body,  in  which  the  two  chlorine  atoms  were 
attached  to  the  same  carbon  atom,  search  was  made  for  two  series  of 
esters.  However,  the  action  of  alkyl  iodides  upon  the  silver  salt,  and 
that  of  alcohols  upon  the  chloride,  produced  the  same  esters  (A.  238, 
318).  The  methyl  ester  boils  at  280°  and  the  ethyl  ester  at  288°  (B.  16, 
860).  These  esters  condense  with  acetic  ester,  acetone,  and  similar 
bodies  in  the  presence  of  sodium  ethylate,  forming  diketo-hydrindene 
derivatives.  The  phenyl  ester  melts  at  70°  (B.  7,  705  ;  28,  108).  The 
ethyl  ester  acid  is  a  heavy  oil. 

Chlorides.  —  The  chloride  of  the  ethyl-ester  acid  is  a  decomposable 
oil,  produced  when  PC13  acts  upon  the  ethyl-ester  acid  (B.  20,  ion). 

Phthalyl  chloride  C^a  Qr  c.H4Wo.  solidifies  at  0<> 


and  boils  at  275°.  It  results  upon  heating  the  anhydride  for  several 
hours  with  an  equi-molecular  quantity  of  PC15  at  200°  (A.  238,  329). 
The  conversion  of  phthalyl  chloride  with  glacial  acetic  acid  and  sodium 
amalgam  into  o-phthalyl  alcohol  is  an  argument  favouring  the 
sym.  formula.  The  unsym.  formula  is  evident  from  conversion  of 
the  chloride  by  zinc  and  acetic  acid  into  phthalide,  diphthalyl 
C«H4^°>0  0<C°\c6H4  and  hydro-diphthalyl,  and  with  benzene 

and  aluminium  chloride  into  phthalo-phenone  or  diphenyl-phthalide. 
With  lead  thio-phenate,  phthalyl  chloride  is  converted  into  bi-thio- 

phenyl-phthalide  C6H4/c(SC6H5)i^>O,  m.p.   85°.     This  is  oxidised  by 

permanganate  to  diphenyl-sulphone-phthalide,  m.p.  194°,  which  is 
also  formed  direct  from  phthalyl  chloride  with  sodium  benzol 
sulphonate  (/.  pr.  Ch.  2,  66,  345). 


356  ORGANIC  CHEMISTRY 

Phthalylene  Tetrachlorides.  —  PC15  converts  phthalyl  chloride  into 
two  phthalylene  tetrachlorides,  melting  at  88°  and  47°.  These  cannot 
be  changed  into  one  another.  Their  crystals  have  been  measured. 
Both  yield  phthalic  acid,  and  have  been  assigned  the  formulas 

C6H4|^Q3   andC6H4/CCl2\0     The  formation  of  the  two  chlorides  is 

UCOCl  UC/O1.2/ 

only  comprehensible  from  the  unsymmetrical  phthalyl-chloride  formula 
(B.  19,  1188).  The  chloride,  melting  at  88°,  is  also  obtained  in  the 
action  of  PC15  upon  phthalide  chloride.  This  reaction  argues  for  the 
unsymmetrical  formula,  just  as  well  as  the  conversion  into  diphenyl- 
an  throne  (see  this)  by  condensation  with  benzene  by  means  of  A12C16 
or  concentrated  sulphuric  acid  (B.  28,  R.  772). 

Phthalic  anhydride  C6H4/WCO\0,  melting  at  128°  and  boiling  at 
^L2jcu/ 

284°,  sublimes  readily  in  long  needles.  It  results  upon  fusing  phthalic 
acid  or  digesting  it  with  acetyl  chloride  (B.  10,  326).  Phthalic  anhy- 
dride yields  condensation  products  as  readily  as  benzaldehyde. 

Thus  phthalyl-acetic  acid  is  formed  on  boiling  the  anhydride  (with 
acetic  anhydride.  It  reacts  in  like  manner  with  malonic  ester  and 
aceto-acetic  ester.  At  more  elevated  temperatures  it  combines  with 
homologous  fatty  acids,  with  the  elimination  of  CO2  and  the  formation 
of  alkylidene-phthalides.  It  condenses  with  phthalide  to  diphthalyl 
(see  this).  With  the  phenols  it  yields  the  important  phthalei'n  dyes 
(see  these),  a  group  of  triphenyl-methane  dyes,  comprising  certain 
beautifully  fluorescent  compounds.  Thio-phthalie  anhydride  C6H4 
(CO)2S  melts  at  114°  and  boils  at  284°  (B.  17,  1176). 

Phthalo-mono-super  acid  (?)  C6H4(COOH)COOOH,  m.p.  110°,  with 
conversion  into  phthalic  acid,  and  peroxide-phthalie  acid  (COOH. 
C6H4.CO)2O2,  m.p.  156°  with  decomposition,  are  formed  by  shaking 
up  phthalyl  anhydride  with  alkaline  H2O2  solution  ;  the  former  dis- 
solves in  water  easily,  the  latter  with  difficulty. 

Peroxide-phthalie  acid  diethyl  ester  O2(CO.C6H4COOC2H5)2,  m.p. 
59°,  from  ph  thai-ethyl  ester  chloride  with  alkaline  H2O2. 

Phthalyl  peroxide  C6H4(CO2)2  melts  at  133°,  giving  gas  evolution. 
When  heated  rapidry  to  136°  it  explodes.  It  is  formed  when  phthalyl 
chloride  is  acted  upon  with  a  sodium  peroxide  solution  (B.  27,  1511). 

Phthalamic  acid  or  C 


at  148°,  is  formed  from  the  anhydride  and  ammonia,  or  when  baryta 
water  acts  upon  phthalimide  (B.  19,  1402).  Anilic  acid  melts  at  192°. 

Phthalic    diamide    ^{gggj    or    C.Hl{M«>o    melts    at 

i4O°-i6o°,  changing  at  the  same  time  to  phthalimide.  It  is  pro- 
duced when  ammonia  acts  upon  the  ester  (B.  19,  1399  ;  21,  R.  612  ;  24, 
R.  320  ;  25,  R.  911). 

Phthalimide  c.H4{££2>NH  or  C6H4{W££^>o,    melting   at 

238°,  is  obtained  : 

By  heating  phthalic  anhydride  or  chloride  in  ammonia  gas  ; 

By  heating  phthalic  acid  with  ammonium  sulpho-cyanide  (B.  19, 
2283)  ;  from  phthalamide,  and 

By  the  molecular  rearrangement  of  the  isomeric  o-cyano-benzoic 
acid. 


DICARBOXYLIC   ACIDS  357 

It  forms  potassium  phthalimide  C6H4(CO)2NK  by  the  action  of 
alcoholic  potash. 

Salts  of  the  heavy  metals  can  be  obtained  from  it  by  double  decom- 
position. Potassium  phthalimide  is  readily  rearranged,  or  transposed, 
with  organic  halogen  derivatives ;  consequently  it  is  frequently  em- 
ployed in  the  preparation  of  numerous  amines.  While  by  this  means 
alkylogens  yield  symmetrical  alkylimides  of  the  formula  C6H4(CO)NR 
— e.g.  sym.  methyl- and  benzyl-phthalimide,  melting  at  132°  and  115°, — 

unsymmetrical  alkylimides  of  the  formula  C6H4/ £'(  ^No  are  ob- 
tained from  the  interaction  of  phthal-alkylamic  acids  and  acetyl 
chloride  :  unsym.  methyl-  and  benzyl-phthalimide  melt  at  78°  and  81° 
(B.  27,  R.  737). 

On  brominating  sym.  methyl-phthalimide  we  obtain  bromo-methyl- 
phthalimide  C6H4(CO)2NCH2Br,  m.p.  150°  ;  on  heating  with  water  this 
becomes  oxy-methyl-phthalimide  C6H4(CO)2N.CH2OH,  m.p.  142°,  also 
obtained  from  phthalimide  with  formaldehyde,  at  100°,  and  easily  dis- 
solved again  into  these  constituents  ;  by  condensation  with  benzols 
by  means  of  concentrated  sulphuric  acid,  oxy-methyl-phthalimide  is 
converted  into  benzyl-phthalimides  (C.  1902,  II.  1164).  From  ethyl- 
phthalimide  with  alkyl-magnesium  haloids  we  get  products  of  the 

formula  ceH4{£[^^NC2H5  (B.  37,  385). 

On  reduction,  phthalimide  becomes  phthalimidin  ;  with  bromine 
and  alkaline  hydrate  it  becomes  anthranilic  acid.  The  bromyl-phthal- 
imide  C6H4(CO)2NBr  occurring  as  an  intermediate  product  in  the  latter 
reaction,  and  melting  at  206°  or  207°,  is  also  obtained  from  sodium 
phthalimide  with  one  molecule  bromine  in  aqueous  solution  at  o°  ; 
chloryl-phthalimide  C6H4(CO)2NC1,  m.p.  i83°-i85°,  is  obtained  by  the 
action  of  chlorine  upon  phthalimide  shaken  up  with  water  (C.  1903, 
I.  744).  With  sodium  alcoholates  these  compounds  give,  in  the  first 
instance,  carbox-alkyl-anthranilic  acid  ester  (B.  33,  21). 

From  phthalic  acid  and  aniline  we  obtain  sym.  phthalanile  C6H4(CO)2 

NCeH5,  m.p.  208°.    Unsym.  phthalanile  C6H4{^C«H5))>O,  m.p.  116°, 

is  obtained  from  phthalanilic  acid  with  acetyl  chloride  (B.  32,  1991  ; 
36,  996  ;  C.  1903,  II.  432). 

Phthalyl-phenyl-hydrazide  C6H5(CO)2(NHNHC6H5)2  melts  at  161°. 
Phthalyl-hydrazin  C6H4(CO)2(NH)2,  from  phthalic  anhydride  and 
hydrazin  hydrate,  sublimes  at  200°.  Phthalimide  and  hydrazin  yield 
an  isomeric  phthal-hydrazin  (B.  28,  R.  429  ;  29,  R.  987). 

a-Phthalyl-phenyl-hydrazin  C6H4(CO)2N.NHC6H5  melts  at  178°. 

jS-Phthalyl-phenyl-hydrazin  C6H4{^  *?      melts  at  210°  (B.  19, 

L  CxOpJC/gHg 

R.  303  ;  20,  R.  255). 

Phthalyl-hydroxylaminie  acid  C6H4(COOH)C(OH)NHOH,  m.p.  220° 
with  decomposition,  from  cold  phthalic  anhydride  and  hydroxylamine. 
On  heating  the  solution  it  becomes  phthalyl-hydroxylamine  C6H4(CO2) 
NOH,  m.p.  230°  ;  both  bodies  are  transformed  into  anthranilic  acid 
by  treatment  with  alkali  (C.  1902,  I.  1083  ;  II.  1286,  1439). 

Phthalyl-glycocoll  C6H4(CO)2NCH2COOH,  m.p.  192°,  formed  by 
introducing  glycocoll  into  molten  phthalic  anhydride  ;  sodium  ethylate 
transposes  the  ester  into  the  iosmeric  oxy-iso-carbo-styrile-carboxylic 


358  ORGANIC  CHEMISTRY 

ester  (q.v.)  (B.  33,  981  ;  40,  4409)  ;  the  chloride,  m.p.  85°,  decomposes 
on  distillation,  at  ordinaty  pressure,  into  CO  and  chloro-methyl-phthal- 
imide  C6H4(CO) 2N.CH2C1.  Phthalyl-alanin  C6H4(CO) 2N.CH (CH3)CO2H, 
m.p.  162° ;  chloride,  m.p.  73°.  j3-Phthalimido-propionie  acid  C6H4 
(CO)2N.CH2.CH2CO2H,  m.p.  151°;  chloride,  m.p.  108°  (B.  38,  633; 
41,  242). 

Nitrites  of  Phthalic  Acid. — o-Cyano-benzoic  acid  is  produced  when 
anthranilic  acid  is  treated  with  nitrous  acid  and  cuprous  cyanide.  It 
rearranges  itself,  upon  the  application  of  heat,  into  phthalimide  (B.  18, 
1496;  19,  2283;  25,  R.  910).  o-Cyano-benzoic  acid  ester  melts 
at  70°  (B.  19,  1491).  o-Cyano-benzo-triehloride  CN[2]C6H4CC13, 
m.p.  94°  and  b.p.  280°,  is  obtained  from  o-tolu-nitrile  (B.  20,  3199). 
o-Cyano-benzamide,  o-phthalo-nitrilamide,  is  formed,  besides  other  pro- 
ducts, on  brief  heating  of  phthalimide  with  acetic  anhydride,  and  in 
the  transformation  of  o-cyano-benzol  chloride  with  hydroxylamine. 
On  heating  above  the  m.p.  (173°),  it  passes  into  the  isomeric  imido- 
phthalimide ;  and,  on  boiling  with  excess  of  acetic  anhydride,  into 
o-phthalo-nitrile  (B.  40,  2709). 

o-Phthalo-nitrile  C6H4[i,  2](CN)2,  m.p.  141°,  is  also  obtained  from 
o-amido-benzo-nitrile  through  the  diazo-compound  (B.  29,  630). 

Substituted  o- Phthalic  Acids  are  obtained,  partly  by  direct  substitu- 
tion of  the  phthalic  acid,  and  partly  by  the  oxidation  of  substituted 
naphthalins  and  toluic  acids. 

All  the  mono-  and  dichloro-phthalic  acids  are  known  : 

4-Chloro-phthalic  anhydride  .  m.p.     98°  b.p.  297° 

3-Chloro-phthalic  anhydride  .  „  122°  „     313° 

4, 5-Dichloro-phthalic  anhydride  .  „  186°  „     313°^ 

3,  4-Dichloro-phthalic  anhydride  .  „  121°  „     329°  I  (B.  42,  3532) 

3, 6-Dichloro-phthalic  anhydride  .  „  191°  „     339° ) 
3, 5-Dichloro-phthalic  anhydride                  89°  .         .         .  (C.  1903,  I.  140) 

3,  4,  6-Trichloro-phthalic  anhydride  .  „  148°  .         .         .  (B.  34,  2107) 

Tetrachloro-phthalic  anhydride  ,,  250°.         .         .  (A.  149,  18). 

The  mono-,  tri-,  and  tetrachloro-phthalic  acids  have  been  obtained 
by  oxidation  of  the  corresponding  chlorinated  o-toluic  acids  or  naph- 
thalins. 4,  5-,  3,  4-,  and  3,  6-dichloro-phthalic  acids  are  formed  to- 
gether, on  conducting  chlorine  into  a  solution  of  phthalic  anhydride 
in  fuming  sulphuric  acid  ;  and  the  3,  5-acid  in  small  quantity  by  the 
action  of  PC15  upon  dimethyl-dihydro-resorcin  (q.v.). 

4,  5-Dibromo-phthalic  acid,  m.p.  135°,  and  anhydride,  m.p.  214°, 
from  phthalic  anhydride  with  bromine  in  concentrated  sulphuric  acid, 
or  by  oxidation  of  dibromo-naphthalin  with  nitric  acid.  On  boiling 
with  KHO  it  gives  dioxy-phthalic  acid  (B.  34,  2741  ;  C.  1907,  I. 
1119). 

3-  and  4-Iodo-o-phthalic  acids  melt  at  206°  and  at  182°  (B.  29, 1575. 
R.  792).  Tetra-iodo-o-phthalie  acid  melts  at  324°-327°  (B.  29,  1634), 
3-  and  4-Nitro-o-phthalie  acids,  melting  at  219°  and  161°  respectively, 
are  formed  together  on  nitrifying  phthalic  acid  ;  the  anhydrides  melt 
at  164°  and  114°,  the  imides  at  216°  and  202°.  3-Nitro-phthalyl 
chloride,  m.p.  77°  (B.  34,  3735,  4351 ;  C.  1902,  II.  359;  1903,  II.  430). 
Concerning  the  formation  of  3-nitro-phthalie  ester  acids,  a-,  m.p.  144°, 
and  j8-,  m.p.  157°,  and  their  relation  to  V,  Meyer's  esterification  .rule, 


DICARBOXYLIC   ACIDS  359 

see  B.  35,  3857.  On  reduction  of  nitro-phthalic  acids,  3-  and  4-amido- 
phthalic  acids  are  formed  (B.  36,  2494). 

Sulpho-o-phthalie  acid  is  obtained  by  heating  naphthols,  naphthyl- 
amines,  and  naphthalene-sulphonic  acids  with  concentrated  sulphonic 
acid  and  mercury  to  22O°-3OO°  (B.  29,  2806). 

Oxy-o-phthalie  acids.  —  They  are  recognised  by  the  melting-points 
of  their  anhydrides,  into  which  they  change  upon  the  application  of 
heat. 

3-Oxy-o-phthalic  acid  anhydride  melts  at  147°  (B.  16,  1965).  Di- 
nitro-3-oxy-o-phthalic  acid  is  juglonic  acid,  which  can  also  be  obtained 
by  the  action  of  nitric  acid  upon  juglone,  a  naphthalene  derivative 
(B.  19,  168  ;  C.  1907,  1.  1120).  4-Oxy-o-phthalie  acid  anhydride  melts  at 
165°  (A.  233,  232).  p-Dioxy-o-phthalo-nitrile,  o-dicyano-hydroquinone 
(HO)2[3,  6]C6H2[i,  2](CN)2+2H2O,  is  formed  from  quinone  with 
nascent  prussic  acid  ;  on  heating  with  concentrated  sulpkuric  acid  it 
becomes  dioxy-phthalimide  C6H2(OH)2(CO)2NH,  which,  on  boiling  with 
HC1,  splits  off  CO  2  and  becomes  p-dioxy-benzoic  acid  (B.  33,  675  ; 
A.  349,  45). 

Nor-hemi-pinie  acid,  3,  4-dioxy-phthalie  acid  anhydride,  melting 
at  238°,  is  produced  when  3,  4-diehloro-methoxy-phthalie  acid  anhy- 
dride (C1CH2O)/;6H2(CO)2O,  m.p.  156°—  the  reaction  product  of  PC15 
and  hemi-pinic  acid  at  180°  —  is  digested  with  water.  Hemi-pinic 
anhydride,  3,  4-dimethoxy-phthalic  anhydride,  melts  at  167°.  The  acid 
is  formed,  together  with  opianic  acid  and  meconin,  in  the  oxidation  of 
narcotin  ;  also  with  meconin  on  fusing  opianic  acid  with  caustic 
potash  : 


Hemi-pinic  acid  Opianic  acid  Meconin. 

Consult  B.  29,  R.  96,  for  the  hemi-pinamido-acids,  the  hemi-pinic 
esters,  and  the  hemi-pinimides. 

6-Amido-hemi-pinic  acid  is  produced  on  boiling  its  anhydride  with 
baryta  water.  The  anhydride  is  azo-opianic  acid  or  2,  3-dimethoxy- 
5,  6-anthranile-carboxylic  acid. 

Nor-meta-hemi-pinic  anhydride  melts  at  247°.  Meta-hemi-pinic 
anhydride  melts  at  175°.  Meta-hemi-pinic  acid  or  4,  5-dimethoxy-o- 
phthalic  acid  was  obtained  in  the  decomposition  of  papaverin  (B.  24, 
R.  902).  Methylene-meta-hemi-pinic  ether  acid  (CH2O2)C6H2(COOH)2 
is  hydrastie  acid,  formed  in  the  oxidation  of  hydrastinine.  The  oxida- 
tion of  cotarnine  yields  cotarnic  acid  or  methylene-methyl  ether  —  3,  4,  5- 
trio%y-o-phthalic  acid  (CH2O2)(CH3O)C6H(COOH)2. 

Iso-phthalie     acid,     benzene-m-dicarboxylic     acid    c6H4 


melts  above  300°  and  sublimes.  It  is  formed  by  oxidising  m-xylol  and 
m-toluic  acid  with  a  chromic  acid  mixture  or  permanganate  (B.  36, 
1798)  ;  by  the  further  oxidation  of  m-phthalyl  alcohol  ethyl  ether,  ob- 
tained from  m-xylylene  bromide  and  alcoholic  potash  (B.  21,  47),  and 
from  m-dicyano-benzol  and  m-cyano-benzoic  acid.  The  last  two 
methods  permit  of  nuclear  syntheses  from  the  corresponding  amido- 
compounds,  m-phenylene-diamine  and  m-amido-benzoic  acid. 

The    acid    is    also    formed    when    potassium    m-sulpho-benzoate, 


360  ORGANIC   CHEMISTRY 

m-bromo-benzoate,  and  benzoate  are  fused  with  potassium  formate 
(terephthalic  acid  is  also  formed  in  the  last  two  cases)  ;  by  the  action 
of  the  ester  of  chloro-carbonic  acid  and  sodium  amalgam  upon 
m-dibromo- benzene  ;  also  by  heating  hydro-pyro-mellitic  and  hydro- 
prehnitic  acids. 

Iso-phthalic  acid  is  soluble  in  460  parts  boiling  and  7800  parts  cold 
water.  It  does  not  yield  an  anhydride.  Reduction  changes  it  to 
tetrahydro-iso-phthalic  acid.  The  barium  salt  C6H4(CO2)2Ba+6H2O 
(A.  260,  30)  is  very  soluble  in  water  (distinction  between  phthalic  and 
terephthalic  acids). 

The  dimethyl  ester  melts  at  64°. 

The  dichloride  melts  at  41°  and  boils  at  276°.  The  dihydrazide  melts 
at  220°.  Nitrous  acid  converts  it  into  iso-phthalazide  C6H4(CON3)2, 
melting  at  56°.  Boiling  alcohol  converts  it  into  m-phenylene-urethane 
C6H4(NHC02C2H5)2  (B.  29,  R.  987). 

m-Cyano-benzoic  acid  melts  at  217°  (B.  20,  524). 

m-Dicyano-benzol  melts  at  158°  (B.  17,  1430). 

Substituted  Iso-phthalic  Acids. — The  5-chloro-,  5-iodo-,  and  5- 
amido-phthalic  acids  can  be  prepared  from  5-nitro-iso-phthalic  acid. 
The  nitration  and  sulphonation  of  iso-phthalic  acid  produce  5-nitro-iso- 
phthalic  acid  and  5-sulpho-iso-phthalic  acid  (see  Benzoic  acid).  The 
4-bromo-,  4-iodo-,  4-amido-,  and  4-sulpho-iso-phthalic  acids  are  obtained 
by  the  oxidation  of  the  corresponding  toluic  acids  (B.  24,  3778  ;  28, 
84  ;  25,  2795  ;  14,  2278).  2-Nitro-  and  2-amido-iso-phthalic  acids  are 
formed  from  2-nitro-m-xylol  (B.  39,  73).  4-Chloro-iso-phthalic  acid, 
m.p.  294° ;  4-acetamido-iso-phthalic  acid,  m.p.  289° ;  and  4,  6-diamido- 
iso-phthalic  acid  are  obtained  from  chloro-,  acetamido-,  and  diacet- 
amido-m-xylol,  by  oxidation  with  permanganates  (B.  36,  1799,  1803  ; 
C.  1909,  II.  1234). 

Tetraehloro-,  tetrabromo-,  and  tetraiodo-phthalic  acids  melt  at  181°, 
290°,  and  310°  (B.  29, 1632).  Tetra-amido-iso-phthalic  acid  C6(NH2)4 
(COOH)2  has  been  obtained  by  way  of  the  iso-purpuric  acid,  which  is 
probably  the  dinitrile  of  a  dinitro-hydroxylamino-oxy-iso-phthalic 
acid. 

Homologous  Iso-phthalic  Acids. — There  are  four  theoretically 
possible  methyl-iso-phthalic  acids,  of  which  uvitinic  acid  may  be 
mentioned. 

Uvitinic  acid,  mesidic  acid,  ^-methyl-iso-phthalic  acid  CH3[5]C6H3 
[i,  3](CO2H)2,  melting  at  287°,  is  obtained  by  oxidising  mesitylene 
with  dilute  nitric  acid.  Synthetically,  it  has  been  prepared  from 
pyro-racemic  acid.  In  this  reaction  a  condensation  product  resembling 
an  aldol  is  first  formed  from  two  molecules  pyro-racemic  acid  by  boiling 
with  baryta  water  or,  better,  with  NaHO.  This  product  is  para-pyro- 
racemic  acid  ;  two  molecules  of  this  condense,  with  elimination  of 
oxalic  acid  and  water,  to  form  methyl-dihydro-trimesinic  acid,  which 
on  prolonged  boiling  with  baryta  water,  or  with  concentrated  H2SO4, 
splits  off  CO 2  and  2H  atoms  and  passes  into  uvitinic  acid  (Latin  uva,  a 
grape)  (Wolff,  305,  125)  : 

CO.CO2H 
CH3v    OHCH2.C(OH)^-CO2H     CH3v         /CH=C— CO2H  ,<Z 

\/**  i  \  /"*TT  \^'  ^\/~*"LT  /~*TT   r* / 

VV\.  ^^3     ~  /     \  //  ^-tl3v-/v\ 

CO2HX          CH2— CO CO2H  CO2HX        NCH2— (%-CO2H 


DICARBOXYLIC   ACIDS  361 

If  a  mixture  of  pyro-racemic  acid  and  propyl-  or  iso-butyl-aldehyde 
is  used,  we  obtain  5-ethyl  and  5-iso-propyl-iso-phthalie  acid  (Dobner, 
B.  23,  377  ;  24,  1746).  Chromic  acid  oxidises  these  to  trimesinic  acid. 

Distilled  with  lime,  uvitinic  acid  at  first  yields  meta-toluic  acid, 
then  toluol. 

Xylidic  acid,  ^-methyl-iso-phthalic  acid  CH3[4]C6H3[i,  3](CO2H)2, 
melting  at  282°,  is  obtained  by  oxidising  pseudo-cumol,  xylic  acid, 
and  iso-xylic  acid  with  dilute  nitric  acid.  Potassium  permanganate 
oxidises  it  to  trimellitic  acid. 

2-Mesityl-iso-phthalic  acid,  m.p.  235°,  results  from  the  reduction 
of  2,  6-dicarbon-phenyl-glyoxylic  acid  with  phosphorus  and  HI  (B.  29, 
R.  283). 

Oxy-iso-phthalie  acids  are  obtained  by  the  same  methods  from  oxy- 
benzoic  acids  and  aldehyde-oxy-benzoic  acids  as  the  latter  are  got  from 
phenols  and  phenol-aldehydes.  Amido-  and  sulpho-carboxylic  acids 
also  serve  as  foundation  material  (B.  16,  1966  ;  25,  R.  9). 

2-Oxy-,  4-oxy-,  and  5-oxy-iso-phthalic  acids  melt  at  243°,  305°,  and 
288°  respectively.  The  4-oxy-iso-phthalic  ethyl  ester,  m.p.  57°,  is 
formed  in  small  quantity  in  a  peculiar  condensation  process  during  the 
action  of  sodium  etlvylate  free  from  alcohol  upon  glutaconic  acid  ester 
(B.  37,  2117). 

5, 2-Nitro-oxy-iso-phthalie  acid,  m.p.  214°,  from  nitro-malonic 
aldehyde  and  acetone-dicarboxylic  acid  (C.  1900,  II.  561). 

Dioxy-iso-phthalic  acid,  reso-dicarboxylic  acid,  m.p.  305°,  see  B. 
32,  2796. 

Oxy-uvitinic  Acids. — Mention  may  be  made  of  4-oxy-uvitinie  acid 
(CH3)[5](HO)[4]C6H2[i,3](CO2H)2,  produced  by  the  action  of  chloro- 
form, chloral,  or  trichloro-acetic  ester  upon  sodium  aceto-acetic  ester 
(A.  222, 249).  Methenyl-bis-acetic  acid  ester  (Vol.  I.)  is  an  intermediate 
link  (A.  297,  n). 

Terephthalic  acid,  benzol-p-dicarbo xylic  acid  C6H4[i,  4](CO2H)2, 
sublimes  without  melting.  Iso-phthalic  acid  was  obtained  from  m- 
derivatives  of  benzene  ;  in  a  similar  manner  terephthalic  acid  is 
formed  from  p-di-derivatives  :  p-xylol,  p-toluic  acid,  p-dicyano-benzol, 
p-cyano-benzoic  acid,  p-dibromo-benzol,  etc.  It  is  obtained  in  small 
quantities  by  the  action  of  Mg  and  CO2  upon  p-dibromo-benzol  (B. 
38,  3796). 

The  best  course  to  pursue  in  forming  terephthalic  acid  is  to  oxidise 
carraway  oil  (a  mixture  of  cymol  and  cuminol)  with  chromic  acid ;  or 
it  may  be  prepared  from  p-toluidin  (B.  22,  2178). 

Terephthalic  acid  is  almost  perfectly  insoluble  in  water,  alcohol, 
and  ether.  When  reduced  it  yields  di-,  tetra-,  and  hexahydro-tere- 
phthalic  acids.  It  forms  no  anhydride. 

The  barium  salt  CbH4O4Ba+4H2O  is  very  slightly  soluble  in  water. 
The  methyl  ester  melts  at  140°. 

The  chloride  melts  at  78°  and  boils  at  259°.  The  amie  acid  melts 
at  214°.  The  dihydrazide  melts  above  300°.  The  diazide  C6H4[i,  4] 
(CON3)2  melts  at  110°  (B.  29,  R.  987). 

Terephthalic  di-super-aeid  (?)  C6H4[i,  4](COOOH)2,  in  rather  in- 
soluble explosive  needles,  from  terephthalyl  chloride  with  alkaline 
H2O2,  is  precipitated  by  CO2  from  the  alkaline  solution  as  a  mono- 
sodium  salt;  its  ethyl  ester  C6H4(CO2.OC2H6)2,  m.p.  37°,  from  tere- 


362  ORGANIC   CHEMISTRY 

phthalyl  chloride  with  barium  ethyl  peroxide  Ba(O.OC2H5)2    (B.  34, 
766).    ' 

p-Cyano-benzoie  acid  CN[4]C6H4CO2H,  from  p-amido-benzoic  acid, 
melts  at  214°. 

p-Dieyano-benzol  C6H4[i,  4](CN)2  melts  at  215°. 

Mononitro-terephthalic  acid  melts  at  259°. 

It,  and  sulpho-terephthalie  acid,  are  produced  in  the  nitration  and 
sulphonation  of  terephthalic  acid.  2, 3-,  2, 6-,  and  2, 5-Dinitro-phthalic 
acids  are  also  known  (B.  28,  81).  2, 5-Diamido-terephthalic  acid 
(NH2)2[2,  5]C6H2[i,  4](COOH)2  is  infusible;  its  diethyl  ester  is  pro- 
duced by  the  oxidation  of  di-imino-succinyl-succinic  ester  with 
bromine.  Like  anthranilic  acid,  this  acid,  which  contains  the  same 
grouping  doubled,  is  capable  of  forming  numerous  o-condensation 
products  (C.  1907,  II.  542).  Consult  B.  29,  1625,  2833,  for  tetra- 
chloro-,  tetrabromo-  and  tetraiodo-terephthalic  acids. 

Alkyl-terephthalic  Acids. — The  oxidation  of  pseudo-cumol  and 
durol  gives  rise  to  4-methyl-terephthalie  acid,  a-xylidic  acid,  melting  at 
282°,  and  to  2,  5-dimethyl-terephthalie  acid,  j8-eumidic  acid  (B.  19, 2510). 

Oxy-terephthalie  Acids. — Oxy-terephthalie  acid  has  been  obtained 
from  nitro-terephthalic  acid.  It  sublimes  without  melting.  3,  5-Di- 
oxy-terephthalic  acid  is  the  most  interesting  of  the  three  possible  dioxy- 
terephthalic  acids.  Mention  is  made  of  it  because  of  its  connection 
with  succinyl-succinic  ester.  Its  diethyl  ester  may  be  prepared  by 
withdrawing  two  hydrogen  atoms  from  succinyl-succinic  ester  by 
means  of  bromine  or  PC15  (B.  22,  2107),  or  by  the  action  of  sodium 
ethylate  upon  dibromo-aceto-acetic  ester  (A.  219,  78). 

2,  5-Dioxy-terephthalie  acid  (HO)2C6H2(CO2H)2+2H2O  crystallises 
from  alcohol  in  yellow  flakes.  Ferric  chloride  imparts  a  deep-blue 
coloration  to  its  solution.  When  rapidly  distilled  it  decomposes  into 
two  molecules  of  carbon  dioxide  and  hydroquinone. 

2,  5-Dioxy-terephthalic  ethyl  ester  crystallises  in  two  distinct  forms 
at  the  ordinary  temperature  in  yellowish-green  prisms  or  plates  ;  at 
higher  temperatures  in  colourless  flakes.  It  also  sublimes  in  the  latter 
form.  It  melts  at  133°.  In  most  of  its  reactions  the  ester  conducts 
itself  like  an  hydroxyl  derivative.  It  does  not  combine  with  hydroxyl- 
amine  or  phenyl-hydrazin,  and  with  sodium  and  alkyl  iodides  yields 
dialkyl  ether.  It,  however,  does  not  react  with  phenyl  cyanate 
(B.  23,  259),  and  shows  some  analogies  with  succino-succinic  ester. 
Hence,  it  is  considered  a  quinone-  or  diketo-derivative  : 

C02C2H5    or 

Dioxy-terephthalic  ester,  by  reduction  (boiling  with  zinc  and  hydro- 
chloric acid  in  alcoholic  solution),  is  again  changed  to  succinyl-succinic 
ester  (B.  19,  432  ;  22,  2169).  A  dihydroxamic  acid  is  formed  with 
hydroxylamine  hydrochloride ;  tetrahydro-dioxy-terephthalie  acid  is 
produced  at  the  same  time  (B.  22,  1280).  The  different  physical 
modifications  of  the  ester  and  analogous  compounds,  according  to 
Hantzsch,  correspond  to  two  desmotropic  conditions — the  coloured 
variety  agreeing  with  the  quinone  formula,  while  the  colourless  corre- 
sponds to  the  hydroxyl  formula  (B.  22,  1294).  However,  the  colour 
cannot  be  regarded  as  a  certain  criterion  for  the  distinction  of  the 


DICAIJBOXYLIC  ACIDS  363 

ketone  from  the  hydroxyl  form.  Even  chemical  reactions  do  not 
prove  that  desmotropic  forms  can  be  accepted  (Nef,  B.  23,  R.  585  ; 
Goldschmidt,  B.  23,  R.  260). 

Succinyl-succinic  acid,  whose  ester,  by  the  removal  of  hydrogen, 
yields  2,  5-dioxy-terephthalic  ester,  will  be  discussed  in  connection 
with  the  hydro-aromatic  compounds. 

Trioxy-dicarboxylic  Acids. — Phloro-glucin-dicarboxylie  ester,  whose 
formation  by  the  condensation  of  three  molecules  sodium-malonic  ester 
was  mentioned  in  the  discussion  of  benzene  ring  formations,  is  dealt 
with  as  a  derivative  of  triketo-cyclo-hexane  among  the  hydro-aromatic 
compounds. 

Gallo-earboxylie  acid,  trioxy-o-phthalic  acid  (HO)3[3, 4, 5]C6H 
(CO2H)2,  melts  at  270°  with  decomposition.  It  may  be  prepared  from 
pyrogallol  by  heating  it  to  130°  with  ammonium  carbonate.  Pyro- 
gallo-carboxylic  acid  is  formed  at  the  same  time  (B.  13,  1876). 

(b)  Aromatic  Dicarboxylic  Acids  containing  iCO2H  in  the  nucleus 
and  iCO2H  in  the  side  chain. — The  three  a-homo-phthalic  acids,  or 
phenyl-acetic-carboxylic  acids,  are  known.  The  o-acid  readily  forms 
heterocyclic  derivatives. 

Phenyl-aceto-o-carboxylic  acid,  o-a-homo-phthalic  acid  CO2H[2] 
C6H4CH2.CO2H,  melting  at  175°,  with  the  elimination  of  water,  may 
be  obtained  by  fusing  gamboge  with  caustic  potash  (B.  19,  1654)  ;  by 
oxidising  indene  with  KMnO4  (B.  32,  29)  ;  by  reducing  phthalonic 
acid  with  HI  (B.  31,  375)  ;  and  by  saponification  of  its  nitriles.  Its 
anhydride  melts  at  141°.  On  heating,  it  splits  off  CO  and  becomes 
hydro-diphthal-lactonic  acid  (B.  31,  376). 

o-Homo-phthalimide,  melting  at  233°,  is  produced  when  the 
ammonium  salt  is  heated,  and  when  acids  act  upon  the  dinitrile.  In 
the  latter  case  o-cyano-phenyl-acetic  acid,  produced  at  first,  rearranges 
itself  into  homo-phthalimide,  just  as  o-cyano-benzoic  acid  yields 
phthalimide  (B.  23,  2478).  It  is  rather  remarkable  that  o-homo- 
phthalimide,  when  heated  with  phosphorus  oxy-chloride,  yields 
dichloro-iso-quinolin,  which  becomes  iso-quinolin  when  further  heated 
with  hydriodic  acid  (B.  27,  2232,  2492)  : 

/  ( [i]CH2CN  /CH2.CO  POCI,  /CH  :  CC1  ,CH  :  CH 

CeH/J  — ^C6H4<  |        — >CflH4<(  |     *C6H4< 

x  ( [2]CN  XCO  .  NH  XCC1 :  N  XCH  :  N 

o-Cyano-benzyl  Homo-phthali-         Dichloro-iso-quino-          Iso-quinolin. 

cyanide  mide  lin 

Homo-phthalimide  is  directly  converted  into  iso-quinolin  when  it 
is  heated  with  zinc  dust. 

The  hydrogen  atoms  of  the  CH2  groups  are  replaced  by  two  alkyls 
when  homo-phthalimide  is  heated  with  caustic  potash  and  alkyl 
iodides.  Afowo-alkyl-o-benzyl  cyanides  yield  mono-alkyl-homo-phthal- 
imides,  which  rearrange  themselves  in  the  same  manner  as  homo-phthal- 
imide into  alkyl-iso-quinolins  (B.  20,  2499). 

w-Cyan-o-toluic  acid  CO2H[2]C6H4CH2CN  melts  with  decom- 
position at  116°.  Its  potassium  salt  is  obtained  from  phthalide  and 
potassium  cyanide  (A.  233,  102). 

o-Cyano-benzyl  cyanide,  o-fi-homo-phthalo-nitrile  CN[2]C6H4CH2CN, 
melting  at  81°,  is  obtained  from  o-cyano-benzyl  chloride.  Caustic  potash 
and  alkylogens  effect  the  replacement  of  an  hydrogen  atom  in  the 


364  ORGANIC   CHEMISTRY 

methylene  group  by  an  alcohol  radicle  (see  Homo-phthalimide) .  Acetyl 
chloride  converts  it  into  0-diaeetyl-o-eyano-benzyl  cyanide  CN.C6H4C 
(CN)  :  C(CH3)OCOCH3,  which  may  be  rearranged  into  3-methyl-iso- 
quinolin  (B.  27,  2232). 

Homo-iso-phthalic  acid  and  homo-terephthalie  acid  melt  at  185° 
(B.  36,  3611).  Both  sublime,  m-  and  p-Cyano-benzyl  cyanides  melt 
at  88°  and  100°  (B.  24,  2416).  The  dinitrile,  and  the  two  nitrite-  and 
amine-acids,  the  two  possible  amido-nitriles,  and  the  diamide  of  homo- 
terephthalic  acid  have  been  prepared  (B.  22,  3207 ;  26,  R.  89,  602). 

o-Hydro-cinnamic-carboxylic  acid  CO2H[2]C6H4CH2CH2CO2H  melts 
at  165°.  It  is  formed  by  oxidising  tetrahydro-/3-naphthyl-amine  with 
potassium  permanganate,  and  by  the  reduction  of  dihydro-iso-cumarin 
carboxylic  acid  (B.  26,  1841),  as  well  as  from  o-carbo-phenyl-glyceric- 
acid-S-lactone  (B.  25,  888).  It  yields  a-hydrindone  (B.  26,  708)  upon 
dry  distillation. 

o-Cyano-benzyl-acetie  ester,  eyano-hydro-cinnamic  ester  CN[2]C6H4 
[i]CH2.CH2.CO2C2H5,  melting  at  98°,  is  produced  by  the  rearrange- 
ment of  the  product  resulting  from  the  action  of  aceto-acetic  ester,  or 
malonic  ester,  and  sodium  ethylate  upon  cyano-benzyl  chloride  (B.  22, 
2017).  Concentrated  hydrochloric  acid  converts  it  into  a-hydrindone 

(q.v.)  :  C6H4<^>CH2. 

Phenyl-butyric-o-carboxylic  acid  CO2H[2]C6H4CH2.CH2.CH2.CO2H 
melts  at  138°  (B.  18,  3118). 

(c)  Aromatic  Diearboxylic  Acids,  having  both  carboxyls  in  different 
side-groups. 

o-,  m-,  and  p-Phenylene-diaeetie  acids  C6H4(CH2CO2H)2,  melting  at 
150°,  170°,  and  244°,  have  been  obtained  from  the  xylylene  cyanides 
(B.  26,  R.  941).  o-Phenylene-diacetic  acid  has  also  been  prepared  by 
oxidising  dihydro-naphthalene  (q.v.).  Its  calcium  salt  yields  /3-hydrin- 
done  upon  distillation  (q.v.)  (B.  26,  1833). 

o-Phenylene-aeeto-propionic  acid  C6H4(CH2.COOH)[2](CH2.CH2 
COOH),  m.p.  139°,  is  obtained  from  J3-oxy-a-naphthoic  acid,  by 
rupture  of  the  ring,  effected  by  sodium  and  amyl  alcohol,  just  as  pimelic 
acid  is  formed  from  salicylic  acid.  It  reverts  to  j8-keto-tetrahydro- 
naphthalene  when  its  calcium  salt  is  distilled  (B.  28,  R.  745). 

o-,  m-,  and  p-Phenylene-dipropionic  acids  C6H4(CH2.CH2.CO2H)2, 
m.p.  161°,  146°,  and  223°,  are  formed  from  xylylene-dimalonic  acids 
(B.  19,  436  ;  21,  37).  Also  p-phenylene-di-iso-butyric  acid  C6H4[CH2 
CH(CH3)COOH]2,  m.p.  169°,  from  p-xylylene-dimethyl-malonic  acid 
(B.  34,  2789). 

(9)  ALDEHYDO-DICARBOXYLIC  ACIDS. 

2-Aldehydo-iso-phthalic  acid,  m.p.  176°,  results  from  heating 
2,  6-dicarbo-phenyl-glyoxylic  acid  (B.  26,  1767  ;  30,  695). 

5-Aldehydo-4-oxy-  and  5-aldehydo-2-oxy-iso-phthalie  acids  are 
formed  from  the  corresponding  oxy-iso-phthalic  acids  by  means  of 
chloroform  and  caustic  potash  (B.  11,  793). 

(10)  TRICARBOXYLIC  ACIDS. 

The  three  isomeric  benzene-tricarboxylic  acids  C6H3(CO2H)3  are 
known.  Trimesic  acid,  (1,  3,  5) -benzol- tricarboxylic  acid,  melts  about 


TRICARBOXYLIC  ACIDS  365 

300°,  and  sublimes  near  300°.  It  is  formed  (i)  when  mesitylenic  and 
uvitinic  acids  are  oxidised  with  a  chromic  acid  mixture ;  (2)  by  heating 
mellitic  acid  with  glycerol,  or  hydro-  and  iso-hydro-mellitic  acid  with 
sulphuric  acid.  A  synthetic  method  for  its  production  consists  in 
(3)  heating  benzol-i,  3,  5-trisulphonic  acid  with  potassium  cyanide,  and 
saponifying  the  resulting  tricyano-benzol.  By  the  condensation  of 
certain  aliphatic  substances  the  acid  and  its  esters  have  been  obtained 
(i)  by  polymerising  propiolic  acid  ;  (2)  by  the  production  of  its  mono- 
methyl  ester  through  the  action  of  caustic  potash  upon  coumalic  acid 
(B.  24,  R.  750)  ;  (3)  its  triethyl  ester  from  formyl-acetic  ester. 

The  intermediate  formation  of  the  latter  may  also  explain  (4)  the 
synthesis  of  trimesinic  acid  ester  from  formic  and  halogen-acetic  esters 
with  zinc  (C.  1898,  II.  472). 

Its  trimethyl  ester  melts  at  143°.     Its  triethyl  ester  melts  at  133°. 

Trimellitic  acid,  (r,  2,  4)-benzol-tricarboxylic  acid. — This  is  obtained 
(together  with  iso-phthalic  acid)  by  heating  hydro-pyro-mellitic  acid 
with  sulphuric  acid,  or  upon  oxidising  xylidic  acid  with  potassium 
permanganate,  also  from  amido-terephthalic  acid  (B.  19,  1635).  It 
is  prepared  most  readily  (along  with  iso-phthalic  acid)  by  oxidising 
colophonium  with  nitric  acid  (A.  172,  97).  It  melts  at  216°,  decompos- 
ing into  water  and  the  anhydride  C6H2(CO2H)(CO)2O.  The  latter 
melts  at  158°. 

Hemi  -  mellitic  acid,  (i,  2,  3)-benzol-tricarboxylic  acid.  —  This  is 
formed  on  heating  hydro-mellophanic  acid  (below)  with  sulphuric 
acid,  as  well  as  in  the  oxidation  of  phenyl-glyoxyl-dicarboxylic  acid, 
formed  from  naphthalic  acid  by  action  of  KMnO4  (B.  29,  283).  It 
melts  at  185°  and  decomposes  into  phthalic  anhydride.  Triethyl  ester, 
m.p.  39°  (B.  29,  R.  283  ;  31,  2084). 

Oxy-tricarboxylic  acids  have  been  obtained  from  the  sulpho-tri- 
carboxylic  acids  :  oxy-trimesie  acid  (A.  206,  204)  ;  oxy-trimellitic  acid 
— see  B.  16,  192. 

The  condensation  of  sodium-acetone-dicarboxylic  ester  into  dioxy- 
phenyl-aceto-dicarboxylic  ester  is  dealt  with  in  connection  with  hydro- 
aromatic  compounds. 

(n)  AROMATIC  TETRACARBOXYLIC  ACIDS. 

The  three  isomerides  are  known.  Reduction  converts  them  into 
tetrahydro-benzol-tetracarboxylic  acids  (see  these). 

Pyro-mellitic  acid,  i,  2,  4,  $-benzene-tetracarboxylic  #aWC6H2(CO2H)4 
-f-2H2O,  melts  when  anhydrous  at  264°,  and  decomposes  into  water 
and  its  anhydride,  which  is  produced  when  mellitic  acid  is  distilled, 
or,  better,  when  the  sodium  salt  is  subjected  to  the  same  treatment 
with  sulphuric  acid.  The  acid  is  also  produced  by  oxidising  durol 
and  durylic  acid  with  potassium  permanganate. 

The   di-anhydride  C6H2(£°^o)2    melts   at    286°.      The   ethyl   ester 

C6H2(C02.C2H5)4  melts  at  53°. 

Dinitro-  and  diamido-hydro-mellitie  tetra-ethyl  esters  melt  at  130° 
and  134°.  Nitric  acid  oxidises  the  diamido-ether  to — 

Quinone-tetracarboxylic  ester  C6(O2)(CO2.C2H5)4,  crystallising  in 
quinone-yellow  needles,  melting  at  149°.  It  is  odourless,  but  sublimes 
quite  readily.  Zinc  reduces  it  in  glacial  acetic  acid  solution  to — 


366  ORGANIC   CHEMISTRY 

Hydroquinone-tetracarboxylic  ester  C6(OH)2(CO2.C2H5)4,  crystallis- 
ing in  bright  yellow  needles,  melting  at  127°.  It  may  be  obtained 
from  sodium-acetone-dicarboxylic  ester  with  iodine  (B.  30,  2570).  In 
alcoholic  solution  it  is  reduced  by  zinc  dust  and  hydrochloric  acid  to 
p-diketo-hexamethylene-tetracarboxylic  ester  (A.  237,  25). 

Prehnitic  acid,  (i,  2,  3,  4)-benzene-tetracarboxylic  acid  C6H2(CO2H)4 
-f2H2O  melts  when  anhydrous  at  237°,  with  the  formation  of  an  an- 
hydride. It  results  (together  with  mellophanic  acid  and  trimesic  acid) 
upon  heating  hydro-  and  iso-hydro-mellitic  acid  with  sulphuric  acid, 
also  by  oxidising  prehnitol  with  potassium  permanganate  (B.  21,  907). 
The  salts  of  this  acid  form  crystals  resembling  the  mineral  prehnite. 

Mellophanic  acid,  (i,  2,  3,  $)-benzene-tetracarboxylic  acid,  melts  at 
238°,  with  anhydride  formation.  It  is  formed  by  the  oxidation  of 
iso-durol  with  KMnO4  ;  see  Prehnitic  acid. 

(12)  AROMATIC  PENTACARBOXYLIC  ACID. 

Benzene-pentacarboxylic  acid  C6H(CO2)H5+6H2O  decomposes 
when  it  is  melted.  It  is  produced  by  oxidising  pentamethyl-benzene 
with  permanganate  (B.  17,  R.  376).  Also  from  charcoal  with  concen- 
trated sulphuric  acid  (C.  1901,  II.  108). 

(13)  AROMATIC  HEXACARBOXYLIC  ACID. 

Mellitic  acid  C6(CO2H)6.  When  heated  it  melts  and  decomposes 
into  water,  carbon  dioxide,  and  pyro-mellitic  anhydride. 

Honey-stone,  found  in  some  lignite  beds,  is  an  aluminium  salt  of 
mellitic  acid,  crystallising  in  large  quadratic  pyramids  of  bright  yellow 
colour  (B.  10,  566). 

An  interesting  formation  of  mellitic  acid  is  that  whereby  pure 
carbon  (graphite,  charcoal,  etc.)  is  oxidised  with  an  alkaline  solution 
of  potassium  permanganate.  Another  is  when  the  carbon  is  applied 
as  positive  electrode  in  electrolysis  (B.  16,  1209),  and  also  the  oxida- 
tion of  hexamethyl-benzol  with  KMnO4. 

As  hexamethyl-benzol  can  be  synthesised,  this  latter  method  of 
formation  would  be  a  synthesis  of  mellitic  acid. 

Mellitic  acid  crystallises  in  fine  silky  needles,  readily  soluble  in 
water  and  alcohol.  It  is  very  stable,  and  is  not  decomposed  by  acids, 
by  chlorine  or  by  bromine,  even  upon  boiling.  It  yields  benzene  when 
distilled  with  lime. 

History. — Klaproth  (1799)  discovered  mellitic  acid  by  boiling 
honey-stone  for  a  long  period  with  water,  and  named  it  honey-stone 
acid.  In  1870  Baeyer  proved  that  mellitic  acid  was  nothing  more  than 
benzol-hexacarboxylic  acid,  in  that,  by  heating  with  lime,  he  obtained 
benzene,  and  by  reduction  found  hexahydro-mellitic  acid  (A.  suppl.,  7,  i). 

Salts  and  Esters. — The  barium  salt  C12Ba3O12+3H2O  is  insoluble 
in  water.  The  methyl  ester  melts  at  187° ;  the  ethyl  ester  melts  at  73°. 

The  chloride  C6(COC1)6  melts  at  190°. 

Mellimide,  paramide  C6(^\Nn)     is  formed  in  the  dry  distilla- 

\C^vJ/  /3> 

tion  of  the  ammonium  salt.     It  is  a  white,  amorphous  powder,  insoluble 
in  water  and  alcohol.      Heated  to  200°  with  water,  it  is  converted  into 


PHENYL-GLYCOLS  367 

the  tri-ammonium  salt  of  mellitic  acid.  The  alkalies  convert  paramide 
into  euchroic  acid. 

Euchroie     acid    C6[(CO)2NH]2{£°'°^     crystallises     in     colourless 

prisms.  Heated  with  water  to  200°,  it  yields  mellitic  acid.  Nascent 
hydrogen  changes  euchroic  acid  to  euchrone,  a  dark-blue  precipitate, 
which  reverts  to  colourless  euchroic  acid  upon  exposure.  Euchrone 
dissolves  with  a  dark-red  colour  in  alkalies. 


3.  Aromatic  Polyalcohols,  containing  more  than  one  Hydroxyl  Group 
in  the  same  Side  Chain,  and  their  Oxidation  Products. 

Of  the  aromatic  polyalcohols,  having  the  hydroxyl  groups  attached 
to  different  carbon  atoms  of  the  same  side  chain,  it  is  only  the  glycols, 
and  their  oxidation  products,  which  have  been  studied  in  any  sense 
completely.  A  more  detailed  classification  of  the  polyhydric  alcohols 
and  their  oxidation  products  is  therefore  unnecessary  ;  the  compounds 
belonging  here  will,  for  practical  considerations,  be  included  with  the 
glycols  and  their  oxidation  products. 

(i)  PHENYL-GLYCOLS  AND  PHENYL-GLYCERIN. 

Phenyl-glycols  are  produced  (i)  from  the  dibromides  or  bromo- 
hydrins  of  the  olefin-benzols  with  potassium  carbonate  or  baryta 
water  ;  (2)  by  gentle  oxidation  of  the  olefin-benzols  with  potassium 
permanganate ;  (3)  by  nuclear  synthesis  in  the  action  of  alkyl- 
magnesium  haloids  upon  aromatic  oxy-acid  esters  and  oxy-ketones,  e.g. 
C6H5CH(OH)C02R  .JEM5U  C6H5CH(OH).C(OH)(CH3)2.  On  heating 
with  dilute  sulphuric  acid  the  i,  2-phenyl-glycols  split  off  water  and 
form  aldehydes  and  ketones,  the  primary-secondary  and  primary- 
tertiary  glycols  becoming  aldehydes  without  transposition,  and  the 
di-secondary  and  secondary-tertiary  glycols  becoming  ketones,  or  alde- 
hydes, with  migration  of  the  phenyl  group  (Tiffeneau,  C.  1907,  I.  1577). 

Styrolene  alcohol  C6H5.CH(OH).CH2.OH,  phenyl-glycol,  melts  at 
67°,  boils  at  273°,  and  is  obtained  from  styrol  dibromide  by  the  action 
of  a  potash  solution.  Dilute  nitric  acid  oxidises  it  to  benzoyl-carbinol 
and  benzoyl-formic  acid  (A.  216,  293). 

Heated  with  dilute  sulphuric  acid,  it  becomes  phenyl-acetaldehyde. 
By  the  action  of  65  per  cent,  sulphuric  acid  two  molecules  are  condensed 
to  j8-phenyl-naphthalin  (g.v.).  Methylene  ether,  b.p.  218°,  from 
phenyl-glycol  and  formaldehyde  (B.  32,  568). 

Sym.  phenyl-methyl-glycol  C6H5CH(OH).CH(OH).CH3,  a-modifi- 
cation,  m.p.  57°,  /^-modification,  m.p.  93°.  This  glycol  occurs,  like 
hydro-benzoin,  in  two  modifications,  generated  from  the  corresponding 
dibromide  (from  n-propyl-benzol) .  Both  modifications,  on  boiling 
with  dilute  H2SO4,  yield  phenyl-acetone,  and,  on  oxidation  with  HNO3, 
phenyl-methyl-glyoxal  (B.  43,  849). 

Unsym.  phenyl-methyl-glycol  C6H5(CH3)COH.CH2OH,  m.p.  41°, 
b.p.  26  161°,  by  methods  i  and  3;  yields  on  heating  with  dilute 
H2SO4  hydratropic  aldehyde  (C.  1907,  I.  1578). 

l-Phenyl-2, 3-propylene-glycol  C6H5CH2.CH(OH).CH2(OH),  b.p.12 
i63°,andl-phenyl-3,4-butylene-glycolC6H5CH2.CH2.CH(OH).CH2(OH), 


368  ORGANIC   CHEMISTRY 

b.p-14  I7S°,  are  formed  by  the  action  of  phenyl-  and  benzyl-magnesium 
bromide  respectively,  upon  glycerin-a-monochloro-hydrin  (C.  1905, 
II.  1752  ;  1907,  I.  1033). 

Sym.  dimethyl-  and  diethyl-phenyl-glyeol  C?H5CH(OH).C(OH)R2, 
m.p.  63°  and  78°,  by  method  3.  On  heating  with  dilute  H2SO4  they 
pass  into  dimethyl-  and  diethyl-phenyl-acetaldehyde  respectively,  with 
"  phenyl  migration  "  (C.  1909,  I.  1335). 

Phenyl-butylene-glycol  C6H5CH(OH)CH2.CH2.CH2(OH),  melting  at 
75°,  is  obtained  by  reduction  from  benzoyl-propionic  aldehyde  and 
benzovl-propyl  alcohol. 

Phenyl-iso-propyl-ethylene-glyeol  C6H5CH(OH)CH(OH)CH(CH3)2, 
melting  at  81°  and  boiling  at  286°,  results  from  the  reduction  of  benz- 
aldehyde  and  iso-butyl-aldehyde. 

Methylene-m,  p-dioxy-benzyl-glycol  [CH202][?,  4]C6H3CH2CH(OH) 
CHo(OH)  melting  at  82°,  and  methylene-m,  p-dioxy-phenyl-ethylene- 
methyl-glyeol  (CH2O2)[3,  4]C6H3.CH(OH).CH(OH).CH3,  melting  at 
101°,  result  from  the  action  of  KMnO4  (B.  24,  3488)  upon  safrol  and 
iso-safrol.  The  corresponding  glycols,  melting  at  68°  and  88°,  are 
obtained  from  anethol,  eugenol,  and  iso-eugenol. 

Stycerine  C6H5.CH(OH).CH(OH).CH2.OH,  a  rubber-like  mass,  is 
obtained  from  styrone  bromide  and  cinnamic  alcohol,  C6H5.CHBr. 
CHBr.CH2.OH,  with  potassium  permanganate  (B.  24,  3491). 

Phenyl-alkylene  oxides  are  obtained  from  the  halogen  hydrins  of 
the  phenyl-glycols  by  treatment  with  alkali.  On  heating  by  themselves, 
or  by  warming  with  dilute  sulphuric  acid,  they  are  converted  into 
aldehydes  or  ketones  (C.  1905,  II.  1628).  _ 

Styrol  oxide,  phenyl-zthylene  oxide  C6H5CH  O.CH2,  b.p.  191°,  from 
phenyl-glycol-iodo-hydrin  and  caustic  potash  ;  gives  phenyl-acetalde- 
hyde  and  diphenyl-diethylene  oxide  with  dilute  acids  (C.  1908,  1.  1776). 

Unsym.  phenyl-methyl-ethylene  oxide  C6H6(CH3)C.O.CH2,  b.p.17 
85°-88°,  converted  into  hydratropic  aldehyde  with  dilute  acids  or  on 
heating'alone  (B.  38,  1969).  _ 

Sym.  phenyl-methyl-ethylene  oxide  C6H5CH.O.CH.CH3,  b.p.15  93°, 
y-Phenyl-propylene  oxide  C6H5CH2CH.O.CH2,  b.p.15  94°-98°  (c-  T9°5, 

II-  237). 

Haloid  Esters  of  the  Phenyl-glycols.  —  (a)  Halogen  Hydrins.  —  Of 

particular  interest  is  the  behaviour  of  the  halogen  hydrins  of  phenyl- 
glycols  in  the  presence  of  silver  nitrate  and  mercuric  oxide  respec- 
tively. While  caustic  alkalies  transform  them,  as  above  mentioned, 
into  the  corresponding  alkylene  oxides  with  elimination  of  hydrogen 
haloids,  the  action  of  silver  nitrate,  or  mercuric  oxides,  with  the  same 
elimination,  produces  aldehydes  and  ketones  respectively,  with  migra- 
tion of  the  phenyl  group  (Tiffeneau,  C.  1907,  I.  1577)  : 

C.H6CH(OH).CHLCH3  -=^U  OCH.CH/™ 

^ 


C«H6\C(OH).CH2I   -=^->  CH3CO.CH2.C6H6. 
CH/ 


That  in  these  transpositions  the  splitting  off  of  HI  probably  takes 
place  at  the  same  carbon  atom,  is  indicated  by  the  fact  that  the  iodo- 


PHENYL-GLYCOLS  369 

hydrin  ethers,  treated  with  mercuric  oxide,  also  pass  into  phenyl- 
vinyl  ethers  with  migration  of  the  phenyl  (C.  1908, 1.  828)  : 

TTT 

CH3OC6H4CH(OC2H6).CHI.CH3 >  C2H5OCH  : 

a-Phenyl-ethylene-j3-iodo-hydrin  C6H5CH(OH).CH2I,  b.p.18  148°- 
152°,  with  decomposition  into  HI  and  aceto-phenone  ;  formed  from 
styrol  (q.v.)  with  iodine,  and  yellow  HgO,  in  aqueous  etheric  solution. 
The  isomeric  a-phenyl-ethylene-a-iodo-hydrin  C6H5CHI.CH2(OH), 
m.p.  79°,  is  obtained  by  the  attachment  of  HI  to  styrol  oxide  (C.  1908, 
I.  42,  1777). 

j3-Phenyl-propylene-glyeol-a-ehloro-hydrm  C6H5(CH3)C(OH) .CH2C1, 
b.p.17  124°,  is  formed  by  the  action  of  C6H5MgBr  upon  chloro-acetone 
and  of  CH3MgI  upon  co-chloro-aceto-phenone,  or  by  the  attachment 
of  hypo-chlorous  acid  to  iso-propenyl-benzol. 

Bromo-hydrin,  b.p.19  141°.  lodo-hydrin,  b.p.12  145°  (C.  1907,  I. 
1200). 

Benzyl-glycol-chloro-hydrin  C6H5CH2CH(OH).CH2C1,  b.p.27  153°, 
by  the  action  of  C6H5MgBr  upon  epi-chloro-hydrih  (C.  1908,  I.  830). 

(b)  Dihaloids. — These  are  formed  by  the  attachment  of  halogens 
to  olenn-benzols.  In  the  dibromides  of  the  olenn-phenols,  and  their 
ethers,  as  in  the  oxy-phenyl  (or  pseudo-phenol)  haloids,  the  bromine 
atom  occupying  the  a-position  towards  the  phenyl  group  is  very  mobile, 
and  by  treatment  with  aqueous  acetone,  sodium  alcoholate,  potassium 
acetate,  aniline,  etc.,  it  can  be  easily  replaced  by  the  groups  OH,  OC2H5, 
OCOCH3,  or  NHC6H5.  The  action  of  concentrated  nitric  acid  upon 
these  dibromides  is  peculiar,  the  a-bromine  atom  migrating  to  the 
nucleus,  and  a-ketones  being  formed.  Thus  anethol  dibromide  yields 
(CH3O)BrC6H3CO.CHBr.CH3  (B.  38,  3458). 

Styrol  dichloride,  a,  p-dichloro-ethyl-benzol  C6H5CHC1CH2C1,  liquid. 
Styrol  dibromide,  m.p.  60°.  Anethol  dibromide  CH3OC6H4CHBr. 
CHBrCH3,m.p.  65°.  Iso-safrol  dibromide  CH2(O)2C6H3CHBr.CHBrCH3, 
liquid  (B.  28,  2719). 

Phenyl-oxalkyl-amines. — These  compounds  have  attained  great 
importance  since  it  has  been  found  that  adrenalin,  a  body  of  great 
physiological  significance,  belongs  to  this  class  of  compounds.  These 
substances  are  obtained  (i)  from  phenyl-glycol  halogen  hydrins  by 
transformation  with  amines  ;  (2)  by  reduction  of  the  aromatic  amido- 
ketones  ;  and  (3)  of  the  oxy-acid  nitriles. 

Phenyl-oxethyl-amine  C6H5CH(OH).CH2NH2.  The  chlorohydrate 
melts  at  177°,  the  picrate  at  154°.  By  reduction  of  mandelic  acid 
nitrile  with  sodium  amalgam  (C.  1908,  I.  430). 

l-Methyl-amido-2-phenyl-2-propanol  C6H5(CH3)C(OH)  .CH2NHCH3, 
b-P-33  I37°J  and  l-methyl-amido-3-phenyl-2-propanol  C6H5CH2.CH 
(OH).CHVNHCH3,  b.p.20  148°,  by  method  i  (C.  1905,  I.  232). 

Ephedrin  C6H5CH  (OH)  .CH (NHCH8) .CH3 (?) ,m.p. 39°;  chlorohydrate, 
m.p.  210°,  has  been  isolated  from  Ephedra  vulgaris  besides  the  stereo- 
isomeric  (?)  pseudo-ephedrin  (B.  22,  1823).  By  heating  with  HC1,  or 
acetic  anhydride,  they  can  be  converted  into  each  other  (C.  1910,  II. 
1480) .  Both  chlorohydrates  decompose  in  dry  heat  into  methyl-amine 
chloride  and  propio-phenone  (C.  1909,  I.  1705). 

3,  4-Dioxy-phenyl-oxethyl-amine      (OH)a[s,  4]C6H3[i]CH(OH).CH2 

VOL.  II.  2  B 


370  ORGANIC  CHEMISTRY 

NH2,  white  crystalline  meal,  melting  at  191°  with  decomposition,  is 
formed  by  the  reduction  of  amido-aceto-pyro-catechin  or  of  proto- 
catechin  -  aldehyde  -  cyano  -  Irydrin  with  sodium  amalgam  (C.  1908, 
I.  430). 

Adrenalin,  suprarenin  (HO)2[3, 4]C6H3[i]CH(OH).CH2NHCH3, 
m.p.  about  216°  with  decomposition,  was  isolated  in  1901  by  J.  Taka- 
mine  (C.  1901,  II.  1354)  from  the  extract  of  suprarenal  capsules,  whence 
the  name  (Latin  renes,  kidneys).  It  is  of  great  physiological  and  phar- 
maceutical importance,  since  even  in  very  small  quantities  it  produces 
a  great  increase  of  the  blood-pressure  and  a  contraction  of  the  peri- 
pheral blood-vessels. 

Adrenalin  is  optically  active,  its  specific  rotatory  power  for  D  being 
— 53 '5°-  It  dissolves  with  difficulty  in  water  and  the  organic  solvents, 
but  easily  in  acids  and  alkalies.  On  heating  with  NaHO,  it  decom- 
poses with  elimination  of  methyl-amine.  Methylation,  and  subsequent 
oxidation,  produce  veratric  acid.  This  settles  its  constitution,  which 
is  confirmed  by  synthesis.  The  latter  starts  from  chloraceto-pyro- 
catechin  (obtained  from  pyro-catechin  and  chloracetyl  chloride) ,  which 
yields  inactive  adrenalin  by  transformation  with  methyl-amine  and 
reduction  with  Al  amalgam  (F.  Stolz,  B.  37,  4149  ;  C.  1905, 1.  315)  : 

/MCO.CH.Cl  rCO.CH2NHCH,  ,CH(OH).CHaNHCH, 

C,H«  {  "£ ->  C6H3  {  [3]OH  >  C,H,  {  OH  >  C,H,  {  OH 

l[4]OH  \OH  I  OH 

The  racemic  adrenalin  so  obtained  can  be  decomposed  into  its 
optically  active  components  by  means  of  its  tartrates.  The  laevo- 
modification  agrees  in  all  its  properties  with  the  natural  product  (Z. 
physiol.  Ch.  58,  189).  It  is  remarkable  that  the  physiological  effects 
of  lasvo-rotatory  adrenalin  are  about  fifteen  times  as  great  as  those  of 
the  dextro-rotatory  modification. 

A  number  of  derivatives  of  adrenalin  have  been  obtained  syntheti- 
cally, and  some  of  them  show  similar  physiological  effects. 

Adrenalin-dimethyl  ether  (CH3O)2C6H3CH(OH).CH2NHCH3,  m.p. 
104°,  and  adrenalin-methylene  ether  CH2(O)2C?H3CH(OH).CH2NHCH3, 
m.p.  96°,  are  obtained  from  the  bromo-hydrins  of  the  corresponding 
olefin-phenol  ethers,  by  transformation  with  methyl-amine  (C.  1910, 
I.  2115). 

(2)  PHENYL-ALCOHOL  ALDEHYDES. 

Just  as  two  molecules  of  acetaldehyde  condense  to  aldol,  so  the 
nitro-benzaldehydes  combine  with  acetaldehyde,  under  the  influence 
of  very  dilute  sodium  hydroxide  (2  per  cent.)  to  the  corresponding 
aldols,  the  nitro-phenyl-lactic  acid  aldehydes  NO2C6H4CH(OH)CH2CHO, 
which  unite  with  an  additional  molecule  of  acetaldehyde.  Dehydrating 
agents,  like  acetic  anhydride,  convert  them  into  the  corresponding 
nitro-cinnamic  aldehydes  (B.  18,  719). 

o-Oxy-mandelie  aldehyde,  o-oxy-phenyl-glyeol  aldehyde  HO[2]C6H4 
CH(OH)CHO,  m.p.  64°,  has  been  obtained  from  cumarone  dichloride 
by  splitting  up  with  sodium  acetate  (A.  313,  96). 

Phenyl-glyeerin  aldehyde  C6H5CH(OH)CH)OH(CHO ;  its  dimethyl- 
acetal,  m.p.  80°,  is  formed  by  oxidation  of  cinnamic  aldehyde-acetal 
with  permanganate  ;  phenyl-hydrazone,  m.p.  170°  (B.  31, 1995). 


PHENYL   KETOLS  371 

Phenyl-tetrose  C6H5.CH(OH)CH.OH.CH(OH).COH  is  a  colourless 
syrup  resulting  from  the  reduction  of  phenyl-trioxy-butyric  acid  lactone 
(q.v.).  Its  phenyl-hydrazone  melts  at  154°. 

(3)  PHENYL  KETOLS. 

Aceto-phenone  alcohol,  benzoyl-carbinol  CgHg.CO.CHg.OH,  cry- 
stallises from  water  and  dilute  alcohol  in  large,  brilliant  flakes,  which 
contain  water  of  crystallisation,  and  melt  at  73°.  It  crystallises  from 
ether  in  shining  anhydrous  plates,  and  melts  at  85°.  It  is  produced 
in  the  oxidation  of  phenyl-glycol,  and  from  its  chloride,  o>-chloraceto- 
phenone,  by  its  conversion  into  acetate  and  saponification  with  potas- 
sium carbonate  (B.  16,  1290  ;  39,  2294).  Also  from  co-diazo-aceto- 
phenone  by  means  of  dilute  H2SO4;  and  by  the  action  of  benzene  and 
A1C13  upon  acetyl-gly colic  acid  chloride  (A.  368,  89). 

When  distilled  it  decomposes,  with  formation  of  bitter-almond  oil. 
Being  a  ketone,  it  forms  crystalline  compounds  with  primary  alkaline 
sulphites.  With  hydroxylamine  it  forms  an  oxime,  melting  at  70°; 
with  phenyl-hydrazin,  a  phenyl-hydrazone,  m.p.  112° ;  and  further,  the 
osazone  of  phenyl-glyoxal.  Like  acetyl-carbinol,  it  reduces  a  cold 
ammoniacal  silver  or  copper  solution  (forming  benzaldehyde  and  ben- 
zoic  acid),  and  is  oxidised  to  mandelic  acid  (B.  14,  2100).  Nitric 
acid  oxidises  it  to  phenyl-glyoxylic  acid.  It  yields  cyano-hydrin 
with  CNH,  which  then  forms  a-phenyl-glyceric  acid,  or  atro-glyceric 
acid  (q.v.). 

C6H5C(O.CH3)— O— CH2 

Bis-methyl-benzoyl-earbinol  ,  melt- 

CH2- 0-C(OCH3)C6H5  (?) 

ing  at  192°,  is  formed  from  benzoyl-carbinol  with  methyl  alcohol  and 
hydrochloric  acid  (B.  28,  1161). 

Benzoyl-carbinol  acetate  C6H5CO.CH2.O.COCH3  melts  at  49°  and 
boils  at  270°.  The  benzoate  melts  at  117°.  The  phenyl  ether  melts 
at  72°. 

co-Chloro-aceto-phenone,  phenacyl  chloride,  benzoyl-carbinol  chloride 
C6H5COCH2C1,  melting  at  59°  and  boiling  at  245°,  results  from  the 
chlorination  of  boiling  aceto-phenone  (B.  10,  1830),  as  well  as  from 
benzene,  chloracetyl  chloride,  and  aluminium  chloride. 

o)-Bromo-aceto-phenone,  phenacyl  bromide  C6H5.CO.CH2Br,  melting 
at  50°,  attacks  the  mucous  membrane  quite  powerfully.  It  is  obtained 
from  aceto-phenone  and  bromine,  also  by  heating  dibromatro-lactinic 
acid  with  water  (B.  14, 1238).  An  excess  of  alcoholic  ammonia  changes 
it  to  iso-indol — a  hydrazin  derivative.  With  methyl-ethyl  sulphide 
it  combines  to  phenacyl-methyl-ethyl-sulphinium  bromide  C6H5COCH2S 
(CH3)(C2H5)Br,  which  may  be  split  up  into  optically  active  components 
by  means  of  bromo-camphor-sulphonic  acid  (see  unsym.  sulphur 
atom,  C.  1900,  II.  960).  The  acid  amides  and  thiamides  change  the 
co-haloid  aceto-phenones  into  oxazole  and  thiazole  derivatives  (q.v.). 
With  excess  of  alcoholic  ammonia,  'phenacyl  bromide  passes  into 
diphenyl-dihydro-pyrazin. 

Gallo-chloro-aeeto-phenone  C6H2(OH)3COCH2C1,  and  co-bromo- 
resaeeto-phenone,  containing  the  hydroxyl  group  in  the  ortho-position, 
part  with  halogen  hydrides,  and  become  cumarone  derivatives  (B. 
30,  299). 


372  ORGANIC  CHEMISTRY 

o)-Iodo-aeeto-phenone,  phenacyl  iodide  C6H5COCH2I,  m.p.  30°, 
from  o>-chloro-  or  bromo-aceto-phenone  with  potassium  iodide  (C.  1899, 
1.559;  B.  32,  532).  It  forms  with  Ag  nitrite  : 

co-Nitro-aeeto-phenone  C6H5COCH2.NO2,  m.p.  108°.  This  is  also 
obtained  from  its  dimethyl-acetal  C6H5C(OCH3)2CH2.NO2,  m.p.  56° 
(B.  36,  2558).  In  potash  it  dissolves  to  form  the  salt  C6H5COCH  : 
NOOK.  Stannous  chloride  reduces  it  to — 

co-Amido-aeeto-phenone  C6H5.CO.CH2.NH2  which  is  unknown 
in  a  free  condition.  The  chlorohydrate  C6H5.CO.CH2.NH2HC1, 
melting  at  183°,  is  formed  when  the  iso  -  nitroso  -  aceto  -  phenone 
is  reduced  with  tin  and  hydrochloric  acid  (B.  28,  254),  or  by  the 
breaking  up  of  phthalimino-aceto-phenone  C6H4(CO)2NHCH2COC6H5 
with  concentrated  HC1.  The  free  o>  -  amido  -  aceto  -  phenone  is 
unstable,  like  the  a-amido-ketones  of  the  aliphatic  series.  Liber- 
ated from  its  chlorohydrate  with  NaHO,  or  ammonia,  it  immedi- 
ately splits  off  water  and  passes  into  diphenyl  -  dihydro  -  pyrazin 

C6H6C^^r^^CC6H5  which  is  also  obtained,  with  small  quantities 

of  diphenaeyl-amine  (C6H5COCH2)2NH,  m.p.  75°,  by  the  action  of 
ammonia  upon  co-bromo-aceto-phenone.  Heating  with  HC1  regenerates 
the  chlorohydrate.  With  excess  of  NaHO  it  loses  water,  and  easily 
passes  into  a  base  isomeric  with  diphenyl-dehydro-pyrazin,  probably 
3,  5-diphenyl-4-amido-pyrrol  NH<(CH==C.NH2  (R  ^  ^  With 

\C(C6rl5)  :  U.L/6H5 

sodium  nitrite  the  w-amido-aceto-phenone  chloride  yields  o>-diazo- 
aeeto-phenone,  benzoyl-diazo-methane  c6H6COCH<^v,  m.p.  50°,  which 

also  results  from  benzoyl-acetone-diazo-anhydride  by  splitting  up 
with  ammonia.  Diazo-aceto-phenone,  on  boiling  with  dilute  H2SO4, 
is  decomposed  into  N2  and  benzoyl-carbinol.  With  iodine  it  yields 
a>-di-iodo-aceto-phenone  C6H5COCHI2 ;  with  KCN  it  forms  a  potas- 
sium salt  of  phenacyl-azo-eyanide  C6H6COCH2N  :  NCN,  colourless 
crystals,  m.p.  72°  with  decomposition,  which,  with  H2SO4,  yields 
phenaeyl-azo-earbonamide  C6H5.COCH2N  :  NCONH2,  m.p.  217°  with 
decomposition  (A.  325, 141). 

co-Methyl-amido-,  dimethyl-amido-aceto-phenone,  and  co-trimethyl- 
amido-aceto-phenone  bromide  C6H5COCH2N(CH3)Br  are  generated 
from  phenacyl  bromide  with  mono-,  di-,  and  trimethyl-amine  (C.  1899, 
I.  1284). 

co-Aceto-phenone-anilide,  phenacyl-anilide  C6H5.CO.CH2NHC6H5, 
m.p.  93°,  from  eo-bromo-aceto-phenone  and  aniline  (B.  15,  2467),  may 
be  condensed  to  a-phenyl-indol  (B.  21,  1071,  2196,  2595). 

p-Amido-benzoyl-carbinol  NH2[4]C6H4COCH2OH,  m.p.  165°,  is 
obtained  by  transforming  a  body  obtained  synthetically  from  acet- 
anilide  and  chloracetyl  chloride  by  means  of  A1C13,  viz.  p-acetamido- 
phenacyl  chloride  CH3CONHC6H4COCH2C1,  m.p.  212°  (B.  33,  2644). 

a-Amido-propio-phenone  C6H5.CO.CH(NH2)CH3,  chlorohydrate, 
m.p.  183°,  by  reduction  of  iso-nitroso-propio-phenone,  or  from  phthalyl- 
alanyl  chloride,  benzol,  and  A1C13.  Like  co-amido-aceto-phenone,  the 
free  base  liberates  water  and  passes  spontaneously  into  2,  $-dimethyl- 

3,  6-diphenyl-dihydro-pyrazin  C6H6C<^~™(^^)cc6H6,  from  which 
HC1  generates,  besides  some  of  the  original  amido-ketone,  the  isomeric 


PHENYL  KETOLS  373 

a-amido-a-phenyl-acetone  C6H5CH(NH2)COCH3,  which  may  be  ob- 
tained by  reduction  of  the  iso-nitroso-phenyl-acetone  (B.  41,  1146). 

Phenyl-aeetyl-carbinol  C6H5CH(OH)COCH3,  b.p.tt  135°,  from  a- 
bromo-benzyl-methyl-ketone  C6H5CHBrCOCH3  by  way  of  the  acetate 
(C.  1904,  I.  24). 

a-Benzyl-amido-acetone  C6H5CH2CH(NH2)COCH3  whose  chloro- 
hydrate  melts  at  127°,  is  formed  by  reduction  of  iso-nitroso-benzyl- 
acetone  (B.  40,  4666). 

Corresponding  to  the  nitro-phenyl-lactic  aldehydes  we  have  o-  and 
p-nitro-phenyl-laetie  ketones,  m.p.  69°  and  58°,  the  condensation  pro- 
ducts of  o-  and  p-nitro-benzaldehyde  and  acetone,  in  the  presence  of 
very  dilute  NaHO.  By  boiling  with  water  or  by  excess  of  NaHO  the 
o-nitro-ketone  is  converted  into  indigo  (q.v.)  with  rejection  of  acetic 
acid  and  water  (B.  16,  1968).  See  also  Nitro-benzylidene-acetones. 

a>-Chloraceto-pyro-cateehin  (OH)2[3,  4]C6H3COCH2C1,  m.p.  173°, 
from  pyro-catechin  and  chloracetyl  chloride,  yields  with  methyl-amine 
co-methyl-amido-aceto-pyro-catechin  (OH)2C6H3COCH2NHCH3,  chloro- 
hydrate,  m.p.  240°  (B.  37,  4152). 

BenzoyMwtyl-carbinol  C6H5.CO.[CH2]3.CH2OH,  m.p.  40°  (B.  23, 
R.  500). 

j3-Amido-propio-phenone  C6H5COCH2.CH2NH2,  chlorohydrate,  m.p. 
128°,  is  formed  from  a-phthalyl-anyl  chloride,  benzene,  and  A1C13. 
NaHO  liberates  the  free  base  as  an  oil  (B.  41,  244). 

y-Amido-butyro-phenone  C6H5CO.CH2.CH2.CH2NH2  is  unstable ; 

it   passes   spontaneously   into   2-phenyl-pyrrolin  ceH5C^^~ £^a   (B. 

41,  513)  with  liberation  of  water.  A  similar  dehydration  occurs  in 
S-amido-valero-phenone  C6H5COCH2.CH2.CH2.CH2NH2,  from  phthal- 
imido-valerianic  acid,  which  is  easily  reduced  to  2-phenyl-tetra-hydro- 
pyridin.  On  the  other  hand,  €-amido-capro-phenone  C6H5CO[CH2]4 
CH2NH2,  whose  chlorohydrate  melts  at  154°,  shows  no  tendency  to 
split  off  water.  The  free  base  is  an  oil  volatile  in  steam,  and  has  a 
peculiar  odour  (B.  41,  2014). 

Triphenyl-acyl-methyl-amine  [C6H5COCH2CH2]3N,  chlorohydrate, 
m.p.  201°,  is  formed  on  heating  aceto-phenone,  AmCl,  and  formaldehyde 
solution  ;  on  distilling  with  steam,  it  decomposes,  forming  phenyl- 
vinyl-ketone  (B.  39,  2181). 

(4)  PHENYL-ALDEHYDE  KETONES. 

a-Ketone-aldehydes.  —  Phenyl-glyoxal,  benzoyl-formaldehyde  C6H5- 
CO.CH(OH)2,  melts  at  73°.  The  anhydrous  aldehyde  boils  at  142° 
(125  mm.).  It  has  a  penetrating  odour.  It  is  obtained  from  its 
aldoxime,  iso-nitroso-aceto-phenone,  upon  boiling  the  sodium  sulphite 
derivative  with  dilute  sulphuric  acid  (B.  22,  2557).  Alkalies  convert 
it  into  almond  acid  ;  potassium  cyanide  condenses  it  to  benzoyl- 
formoin,  just  as  it  changes  benzaldehyde  to  benzoin.  It  yields  quin- 
oxalins  with  o-diamines. 

w-Diehloro-aceto-phenone  C6H5.CO.CHC12  boils  at  253°  (B.  10, 
531).  a;-Dibromo-aeeto-phenone  C6H5.CO.CHBr2.,  m.p.  36°  (B.  10, 
2010  ;  A.  195,  161).  co-Dibromo-p-iodo-aceto-phenone  (B.  24,  997). 
co-Dichloro-o-nitro-aceto-phenone  melts  at  73°  (A.  221,  328).  o>-Di- 


374  ORGANIC  CHEMISTRY 

bromo-o-,  m-,  and  p-nitro-aceto-phenone  melt  at  85°,  59°,  and  98° 
(B.  20,  2203  ;   18,  2240  ;   22,  204). 

Iso-nitroso-aceto-phenone,  benzoyl-formoxime  C6H5CO.CH(N.OH), 
m.p.  127°,  is  obtained  from  aceto-phenone  (B.  24,  1382  ;  25,  3459  ; 

A.  358,  56).     It  forms  diphenyl-pyrazin  (q.v.)  by  reduction.     Phenyl- 
glyoxime    C6H5C(NOH).CH(NOH)    is    known    in    two    modifications 
(compare  benzile  dioximes)  : 

C6H5.C C.H       ?  C6H5.C— C.H      .?. 

N.OHN.OHM  HO.N    N.OH  U 

Phenyl-amphi-glyoxime,  m.p.  168°     Phenyl-anti-glyoxime,  m.p.  180°. 

Phenyl-amphi-gryoxime  is  produced  when  hydroxylamine  acts 
upon  oj-dibromo-aceto-phenone  and  iso-nitroso-aceto-phenone.  When 
treated  in  absolute  ether  with  hydrochloric  acid  gas,  it  changes  to  the 
anti-modification,  which  reverts  to  the  amphi-modification  by  recrystal- 
lisation  from  indifferent  solvents  (B.  24,  3497).  See  also  Phenyl- 
furoxane. 

a-Phenyl-glyoxal-phenyl-hydrazone  C6H5C(NNHC6H5)CHO  (?),m.p. 
142°,  from  phenyl-glyoxal  with  phenyl-hydrazin,  and  the  /Miydrazone 
C6H5COCH  :  NNHC6H5,  two  modifications  easily  converted  into  each 
other,  m.p.  138°  and  114°,  from  benzoyl-acetic  acid  with  diazo-benzol 
(B.  22,  2557  ;  34,  2001). 

Phenyl  -  glyoxal  -  phenyl  -  osazone  C6H5 .  C  :  (N .  NH .  C6H5) .  CH  : 
(N.NHC6H5)  melts  at  152°.  (See  Benzoyl-carbinol-phenyl-hydrazone, 

B.  22,  2258).      Phenyl-glyoxal-methyl-phenyl-osazone  melts  at  152° 
(B.  21,  2597). 

p-Toluic  formaldehyde  CH3C6H4CO.CH(OH)2  melts  at  101°  (B. 
22,  2560). 

( [i]C— CHO 

Anthroxan-aldehyde  C6Hj      |  \o     ,  melting  at  72°,  is   formed 

I  [2]« 

from  o-nitro-phenyl-glycidic  acid  (B.  16,  2222)  (compare  anthranile). 

jS-Ketone-aldehydes. — Formyl-aceto-phenone,  or  benzoyl-acetaldehyde, 
was  formerly  regarded  as  j8-ket one-aldehyde,  in  which,  as  in  formyl- 
acetone,  an  unsaturated  ketol,  oxy-methylene-aceto-phenone,  is  present. 
This  will,  therefore,  be  discussed  later  in  connection  with  the  com- 
pounds containing  an  unsaturated  side  chain.  The  sodium  salt  of 
oxy-methylene-aceto-phenone  and  hydroxylamine  hydrochloride  yield 
benzoyl-aeetaldoxime  C6H5.CO.CH2.CH  :  N.OH,  melting  at  86°,  which 
acetic  anhydride  converts  into  cyanaceto-phenone  and  acetyl  chloride 
into  the  isomeric  phenyl-isoxazole. 

y-Ketone-aldehydes.  —  Benzoyl-propio-aldehyde  C6H5CO.CH2.CH2. 
CHO  boils  at  245°. 

(5)  PHENYL-PARAFFIN  DIKETONES. 

a-Diketones,  or  ortho-diketones,  are  produced  from  their  monoximes, 
the  phenyl-iso-nitroso-ketones  (compare  phenyl-glyoxal)  by  distillation 
with  dilute  acids,  or  by  digesting  with  amyl  nitrite  (B.  21,  2177). 
Benzoyl-acetyl  C6H5.CO.CO.CH3,  boiling  at  214°,  is  a  yellow  oil  with  a 
peculiar  odour  (B.  21,  2119,  2176).  It  is  formed  by  the  oxidation  of 
the  two  stereo-isomeric  phenyl-methyl-glycols  with  NO3H  (B.  43,  855). 
Acetyl-benzoyl-aeeto-hydrazone  CH3CO.C(NNHCOCH3)C6H5,  m.p.  154°, 
is  dissolved  in  NaHO  to  the  sodium  salt  of  a  pseudo-form  (B.  36,  3187). 


PHENYL-PARAFFIN   DIKETONES  375 

a-Oximido-propio-phenone  C6H5.CO.C  :  (NOH).CH3,  melting  at  113°, 
results  from  the  action  of  nitrous  acid  upon  methyl-benzoyl-acetic  ester, 
or  by  the  action  of  diazo-benzol  chloride  upon  an  alkaline  solution  of 
iso-nitroso-acetone,  probably  with  intermediate  formation  of  a  phenyl- 
azo-aldoxime  (B.  40,  737)  : 

CH3COCH  :  NOH >  [CH3COC(  :  NOH).N  :  NC6H5] >  CH3COC( :  NOH)C6H5. 

jS-Oximido-propio-phenone,  iso-nitroso-phenyl-acetone  C6H5C  :  (NOH) 
COCH3,  from  phenyl-acetone,  with  amyl  nitrite  and  sodium  alcoholate. 

Phenyl-methyl-glyoxime  C6H5C  :  (NOH)C  :  (NOH)CH3,  m.p.  118° 
(A.  291,  280).  p-Methoxy-phenyl-methyl-glyoxime  CH3O[4]C6H4C 
(NOH).C(NOH)CH3,  m.p.  206°  with  decomposition,  is  formed,  beside 
the  corresponding  peroxide,  m.p.  97°,  from  anethol  with  nitrous  acid 
(A.  329,  262). 

The  p-  or  meta-diketones  result,  together  with  aceto-phenone,  (i) 
from  the  decomposition  of  the  benzoyl-aceto-acetic  esters  (B.  16,  2239)  ; 
further,  by  (2)  a  remarkable  condensation  induced  by  sodium  alcoholate 
(Claisen,  B.  20,  2178). 

The  jS-diketones  behave  like  the  j3-diketones  of  the  fatty  series. 
They  dissolve  in  alkalies.  This  distinguishes  them  from  the  other 
diketones.  They  are  coloured  an  intense  red  by  ferric  chloride.  They 
condense  to  isoxazols  with  hydroxylamine  (B.  21,  1150).  They  form 
pyrazol  compounds  with  phenyl-hydrazin,  just  like  the  oxy-methylene- 
j8-ketones. 

Benzoyl-acetone,  acetyl-aceto-phenone  C6H5.CO.CH2.CO.CH3,  melts 
at  6i°-6o°,  boils  at  26o°-262°,  and  readily  volatilises  with  steam.  It 
is  formed  from  benzoyl-aceto-acetic  ester,  from  ethyl  benzoate  and 
acetone,  or  ethyl  acetate  and  aceto-phenone  with  sodium  ethylate,  free 
from  alcohol.  See  B.  27,  1571,  for  the  addition  of  CNH  to  benzoyl- 
acetone.  See  /.  pr.  Ch.  2,  48,  489,  for  the  action  of  urea  and  guanidin. 

The  Cu-compound  of  benzoyl-acetone  gives,  with  SC12  :  thio- 
benzoyl-acetoneS[CH(COCH3)COC6H5]2,m.p.  95°;  with  S2C12  :  dithio- 
benzoyl  acetone  S2[CH(COCH3)COC6H5]2,  m.p.  118°  (C.  1903,  II.  243). 
o-Nitro-benzoyl-aeetone,  m.p.  55°  (A.  221, 332).  Benzoyl-nitro-acetone, 
in  the  form  of  its  oxime  C6H5C(NOH).CH(NO2)COCH3,  results  from 
benzylidene-acetone  when  treated  with  N2O3  (B.  36,  3021). 

Propionyl-,  butyryl-,  iso-butyryl-,  and  valeryl-aeeto-phenones  boil  at 
172°  (30  mm.),  174°  (24  mm.),  170°  (26  mm.),  and  183°  (30  mm.) 
(B.  20,  2181). 

Phenyl-acetyl-acetone  CnHj2O2-C6H5.CH2.CO.CH2.CO.CH3,  boiling 
at  266°,  results  from  the  decomposition  of  phenyl-acetyl-aceto-acetic 
ester  (B.  18,  2137). 

The  following  is  a  y-diketone  : 

Aceto  -  phenone  -  acetone,  phenacyl-acetone  C6H5.CO.CH2.CH2.CO. 
CH3,  is  obtained  from  aceto-phenone-aceto-acetic  ester.  It  is  a 
yellow  oil,  boiling  with  decomposition  (B.  17,  2756). 

Being  a  y-diketone,  it  can  split  off  water  and  yield  phenyl-methyl- 
furfurane,  phenyl-methyl-thio-phene,  and  phenyl-methyl-pyrrol. 

Triketones.— Phenyl-methyl-triketone,  phenyl-triketo-butane,  b.p.24 
138°,  is  a  reddish-yellow  oil,  combining  easily  with  water  to  a  colourless 
hydrate  melting  at  54°-58°.  With  acetyl-acetone  and  similar  bodies 
it  forms  addition  products.  It  reduces  copper  salts.  Phenyl-triketo- 


376  ORGANIC   CHEMISTRY 

butane  was  obtained  by  the  disintegration  of  its  dimethyl-amido-anile 
C6H5COC[NC6H-N(CH3)2]COCH3,  m.p.  99°,  formed  from  benzoyl- 
acetone  with  nitroso-dimethyl-aniline.  With  diazo-benzol,  benzoyl- 
acetone  forms  phenyl-azo-benzoyl-aeetone  C6H5COC(HN2C6H5)COCH3, 
m.p.  99°.  With  HNO2  it  gives  iso-nitroso-benzoyl-acetone  C^COC 
(NOH)COCH3,  m.p.  125°.  This  gives,  by  reduction  with  zinc  and 
sulphuric  acid,  benzoyl-amido-acetone,  and  this  again,  treated  with 

HNO2,  gives  benzoyl-aeetone-diazo-anhydride  N^N— CCQC  H  ' m>p'  66°' 
'This  diazo-anhydride  is  split  up  by  ammonia  into  acetic  acid  and 
diaceto-phenone,  and  by  boiling  with  water  and  transposition  into 
nitrogen,  CO2  and  benzyl-methyl-ketone  C6H5CH2COCH3  ;  for  further 
transformations,  see  Heterocyclic  compounds :  furo-[a  b]-diazols  (A. 
325,  136). 

Phenacyl-diacetyl-methane  C6H5COCH2CH(COCH3)2,  m.p.  58°,  from 
phenacyl  bromide  and  sodium-acetyl-acetone,  is  both  a  i,  3-  and  a  i,  4- 
diketone,  and  therefore  yields  both  isoxazols  and  pyrazols,  as  well  as 
furfuranes  and  pyrrols  (C.  1902,  I.  1164). 

Tetraketones.— Benzal-bis-aeetyl-acetone  C6H5CH[CH(COCH3)  2]  2 
results  from  the  condensation  of  benzaldehyde  with  acetyl-acetone  in 
the  presence  of  piperidin,  and  has  been  obtained  in  the  six  possible 
allotropic  modifications  of  the  keto-  and  enol  forms  with  the  corre- 
sponding as-  and  trans-iorms  (C.  1900,  I.  1099). 

(6)  PHENYL-PARAFFIN  ALCOHOL  ACIDS. 

A.  Monoxy-alcohol  Acids. — Phenyl-alcohol-carboxylic  acids,  like 
the  aliphatic-alcohol  acids,  are  produced  (i)  by  the  reduction  of  the 
corresponding  ketonic  acids  ;  (2)  from  aldehydes  and  ketones  (B.  12, 
815)  by  the  addition  of  hydrocyanic  acid  and  the  saponification  of  the 
a-oxy-acid  nitrile  ;  (3)  from  the  corresponding  monohalogen  acids  ; 
(4)  from  unsaturated  monocarboxylic  acids,  etc. 

a-  and  j3-0xy-acids. — Almond  acid,  phenyl-glyeollie  acid  C6H5. 
*CHOH.CO2H,  is  isomeric  with  the  cresotinic  acids,  and  the  oxy-methyl- 
benzoic  acids,  or  carbinol-benzoic  acids.  It  contains  an  asymmetric 
carbon  atom,  and  therefore,  like  the  lactic  acid  of  fermentation, 
appears  in  one  inactive,  decomposable,  and  two  optically  active 
modifications. 

Para-mandelic  acid,  inactive  mandelic  acid,  melting  at  118°,  is  formed 
(i)  from  benzaldehyde,  prussic  acid,  and  hydrochloric  acid  (B.  14,  239, 
1965)  ;  (2)  from  benzoyl-formic  acid,  by  reduction  with  sodium 
amalgam  ;  and  (3)  from  phenyl-chloracetic  acid  by  boiling  it  with 
alkalies  (B.  14,  239),  (4)  as  well  as  from  w-dibromo-aceto-phenone  or 
phenyl-glyoxal  by  the  action  of  alkalies  : 

C6H5.CO.CHO >  C6H5.CHOH.C02H. 

The  production  of  alcohol  and  carboxylic  acid,  which  completes 
itself  extra-molecularly  in  the  action  of  caustic  alkali  upon  benzaldehyde, 
in  the  case  of  the  conversion  of  phenyl-glyoxal  into  mandelic  acid 
proceeds  intra-molecularly.  See  below  for  the  formation  of  para- 
mandelic  acid  from  laevo-  and  dextro-mandelic  acids. 

One  hundred  parts  water  at  20°  dissolve  15-9  parts  of  para-mandelic 


PHENYL-PARAFFIN   ALCOHOL  ACIDS  377 

acid.  Dilute  nitric  acid  converts  it,  first,  into  benzoyl-formic  acid, 
then  into  benzoic  acid.  When  heated  with  hydriodic  acid  it  forms 
phenyl-acetic  acid  ;  with  hydrobromic  and  hydrochloric  acids  chloro- 
phenyl  or  bromo-phenyl-acetic  acids  are  formed.  On  the  decomposi- 
tion of  mandelic  acid  by  sulphuric  acid,  see  C.  1903,  II.  284. 

L<zvo-  and  dextro-mandelic  acids  melt  at  133°.  They  have  equal, 
but  opposite,  molecular  rotatory  power.  Towards  reagents  they  behave 
like  para-mandelic  acid.  Laevo-mandelic  acid,  natural  mandelic  acid, 
results  upon  digesting  amygdalin  (q.v.)  with  fuming  hydrochloric  acid 
(1848  :  Wohler,  A.  66,  240).  Fermentation  of  ammonium-para-mande- 
late  with  Penicillium  glaucum  destroys  the  laevo-acid,  and  there  remains 
the  dextro-acid.  Schizomyceten  first  destroys  the  dextro-mandelic  acid 
in  para-mandelic  acid  ;  the  laevo-acid  remains  (Lewkowitsch,  B.  17, 
2723).  The  direct  splitting  up  of  para-mandelic  acid  into  the  dextro- 
and  laevo-acids  can  be  brought  about  by  the  crystallisation  of  the 
cinchonine  salt.  The  mixing  together  of  the  dextro-  and  laevo-acids 
(molecular  quantities)  results  in  the  formation  of  inactive  para-mandelic 
acid.  When  the  dextro-  or  laevo-acid  is  heated  in  a  tube  to  160°  it  is 
converted  into  the  inactive  mandelic  acid. 

A  direct  transformation  of  the  two  active  forms  into  each  other  is 
accomplished  as  follows  : — With  PC15,  d-mandelic  acid  gives  1-phenyl- 
chloracetic  acid,  and  this,  with  NH3,  gives  d-phenyl-alanin,  which  is 
converted  into  1-mandelic  acid  by  means  of  HNO2  (Walden's  reversal, 
Vol.  I.).  The  transformation  of  1-mandelic  acid  into  the  dextro-form 
is  done  in  a  similar  manner  (C.  1909,  II.  23). 

Derivatives  of  Para-mandelic  Acid. — The  methyl  and  ethyl  esters 
melt  at  52°  and  34°  (B.  28,  259).  Amide,  m.p.  131°  (B.  25,  2212). 
Hydrazide,  m.p.  132°,  gives,  with  HNO2,  the  very  unstable  azide,  which, 
in  contrast  with  other  carboxylic  azides,  decomposes  with  alcohol  into 
benzaldehyde,  N2,  and  allophanic  acid  ester  (B.  34,  2794).  Methyl- 
ether  acid,  m.p.  71°.  Dimethyl-ether  ester,  m.p.  246°  (A.  220,  40). 
Diethyl-ether  ester,  see  C.  1899,  II.  622.  Aeetyl-mandelie  acid,  m.p. 
80°.  Acetyl-mandelic  chloride,  b.p.12 132° ;  amide,  m.p.  112° ;  anilide, 
m.p.  117-5°;  ethyl  ester,  m.p.  74°  (A.  368,  57). 

Mandelic  chloralide,  m.p.  82°  (A.  193,  40).  Diphenyl-glycolide 
C6H5CH<^^^CHC6H5,  m.p.  240°,  from  mandelic  acid  in  pyridin  with 

phosgene  (B.  35,  3642). 

Mandelic  acid  nitrile  C6H5.CHOH.CN  is  a  colourless  oil,  solidifying 
at  — 10°.  At  170°  it  breaks  down  into  prussic  acid  and  benzaldehyde. 
Like  mandelic  acid,  the  nitrile  is  also  obtained  in  a  laevo-  and  a  dextro- 
form,  from  which,  by  saponification  and  reversal,  active  mandelic 
acids  can  be  prepared. 

On  standing  with  fuming  hydrochloric  acid  it  passes  into  the 
amide  ;  and,  when  heated,  into  phenyl-chloracetic  acid  (B.  14,  1967). 
It  condenses  with  benzaldehyde  in  different  ways :  by  the  action  of 
alcoholic  dilute  HC1  to  C6H5CH[OCH(CN)C6H5]2,  and  by  the  action  of 
etheric  HC1  to  diphenyl-oxazol  and  benzylidene-mandelic  amide 
C6H5CH  :  NCOCH(OH)C6H5  (B.  29,  207,  R.  791 ;  35,  1590). 

Derivatives  of  mandelic  acid  are  trichloro-methyl-  and  tribromo- 
methyl-phenyl-carbinol  CC13CH(OH)C6H5,  b.p.25  155°,  and  CBr3CH 
(OH)C6H5,  m.p.  78°  ;  these  compounds  are  prepared,  in  a  manner 


378  ORGANIC   CHEMISTRY 

analogous  to  acetone-chloroform,  by  combination  of  benzaldehyde 
with  CC13H  and  CBr3H,  by  means  of  caustic  potash,  or  by  the  action 
of  C6H5MgBr  upon  chloral ;  they  are  convertible  into  mahdelic  acid, 
or,  by  reduction  with  zinc  dust,  into  styrol  and  halogen  styrols  (C.  1900, 
II.  326)  ;  on  boiling  with  potassium  carbonate  they  decompose  into 
CHC13  (or  CHBr3)  and  benzaldehyde  (C.  1908,  I.  1388). 

p-Dimethyl-amido-phenyl-trichlor-ethyl  alcohol  (CH3)  2NC6H4CH 
(OH)CC13,  from  dimethyl-aniline  and  chloral  (B.  19,  365)  ;  p-dimethyl- 
amido-mandelie  nitrile  (CH3)2N[4]C6H4CH(OH)CN,  m.p.  114°,  from 
p-dimethyl-amido-benzaldehyde  (B.  35,  3571). 

p-Bromo-  and  p-iodo-mandelic  acids  melt  at  117°  and  133°  (B.  24, 
997  ;  23,  3467).  o-,  m-,  and  p-Nitro-mandelic  acids  melt  at  140°,  119°, 
and  126°  (B.  20,  2203  ;  22,  208).  For  a  peculiar  reduction  product 
of  the  latter,  see  B.  41,  373. 

o-Amido-mandelic  acid,  hydrindic  acid  NH2[2]C6H4CH(OH)CO2H, 
is  not  stable  in  a  free  condition.  Its  sodium  salt  C8H8NO3Na-fH2O  is 
formed  in  the  reduction  of  isatin  with  sodium  amalgam.  From  con- 
centrated solutions  of  the  sodium  salt,  acids  separate. 

Dioxindol,  o-amido-mandelic  acid  lactame  C6H4/[l^^(OH)(]:O.     This 

L  [2J.NH. 

is  also  produced  when  isatin  and  zinc  dust,  water,  and  some  hydro- 
chloric acid  are  boiled. 

Acetyl-dioxindol,  melting  at  127°,  is  converted  by  baryta  water  into 
o-acetamido-mandelie  acid  CH3CONH[2]C6H4CH(OH)CO2H,  melting 
at  142°,  which  also  results  from  the  reduction  of  acetyl-isatinic  acid. 
Hydriodic  acid  or  sodium  amalgam  change  it  to  oxindol  (p.  310). 

o-Oxy-mandelic  acid,  obtained  from  salicyl-aldehyde,  prussic  acid, 
and  also  from  o-oxy-phenyl-glyoxylic  acid,  is  a  syrupy  mass.  An 
optically  active  oxy-mandelic  acid  is  formed  from  helicin  tetra-acetate 
with  HCN  and  saponification  (C.  1902,  II.  214).  Its  lactone  melts  at 
49°  and  boils  at  237°  (B.  14,  1317  ;  17,  974).  p-Methoxy-mandelic 
acid,  from  anisaldehyde,  melts  at  93°  (B.  14,  1976).  2,  5-Dioxy- 
mandelic  acid,  m.p.  143°  with  decomposition,  by  reduction  of  hydro- 
quinone-glyoxylic  acid. 

Phenyl-chloracetie  acid  C6H5.CHC1.CO2H,  melting  at  78°,  is  produced 
when  mandelic  acid  is  heated  with  concentrated  hydrochloric  acid  to 
140° ;  from  trichloro-methyl-phenyl-carbinol  with  KHO  (C.  1897,  I. 
1014) ;  and  by  action  of  water  upon  its  chloride.  Its  chloride  C6H5. 
CHC1.COC1,  formed  by  the  action  of  PC15  upon  mandelic  acid,  boils  at 
125°  (45  mm.)  (A.  279,  122). 

Phenyl-bromacetie  acid  C6H5.CHBrCO2H  melts  at  83°.  Its  ethyl 
ester,  boiling  at  145°  (10  mm.)  (B.  24, 1877),  when  heated  with  potassium 
cyanide  becomes  diphenyl-succinic  ester.  Chloride,  b.p.18  118°.  Its 
nitrile,  from  benzyl  cyanide  and  bromine,  when  heated  alone  becomes 
stilbene  ;  when  heated  with  potassium  cyanide  it  yields  stilbene  or 
dicyano-dibenzyl  (q.v.) ;  while  with  alcoholic  potash  stilbene-dicar- 
boxylic  acid  or  diphenyl-maleic  acid  is  produced. 

Phenyl-nitro-aeetic  ester  and  phenyl-nitro-aceto-nitrile  are  formed 
as  sodium  salts  C6H5C(NOONa)CO2C2H5  and  C6H5C(NOONa)CN  from 
phenyl-acetic  ester  and  benzyl  cyanide,  with  ethyl  nitrate  and  sodium 
alcoholate  ;  the  free  acids  are  very  unstable  ;  saponification  with  NaHO 
yields  sodium-phenyl-nitro-methane  •  and  reduction  of  sodium-phenyl- 


PHENYL-PARAFFIN   ALCOHOL  ACIDS  379 

nitro-acetonitrile,  with  zinc  dust,  yields  iso-nitroso-benzyl  cyanide 
C6H5C(NOH)CN  (B.  35,  1755  ;  42,  1930). 

Phenyl-amido-acetic  acid  C6H5.CH(NH2).CO2H  melts  at  256°.  It 
yields  CO2  and  benzyl-amine  when  it  is  distilled.  It  results  (i)  on 
treating  phenyl-bromo-acetic  acid  with  aqueous  ammonia  (B.  11,  2002)  ; 

(2)  on  boiling  its  nitrile  with  dilute  sulphuric  acid  (B.  13,  383)  ;    and 

(3)  by  the  reduction  of  its  oxime  or  the  phenyl-hydrazone  of  benzoyl- 
formic  acid  (A.  227,  344). 

By  means  of  d-camphor-sulphonic  acid,  or  by  decomposition  of  the 
formyl  compound,  m.p.  180°,  with  cinchonin  or  quinine,  phenyl- 
amido-acetic  acid  has  been  split  up  into  its  optically  active  components 
with  coefficient  157-8°.  The  1-acid  is  also  formed  on  partial  fermenta- 
tion of  the  racemic  acid  with  yeast  (B.  41, 1286,  2071).  Its  methyl  ester 
melts  at  32°.  Cyclic  double-acid  amide  C6H5.CH<^~^^)>CH.C6H5 

melts  with  decomposition  at  274°  (B.  24,  4149).  Its  nitrile  is  a  yellow 
oil,  which  gradually  solidifies  to  a  crystalline  mass.  It  is  very  decom- 
posable. It  results  from  the  action  of  ammonia  upon  mandelic  nitrile. 

Alkylic  and  phenylated  phenyl-amido-acetic  acids  are  obtained  as 
the  result  of  the  action  of  methyl-amine,  aniline,  and  similar  bases 
upon  phenyl-bromo-acetic  acid  (B.  15,  2031).  Starting  from  phenyl- 
bromo-acetic  chloride,  a  number  of  di-  and  poly-peptides,  like  phenyl- 
glycyl-glycin,  phenyl-glycyl-alanin,  etc.,  have  been  prepared  (A. 
340,  190). 

a-Anffido-phenyl-acetic  nitrite  C6H5CH(NHC6H5)CN,  m.p.  85°,  is 
easily  obtained  from  benzylidene-aniline  and  prussic  acid,  as  well  as 
from  mandelic  acid  nitrile  with  aniline  ;  on  boiling  with  alcoholic 
potash,  it  combines  with  benzaldehyde  to  form  the  benzylidene  compound 
of  the  corresponding  acid  amide  : 

C6H5CH(NHC6H5)CN+C6H5CHO=C6H5CH(NHC6H5)CON  :  CHC6H5. 

The  latter  substance  is  very  stable,  and  is  also  formed  by  the  action 
of  KCN  upon  a  mixture  of  benzylidene-aniline  and  benzaldehyde 
(B.  31,  2699).  p-Dimethyl-amido-phenyl-anilido-aceto-nitrile  (CH3)2 
NC6H4CH(NHC6H5)CN,  m.p.  114°  (B.  35,  3572)- 

Urethano-phenyl-aceto-nitrile  C6H5CH(NHCO2C2H5)CN,  m.p.  83°, 
from  mandelic  acid  nitrile  with  urethane  and  zinc  chloride  (B.  34,  370). 

Of  the  alphyl-glycollic  acids,  mention  may  yet  be  made  of  p-iso- 
propyl-mandelie  acid,  prepared  from  cumic  aldehyde,  prussic  acid,  and 
hydrochloric  acid.  It,  too,  has  been  resolved  by  means  of  quinine  into 
its  active  isomerides  (B.  26,  R.  89). 

Phenyl-oxy-propionic  Acids,  Phenyl-lactic  Acids. — There  are  four 
possible  structural  isomerides.  All  are  known,  and  contain  an  asym- 
metric carbon  atom  : 

C02H  C02H  C02H  C02H 

C6H5.COH  CHOH  C,H5.CH  CH2 

CH3  C6H5.CH2  CH2.OH  C6H5.CHOH 

a- Phenyl-lactic  acid,  jS-Phenyl-lactic  a-Phenyl-hydracrylic  acid,  jS-Phenyl-hydra- 
atro-lactinic  acid  acid  tropaic  acid  crylic  acid. 

i.  Atro-lactinie  acid,  a-phenyl-lactic  acid  C9H10O3+iJH2O,  melts 
when  in  the  hydrous  state  at  90°,  and  when  anhydrous  at  94°.  It  is 


380  ORGANIC   CHEMISTRY 

obtained  from  a-bromo-hydro-atropic  acid  when  the  latter  is  boiled  with 
a  soda  solution,  from  hydratropic  acid  with  KMnO4,  from  its  nitrile, 
the  addition  product  of  prussic  acid  on  aceto-phenone,  by  boiling 
with  dilute  HC1  (B.  14, 1980)  ;  its  ethyl  ester,  b.p.  259°,  is  also  formed 
from  phenyl-glyoxylic  ester  with  methyl-magnesium  iodide.  When 
boiled  with  concentrated  hydrochloric  acid  it  decomposes  into  water 
and  atropic  acid. 

Corresponding  to  atro-lactinic  acid  are  a-chloro-  and  a-bromo-hydra- 
tropic  acids,  melting  at  73°  and  93°,  which  are  produced  when  it  stands 
in  contact  with  concentrated  haloid  acids  (A.  209,  3).  a-Amido-hydra- 
tropic  acid  sublimes,  without  melting,  at  260°  (B.  14, 1981). 

2.  Tropic  acid,  a-phenyl-hydr  aery  lie  acid,  is  known  in  an  inactive, 
decomposable,  and  two  optically  active  modifications. 

Inactive  tropic  acid,  melting  at  117°,  is  obtained,  together  with 
tropine  (q.v.)  (A.  138,  233  ;  B.  13,  254),  on  digesting  (60°)  the  alkaloids 
atropine  and  hyoscyamine  with  baryta  water.  It  was  made  syntheti- 
cally from  atropic  acid,  the  decomposition  product  of  atro-lactinic  acid, 
by  changing  it  with  concentrated  hydrochloric  acid  into  jS-chloro- 
hydratropic  acid,  which  boiling  potassium  carbonate  converts  into 
inactive  tropic  acid  : 

CO2H  CO2H  CO2H  CO2H 

C6H5.COH  >  C6H5.C  --*  C6H5.CH       -^~->  C6H5.CH 

CH3  CH2  CH2C1  CH2OH 

Atro-lactinic  acid       Atropic  acid  /?-Chl6ro-hydra tropic  acid     Tropic  acid. 

Lsevo-  and  dextro-tropic  acids,  melting  at  128°  and  123°,  can  be 
separated  by  the  fractional  crystallisation  of  their  quinine  salts,  and 
are  thus  prepared  from  r-tropic  acid.  The  dextro-quinine  salt,  more 
sparingly  soluble  in  dilute  alcohol,  melts  at  186°,  and  the  laevo-salt  at 
178°  (B.  22,  2591). 

j8-Chloro-  and  jS-bromo-hydratropie  acids  melt  at  87°  and  93°. 

j8-Amido-hydratropic  acid  melts  at  119°  (A.  209,  3). 

3.  j3-Phenyl-lactic  acid,  benzyl-glycollic  acid  C6H5.CH2.CH.(OH). 
CO2H,   melting   at   97°,  is  derived   from   phenyl-acetaldehyde,   with 
prussic  acid  and  hydrochloric  acid,  and  from  benzyl-tartronic  acid  upon 
heating  it  to  180°.     Heated  with  dilute  sulphuric  acid,  it  decomposes 
into  phenyl-acetaldehyde  and  formic  acid. 

a-Bromo-hydro-cinnamie  acid  C6H5CH2.CHBr.COOH,  m.p.  49°, 
is  formed  from  benzyl-malonic  acid  by  bromi nation  and  CO2  elimina- 
tion. Chloride,  b.p.12  133°  (B.  39,  3999). 

Phenyl-alanin,  J3-phenyl-a-amido-propionic  acid  C6H5.  CH  2.  CH 
(NH2).CO2H  sublimes  without  decomposition  when  it  is  slowly  heated. 
Upon  rapid  heating  it  yields  phenyl-ethyl-amine  and  a  cyclic  double- 
acid  amide  C6H5.CH2.CH./^9;^\CH.CH2.C6H5,  m.p.  290°  (A.  219, 

\.N  J~l.V_xV_// 

188  ;  271,  169).  It  is  found  along  with  asparagin  in  the  sprouts 
of  Lupinus  luteus,  and  is  formed  in  the  decay,  or  by  the  chemical  de- 
composition, of  albumen,  casein,  or  gelatin,  and  can  be  separated  out 
from  mixtures  by  means  of  its  sparsely  soluble  phospho-tungstate 
compound  (C.  1902,  II.  272).  Synthetically,  the  optically  inactive  form 
is  prepared  from  its  nitrile,  the  product  of  the  action  of  ammonia  upon 
the  nitrile  of  jS-phenyl-lactic  acid,  with  hydrochloric  acid  ;  further, 


PHENYL-PARAFFIN   ALCOHOL  ACIDS  381 

by  the  reduction  of  a-amido-cinnamic  acid  (B.  17,  1623),  and  of  a-iso- 
nitroso-/3-phenyl-propionic  acid  (A.  271,  169).  Also  from  phthal- 
imido-benzyl-malonic  ester  C6H4(CO)2NC(CH2C6H5)(COOR)2  by  split- 
ting (C.  1903,  II.  33)  and  by  the  action  of  NH3  upon  a-bromo-hydro- 
cinnamic  acid.  From  the  inactive  phenyl-alanin  thus  obtained,  the 
d-  and  1-bodies  of  rotation  coefficient  ±35°  are  obtained  by  partial  fer- 
mentation with  yeast,  or  by  breaking  up  the  formyl  compound  with 
brucin  (A.  357,  2  ;  C.  1908,  I.  1632). 

Benzoyl-phenyl-alanin,  from  benzoyl-amido-cinnamic  acid  by  re- 
duction, melts  at  182°  (A.  275,  15). 

Phenaeetyl-phenyl-alanin  C6H5CH2CH(NHCOCH2C6H5)COOH,  m.p. 
126°,  is  obtained  in  the  same  way  ;  and  also  by  a  peculiar  reaction 
of  ammonia  with  phenyl-pyro-racemic  acid  (A.  307,  146).  Phenyl- 
alanin-ethyl  ester,  b.p.10  143°  (C.  1901, 1.  679). 

A  considerable  number  of  di-  and  polypeptides  containing  the  phenyl- 
alanin  complex,  like  phenyl-alanyl-glycin,  phenyl-alanyl-phenyl-alanin, 
and  leucyl-glycyl-phenyl-alanin,  have  been  obtained  by  the  methods 
described  in  Vol.  1.,  starting  from  active  and  inactive  phenyl-alanin 
or  from  a-bromo-hydro-cinnamic  chloride  (A.  354,  I  ;  357,  i). 

o-  and  p-Nitro-phenyl-laetie  acids  are  produced  in  the  nitration 
of  phenyl-lactic  acid.  When  reduced  the  o-acid  yields  oxy-hydro- 

r[i]CH2— CH.OH 

carbo-styril  C6H4{  ,  m.p.  197°,  and  the  p-acid,  p-amido- 

H2JNH— CO 

jS-phenyl-lactie  acid  NH2[4]C6H4.CH2.CH(OH)CO2H,  melting  with 
decomposition  at  188°. 

o-Oxy-plienyl-lactic  acid,  salicyl-lactic  acid  HO[2]C6H4CH2CH 
(OH)CO2H,  is  a  syrup -like  mass.  It  results  from  the  action  of 
sodium  amalgam  upon  o-oxy-phenyl-pyro-racemic  acid  (B.  18,  1188). 
Its  inner  phenol  -  alcohol  anhydride  is  hydro  -  eumarilic  acid 

/-[i]CH2.CH.CO2H 
C6HJ  '    ,  melting   at   118°.     This  is  the  reduction  pro- 

\[2]o — ! 

duct  of  eumarilic  acid  (A.  216,  166).  p-Oxy-phenyl-lactic  acid 
melts  at  144°  in  the  anhydrous  condition.  It  is  formed  when  an  excess 
of  nitrous  acid  acts  upon  p-amido-phenyl-alanin  (A.  219,  226). 

2,  4-Dioxy-phenyl-laetie  acid,  hydroquinone  lactic  acid,  m.p.  87°,  see 
C.  1907,  II.  901.  p-Iodo-phenyl-alanin,  m.p.  270°  with  decomposition 
(see  C.  1909,  I.  70  ;  B.  42,  3411). 

p-Nitro- phenyl-alanin  NO2[4]C6H4CH2.CH(NH2)CO2H  decom- 
poses at  240°.  It  is  formed  in  the  nitration  of  phenyl-alanin. 

p-Amido-phenyl-alanin  NH2[4]C6H4.CH2.CH(NH2).CO2H  is  pro- 
duced in  the  reduction  of  p-nitro-phenyl-alanin  and  p-nitro-phenyl- 
a-nitro-acrylic  acid. 

Tyrosin,  p-oxy-  phenyl  -  alanin  HO[4]C6H4.CH2CH(NH2)CO2H, 
melts  at  235°.  It  occurs  in  the  liver  when  its  functions  are  disturbed, 
the  spleen,  the  pancreas,  and  in  stale  cheese  (rvpos),  and  is  formed 
from  animal  substances  (urea,  horn,  hair,  albumen)  on  boiling  them 
with  hydrochloric  or  sulphuric  acid  ;  by  fusion  with  alkalies  or  by 
putrefaction  (together  with  leucine,  aspartic  acid,  etc.).  It  may  be 
prepared  synthetically  from  p-amido-phenyl-alanin  by  the  action  of 
one  molecule  of  potassium  nitrite  upon  the  hydrochloric  acid  salt,  or 
by  splitting  up  synthetic  benzoyl-tyrosin. 


382  ORGANIC  CHEMISTRY 

History. — Liebig  discovered  tyrosin  upon  fusing  freshly  prepared 
cheese  with  caustic  potash  (1846)  (A.  57,  127  ;  62,  269).  E.  Erlen- 
meyer,  sen.,  and  Lipp  (A.  219,  161)  succeeded  in  synthesising  tyrosin, 
beginning  with  phenyl-acetaldehyde. 

Synthesis  of  Tyrosin. — Phenyl-acetaldehyde  and  prussic  acid  yield 
the  nitrile  of  phenyl-lactic  acid.  Ammonia  changes  the  latter  to  the 
nitrile  of  phenyl-alanin,  which  hydrochloric  acid  converts  into  phenyl- 
alanin.  The  latter  by  nitration  yields  p-nitro-phenyl-alanin,  whose 
reduction  product,  p-amido-phenyl-alanin  hydrochloride,  is  changed 
by  an  equimolecular  quantity  of  nitrous  acid  into  tyrosin  : 

CN  CN  CO2H  CO2H  CO2H  CO2H 

CHO       CHOH        CHNH2       CHNH2        CHNH2         CHNH2         CH.NH2 
CH2         CH2  CH2  CH2  CH2  "*"  CH2  CH2 

C6H5        C6H5           C6H5            C6H5  C6H4[4]N02  i6H4[4]NH2  C6H4[4]OH 

Phenyl-    Nitrile         Amido-      Phenyl-  p-Nitro-        p-Amido-        Tyrosin. 

acetalde-       of          phenyl-lac-    alanin  phenyl-          phenyl- 

hyde       phenyl-        tic  acid  alanin            alanin 
lactic  acid      nitrile 

A  more  convenient  method  has  recently  been  found  by  E.  Erlen- 
meyer,  jun.  (see  A.  307, 138  ;  B.  32,  3638). 

Properties  and  Behaviour.- — It  dissolves  in  150  parts  of  boiling  water, 
and  crystallises  in  delicate,  silky  needles.  It  dissolves  in  alcohol  with 
difficulty,  and  is  insoluble  in  ether. 

Mercuric  nitrate  produces  a  yellow  precipitate,  which  becomes  dark 
red  in  colour  if  it  be  boiled  with  fuming  nitric  acid  to  which  consider- 
able water  has  been  added  (delicate  reaction).  Being  an  amido-acid, 
tyrosin  unites  with  acids  and  bases,  forming  salts.  If  it  be  heated  to 
270°  it  decomposes  into  carbon  dioxide  and  oxy-phenyl-ethyl-amine 
C6H4(OH).CH2.CH2.NH2.  When  fused  with  caustic  potash  it  yields 
para-oxy-benzoic  acid,  ammonia,  and  acetic  acid.  Putrefaction  causes 
the  formation  of  hydro-para-cumaric  acid,  and  nitrous  acid  converts  the 
tyrosin  into  para-oxy-phenyl-lactic  acid  (A.  219,  226).  Many  di-  and 
polypeptides  have  been  formed  by  the  combination  of  active  and  in- 
active tyrosin  with  other  amido-acids  (B.  41,  2840,  2860).  By  analyti- 
cal methods  also,  such  as  the  hydrolysis  of  silk  fibroin  with  HC1,  a 
dipeptide  containing  the  tyrosin  complex,  glycyl-ty rosin,  as  well  as  a 
tetrapeptide,  have  been  isolated  (B.  40,  3544). 

Very  noteworthy  is  the  natural  occurrence  of  inactive  3,  5-di-iodo- 
tyrosin  OH[4]I2[3, 5]C6H2CH2.CH(NH2).CO2H,  m.p.  213°,  first  ex- 
tracted from  the  coral  Gorgonia  Carolinii  (C.  1896,  I.  864),  and  hence 
called  iodogorgic  acid.  Synthetically,  it  has  been  prepared  by  iodina- 
tion  of  tyrosin  in  alkaline  solution  (C.  1905,  I.  1388).  On  polypeptides 
with  3,  5-di-iodo-l-tyrosin,  see  B.  41,  1237. 

4.  j8-Phenyl-hydraerylic  acid  C6H5.CH(OH).CH2.CO2H,  commonly 
called  phenyl-lactic  acid,  results  on  boiling  jS-bromo-hydro-cinnamic  acid 
with  water  (A.  195,  138),  and  in  the  reduction  of  benzoyl-acetic  ester, 
as  well  as  by  the  addition  of  hypochlorous  acid  to  cinnamic  acid,  and 
then  reducing  the  resulting  chloro-acid  with  sodium  amalgam.  The 
acid  melts  at  93°.  When  heated  with  dilute  sulphuric  acid  it  decom- 
poses (like  the  aliphatic  j8-oxy-acids)  at  190°  into  water  and  cinnamic 


PHENYL-PARAFFIN   ALCOHOL  ACIDS  383 

acid  (together  with  a  little  styrol)  (B.  13,  304).  When  digested  with 
concentrated  haloid  acids  it  forms  j8-halogen-hydro-cinnamic  acids  (q.v.). 
a-  and  /3-Alkylated  jS-phenyl-hydracrylic  acids  have  been  obtained  by 
the  action  of  a-bromo-aliphatic  acid  esters,  and  zinc,  upon  benzaldehyde 
and  aromatic  a-ketones. 

a-Methyl-^-phenyl-ethylene  -  lactic  acid  C6H5CH(OH)CH(CH3) 
COOH,  m.p.  95°.  a-Dimethyl-/?,  p-tolyl-ethylene-laetie  acid,  m.p.  112°. 
a-Iso-propyl-phenyl-ethylene-lactic  acid,  m.p.  107°  (C.  1898,  I.  668, 
884;  1900,  II.  533;  1902,  I.  1293;  1903,  II.  566  ;  B.  40,  1589  ;  41,  5). 

o-,  m-,  and  p-Nitro-phenyl-laetic  acids,  or  -hydr  acrylic  acids  NO2. 
C6H4CH(OH).CH2.C02H,  melt  at  126°,  105°,  and  132°.  The  three  iso- 
merides  result  upon  treating  the  three  nitro-jS-bromo-hydro-cinnamic 
acids  with  sodium  carbonate,  when  (in  the  cold)  the  0-,  m-,  and  p-nitro- 

O— CO 
phenyl-lactic  acid  lactones,  I      ,  melting  at  124°,  98°,  and 

N02C6H4CH.CH2 

92°,  are  also  produced.  These  are  the  only  fi-lactones  known  (B.  17, 
595,  1659). 

The  ortho-nitro-acid  results,  further,  by  oxidising  the  aldehyde  first 
produced  with  silver  oxide  (B.  16,  2206).  When  heated  to  190°  with 
dilute  sulphuric  acid  it  yields  o-nitro-cinnamic  acid.  Its  lac  tone  de- 
composes on  boiling  with  water  into  carbon  dioxide  and  o-nitro-styrol ; 
it  yields  /?-oxy-hydro-carbo-styrol  when  reduced. 

/2-Chloro-,  bromo-,  and  iodo-hydro-cinnamie  acids  C6H5.CHX.CH2. 
CO2H  melt  at  126°,  137°,  and  120°.  They  are  obtained  from  cinnamic 
acid  or  /3-phenyl-acrylic  acid  by  the  addition  of  halogen  hydrides  in 
aqueous  or  glacial  acetic  acid  solution  (B.  11,  1211)  and  from  j8-phenyl- 
hydracrylic  acid  (q.v.).  When  heated  or  boiled  with  water  the  free 
acids  decompose,  with  previous  formation  of  j8-oxy-acids,  into  halogen 
hydride  and  cinnamic  acid.  When  neutralised,  even  in  the  cold,  with 
alkali  carbonates  they  break  down  into  haloid  acid,  carbon  dioxide, 
and  styrol  C6H5.CH  :  CH2. 

o-,  m-,  and  p-Nitro-j8-bromo-hydro-einnamie  acids  NO2C6H4CHBr. 
CH2.CO2H  are  produced  by  the  addition  of  hydrogen  bromide,  in 
glacial  acetic  acid,  to  the  three  nitro-cinnamic  acids  (B.  17,  596,  1494) 
(see  also  Nitro-phenyl-lactic  acid  lactone) . 

jS-Hydroxylamin6-hydro-cinnamicacidC6H5CH(NHOH).CH2COOH, 
m.p.  166°  with  decomposition,  is  formed  by  the  attachment  of  free 
hydroxylamine  to  cinnamic  acid.  By  oxidation  with  ammoniacal 
silver  solution  it  becomes  y-phenyl-isoxazolone  (q.v.),  and  with  HNO2 
it  becomes  N-oxy-y-phenyl-isoxazolidone  (B.  39,  3115).  On  reduction 
it  forms  : 

j3-Amido-hydro-einnamie  acid  C6H5.CH(NH2)CH2.CO2H  melts  at 
131°,  which  with  HNO2  yields  j8-phenyl-hydracrylic  acid  (B.  38,  2316). 

y-Phenyl-a-amido-butyrie  acid  C6H5CH2.CH2CH(NH2)COOH,  m.p. 
295°,  by  reduction  of  benzyl-pyro-racemic  acid  oxime  (B.  39, 1478). 

y-  and  8-Oxy-acids. —  y-Oxy-acids,  beginning  with  the  phenyl- 
oxy-butyric  acids,  are  known.  They  pass  readily  into  their  lactones. 
y-Phenyi-y-oxy-butyrie  acid  C6H5CH(OH).CH2.CH2.CO2H  melts  at 
75°,  and  slowly  decomposes,  even  at  65°-7O°,  into  water  and  its 
lactone,  phenyl-butyro-Iaetone  C10H10O2.  The  latter  melts  at  37°  and 
boils  at  306°. 

It  is  obtained  from  jS-benzoyl-propionic  acid  (B.  15,  889)  and  from 


384  ORGANIC  CHEMISTRY 

phenyl-bromo-butyric  acid.  Its  lactone  is  formed  on  boiling  phenyl- 
iso-crotonic  acid  and  phenyl-paraconic  acid  with  dilute  sulphuric  acid 
(A.  228, 178  ;  B.  29,  R.  14  ;  33,  3519).  

On  the  relations  of  m-tolyl-butyro-lactoneCH3C6H4CHCH2CH2Co6 
towards  cannabinol,  the  poisonous  resin  of  Indian  hemp,  Cannabis 
indica,  see  C.  1899,  I.  118. 

a-Phenyl-y-oxy-valeric  acid,  only  stable  in  the  form  of  liquid 
lactone  (B.  17,  73). 

y-Phenyl-y-valero-lactone,  b.p.16 169°  (C.  1902,  II.  1359). 

8-Benzyl-y-oxy-valeric  acid  melts  at  101°,  and  its  lactone  at  33° 
(A.  268,  94). 

j3-Benzyl-y-oxy-valeric  acid  melts  at  75°,  and  its  lactone  at  86° 
(A.  254,  215).  It  is  obtained  from  benzal-laevulinic  acid. 

a-Benzyl-S-oxy- valeric  acid  (B.  24,  2447). 

B.  Dioxy-aleohol  Acids  are  chiefly  obtained  by  oxidising  the  phenyl- 
olefin-carboxylic  acids  with  potassium  permanganate  (A.  268,  44  ; 
283,  338).  The  two  possible  phenyl-gly eerie  acids  are  known. 

Atro-glyceric  acid,  a-phenyl-glyceric  acid  CH2OH.C(C6H3)OH. 
CO2H,  melting  at  146°,  results  on  boiling  a,  j3-dibromo-hydratropic 
acid  with  excess  of  alkalies,  and,  from  benzoyl-carbinol,  by  means  of 
prussic  acid  and  hydrochloric  acid  (B.  16,  1292).  It  breaks  down  into 
CO  2  and  phenyl-acetaldehyde  upon  heating. 

Dibromo-hydratropie  acid  CH2Br.C(C6H5)Br.CO2H,  melting  at 
115°,  is  produced  when  bromine  acts  upon  atropic  acid.  It  decom- 
poses on  boiling  with  water  into  aceto-phenone,  CO2,  and  HBr. 

Styceric  acid,  j3-phenyl-glyceric  acid  C6H5.CHOH.CHOH.COOH, 
contains  two  unsym.  carbon  atoms,  and  therefore  occurs  in  different 
modifications.  An  acid  of  m.p.  121°  is  obtained  by  saponification  with 
alcoholic  potash  from  its  dibenzoyl-ethyl  ester  C6H5CH(OCOC6H5)CH 
(OCOC6H5)COOC2H5,  m.p.  109°,  the  result  of  the  action  of  silver  benzo- 
ate  upon  cinnamic  ester  dibromide ;  on  saponifying  the  dibenzoyl  ester 
with  aqueous  alkaline  hydroxide  an  acid  is  formed,  melting  at  141° 
with  decomposition,  which  is  also  obtained  by  the  oxidation  of 
cinnamic  acid  with  KMnO4.  It  dissolves  in  ether  with  difficulty,  and 
yields  on  the  gradual  benzoylation  of  its  ethyl  ester  a  dibenzoyl  ester 
of  m.p.  85°,  while  benzoylation  at  a  higher  temperature  produces 
transposition  into  an  ester  of  m.p.  109°.  The  m.p.  121°  acid  is 
racemic,  and  may  be  split  up  into  two  optical  antipodes  by  means 
of  the  stycerin  salt,  a-  and  1-styceric  acid,  m.p.  167°,  aD=+3i-o8° 
and  —30-23°  respectively,  while  the  m.p.  141°  acid  has  not  hitherto 
been  so  split  up  (B.  30,  1600).  It  is  significant  that  oxidation  of 
the  ordinary  fumaroid  cinnamic  acid  with  KMnO4  yields  the  m.p. 
141°  acid,  while  the  maleiinoid  allo-cinnamic  acid  yields  the  m.p.  121° 
acid  (B.  41,  2411).  On  heating  above  their  melting-points,  the  acids 
break  up  into  CO2  and  phenyl-acetaldehyde.  On  warming  with  H2SO4, 
concentrated  HC1,  or  acetic  anhydride  water,  is  split  off  and  phenyl- 
pyro-racemic  acid  formed  (B.  43,  1032).  With  HBr  the  m.p.  121°  acid 
gives  a  phenyl-jS-bromo-a-oxy-propionic  acid  of  m.p.  157°,  while  the 
other  gives  a  bromoxy-acid  of  m.p.  165°. 

Benzal-phenyl-glyceric  ester  c  H  £H____CH  co  c  H   is  Pr°duced 


PHENYL-PARAFFIN   ALCOHOL  ACIDS  3^5 

In  two  stereo-isomeric  forms,  melting  at  104°  and  61°  respectively, 
by  the  action  of  diazo-acetic  ester  upon  benzaldehyde.  The  benzal- 
phenyl-glyceric  acids,  m.p.  132°  and  156°  respectively,  are  split  up  by 
acetic  acid  into  benzaldehyde  and  the  phenyl-glyceric  acids,  m.p. 
121°  and  141°.  The  latter,  on  shaking  up  with  benzaldehyde  and 
50  per  cent.  H2SO4,  regenerates  the  benzal-phenyl-gly eerie  acid;  m.p. 
156°  (B.  43,  1024). 

p-Nitro-phenyl-glyceric  acid,  melting  at  167°,  is  obtained  from 
p-nitro-phenyl-glycidic  acid. 

o-Amido-phenyl-glycerie  acid,  m.p.  218°. 

Phenyl-a-chloro-£-laetie  acid  C6H5.CH(OH)CH.C1.CO2H+H20 
melts  at  56°,  and,  when  anhydrous,  at  86°.  It  results  from  the  action 
of  hypochlorous  acid  upon  cinnamic  acid.  Sodium  amalgam  reduces 
it  to  phenyl-lactic  acid,  alkalies  change  it  to  phenyl-glycidic  acid  and 
phenyl-glyceric  acid,  while,  with  fuming  hydrochloric  acid,  it  yields 
phenyl-dichloro-propionic  acid  (B.  22,  3140). 

Phenyl-a-bromo-jS-lactie  acid  C6H5.CH(OH).CHBr.CO2H+H2O 
melts  at  125°  when  anhydrous.  It  is  formed  on  boiling  phenyl-dibromo- 
propionic  acid  with  water  (B.  13,  310).  It  has  been  separated,  by  means 
of  cinchonin,  into  two  optically  active  components  (B.  24,  2831  ; 
32,  2375). 

Phenyl-a-iodo-£-laetie  acid  C6H5.CH(OH).CHI.CO2H  melts  at  137° 
with  decomposition.  It  results  from  the  action  of  an  aqueous  chloro- 
iodine  solution  upon  cinnamic  acid  (B.  19,  2464).  o-  and  p-Nitro- 
phenyl-a-chloro-lactic  acids  melt  at  119°  and  165°.  The  o-  body  is 
converted  by  sodium  amalgam  into  indol  (B.  13,  2261  ;  19,  2646). 

£-Phenyl-a-amido-hydracrylic  acid,  phenyl-serin  C6H5.CH.(OH). 
CH(NH2).CO2H+H2O,  decomposing  at  194°,  is  formed  from  its 
benzylidene  compound,  the  condensation  product  of  benzaldehyde 
and  glycocoll,  obtained  with  NaHO  and  acids,  besides  a  more 
soluble  stereo-isomeric  acid  (A.  307,  84). 

The  isomeric  j8-phenyl-j8-amido-laetie  acid,  phenyl-iso-serin  C6H5 
CH(NH2).CH(OH).CO2H,  m.p.  241°  with  decomposition,  is  obtained 
by  the  attachment  of  NH3  to  sodium  in  the  cold  (B.  39,  791). 

j8-Phenyl-jS-ehloro-a-oxy-propiomc  acid  C6H5.CHC1.CH(OH).CO2H, 
m.p.  141°,  and  phenyl-jS-bromo-a-oxy-propionic  acid  are  obtained  from 
phenyl-glyceric  acid  with  fuming  halogen  hydrates  (B.  16,  1290). 

o-  and  p-Nitro-phenyl-/?-ehloro-laetic  acids,  melting  at  125°  and  167°, 
are  obtained  by  the  action  of  fuming  hydrochloric  acid  upon  the  corre- 
sponding glycidic  acids  (B.  19,  2646). 

o-Nitro-phenyl-j8-bromo-lactie  acid  melts  at  135°  (B.  17,  221). 

Cinnamic  acid  diehloride,  a,  f$-dichloro-hydro-cinnamic  acid  C6H5. 
CHC1.CHC1.CO2H,  melting  at  163°,  results  when  chlorine  acts  upon 
cinnamic  acid  in  carbon  disulphide  solution  and  on  treating  phenyl-a- 
chloro-lactic  acid  with  fuming  hydrochloric  acid  (B.  14,  1867). 

Allo-cinnamic  acid  diehloride  is  an  oil  decomposable  by  strychnine 
into  two  optically  active  components  (B.  27,  2041). 

Ginnamic  acid  dibromide,  a,  fi-dibromo-hydro-cinnamic  acid,  melting 
at  195°,  yields  CO2,  phenyl-acetaldehyde,  cinnamic  acid,  and  phenyl-a- 
bromo-lactic  acid  on  boiling  with  water.  Strychnine  resolves  it  into 
two  optically  active  components  (B.  26,  1664).  The  methyl  ester  melts 
at  117°.  The  ethyl  ester  melts  at  69°  (B.  22,  1181 ;  C.  1903,  II.  115). 

VOL.  II.  2  C 


386  ORGANIC  CHEMISTRY 

Allo-cinnamie  aeid  dibromide  melts^at  9i°-93°.  It  is  separated  into 
two  optically  active  components  by  cinch onin  (B.  27,  2039).  The 
methyl  ester  melts  at  52°-53°. 

o-  and  p-Nitro-a,  jS-dibromo-hydro-cinnamic  aeids  melt  at  180°  and 
227°.  The  o-  and  p-ethyl  esters  melt  at  71°  and  110°  (A.  212,  151). 

o-Methoxy-einnamie  aeid  dibromide,  m.p.  170° ;  piper onyl  aeid 
dibromide,  m.p.  156°.  In  these  dibromides  the  Br  atom  adjoining  the 
phenyl  nucleus  is  very  reactive  (B.  39,  27  ;  40,  2174). 

Phenyl-glyeidic  aeid  c  H  ^jJ^H  co  H,  separated  from  the  sodium 

salt,  is  an  oil  solidifying  at  o°.  It  results  from  the  action  of  alkalies 
upon  a-  and  jS-chloro-phenyl-lactic  acids,  as  well  as  by  the  condensa- 
tion of  benzaldehyde  with  chloracetic  ester  (A.  271,  137).  Phenyl- 
glyeidic  acid  is  very  unstable.  It  readily  decomposes  into  CO2  and 
phenyl-acetaldehyde.  On  boiling  with  water  phenyl-glyceric  acid  is 
also  produced.  Hot  concentrated  HC1  partly  converts  phenyl-glycidic 
acid  into  the  isomeric  phenyl-pyro-racemic  acid  (B.  33,  3001).  From 
the  optically  active  phenyl-a-bromo-lactic  acids  the  optically  active 
phenyl-glycidic  acids  are  obtained  in  the  form  of  their  sodium  salts. 

Numerous  homologous  phenyl-glycidic  esters  have  been  obtained 
by  condensation  of  aromatic  aldehydes  and  ketones  with  chloracetic 
ester,  or  chloro-propionic  ester,  by  means  of  Na  ethylate  or  amide 
(C.  1905,  I.  346  ;  1906,  I.  669  ;  B.  38,  699).  The  free  acids  obtained 
by  saponification,  like  the  phenyl-glycidic  acid  itself,  easily  splits  up 
into  CO 2  and  aldehydes  or  ketones.  /2-Methyl-  and  ethyl-phenyl- 
glyeidie  ethyl  ester,  b.p.  148°  and  149°.  a-Methyl-phenyl-glycidie 
ethyl  ester,  b.p.18  153°. 

o-Nitro-phenyl-glycidie  acid  NO2[2]C6H4CH/^\CH.CO2H+H2O  melts 
at  94°,  and  at  125°  when  anhydrous.  It  is  produced  when  alcoholic 
potash  acts  upon  o-nitro-phenyl-lactic  acid,  or  by  the  action  of  sodium 
hypochlorite  upon  o-nitro-phenyl-lactic  acid  ketone  (A.  284,  135).  It 
breaks  down,  on  heating,  into  CO2  and  indigo.  It  yields  anthranile 
and  anthroxan-aldehyde  on  boiling  with  water  (B.  19,  2649). 

Phenyl-a-oxy-butyro-lactone  C6H5CH.CH2.CH(OH)COO,  m.p.  125°, 
from  benzoyl-pyro-racemic  acid  by  reduction  with  Na  amalgam,  is 
transformed  into  j8-benzoyl-propionic  acid  by  boiling  with  dilute 
HC1  (B.  35,  3767). 

C.  Trioxy-alcohol  Aeids.  —  y -Phenyl- trio xy- butyric  acid  C6H5 
[CH.OH]3CO2H  passes  readily  into  the  lactone,  melting  at  Ii5°-ii7°  ; 
by  reduction  this  yields  phenyl-tetrose.  y-Phenyl-trioxy-butyric  acid 
is  prepared  by  starting  with  the  dibromide  of  cinnamic  aldehyde 
cyanhydrin  (B.  25,  2556  ;  A.  319,  206). 

(7)  PHENYL-PARAFFIN-ALDEHYDE-CARBOXYLIC  ACIDS. 

As  explained  under  the  aliphatic  unsaturated  ketols,  oxy-olefin- 
carboxylic  acids  and  oxy-ketone-carboxylic  acids,  the  oxy-methylene 
derivatives  are  produced  by  the  condensation  of  acetone,  acetic  ester, 
aceto-acetic  ester,  and  other  bodies  with  formic  ester  in  the  presence 
of  sodium  ethylate.  As  these  compounds  conduct  themselves  in  many 
respects  like  aldehydes,  it  was  originally  supposed  that  they  contained 


PHENYL-PARAFFIN-KETONE-CARBOXYLIC  ACIDS    387 

the  aldehyde  group,  and  it  was  only  their  very  pronounced  acid  char- 
acter which  led  to  considering  them  as  oxy-methylene  compounds.  It 
is  rather  remarkable  that  two  isomeric  esters  are  formed  in  the  con- 
densation of  phenyl-acetic  ester  and  formic  ester  by  means  of  sodium 
ethylate.  Both  bodies  yield  the  same  derivatives  with  phenyl-hydrazin. 
The  one  is  a  liquid  and  the  other  a  solid. 

Both  forms,  especially  when  dissolved,  can  quite  easily  be  converted 
into  each  other.  The  liquid  form  is  that  of  the  metallic  compounds, 
and  is  distinguished  from  the  solid  form  by  the  strong  blue-violet 
colour  produced  by  ferric  chloride.  It  also  reacts  more  easily  with 
phenyl  cyanate.  It  is  assumed  that  the  liquid  form  corresponds  to 
the  enol  form  of  formyl-phenyl-acetic  ester,  and  the  solid  form  to  the 
aldo  form  of  the  same  (W.  Wislicenus,  A.  312,  34  ;  also  B.  39,  203). 

Oxy-methylene-phenyl-acetie  ethyl  ester  CH(OH)  :  C(C6H5)CO2C2H5 
is  a  liquid  boiling  at  144°  (16  mm.).  Ferric  chloride  imparts  a  violet 
colour  to  it.  Its  sodium  compound  gives,  with  benzoyl  chloride, 
a  liquid,  unstable  a-benzoate  CH(OCOC6H5)  :  CH(C6H5)CO2C2H5,  which 
is  converted,  on  distillation,  into  a  geometrically  isomeric  stable 
jS-benzoate,  m.p.  88°.  Methyl  ester,  m.p.  41°. 

Phenyl-formyl-aeetie  ethyl  ester  CHO.CH(C6H5)CO2C2H5  melts  at 
70°,  passing  at  the  same  time  into  the  liquid  isomeric  ester.  Methyl 
ester,  m.p.  73°  (C.  1900,  I.  122). 

(8)  PHENYL-PARAFFIN-KETONE-CARBOXYLIC  ACIDS. 

The  acids  belonging  to  this  group  can  be  arranged,  like  the  aliphatic 
ketone-carboxylic  acids,  as  a-,  /?-,  and  y-ketone-carboxylic  acids,  and 
in  each  of  these  groups  we  can  have  sub-groups,  depending  upon  whether 
the  ketone  group  is  in  direct  union  with  the  benzene  nucleus  or  not. 

A.  a-Ketone-carboxylie  Acids  result  from  the  oxidation  (i)  of 
ketones ;  (2)  of  glycols  ;  (3)  of  ketone  alcohols  ;  (4)  of  alcohol-car- 
boxylic  acids ;  (5)  (nuclear  synthetic)  from  cyanides  of  the  acid 
radicles  by  saponification  with  cold  concentrated  hydrochloric  acid  ; 
(6)  from  benzenes  by  the  action  of  chloroxalic  esters  in  the  presence  of 
aluminium  chloride  (B.  20,  2045  ;  C.  1898,  I.  26,  42). 

Phenyl-glyoxylic  acid,  benzoyl-formic  acid  C6H5.CO.CO2H,  melting 
at  65°,  and  isomeric  with  the  phthal-aldehydic  acids,  is  obtained  by 
oxidising  aceto-phenone  with  potassium  ferricyanide  (B.  20,  389),  as 
well  as  by  oxidising  phenyl-glycol,  benzoyl-carbinol,  and  mandelic  acid 
with  nitric  acid  : 

C6H5CO.CH3—  -x C-H.COCOOH  « / C6H5CO.CH2OH 

C6H5CH(OH).CH2OH  -/  \ C6H5CH(OH)CO2H 

The  acid  was  first  prepared  (by  nuclear  synthesis)  by  saponifying 
benzoyl  cyanide,  its  nitrile,  obtained  from  benzoyl  chloride  and 
mercury,  or  silver  cyanide  (Claisen).  Its  ethyl  ester  is  formed  when 
ethyl-chloroxalic  ester  acts  upon  mercury  diphenyl  or  upon  benzene 
in  the  presence  of  A1C13. 

The  acid  is  very  soluble  in  water,  and,  when  distilled,  decomposes 
into  CO  and  benzoic  acid,  with  a  small  division  into  CO2  and  benz- 
aldehyde.  Heating  with  aniline  splits  it  up  into  CO2  and  benzylidene- 
aniline,  a  reaction  useful  for  forming  aldehydes.  When  mixed  with 
benzene  containing  thio-phene  and  sulphuric  acid  it  is  coloured  deep 


388  ORGANIC   CHEMISTRY 

red,  afterwards  blue-violet ;  all  its  derivatives,  and  also  isatin,  react 

similarly. 

?£j  Being  a  ketonic  acid,  it  unites  with  sodium  bisulphite  and  with 

CNH  (see  Phenyl-tartronic  acid).     Sodium  amalgam  converts  it  into 

mandelic  acid,  and  hydriodic  acid  into  phenyl-acetic  acid.     H2S  and 

the  alkali  produce  thio-phenyl-acetic  acid  (C.  1903,  II.  1271). 

Its  methyl  ester  boils  at  247°.  Its  ethyl  ester  boils  at  257°.  The 
a-amide  melts  at  90°.  The  j8-amide  hydrate  C6H5.CO.CONH2-fH2O 
melts  at  64°.  The  y-amide  melts  at  134°  (B.  12,  633  ;  20,  397).  The 
anilide,  from  y-benzil-monoxime  (q.v.)  and  PC15,  melts  at  63°. 

Benzoyl  cyanide  C6H5.CO.CN,  melting  at  32°  and  boiling  at  207°,  is 
obtained  in  the  distillation  of  benzoyl  chloride  with  mercuric  cyanide, 
and  by  the  action  of  acetyl  chloride  (B.  20,  2196)  upon  iso-nitroso- 
aceto-phenone.  Sodium,  in  absolute  alcohol,  converts  it  into  poly- 
benzoyl  cyanide  (CSH5NO2)#,  melting  at  95°  (/.  pr.  Ch.  2,  39,  260). 
Alkalies  change  benzoyl  cyanide  to  benzoic  acid  and  potassium  cyanide, 
while  concentrated  hydrochloric  acid  converts  it  into  benzoyl- 
formic  acid. 

Concerning  a  trimolecular  benzoyl  cyanide  (C8H5NO)3,  yellow 
needles,  m.p.  194°,  obtained  by  transforming  benzoyl  bromide  with 
silver  cyanide,  see  B.  40,  1655. 

Chloro-iso-nitroso-aceto-phenone,  benzoyl-formoximic  acid  chloride 
C6H5.CO.C(:  NOH)C1,  melting  at  131°,  is  produced  in  the  chlorination 
of  iso-nitroso-aceto-phenone  (B.  26,  R.  313). 

Formazyl-phenyl-ketone  C6H5COC(N  :  NC6H5)  :  NNHC6H5,  m.p. 
142°,  from  benzoyl-acetic  acid  or  benzoyl-acetone  with  diazo-benzol,  is 
split  by  reduction  into  aniline  and  benzoyl-amidrazone  C6H5CO(NH2)  : 
NNHC6H5,  m.p.  152°  (/.  pr.  Ch.  2,  65,  139). 

Benzoyl  cyanide  anile  CeH5C(:  NC6H5)CN,  m.p.  72°,  from  phenyl- 
anilido-aceto-nitrile  by  oxidation  with  permanganate  in  acetone. 
Similarly  we  obtain  p-dimethyl-amido-benzoyl  cyanide  anile,  m.p. 

121°  (B.  35,  3569)- 

//NH\ 

Phenyl-hydrazi-methylene-carboxylie  acid  c6H5.c(  <^  |  J.co2H.  The 
hydrazin  salt  melts  at  119°.  Diphenyl-glyoxylic  acid  hydrazone 

C6H5.C( :  N)CO2H 

I        '    .     Its  diethyl  ester  melts  at  138°  (/.  pr.  Ch.  2,  44,  567). 
C6H5.C( :  N)C02H 

Phenyl-glyoxylie  acid  phenyl-hydrazone  melts  at  153°  (A.  227,  341). 

(jS-),  Syn-phenyl-glyoxylie  acid  oxime  melts  at  147°.  (a-),  Anti- 
phenyl-glyoxylic  acid  oxime,  iso-nitroso-phenyl-acetic  acid  C6H5.C 
( :  NOH)CO2H  melts  at  128°  (B.  24, 42) .  The  methyl  ester  melts  at  138°. 
The  dimethyl  ester  melts  at  56°  (B.  16,  519).  Benzoyl  cyanide  oxime 
C6H5.C(:  NOH)CN,  melting  at  129°  (B.  24,  3504),  is  obtained  from 
benzyl  cyanide  by  means  of  amyl  nitrite  and  sodium  or  nitrous  acid 
and  sodium  ethylate.  Also  from  phenyl-glyoxime  by  boiling  with 
NaHO,  or,  direct,  from  co-dibromo-aceto-phenone  with  hydroxyl- 
amine  and  alkali  (B.  24,  3504  ;  /.  pr.  Ch.  2,  66,  353). 

Substituted  Benzoyl- formic  Acids. — o-  and  p-Bromo-benzoyl-formie 
acids  melt  at  93°-io3°  and  108°  (B.  25,  3298,  and  28,  259). 

o-Nitro-benzoyl-formic  acid  NO2.C6H4CO.CO2H+H2O  melts  at 
47°,  and,  when  anhydrous,  at  122°.  The  amide  melts  at  199°.  The 


PHENYL-PARAFFIN-KETONE-CARBOXYLIC  ACIDS    389 

nitrite  melts  at  54°  (B.  23,  1577).  The  oxime,  when  acted  upon  with 
water,  yields  CO2  and  o-nitro-benzo-nitrile.  Salicylic  acid  is  produced 
when  it  is  boiled  with  alkalies  (B.  26,  1252).  It  forms  two  isomeric 
phenyl-hydrazones  (B.  23,  2080). 

m-Nitro-benzoyl-formic  acid  melts  at  77°.  The  amide  melts  at  151°. 
The  nitrite  melts  at  230°  (145  mm.)  (B.  14,  1186). 

p-Nitro-benzoyl  cyanide,  m.p.  116°,  from  iso-nitroso-p-nitro-benzyl 
cyanide  by  splitting  (/.  pr.  Ch.  2,  66,  353). 

o-Amido-benzoyl-formie  acid,  isatinic  acid,  is  produced  on  reduc- 
ing o-nitro-benzoyl-formic  acid  with  ferrous  sulphate  and  sodium 
hydrate,  and  in  the  action  of  alkalies  on  isatin.  If  it  be  separated 
from  its  lead  salt  by  means  of  hydrogen  sulphide,  and  evaporated  under 
greatly  reduced  pressure  at  low  temperature,  it  is  obtained  as  a  white 
powder.  Digestion  of  its  solution  converts  it  at  once  into  its  lactame 
or  lactime  — 

Isatin,  lactame  of  isatinic  acid  C6H4/^      '      ,  or  lactime  of  isatinic 

acid  ceH4/^°\C.OH  (?),  melting  at  201°.     It  was  first  obtained  by 

oxidising  indigo.  It  consists  of  orange-red  prisms.  It  dissolves  in 
the  caustic  alkalies  with  the  formation  of  salts.  The  solution,  violet 
at  first,  soon  becomes  yellow,  owing  to  the  production  of  isatinates. 
Isatin  acts  at  the  same  time  like  a  ketone. 

Its  other  methods  of  formation  and  its  derivatives  will  be  discussed 
later  in  connection  with  the  hydro-indol  derivatives.  The  isatin  deri- 
vatives referable  to  the  lactame  formula  are  designated  pseudo-  or 
^-derivatives,  or  n-derivatives  —  i.e.  those  in  which  the  recently  entered 
group  is  attached  to  nitrogen,  —  whereas  the  true  isatin  derivatives  are 
referred  to  the  lactime  formula,  because  the  latter  appears  to  belong 
to  free  isatin. 

Aceto-isatinic  acid  CHg.CO.NHMCeH^CO.COaH,  melting  at  160°, 
results  upon  treating  acetyl-^-isatin  (see  this)  with  alkalies,  and  then 
with  acids.  Benzoyl-isatinie  acid,  melting  at  188°,  is  produced  when 
benzoyl-tetrahydro-quinolin  is  oxidised  with  KMnO4  (B.  24,  772). 

Acetyl-isatin  C6H4/^^  ^  melts  at  141°.    Benzoyl-isatin 


melts  at  206°. 

Anthroxanie  acid  C6H4J       |  >>0         ,  m.p.  190°,  is  formed,  with 


other  products,  during  the  oxidation  of  isatinic  acid  with  Caro's  acid, 
and  by  reduction  of  o-nitro-phenyl-glyoxalic  acid  with  tin  and  glacial 
acetic  acid  ;  also  by  heating  the  o-nitroso-mandelic  nitrile  with  con- 
centrated HC1  (B.  39,  2344),  and  by  oxidation  of  anthroxane-aldehyde 
with  KMnO4  (B.  16,  2222  ;  /.  pr.  Ch.  2,  81,  254). 

p-Dimethyl-amido-phenyl-glyoxylie  ester  (CH3)2N.C6H4CO.CO2C2H5, 
m.p.  187°,  is  obtained  from  dimethyl-aniline  ethyl-oxalic  acid  chloride, 
or  oxalic  ester  with  A1C13  (B.  10,  2081  ;  C.  1907,  II.  310)  ;  the  corre- 
sponding chloride  results  from  dimethyl-aniline  and  oxalyl  chloride. 
On  heating,  it  decomposes  into  CO  and  p-dimethyl-amido-benzoyl 
chloride  (B.  42,  3486).  p-Amino-phenyl-glyoxalic  acid  and  its  n-alky- 
lated  derivatives  are  also  formed  from  the  related  amino-phenyl- 
tartronic  acids  by  oxidation  (C.  1901,  I.  237,  239). 


390  ORGANIC  CHEMISTRY 

o-Oxy-phenyl-glyoxylic  acid  HO[2]C6H4COCOOH,  m.p.  57°,  from 
isatinic  acid  through  its  diazo-sulphate  ;  the  acid  condenses  with 
phenylene-diamine  to  o-oxy-phenyl-oxy-quinoxalin,  which  may  be 
transformed  into  a  lactone,  the  so-called  cumaro-phenazin,  and  obtained 
from  that  (B.  34,  2294)  : 

HO[2]C6H4C=N\  «  --  C6H4C=N 

4  ---  >  6—  C= 


o-Acetoxy-phenyl-glyoxylie  acid,  m.p.  ioi°-io6°,  with  one  molecule 
H2O,  is  produced  from  its  nitrile,  m.p.  111°,  the  result  of  the  action  of 
silver  cyanide  upon  acetyl-salicylic  chloride  (A.  368,  80).  The  lactone 
corresponding  to  isatin  — 

Cumarandione  c^H^j^co,  in  yellow  needles,  m.p.  178°,  is  ob- 

tained by  the  oxidation  of  the  so-called  oxindigo  with  Cr03  in  glacial 
acetic  acid  (B.  42,  199).     From  it  is  derived  iso-nitroso-cumaranone 

:  NOH,  melting  at  172°  with  decomposition  (B.  35,  1640, 


4346).     The  p-dimethyl-amido-anile  of  cumarandione  C6H4^     ^>C  :  NC6 

H4N(CH3)2)  m.p.  185°,  is  produced  by  the  condensation  of  cumaranone 
with  p-nitroso-dimethyl-aniline  (B.  44,  124). 

Thio-isatin,  thio-naphthene-quinone  C6H4<^g  ^>CO,  yellow  prisms  from 
alcohol,  m.p.  121°,  b.p.  247°,  from  its  anile,  the  transformation  product 
of  dibromo-thio-indoxyl  C6H4<^  /CBr2,  and  from  iso-nitroso-thio- 

\o  _  / 

indoxyl  C6H4\  c    ^>C  :  NOH,  m.p.  172°,  and  by  splitting  up  with  dilute 

\o  _  _/ 

H2SO4.  Dissolves  in  alkalies  with  formation  of  salts  of  thio-phenol- 
o-glyoxylic  acid,  which,  in  the  free  state,  easily  fall  back  into  the 
anhydrides  (B.  41,  227). 

p-Methoxy-phenyl-glyoxylie  acid  melts  at  89°. 

Veratroyl-carboxylie  acid  (CH3O)2[3,  4]C6H3.CO.C02H,  m.p.  138°, 
and  piperonoyl-carboxylie  acid  (CH2O2)[3,  4]C6H3CO.CO2H,  m.p.  148°, 
have  been  produced  by  the  oxidation  of  anethol,  of  iso-eugenol-methyl 
ether,  and  of  iso-safrol  (B.  24,  3488).  The  nitriles  of  the  first  two 
acids,  m.p.  64°  and  117°,  are  prepared  from  anisic  acid  chloride  and 
veratroyl  chloride  and  HCN  respectively  in  the  presence  of  pyridin 
(B.  42,  188).  2,  5-dioxy-phenyl-glyoxylic  acid,  m.p.  141°,  results  from 
oxidation  of  o-oxy-phenyl-glyoxylic  acid  with  K  persulphate  in 
alkaline  solution  (C.  1907,  II.  901). 

Homologous  Phenyl-glyoxylic  Acids.  —  m-Tolyl-glyoxylie  acid  yields 

so-called    methyl-isatin    CH3[5]C6H3{[']^^0,    m.p.    184°.     This   is 

obtained  by  boiling  p-methyl-isatin-p-tolyl-imide,  m.p.  259°,  the  pro- 
duct of  the  action  of  dichloro-acetic  acid  upon  p-toluidin,  with  hydro- 
chloric acid  (B.  16,  2262  ;  18,  198). 

p-Tolyl-glyoxylic  acid  .         .  .  m.p.  96°     (6.14,1750;  20,2049). 

(p-)[2,  5]-Xylyl-glyoxylic  acid  .         .  .  „  75°     (€.1898,1.42). 

(m-)[2,  4]-Xylyl-glyoxylic  acid  .  „  85°     (/.  pr.  Ch.  2,  41,  485). 

(o-)[2,3]-Xylyl-glyoxylicacid.  .  „  92°     (6.30,1766). 

Mesityl-glyoxylic  acid        .  .  „  ii20-ii6°\m  24  R        . 

[2,  4,  5]-Pseudo-cumyl-glyoxylic  acid  .  „  75°          / 


PHENYL-PARAFFIN-KETONE-CARBOXYLIC  ACIDS    391 

2,  3,  4,  6-  and  2,  3,  5,  6-Tetramethyl-phenyl-glyoxylic  acid  (B.  19, 

233  ;  20,  3099).     Cymyl-glyoxylic  acid  (C.  1898,  I.  42). 

Phenyi-pyro-raeemie  acid  C6H5.CH2.CO.CO2H  melts  at  154°  with 
evolution  of  carbon  dioxide.  It  is  formed  when  a-benzoyl-amido- 
cinnamic  acid  (A.  275,  8)  is  boiled  with  caustic  alkali  or  hydrochloric 
acid,  as  well  as  by  boiling  phenyl-oxal-acetic  ester  with  dilute  sulphuric 
acid  (A.  271,  163).  Ammonia  converts  it  into  a-phenacetyl-amido- 
hydro-cinnamic  acid,  or  phenacetyl-phenyl-alanin.  Oxidised  with 
H2O2,  in  alkaline  solution,  it  decomposes  cleanly  into  CO2  and  phenyl- 
acetic  acid  (C.  1904,  I.  194).  With  benzaldehyde  and  concentrated 
HC1  it  unites  to  form  /?,  y-diphenyl-a-keto-butyrol-acetone  (A.  333, 
160). 

o-Oxy-phenyl-pyro-raeemie  acid  HO.C6H4CH2.CO.CO2H  is  pro- 
duced, like  phenyl-pyro-racemic  acid,  from  a-benzoyl-amido-o-oxy- 
cinnamic  acid  and  sodium  hydroxide.  Its  lactone,  a-oxo-hydro- 

(  [i]CH2.  CO 
eumarin  C6nJ  I    (?),  m.p.  152°,  is  produced  when  it  is  boiled 

v  C2]O  -  CO 
with  acids  (B.  18,  1187). 

Nitro-substituted  phenyl-pyro-racemic  acids  are  obtained  syntheti- 
cally by  condensation  of  oxalic  ester,  and  o-  or  p-nitro-toluols  with 
sodium  ethylate  : 

o-Nitro-phenyl-pyrc-raeemic  acid  NO2[2]C6H4CH2COCOOH,  m.p. 
121°,  gives,  on  reduction,  n-oxy-indol  and,  further,  a-indol-carboxylic 

acid  CJEi^CCOOH.    p-Nitro-phenyl-pyro-racemic  acid,  m.p.  194°  ; 


o,  p-  and  o,  m-methyl-nitro-phetiyl-pyro-raeemie  acid,  m.p.  145°  and 
193°  (B.  30,  1030  ;  31,  387). 

Benzyl-pyro-racemic  acid  C6H5CH2CH2COCOOH+iJH2O,  m.p. 
47°,  results  from  the  transposition  of  a-oxy-phenyl-crotonic  acid  by 
means  of  NaHO,  while  HC1  forms  the  isomeric  benzoyl-propionic  acid  ; 
further,  benzyl-pyro-racemic  acid  is  also  obtained  by  splitting  up 
benzoyl-oxal-acetic  ester  (A.  299,  28  ;  B.  31,  3134). 

B.  Phenyl-paraffin-jS-ketone-carboxylie  Acids  are  produced  (i)  by 
a  condensation,  similar  to  the  aceto-acetic  ester  formation,  from  ben- 
zoic  and  fatty  acid  esters,  aceto-phenone,  and  carbonic  acid  esters, 
with  alcohol  elimination,  in  the  presence  of  sodium  alcoholate  (see 
Benzoyl-acetic  ester)  ;  (2)  by  the  introduction  of  alphyl  residues,  by 
means  of  chlorides  —  e.g.  benzyl  chloride,  —  into  aceto-acetic  ester 
(see  Benzyl-aceto-acetic  ester)  ;  (3)  by  action  of  benzaldehydes  upon 
diazo-acetic  ester  (see  Benzoyl-acetic  ester).  ;  (4)  from  malonic  ester 
acid  chlorides  and  benzene,  in  presence  of  A1C13  (C.  1905,  II.  30)  ;  (5)  by 
transposition  of  benzoyl  chloride  or  bromide  with  Mg-a-halogen  ali- 
phatic acid  esters  (A.  347,  71)  ;  (6)  by  hydration  of  phenyl-propiolic 
acid  ester. 

With  hydroxylamine  they  yield  oxime  anhydrides,  lactoximes,  or 
iso-azolones  ;  and  with  hydrazin  and  phenyl-hydrazin,  hydrazin  an- 
hydrides, lactazames,  or  pyrazolones.  ^ 

Benzoyl-acetic  acid  C6H5.CO.CH2.CO2H,  m.p.  103°  with  decom- 
position into  CO  2  and  aceto-phenone.  It  breaks  down,  in  the  same 
manner,  when  it  is  boiled  with  dilute  acids.  It  is  obtained  by  saponi- 
fying its  ethyl  ester  with  caustic  potash  at  the  ordinary  temperature. 
Ferric  chloride  imparts  a  violet-red  coloration  to  its  solution. 


392  ORGANIC  CHEMISTRY 

Benzoyl-acetic  ester  C6H5.CO.CH2.CO2C2H5  boils  at  148°  (n  mm.). 
(i)  It  was  first  prepared  by  dissolving  phenyl-propionic  ester  in  sul- 
phuric acid  and  then  diluting  with  water  (B.  17,  66).  (2)  By  the  action 
of  sulphuric  acid  and  water  upon  a-bromo-cinnamic  ester  (B.  19,  1392). 

(3)  It  is  most  conveniently  made  by  the  action  of  dry  sodium  ethylate 
or  sodium  upon  ethyl  benzoate  and  acetic  ester  (B.  20,  653,  2179). 

(4)  By  splitting  up  benzoyl-acetic  ester  with  ammonia  (A.  291,  70). 

(5)  Small  quantities  of  the  ester  are  produced  when  esters  of  carbonic 
acid  act  upon  aceto-phenone  together  with  sodium  ethylate.     (6)  It 
is  also  formed  when  benzaldehyde  is  heated  with  diazo-acetic  ester. 
(7)  From  malonic  ester  acid  chloride,  benzene,  and  A1C13.     (8)  From 
benzyl  bromide  and  magnesium-bromacetic  ester  : 


C6H4.C=C.C02C2H5 


2.  C6H5.CH=CBr.CO2C2H5  

3.  C6H5.C02CaH5+CH3C02C2H5  - 

4.  C6H5COCH(COCH3)CO2C2H5  NH»-H2° 

5.  C6H5.CO.CH3+C2H5O.C02C2H5  


6.  C6H5.CHO+N2.CH.C02C2H5  - 

7.  C6H6+C1CO.CH2.C02C2H5   -     -    _HQ 

8.  C6H6COBr+BrCH2C02C2H5  ™*- 


C6H5.CO.CH2C02C2H5 
Benzoyl-acetic  ester. 


Benzoyl-acetic  ester  volatilises  with  steam  without  decomposition 
(A.  282,  155).  Its  odour  resembles  that  of  aceto-acetic  ester. 

It  forms  (i)  with  ammonia  an  addition  product  like  that  of  aldehyde- 
ammonia  ;  with  amines  it  splits  off  water  and  yields  imides — e.g.  j8- 
methyl-imido-hydro-einnamic  ester  C6H5C(NCH3)CH2.CO2.C2H5  (B.  29, 
105) ;  (2)  with  hydrazin  it  yields  3-phenyl-pyrazolone  ;  (3)  with  phenyl- 
hydrazin,  diphenyl-pyrazolone  ;  (4)  with  hydroxylamine,  phenyl-is- 
oxazolone;  (5)  with  urea,  phenyl-uracile ;  (6)  with  guanidin,  imido- 
phenyl-uracile  ;  (7)  with  nitrous  acid,  the  oxime  ;  (8)  with  diazo-ben- 
zene  chloride,  the  phenyl-hydrazone  of  benzoyl-glyoxylic  ester  ;  (9) 
with  PC15,  j8-chloro-cinnamic  chloride.  Iodine  converts  its  sodium 
compound  into  dibenzyl-succinic  ester,  while  with  the  alkylogens 
horriologous  benzoyl-acetic  esters  result.  The  hydrogen  atoms  of  the 
CH2  group  are  also  replaceable,  step  by  step,  by  acid  radicles.  It 
yields  j8-ethoxy-cinnamic  esters  when  acted  upon  with  orthoformic 
esters.  The  amide  melts  at  112°  (A.  266,  332),  and  the  anilide  at  107° 
(A.  245,  374). 

The  dimethyl-acetal  C6H5C(OCH3)2CH2CO2CH3,  b.p.16  147°,  is 
formed  from  phenyl-propiolic  acid  methyl  ester  with  alcoholic  Na 
methylate  solution  at  125°  (C.  1903,  II.  664)  ;  diethyl-acetal,  b.p.13 

153°  (C.  1904,  I.  659). 

Benzoyl-aceto-nitrile,  R-cyanaceto-phenone  C6H5.CO.CH2.CN,  melt- 
ing at  80°,  is  produced  on  boiling  benzoyl-cyanacetic  ester  with  water, 
on  acting  upon  sodium  oxy-methylene-aceto-phenone  with  hydroxyl- 
amine hydrochloride  and  sodium  hydroxide  (B.  24,  133),  and  upon 
treating  imido-benzoyl-aceto-nitrile  or  imido-benzoyl-methyl  cyanide 
with  hydrochloric  acid. 

Imido-benzoyl-cyano-methane  C6H5.C(:  NH)CH2CN,  melting  at 
86°,  results  when  sodium  acts  upon  a  dry  ethereal  solution  of  benzo- 


PHENYL-PARAFFIN-KETONE-CARBOXYLIC  ACIDS    393 

nitrile  and  methyl  cyanide  or  aceto-nitrile  (B.  22,  R.  327).  When 
treated  with  hydroxylamine  hydrochloride,  the  imido-group  is  replaced 
by  the  oximido-group,  and  the  latter  adds  itself  to  cyanogen  with  the 

production   of   phenyl-isoxazolonimide  II         |  melting    at 

C6H5C.CH2.C  :  NH 
in0  (B.  26,  R.  272). 

p-Nitro-benzoyl-acetie  acid  C6H4(NO2).CO.CH2.CO2H  melts  at  135°, 
and  is  produced  by  heating  p-nitro-phenyl-propiolic  ester  with  sulphuric 
acid.  It  breaks  down,  on  melting,  into  CO2  and  p-nitro-aceto-phenone. 
o-Nitro-phenyl-propiolic  ester  is  readily  transposed  into  the  isomeric 
isatogenic  ester  (B.  17,  326). 

o-,  m-,  and  p-Nitro-benzoyl-acetic  esters  (liquid,  m.p.  79°  and  75° 
respectively)  are  best  prepared  by  splitting  up  the  corresponding  nitro- 
benzoyl-aceto-acetic  esters  (B.  35,  931,  933  ;  C.  1904,  I.  724). 

Methyl-benzoyl-aeetic  ester,  boiling  at  226°  (225  mm.),  when  treated 
with  nitrous  acid  forms  a-iso-nitroso-propio-phenone  (B.  21,  2119). 
a-Ethyl-  and  diethyl-benzoyl-acetie  ester  boil  at  210°  (90  mm.)  and  223° 
(150  mm.). 

Allyl-benzoyl-acetie  ester  boils  at  220°  (100  mm.).  Benzoyl-tri- 
methylene-carboxylie  acid,  melting  at  148°,  decomposes  at  higher  tem- 
peratures into  CO2  and  benzoyl-trimethylene  (pp.  268  seq.)  (B.  16, 2128, 
2136). 

a-Pheny!-aeeto-aeetie  ester  C6H5CH(COCH3)COOC2H5,  b.p.u  146°, 
is  obtained  by  saponifying  its  nitrile,  m.p.  90°,  a  condensation  product 
of  benzyl  cyanide  and  acetic  ester,  by  means  of  sodium  ethyiate  (B.  31, 
3160)  ;  similarly,  we  obtain  propionyl-phenyl-aeetie  ester  C6H5CH 
(COCH2CH3)CO2C2H5,  b.p.18  155°,  and  propionyl-benzyl  cyanide,  m.p. 
70°  (B.  36,  2242). 

2,  5-Dinitro-phenyl-  and  2,  4,  6-trinitro-phenyl-aeeto-aeetic  ester, 
melting  at  94°  and  98°,  result  from  the  action  of  2,  5-dinitro-bromo- 
benzene  and  2,  4,  6-trinitro-chloro-benzene  upon  sodium  aceto-acetic 
ester  (A.  220,  131 ;  B.  22,  990  ;  23,  2720). 

/CC\  C  TT 

Benzyl-aeeto-aeetic    ester   C6H5.CH2.CH<  ^^   is   derived    from 

\(^(j2f^ti3 

sodium  aceto-acetic  ester  and  benzyl  chloride  (A.  204,  179).  It  boils 
at  276°,  and  by  the  ketone  decomposition  yields  benzyl-acetone  (B.  15, 
1875)  ;  by  the  acid  decomposition  it  forms  phenyl-propionic  acid. 

C.  y-  and  8-Ketone-earboxylic  Acids  C6H5.CO.CH2.CH2.CO2H,  m.p. 
1 1 6°,  are  obtained  (i)  by  the  condensation  of  benzene  and  succinic  an- 
hydride by  means  of  A1C13  (B.  20,  1376)  ;  (2)  by  condensation  of  benz- 
aldehyde  with  maleic  acid,  or  fumaric  acid,  by  means  of  piperidin  at 
I50°-i6o°  (C.  1903,  I.  769)  ;  (3)  by  reducing  j8-benzoyl-acrylic  acid  ; 
(4)  by  the  elimination  of  carbon  dioxide  from  benzoyl-iso-succinic  acid, 
and  (5)  from  phenacyl-benzoyl-acetic  ester  by  the  acid  decomposition  ; 
(6)  by  boiling  the  HCN  addition  product  of  cinnamic  aldehyde  with 
dilute  hydrochloric  acid,  and  carefully  saponifying  the  phenyl-oxy- 
crotonic  acid  produced  at  first  when  cold,  which  with  heat  rearranges 
itself  (B.  29,  2582  ;  A.  299,  23)  : 

C.H5CH  :CH.CH(OH)CN >  C6H5CH  :  CH.CH(OH)COOH  >  C,HSCO.CH,.CH1COOH. 

(7)  Benzoyl-propionic  acid  is  also  formed  by  transposition  of  y- 
phenyl-a-oxy-butyro-lactone  (B.  36,  2529). 


394  ORGANIC  CHEMISTRY 

By    splitting    off    H2O    it    yields    phenyl-A2-eroto-laetone    C6H5 

C  :  CH.CH2COO,  m.p.  91°.  From  the  dibromide  of  cinnamic  aldehyde 
cyano-hydrin  the  isomeric  oily  phenyl-A1-croto-lactone  is  obtained, 

C6H5.CH.CH  :  CH.COO,  which  easily  transposes  into  the  A2-lactone 
(A.  319,  196). 

Reduction  transforms  /?-benzoyl-propionic  acid  into  y-phenyl- 
butyro-lactone. 

Phosphorus  pentasulphide  converts  the  acid  into  phenyl-oxy-thio- 
phene  (B.  19,  553).  It  yields  two  isomeric  oximes,  melting  at  129°  and 
92°  (B.  25,  1932). 

a-  Methyl  -  £  -  benzoyl  -  propionic  acid  C6H5COCH2CH(CH3)COOH, 
m.p.  136°,  by  condensation  of  benzene  and  pyro-tartaric  anhydride 
with  A1C13  (C.  1900,  II.  172). 

y-Benzoyl-butyrie  acid  C6H5COCH2CH2CH2COOH,  m.p.  126°,  from 
glutaric  acid  chloride  with  benzene  and  A1C13,  as  well  as  a-benzoyl- 
glutaric  ester  by  ketone-fission  (B.  31,  2001). 


a-Phenyl-laevulinic     acid     C6H5.CH  ^'    m.p.     126°,    is 

\Urj.2  .  UL/  .  L/  rig 

derived  from  phenyl-aceto-succinic  ester   (B.   17,  72  ;    18,  790).     /?- 
Benzyl-laBVUlinic   acid  C^.CIi^CH^^2^11'  from  fi-benzal-lsevulinic 

\  v>  V-J  .  O-H.O 

acid  (A.  254,  202),  m.p.  98°.     See  Benzal-angelica-lactone.     j8-Phenyl- 

PTT    C'O  T-T 

^S*'I^>tT  '  m.p.  83°.    It  is  obtained 


from  phenyl-dihydro-resorcin  by  the  action  of  alkalies  or  acids  (B.  26, 
2057  '•  A.  294,  322).  Phenyl-dihydro-resorcin  is  again  formed  when 
its  esters  are  condensed  with  sodium  alcoholate. 

(9)  PHENYL-ALCOHOL-KETONE-CARBOXYLIC  ACIDS. 

Benzoyl-glycollic  acid  C6H5.CO.CH(OH)CO2H,  m.p.  125°  (B.  16, 
2133)- 

a-Acidyl-phenyl-glycollic  esters  like  p-toly-acetyl-glycol-methyl 
ester  CH3C6H4C(OH)(COCH3).CO2CH3,  b.p.15  190°,  and  p-dimethyl- 
amido-phenyl-aceotyl-glycollic-methyl  ester  (CH3)2NC6H4C(OH)  (COCH3) 
CO2CH3,  m.p.  81°,  etc.,  are  formed  by  condensation  of  aromatic  hydro- 
carbons and  anilines  with  a,  j8-diketo-butyric  ester  (C.  1909,  I.  1795). 
They  are  easily  reduced  to  the  corresponding  aldehydes. 

Acetoxy-phenyl-pyro-raeemic  nitrile  C6H5CH(O.COCH3).CO.CN, 
m.p.  52-5°,  b.p.10  150°,  by  heating  acetyl-mandelic  chloride  with  silver 
cyanide  (A.  368,  77).  Derived  from  phenyl-oxy-pyro-racemic  acid  is 

/OH 
the   acid   C6H6CH(NHC6H5)C^  -  COOH    ,  m.p.    194°,   whose   nitrile    is 

\N  :  CHC6H5 

obtained  by  condensation  of  phenyl-anilido-acetic  nitrile  with  benz- 
aldehyde  and  KCN  (B.  29,  1732  ;  31,  2701). 

y-Phenyl-y-keto-a-oxy-butyric  acid  C6H5.CO.CH2.CH(OH)CO2H, 
m.p.  125°,  is  obtained  from  its  trichloride,  chloral-aceto-phenone  C6H5. 
CO.CH2.CH(OH)CC13,  m.p.  76°  (B.  26,  557). 

From  the  geometrically  isomeric  phenyl-keto-oxy-butyric  acids 
are  derived  the  bromination  products  of  phenyl-aceto-acetic  ester,  and 
a-propionyl-phenyl-acetic  ester  :  a-bromo-phenyl-aeetie  ester  CH3CO 


DIKETONE-CARBOXYLIC   ACIDS  395 

CBr(C6H5)CO2C2H5  and  a-propionyl-phenyl-bromo-aeetie  ester  CH3CH2 
COCBr(C6H5)CO2C2H5  ;  also  y-bromo-phenyl-aeetie  ester  CH2BrCOCH 
(C6H5)CO3C2H5  and  y-bromo-propionyl-phenyl-acetie  ester  CH3CHBr 
COCH(C6H5)CO2C2H5.  The  first  two,  distilled  with  steam,  disintegrate 
into  CO,  HBr,  and  atropic  acid  ester  or  j3-methyl-atropic  acid  ester  ;  the 
last  two,  on  heating  with  water,  yield  lactones,  viz.,  a-phenyl-tetronie 

acid  CH2.C(OH)  :  C(C6H5)COO,  m.p.  254°,  and  a-Phenyl-y-methyl- 
tetronic  aeid  CH3CH.C(OH)  :  C(C6H5)COO,  m.p.  178°  (B.  39,  3929). 

y-Phenyl-tetronic  acid  C6H5CH.C(OH)  :  CH.C()6,  m.p.  128°,  is  formed 
from  the  transformation  product  of  acetyl-mandelic  chloride  with 
sodium-malonic  ester,  by  saponification  and  elimination  of  CO2  (A. 
368,  65). 

(10)  DIKETONE-CARBOXYLIC  ACIDS. 

Benzoyl-glyoxylie  acid  C6H5.CO.CO.CO2H.  The  ethyl  ester,  an 
orange-coloured  oil,  boiling  at  I50°-I53°  (13  mm.),  is  formed  by  con- 
ducting N2O3  into  a  mixture  of  benzoyl-acetic  ester  and  acetic  an- 
hydride. With  water  and  alcohols  it  forms  colourless  hydrates  and 
alcoholates  (C.  1907,  II.  233). 

The  a-oxime  and  a-phenyl-hydrazone,  of  the  ethyl  ester  of  this 
acid,  have  been  prepared  by  the  action  of  nitrous  acid  and  diazo-benzol 
chloride  (B.  21,  2120)  upon  benzoyl-acetic  ester. 

Benzoyl-iso-nitroso-aeetic  ester  C6H5.CO.C(:  NOH)CO2C2H5,  m.p. 
121°.  Benzoyl  -  a  -  phenyl  -  hydrazone  -  glyoxylic  ester  C6H5.CO.C 
(:  NNHC6H5)CO2C2H5,  m.p.  65°.  The  benzoyl-amido-acetic  ester 
obtained  by  reduction  of  benzoyl-iso-nitro-acetic  ester  yields  on  diazo- 

tising  benzoyl-acetic  ester  diazo-anhydride  c^c  N/N  'B'  36'  3612)' 
Quinisatinic  acid,   o-amido-benzoyl-glyoxylic  aeid  NH2[2]C6H4CO. 

CO.CO2H  at  120°  breaks  down  into  water  and  its  lactame  or  lactime. 

It  is  obtained  by  oxidising  )3,  y-dioxy-carbo-styrile  with  ferric  chloride. 

Its  lactame  or  lactime  is  — 

f[i]CO.CO  f[i]CO.CO 

Quinisatin  C6HJ  I     or  C8HJ  I       ,  m.p.  255°-26o°  (B. 

1[2]NH.CO  U2]N=(I:OH 

17,  985)- 

Benzoyl-pyro-racemic  acid  C6H5.CO.CH2.CO.CO2H,  m.p.  157°,  is 
prepared  from  its  ethyl  ester  (melting  at  43°),  produced  in  the  condensa- 
tion of  aceto-phenone  and  oxalic  acid  (B.  21,  1131).  Ferric  chloride 
imparts  a  blood-red  colour  to  the  alcoholic  solution  of  the  ester.  Ben- 
zoyl-pyro-racemic chloralide,  see  B.  31,  1306.  Nucleus-substituted 
benzoyl-pyro-racemic  esters,  see  B.  34,  2477  ;  36,  2695. 

\Yhen  benzoyl  chloride  acts  upon  aceto-acetic  ester,  it  produces 
benzoyl-aceto-acetic  ester  C6H5.CO.CH.(CO.CH3).CO2C2H5.  This  de- 
composes into  aceto-phenone  and  benzoyl-acetone  (B.  18,  2131). 

o-,  m-,  and  p-Nitro-benzoyl-aceto-acetie  ester  (A.  221,  323  ;  B.  35, 


/COH 
Aceto  -  phenone  -  aceto  -  acetic  ester  C6H6.CO.CH2.CH.<^CO2CH    melts 

at    I30°-i40°,    with    decomposition    into    CO2    and    aceto-phenone- 
acetone.     Its  ethyl  ester  is  produced  by  the  action  of  co-bromo-aceto- 


396  ORGANIC   CHEMISTRY 

phenone  upon  sodium  aceto-acetic  ester  (B.  16,  2866).  Like  aceto- 
phenone  -  acetone,  the  ester  readily  forms  a  furfurane  derivative. 
On  treatment  with  alcoholic  potash  it  passes  into  y-phenyl-a-acetyl- 
crotonic  lactone. 

0-Phenaeyl-laevulinic  acid,  see  B.  34, 1263. 

(n)  PHENYL-PARAFFIN-DICARBOXYLIC  ACIDS. 

The  phenyl-paramn-dicarboxylic  acids,  like  the  aliphatic,  saturated 
dicarboxylic  acids,  can  be  arranged  into  malonic  acids,  ethylene-succinic 
acids,  etc. 

Phenyl-malonic  Acids. — Phenyl-malonie  acid  C6H5.CH(CO2H)2 
melts  at  152°,  splitting  off  CO2  and  forming  phenyl-acetic  acid.  Its  ester, 
boiling  at  171°  (14  mm.),  is  formed  from  phenyl-oxalacetic  ester  by  the 
elimination  of  carbon  monoxide  (B.  27, 1091).  Dinitro-phenyl-malonic 
ester  (NO2)2.C6H3.CH(CO2C2H5)2,  melting  at  51°,  is  obtained  by  the 
action  of  bromo-dinitro-benzene  upon  sodium  malonic  ester  (B.  21, 2472  ; 
22,  1232  ;  23,  R.  460  ;  26,  R.  10). 

2, 4, 6-Trinitro-phenyl-malonic  ester,  picryl-malonic  ester  (NO2)3 
C6H2CH(CO2C2H5)2,  exists  in  two  modifications,  melting  at  58°  and 
64°  (B.  28,  3066;  29,  R.  997;  C.  1899,  H-  25)-  Bromo-thymo- 
quinone-malonie  ester  [C6O2Br(C3H7)]CH(CO2C2H5)2,  m.p.  78°,  gives 
blue  salts  with  metals  (B.  34,  1558). 

Phenyl-eyano-acetie  acid  C6H5CH(CN).COOH,  m.p.  92°.  Its  ethyl 
ester,  b.p.  275°,  is  formed  by  the  action  of  Na  and  carbonic  acid  ester 
upon  benzyl  cyanide.  The  amide,  m.p.  147°,  gives,  on  treatment  with 
PC15,  phenyl-malonic  nitrile  C6H5CH(CN)2,  m.p.  69°,  b.p.21  153° 
(C.  1904,  II.  953). 

Benzyl  -  malonic  acid,  ft  -  phenyl  -  iso  -  succinic  acid  C6H5.CH2.CH 
(CO2H)2,  melting  at  117°,  is  obtained  from  its  ester,  produced  in  the 
action  of  benzyl  chloride  upon  sodium-malonic  ester,  as  well  as  by  the 
reduction  of  benzal-malonic  acid  (A.  218,  139). 

o-  and  p-Nitro-benzyl-malonic  ester  (B.  20,  434).  The  o-acid  is 
condensed  by  sodium  hydroxide  to  n-oxy-a-indol-carboxylic  acid 
(B.  29,  639).  Methyl-benzyl-malonie  acid  (A.  204,  177).  j8-Phenyl- 
ethyl-malonic-aeid  ester  C6H5(CH3)CH.CH(COOC2H5)2,  b.p.15  230°,  by 
attachment  of  CH3MgI  to  benzal-malonic  ester.  The  acid  melts  at 
144°  with  decomposition  into  CO2  and  /3-phenyl-butyric  acid  (C.  1905, 
II.  1023). 

C6H5.CH.CO2H 

Phenyl-succinic  Acids. — Phenyl-succinie  acid  ,  melt- 

CH2.C02H 

ing  at  167°,  results  from  a>-chloro-styrol  C6H5.CH  :  CHC1,  as  well  as  from 
benzal-malonic  ester,  by  means  of  potassium  cyanide  (A.  293,  338)  ;  by 
the  decomposition  of  phenyl-aceto-succinic  ester,  by  means  of  very  con- 
centrated caustic  potash  ;  from  phenyl-ethane-tricarboxylic  acid,  and 
from  the  so-called  hydro-cornicularic  acid  Ci7H16O8.  Its  anhydride 
melts  at  54°  (B.  23,  R.  573),  and  another  modification  at  150°  (M.  24, 
413  ;  C.  1907, 1.  720).  Chloride,  b.p.12  151°.  Dimethyl  ester,  m.p.  58°, 
b.p.12  161°. 

Ester  Acids. — By  semi-esterification  of  phenyl-succinic  acid,  or 
attachment  of  methyl  alcohol  to  the  anhydride,  we  get  about  75  per 
cent,  phenyl-succinic  ^-methyl-ester  a-acid  C6H5CH(CO2H).CH2CO2 


PHENYL-PARAFFIN-DICARBOXYLIC  ACIDS  397 

CH3,  m.p.  92°,  and  about  25  per  cent,  phenyl-succinie  a-methyl-ester 
C6H5CH(CO2CH3).CH2CO?H,  m.p.  103°. 

Pure  a-methyl  ester  /?-acid  is  obtained  by  semi-saponification  of 
the  neutral  ester,  and  the  j3-methyl  ester  a-acid  from  j8-phenyl-£- 
cyano-propionic  methyl  ester  C6H5.CH(CN).CH2CO2CH3,  m.p.  55°,  by 
saponification  of  the  cyanogen  group.  The  constitution  of  the  two 
isomeric  ester  acids  follows  from  the  transformation  of  the  ester  acid 
chlorides  with  benzene  and  ACC13,  whereby  the  j3-methyl  ester  a-acid 
passes  into  desyl-acetic  ester  and  the  a-methyl  j8-acid  into  phenyl- 
phenacyl-acetic  ester  (A.  354,  117). 

Phenyl-succinie  £-amido-a-acid  C6H5CH(COOH).CH2CONH2,  m.p. 
145°,  formed  by  attachment  of  NH3  to  the  anhydride,  the  isomeric 
phenyl-a-amido-^-acid  C6H5CH(CONH2).CH2COOH,  m.p.  159°,  from 
£-phenyl-/?-cyano-propionie  acid  (q.v.). 

o-Oxy-phenyl-succinic  acid  melts  with  decomposition  at  150°.  It 
is  obtained  from  cumarin  and  potassium  cyanide  (A.  293,  366). 

C6H5.CH.CO2H 

Phenyl-methyl-suceinie  acids  have  been  obtained  in 

CH3.CHCO2H 

two  modifications,  melting  at  170°  and  192°  (B.  24,  1876). 
C6H5.CH2.CH.CO2H 

Benzyl-succinic  acid  melts  at  161°,  and  results 

CH2.C02H 

from  sodium  ethan-tricarboxylic  ester,  or  sodium  ethan-tetra-carboxylic 
ester  by  the  action  of  benzyl  chloride,  etc.  (B.  17,  449),  as  well  as  by 
the  reduction  of  phenyl-itaconic  acid  (B.  23,  R.  237).  It  forms  an 
anhydride,  melting  at  102°. 

Phenethyl-succinic  acid  C6H5CH2CH2CH(COOH)CH2COOH,  m.p. 
136°,  by  reduction  of  styryl-succinic  acid,  and  from  hydro-cinnamyl- 
idene-malonic  acid,  with  KCN. 

Phenyl-ghitaric  Acid.— a-Phenyl-glutarie  acid  C6H5CH(COOH)CH2 
CH2COOH,  m.p.  83°,  from  C6H5CH(COOR)CH2CH(COCH3)COOR  or 
C6H5C(COOR)2CH2CH2COOR  by  splitting;  easily  passes  into  the 
anhydride,  m.p.  95°  (B.  34,  4175). 

/3-Phenyl-glutaric  acid  C6H5CH(CH2COOH)2,  m.p.  142°,  by  splitting 
up  j8-phenyl-propane-aa1-tri-  or  tetracarboxylic  ester,  the  condensation 
products  of  cinnamic  ester,  or  benzol-malonic  ester,  with  malonic 
ester  by  means  of  sodium  ethylate.  By  nitration  it  is  transformed 
into  a  mixture  of  o-,  m-,  and  p-nitro-phenyl-glutarie  acids,  m.p.  205°, 
204°,  and  240°.  The  o-nitro-acid  gives,  on  reduction  with  SnCl2 

and  HC1,  hydro-carbo-styrile-y-acetie  acid  c6H4/r[ln]™(CH2COOH)-™a 

UL2jr»lrl U(_)  ' 

m.p.  183°  (B.  40, 1586).  Homologous  and  substituted  jS-phenyl-glutaric 
acids,  see  A.  360, 344.  /3-Phenyl-a-methyl-glutarie  acid,  m.p.  125°,  from 
the  result  of  attaching  methyl-malonic  ester  to  benzal-malonic  ester. 

(12)  PHENYL-ALCOHOL-DICARBOXYLIC  ACIDS. 

A  general  method  for  preparing  these  substances  consists  in  the 
condensation  of  aromatic  hydrocarbons,  anilines,  and  phenols,  and 
mesoxalic  acid  ester  or  alloxane  (all  in  one),  under  the  influence  of 
concentrated  sulphuric  acid  (C.  1909,  I.  1560).  They  are  easily 
oxidised  to  the  corresponding  phenyl-glyoxylic  acids  and  aromatic 
aldehydes  (see  C.  1910,  I.  25). 


398  ORGANIC  CHEMISTRY 

Phenyl-tartronie  methyl  ester  C6H5C(OH)(CO2CH3)2,  m.p.  67°,  b.p.}1 
165°  ;  p-tolyl-tartronie  methyl  ester,  m.p.  72°  ;  p-methoxy-  and  p-di- 
methyl-amido-phenyl-tartronic  methyl  ester  melt  at  118°  and  115°. 

Trinitro-phenyl-tartronie  ester  (NO2)3C6H2C(OH)(CO2C2H5)2,  m.p. 
117°,  by  oxidation  of  trinitro-phenyl-malonic  ester  with  HNO3  (C. 
1899,  II.  25). 

Benzyl-tartronie  acid  C6H5.CH2.C(OH)(CO2H)2  melts  at  143°,  with 
decomposition  into  CO2  and  /3-phenyl-lactic  acid.  It  results  from  the 
action  of  caustic  potash  on  benzyl-chloro-malonic  ester,  the  product 
obtained  from  the  interaction  of  benzyl  chloride  and  sodium  chloro- 
malonic  ester  (A.  209,  243).  a  Anilido-,  phenyl-hydrazido-benzyl- 
malonic  ester,  etc.,  are  produced  by  the  addition  of  the  respective  bases 
to  benzal-malonic  ester  (B.  28,  1451  ;  29,  813). 

j8-Methoxy-benzyl-malonic  acid  C6H5.CH(OCH3).CH(CO2H)2  melts 
at  115°  with  decomposition  into  methyl  alcohol  and  benzal-malonic 
acid,  from  whose  ester  the  j3-methoxy-benzyl-malonic  ester  is  pro- 
duced by  addition  of  sodium  methylate  (B.  27,  289). 

C6H5.C(OH)C02H 

Phenyl-malic  Acids.  —  a-Phenyl-a-oxy-succinie  acid 

in2  .  co2H 

m.p.  187°,  is  produced  by  the  action  of  bromine,  phosphorus,  and  water 
upon  phenyl-succinic  acid. 

C8H5.CH.C02H 

a-Phenyl-S-oxy-suceinie  acid  ,   m.p.    I5o°-i6o°, 

CH(OH).C02H 

results  from  the  interaction  of  phenyl-formyl-acetic  ester,  prussic  acid, 
and  hydrochloric  acid  (B.  23,  R.  573). 

Benzyl-malic  acid  ^^^H^^CO,^  m'p>  I55°'  from  the  con" 
densation  product  of  chloral  with  benzyl-malonic  acid  by  saponification 
with  KOH  (B.  38,  2737). 

Phenyl-itamalic  acid  may  be  obtained  in  the  form  of  its  lactone  acid, 


es..^-a 

phenyl-paraconic    acid  I          ")CH2     ,    m.p.    109°,    by   heating 

benzaldehyde  with  sodium  succinate  and  acetic  anhydride  (A.  256,  63). 
For  other  methods,  see  B.  33,  1294  ;  A.  321,  127  ;  330,  292. 

Phenyl-paraconic  acid,  upon  distillation,  breaks  down  into  carbon 
dioxide,  phenyl-butyro-lactone,  and  phenyl-iso-crotonic  acid.  A  further 
product  is  a-naphthol  (q.v.). 

Phenyl-itaconic  acid  is  produced  when  metallic  sodium,  or  sodium 
ethylate,  acts  upon  phenyl-paraconic  esters.  Hydriodic  acid  reduces 
it  to  benzyl-succinic  acid  and  phenyl-butyric  acid  (B.  29,  15). 

o-,  m-,  and  p-Chloro-phenyl-paraeonie  acids  result  from  the  con- 
densation of  monochloro-benzaldehydes  with  sodium  succinate,  and 
yield  three  chlorinated  naphthols  (B.  21,  R.  733).  1,  3,  4-Diehloro- 
phenyl-paraconic  acid,  m.p.  138°,  forms  two  dichloro-naphthols  (B.  28, 
R.  244). 

a-  and  j8-Methyl-phenyl-paraeonic  acids  are  produced  in  the  con- 
densation of  benzaldehyde  with  pyro-tartaric  acid,  and  yield  methyl-a- 
naphthols  (A.  255,  257). 

a-Phenyl-y-valero-lactone-earboxylie   acid    c6H5.CH.co\o    ^  m  p 

C02H.CH.CH^CH3 
167°,   is    produced   in   the  reduction  of   phenyl-aceto-succinic  ester 


PHENYL-KETONE-DICARBOXYLIC  ACIDS  399 

(B.  18,  791).  S-Phenyl-S-valero-lactone-y-earboxylic  acid,  m.p.  161°, 
by  reduction  of  a-benzoyl-glutaric  acid,  on  distillation,  gives  A3-dihydro- 
cinnamenyl-acrylic  acid. 

(13)  PHENYL-KETONE-DICARBOXYLIC  ACIDS. 

Benzoyl-malonic  ester  C6H5.CO.CH(CO2.C2H5)2  and  o-nitro-benzoyl- 
malonic  ester  are  produced  by  the  action  of  benzoyl  chloride  and  o-nitro- 
benzoyl  chloride  upon  sodium-malonic  ester  (B.  20,  R.  381).  The 
latter  yields  quinolin  derivatives  upon  reduction  (B.  22,  386). 

Benzoyl-cyano-acetic  methyl  ester  c8H5.co.CH<^^2'CH3,  m.p.  74°, 

is  formed  from  cyano-acetic  methyl  ester  and  benzoyl  chloride.  Its 
ethyl  ester,  m.p.  41°,  from  benzoyl-acetic  ester  and  cyanogen  chloride, 
yields  cyano-aceto-phenone  on  boiling  with  water. 

Phenyl-aeetyl-malonie  ester  C6H5CH2.CO.CH(COOC2H5)  2,  from 
phen-acetyl  chloride  and  Na-malonic  ester,  is  condensed  by  concentrated 
H2SO4  to  naphtho-resorcin-carboxylic  ester  (A.  298,  374). 

Benzoyl-iso-succinie  ester  C6H5.CO.CH2.CH(CO2C2H5)2  is  obtained 
from  oj-bromaceto-phenone  and  sodium-malonic  ester  (B.  18,  3324). 

a-Benzoyl-glutarie  ester  C6H5COCH(CO2C2H5)CH2CH2CO2C2H5, 
b.p.12  200°-2io°,  from  Na-benzoyl-acetic  ester  with  /?-iodo-propionic 
ester. 

jS-Benzoyl-glutaric  acid  C6H5COCH(CH2COOH)2,  m.p.  122°,  on 
stronger  heating,  gradually  splits  off  H2O  and  passes  into  the  dilactone 

m.p.  137°.     The  latter  is  formed  synthetically 


_ 

from  benzoic  anhydride  and  sodium  tricarbalkylate  at  i35°-i4o° 
with  rejection  of  CO2  and  H2O  ;  it  can  easily  be  broken  up  into 
j8-benzoyl-glutaric  acid,  and  is  reduced  by  sodium  amalgam  to  phenyl- 

butyro-lactone-acetic  acid  C6H5CH.CH(CH2COOH)CH2COO,  m.p.  114° 
(A.  314,  58). 

C6H5.CH.CO.C02.C2H5 

Phenyl-oxalaeetic  ester  is  formed  from  oxalic 

C02.C2H5 

ester,  phenyl-acetic  ester,  and  sodium  (B.  20,  592).  See  Phenyl- 
malonic  acid. 

C6H5.CH.CO.C02C2H6 
Phenyl-eyano-pyro-raeemic  ester  is    obtained 

CN 

from  oxalic  ester,  benzyl  cyanide,  and  sodium  (A.  271,  172)  .  See  Phenyl- 
pyro-racemic  acid. 

C,H5.CH.C02H 
Phenyl-aceto-suecinie  ester  is  formed  from  sodium 

CH3.CO.CH.C02H 

aceto-acetic  ester  and  phenyl-bromacetic  ester  (B.  17,  71). 

C6H5.CH2.CH.C02H 

Benzyl-aceto-succinic    ester  results    from    the 

CH3.CO.CH.C02H 

interaction  of  sodium  aceto-succinic  ester  and  benzyl  chloride  (B. 
11,  1058). 


Benzyl-oxalacetie  ester  'oul'  an  °U'  from  oxalic  ester' 

with  hydro-cinnamic  ester  and  Na  alcoholate  (B.  31,  554). 


400  ORGANIC   CHEMISTRY 

(14)  PHENYL-OXY-KETONE-DICARBOXYLIC  ACIDS. 

C6H6.CH.CH— CO2C2H5 

Keto-phenyl-paraeonic  ester  I         ^co          (B.  26,  2144). 

O — CO/ 

CO O 

a-Benzoyl-8-ehloro-y-valero-laetone  ,    m.p. 

C6H5COCHCH2.CH.CH2C1 

106°,  from  Na-benzoyl-acetic  ester  with  epichloro-hydrin,  is  split  up 
by  alkali  into  benzoic  acid  and  y,  S-dioxy-valerianic  acid,  or  into  CO2 
and  benzoyl-butane-diol  C6H5.CO.CH2.CH2.CH(OH).CH2OH,  m.p.  91° 
(C.  1901,  II.  237). 

(15)  PHENYL-PARAFFIN-TRICARBOXYLIC  ACIDS. 

Phenyl-earboxyl-sueeinie   acid,  phenyl-ethane-triearboxylic  acid.— 

Its  ester  is  formed  when  phenyl-chloracetic  ester  acts  upon  sodium- 
malonic  ester  (A.  219,  31).  The  acid  breaks  down,  on  heating,  into  CO2 
and  phenyl-succinic  acid  (B.  23,  R.  573). 

a,  j3-Dieyano-£-phenyl-propionie  ethyl  ester  C6H5CH(CN).CH(CN). 
CO2C2H5,  m.p.  68°,  by  condensation  of  mandelic  acid  nitrile  with 
sodium-cyano-acetic  ester  (C.  1906,  II.  1563). 

a-Phenyl-triearballylie  acid  C6H5CH(COOH).CH(COOH)CH2COOH, 
m.p.  110°,  by  saponification  of  the  reaction  products  of  KCN  and 
phenyl-itaconic  acid  ester  (C.  1903,  II.  496). 

Phenyl-butane-triearboxylie  acid  CeH5  CH'(CO  H?CH  co  tr  trans-form 
(+JH2O),  m.p.  195°;  cis-form,  m.p.  179°,  by  saponification,  and  CO2, 
elimination  from  the  condensation  product  of  cinnamic  ester  with 
Na-cyano-acetic  ester  and  bromo-acetic  ester  ;  both  acids  yield  the 
same  anhydride  acid,  m.p.  135°  (C.  1899,  II.  833).  The  same  structure 
is  ascribed  to  the  tricarboxylic  acid  obtained  by  attaching  cinnamic 
acid  to  succinic  acid  ester,  m.p.  200°  with  decomposition,  which,  how- 
ever, has  quite  different  properties  (A.  315,  219). 

jS-Phenyl-pimelin-£1-aearie  acid  ^'^^^L  ™  ,  m.p.  142°, 

Url2.C±l(L'rl2^U2rl)2 

obtained  from  the  condensation  product  of  cinnamic  aldehyde  with 
three  molecules  sodium-malonic  ester,  by  saponification  with  con- 
centrated HBr  (A.  360,  337). 

(16)  PHENYL-KETO-TRICARBOXYLIC  ACIDS. 

a-  and  jS-Benzoyl-tricarballylie  acids  C6H5.CO.CH(COOH)CH(COOH) 
CH2COOH  and  C6H5COC(COOH)(CH2COOH)2.  Their  esters  are 
formed  from  chloro-succinic  ester  and  benzoyl-acetic  ester,  or  from 
benzoyl-acetic  ester  with  bromo-acetic  ester  and  sodium  ethylate  (B.  29, 
R.  788). 

(17)    POLYKETO-POLYCARBOXYLIC   ACIDS. 

(17)  By  condensation  of  benzaldehydes,  and  substitution  benz- 
aldehydes  with  aceto-acetic  esters,  and  similar  substances,  in  the 
presence  of  aliphatic  amines,  several  polyketo-polycarboxylic  acids 
of  the  aromatic  series  have  been  obtained,  which  are  interesting 
partly  by  their  isomeric  forms,  and  partly  on  account  of  their  capacity 
for  further  condensations.  It  is,  however,  doubtful  whether  these 
compounds  still  contain  the  open  aliphatic  chain,  or  whether  they 


PHENYLENE-OXY-DICARBOXYLIC  ACIDS  401 

ought  to  be  regarded  as  cyclic-ketone-alcohol-carboxylic  acids  of  the 
hydro-aromatic  series  (A.  323,  83  ;  332,  22).  Benzylidene-bis-aceto- 
acetic  ester  C6H5CH[CH(COCH3)CO2C2H5]2  (?)  is  obtained  from  benz- 
aldehyde  with  two  molecules  aceto-acetic  ester  in  three  stereo-isomeric 
keto-forms — p,  m.p.  150° ;  £2,  m.p.  154° ;  and  j33,  m.p.  108°, — which, 
through  their  sodium  salts,  can  be  converted  into  the  keto-enol  forms — 
a,  m.p.  61°  ;  a2,  liquid ;  a3,  m.p.  6$°-6j0.  The  benzylidene-bis-aceto- 
acetic  ester  is  easily  condensed  with  elimination  of  H2O  to  a  cyclo- 
hexanone  derivative  (A.  313,  129). 

Addendum. — A  number  of  compounds  attach  themselves  to  the 
phenyl-poly-alcohols  and  their  oxidation  products.  They  may  be 
regarded  as  derived  from  the  various  classes  of  bodies  which  have  just 
been  described,  by  assuming,  in  addition  to  the  one  aliphatic  side 
chain,  a  second  or  more  groups  (mostly  carboxyl  groups)  attached  to 
the  benzene  ring.  Most  of  the  bodies  belonging  here  are  o-di-deriva- 
tives  of  benzene,  o-phenylene  derivatives,  obtained  in  part  from 
o-phthalic  acid,  and  in  part  by  the  oxidation  of  derivatives  of  ortho- 
condensed  hydrocarbons — e.g.  indene  and  naphthalene.  Mention  may 
be  made  of  the  subjoined  compounds.  Some  of  them  are  intimately 
related  to  the  dicarboxylic  acids,  which  have  been  discussed,  carrying 
the  one  carboxyl  group  in  the  nucleus  and  the  other  in  the  side  chain. 

(18)  PHENYLENE-OXY-DICARBOXYLIC  ACIDS. 

o-Carbo-mandelic  acid  CO2H[2]C6H4.CH(OH)CO2H  decomposes 
readily  into  water  and  a  lactone-carboxylic  acid  : 

Phthalide-carboxylic  acid  c«H<{co>ozH'  melting  at  X49°>  and 
beyond  180°  decomposing  into  carbon  dioxide  and  phthalide.  It  is 
formed  by  the  reduction  of  o-carbo-phenyl-glyoxylic  acid  (B.  18,  381  ; 
31,  373),  or  by  boiling  the  eo-dibromo-aceto-phenone-o-carboxylic  acid 
HO2CC6H4COCHBr2,  m.p.  132°,  with  water  (B.  40,  71),  as  well  as  by  the 
action  of  alkali  upon  tetrachloro-hydrindone  (A.  334, 341).  Substituted 
phthalide-carboxylic  acids,  see  A.  296,  344. 

Acetonyl-phthalide  c«H*{co>oH2COCH3>  m-P-  68°'  from  acetone 
with  phthal-aldehydic  acid  (C.  1898,  II.  980). 

Phthalide-acetic  acid  C6H4^^^2-C°2H,  melting  at  150°,  is  derived 
from  phthalyl-acetic  acid  by  reduction  (B.  10,  1558,  2200). 

Meconin-acetic  acid  (HO)2[5>6]C6H2|[*^~QHa-CO8H,  melting  at 
228°,  results  from  the  action  of  hydriodic  acid  upon  meconin-acetic 
acid  (CH30)2[5,6]C6H2^^]™^2-C°2H.  The  latter  is  formed  in  the 

condensation  of  opianic  acid  with  malonic  acid,  glacial  acetic  acid, 
and  sodium  acetate  (B.  19,  2295). 

( [i]CH2.CH.CO2H 

Dihydro-iso-cumarin-carboxylie  acid  C6HJ  '   ,  melting 

( [2]CO— O 

at  153°,  is  isomeric  with  phthalide-acetic  acid.  It  is  produced  in  the 
oxidation  of  dihydro-naphthol  (see  this)  with  potassium  permanganate 
(B.  26,  1841). 

VOL.  II.  2  D 


402  ORGANIC  CHEMISTRY 


Phthalide-propionic  acid  ^,  melting  at  140°, 


results  from  the  reduction  of  phthalyl-propionic  acid  (B.  11,  1681). 

(  [i]CH(C02H)0 
o-Phenylene-aeeto-glyeol-laetone  acid  C6HJ  +iiH2o, 

1  [2]CH2  ---  60 
m.p.    85°,    is     obtained     from    phenylene  -  diacetic     acid,    bromine, 

phosphorus,  and  water  (B.  26,  223). 

f[i]CH(OH).CH.C02H 
o  -  Carbo  -  phenyl  -  glyceric  acid  lactone  C6H4  -{ 

l[2]CO  -  O 

m.p.  202°,  is  produced  when  jS-naphtho-quinone  is  oxidised  with  a 
bleaching-lime  solution.  When  the  lactone  acid  is  heated  with  hydro- 
chloric acid  it  loses  water  and  becomes  o-carbon-a-oxy-cinnamic  acid 
lactone  (B.  27,  198). 

(19)  PHENYLENE-KETONE-DICARBOXYLIC  ACIDS. 
o-Carbo-phenyl-glyoxylic    acid,  phthalonic   acid 

m.p.  I38°-I40°,  is  formed  in  the  oxidation  of  o-hydrindene-carboxylic 
acid  (q.v.),  naphthalene,  a-naphthol,  jS-naphthol,  and  the  oxy-quinone 
of  jS-phenyl-naphthalene  with  potassium  permanganate  (A.  240,  142  ; 

B.  31,  369).     It  yields  o-carbo-mandelic  acid  upon  reduction,  and  also 
homo-phthalic  acid.     Heating  the  acid  alone  gives  phthalic  anhydride, 
phthal-aldehydic   acid,  and  biphthalyl.      Ester  and   ester  acids,  see 

C.  1904,  I.  514. 

Trichloro-aceto-benzoic  acid  c6H4/W^>.cci3^          ^          0>    and 

UL2JCO2H 

tribromo-aeeto-benzoie  acid,  m.p.  160°,  result  when  chlorine  or  bromine, 
in  glacial  acetic  acid,  acts  upon  phthalyl-acetic  acid  (B.  10,  1556). 

o-Carbo-benzoyl-aeetic    acid    CA/?^^  •  •**,  m.p.  90°  with 

U  [2  ]CO2H 

decomposition  into  carbon  dioxide  and  aceto-phenone-o-carboxylic 
acid,  is  formed  when  phthalyl-acetic  acid  is  dissolved  in  an  excess 
of  caustic  soda  and  precipitated  with  acids  (B.  10,  1553). 

co-Cyano-aceto-phenone-o-earboxylie  acid  melts   at   136°   (B.   26, 


Benzoyl-eyano-aeeto-ester-o-earboxylic     acid 

C02H[2]C6H4.CO.CH/C°AH5)  m.p.  I2i°,  is  produced  by  the  action  of 

\CN 
soda  upon  phthalyl-cyano-  acetic  ester  (B.  26,  R.  370). 


o-  Carbo  -  benzoyl  -  propionic    acid  CJBi-*,   m.p. 

I,  [2JCO2H 

137°.     The  double  lactone  C9H4/£^£H2-CH2-CO,  corresponding  to  this 

acid,  is  produced  on  heating  succinic  anhydride  and  phthalic  anhydride 
with  sodium  acetate  (B.  11,  1680  ;  18,  3119). 

(20)  TRI-  AND  TETRACARBOXYLIC  ACIDS. 

Benzyl  -  malonic  -  o  -  earboxylie  acid,  o-carbo-  benzyl  -malonic  acid 
)^    breaks  down    at    I9Qo  into  hydro-cinnamic-o- 


OXY-TRI-,   TETRA-,   AND   PENTACARBOXYLIC  ACIDS    403 

carboxylic  acid  and  CO2.  Its  diethyl  ester  results  from  the  reduc- 
tion of  phthalyl-malonic  ester  (A.  242,  37). 

o-,  m-,  and  p-Xylylene-dimalonic  tetra-ethyl  esters  C6H4[CH2.CH 
(CO2C2H5)2]2  are  produced  in  the  reduction  of  the  three  corresponding 
xylylene-diehloro-dimalonie  esters  CeH^CHaCCltCOgC^sJJ^  which 
are  the  products  of  the  action  of  sodium  chloro-malonic  ester  upon  the 
co-xylylene  dibromides  (B.  21,  31).  The  xylylene-dimalonic  acids 
break  down,  on  heating,  into  phenylene-dipropionic  acids  and  2CO2. 

m-Xylylene-diaceto-acetic  ester  C6H4[i,  3][CH2.CH(COCH3)CO2R]2 
from  m-xylylene  bromide  and  Na-aceto-acetic  ester  (B.  34,  2790). 

(21)  OXY-TRI-,  TETRA-,  AND  PENTACARBOXYLIC  ACIDS. 

(C[CH2.CO2H]2 

Phthalyl-diacetic   acid    c^nJ  ,  m.p.   158°,  is  obtained 

(coo 

from  phthalyl-dimalonic  acid  C6H4{^         '°*H)^  (A  242>  go) 

(coo 
Phthalide-triearboxylicacid  (COOH)2C6H2/CH^OOH,  by  condensa- 

tion of  pyro-racemic  acid  and  diacetyl-glyoxylic  acid  (CH3COO)2CH. 
COOH  with  alkalies.  On  boiling  with  water  the  acid  loses  CO2,  and 

passes  into  phthalide-dicarboxylic  acid    (CO2H)2C6H2/™2\o,  which,  on 

\O(J    r 

oxidation,  yields  prehnitic  acid  (A.  311,  132). 

(22)  KETONE-TRICARBOXYLIC  ACIDS. 

2,  6  -  Diearbo  -  phenyl  -  glyoxylie  acid  (CO2H)  2[2,  6]C6H3CO.CO2H, 
melting  at  238°,  is  formed  when  naphthalic  acid  is  oxidised  with  KMnO4 
(B.  26,  1798).  Hydriodic  acid  and  phosphorus  reduce  it  to  2-methyl- 
iso-phthalic  acid,  and  when  heated  it  becomes  2-aldehydo-iso-phthalic 
acid,  while  more  complete  oxidation  converts  it  into  hemi-mellitic  acid 
(B.  29,  R.  282). 

Iregenone-di-  and  tri-earboxylic  acids   CH2[4]C6H3/W^^)2co2H 

U  [2jCO.CO2H 
and 


Mono-nuclear,  Aromatic  Substances,  with  Unsaturated  Side  Chains. 

The  benzene  derivatives  thus  far  considered  contain  saturated 
side  chains  having  carbon  present  in  them.  To  these  are  attached  the 
compounds  having  unsaturated  side  chains  —  e.g.  : 

Phenyl-ethylene,  Styrol  .  C,H6.CH  :  CHt  Phenyl  Acetylene      .        .    C.HSC  :  CH 

Cinnamyl  Alcohol,  Styrone  .  C8HS.CH  :  CH.CH,OH  Phenyl  Acetylene  Alcohol  .     C8HSC  :  C.CH.OH 

Cinnamyl  Aldehyde          .  .  C.HS.CH  :  CH.CHO  Phenyl  Acetylene  Aldehyde  C.H8C  •  C.CHO 

Cinnamic  Acid         .         .  .  C,H5.CH  :  CH.CO.H  Phenyl  Propiolic  Acid        .     C.H5C  ;  C.CO,H. 

They  can,  like  the  unsaturated  aliphatic  bodies,  be  converted 
by  numerous  additive  reactions  into  saturated  compounds,  as  has 
frequently  been  shown  in  the  preceding  sections. 

la.  OLEFIN-BENZENES. 

For  the  preparation  of  the  olenn-benzols  containing  the  olefin 
linkage  in  the  neighbourhood  of  the  benzene  nucleus,  the  secondary 


404  ORGANIC  CHEMISTRY 

and  tertiary  phenyl-alkyl-carbinols  are  particularly  suited,  and  can 
be  easily  prepared  from  the  synthetic  acidyl-benzols  by  reduction  or 
by  the  action  of  magnesium  alkyl-iodides. 

These  carbinols  are  (i)  made  into  chlorides  by  treatment  with  HC1 
at  o°,  and  HC1  is  split  off  from  the  latter  by  heating  with  pyridin  : 

C6H5COCH3 >  C6H6CH(OH)CH3 >  C6H5CHC1CH3 >  C6H5CH  :  CH2. 

(2)  The  addition  products  obtained  from  acidyl-benzols  or  benzol- 
carboxylic  esters  split  up  on  heating  with  excess  of  AlkMgl  (B,  35, 
2633,  3506) : 

C6H6COCH3 

According  to  the  position  of  the  ethylene  double  linking  to  the  ben- 
zene nucleus  we  distinguish  A1,  A2,  and  A3  olenn-benzols  or  styrols, 
differing  in  density,  boiling-point,  molecular  refraction,  and  heat  of 
combustion  (B.  36,  1628,  3584  ;  37,  2301  ;  A.  373,  288). 

On  heating  with  alcoholic  potash,  the  A2-styrols  are  converted  into 
the  isomeric  A^styrols.  This  is  reversible  to  some  extent  (C.  1905,  II. 
1017). 

Styrol,  phenyl-ethylene,  vinyl-benzol  C6H5.CH  :  CH2,  boiling  at 
144°,  occurs  in  storax  (1-5  per  cent.),  from  which  it  is  obtained  upon 
distillation  with  water.  It  also  accompanies  crude  xylene  in  coal-tar 
(B.  23,  3169,  3269).  It  is  prepared  (i)  from  chlorethyl-benzol  by  heat- 
ing with  pyridin  to  130°  (B.  36,  1632)  ;  (2)  from  j3-bromo-hydro- 
cinnamic  acid,  heated  in  NaHO,  when  it  splits  up  cleanly  into  CO2, 
BrH,  and  styrol ;  (3)  by  heating  cinnamic  acid  with  lime  (B.  23,  3269) 
or  water  to  200°  ;  (4)  from  phenyl-acetylene  by  partial  reduction  with 
zinc  and  glacial  acetic  acid  or  Na  and  methyl  alcohol ;  (5)  by  the  con- 
densation of  acetylene,  C2H2,  upon  application  of  heat.  (6)  From 
vinyl  bromide,  benzene,  and  aluminium  chloride  (A.  235,  331).  (7)  It 
is  best  obtained  from  jS-bromo-hydro-cinnamic  acid,  which  is  immediately 
decomposed  by  a  soda  solution  into  styrol,  carbon  dioxide,  and  hydro- 
bromic  acid.  It  is  a  mobile,  strongly  refracting  liquid,  with  an  agree- 
able odour.  Pure  styrolene  is  optically  inactive  ;  its  sp.  gr.  =  0-925 
at  o°. 

Hydriodic  acid  converts  styrolene  into  ethyl-benzene  C6H5C2H5  ; 
hydrochloric  and  hydrobromic  acids  change  it  to  a-haloid  ethyl- 
benzenes  (B.  26,  1709),  while  with  chlorine  and  bromine  it  yields 
a,jS-di-haloid  ethyl-benzenes  ;  chromic  acid  or  nitric  acid  oxidises  it  to 
benzoic  acid. 

With  xylene  and  sulphuric  acid,  styrol  forms  /?-phenyl-a-tolyl-pro- 
pane  ;  and  with  phenol,  oxy-diphenyl-ethane  (B.  24,  3889).  Nitrous 
acid  converts  it  into  styrol-pseudo-nitrosites  C6H5.C2H3.(N2O3)  (B.  29, 
356).  It  is  polymerised  to  meta-styrol  (C8H8)  on  standing,  or  in 
sunlight,  whence  styrol  is  regenerated  by  distillation  (C.  1899,  II, 
1117;  A.  371,259). 

A.  Styrols  substituted  in  the  Side  Chains. — Two  series  of  mono- 
substituted  styrols  result  from  the  replacement  of  vinyl-hydrogen. 
They  are  known  as  a-  and  co-substituted  products  : 

a-Bromo-styrol  C6H5Br  :  CH2. 
co-Bromo-styrol  C6H5.CH.CHBr. 


OLEFIN-BENZENES  405 

The  a-products  result  on  heating  styrol  chloride  (bromide)  alone, 
with  lime,  or  with  alcoholic  potash.  They  possess  a  penetrating  odour, 
causing  tears.  They  yield  aceto-phenone  (B.  14,  323)  when  they  are 
heated  with  water  (to  180°)  or  with  sulphuric  acid.  a-Chloro-styro 
also  results  from  aceto-phenone  chloride  when  it  is  digested  with  alco- 
holic potash. 

a-Chloro-styrol  boils  at  190°. 

a-Bromo-styrol  „         I5o°-i6o°  (75  mm.). 

to-Chloro-styrol  „         199°. 

a>-Bromo-styrol  „        108°  (20  mm.). 

The  CD-products  are  derived  (along  with  phenyl-acetaldehyde)  from 
the  jS-phenyl-a-chloro-  (bromo-)  lactic  acids,  upon  heating  with  water. 
co-Chloro-styrol  is  obtained  also  from  a>-dichloro-ethyl-benzol  with  alco- 
holic potash.  o>-Bromo-styrol  is  formed  from  dibromo-hydro-cinnamic 
acid  by  boiling  with  water.  When  they  are  heated  with  water,  phenyl- 
acetaldehyde  results.  They  are  oils  having  a  hyacinth-like  odour. 

See,  further,  Phenyl-acetylene  and  Phenyl-propiolic  acid. 

Sym.  dichloro-styrol  C6H5.CC1  :  CHC1  boils  at  221°  (B.  10,  533), 
from  phenyl-acyl  chloride  with  PC15 ;  gives  diphenyl-pyrazin  on  heating 
with  ammonia  (B.  33,  2654  ;  35,  2294). 

Dibromo-styrol  boils  at  253°  (B.  17,  R.  22). 

Di-iodo-styrol,  phenyl-acetylene  di-iodide,  m.p.  76°,  is  obtained  from 
phenyl-acetylene  and  iodine  (B.  26,  R.  18).  Tri-iodo-styrol,  phenyl- 
tri-iodo-ethylene  C6H5.CI  :  CI2,  m.p.  108°,  is  obtained  from  phenyl- 
iodo-acetylene  and  iodine  dissolved  in  CS2  (B.  26,  R.  19). 

Unsym.  dichloro-styrol  C6H5CH  :  CC12,  b.p.  225°,  is  found  among 
the  products  of  the  reaction  of  chloral  upon  benzene  in  presence  of  AC13 
(A.  296,  263  ;  C.  1900,  II.  326).  Triehloro-styrol  C6H5CC1 :  CC12,  b.p. 

235°. 

o»-Nitro-styrols  generally  result  from  the  condensation  of  benzalde- 
hydes  and  nitro-methane  by  means  of  sodium  ethylate  or  aliphatic 
amines  (B.  37,  4502)  ;  in  the  former  case  there  are  intermediate  pro- 
ducts in  the  shape  of  sodium  salts  of  nitro-alcohols  C6H5CH(OH)CH  : 
NOONa,  which  easily  split  off  H2O  and  become  co-nitro-styrols.  On 
reduction  with  Al  amalgam  or  zinc  dust  and  acetic  acid  the  nitro-styrols 
form  aryl-acetaldoximes  C6H5CH2.CH  :  NOH  (C.  1902,  II.  449). 

a>-Nitro-styrol,  phenyl-nitro-ethylene  C6H5.CH  :  CH(NO2),  m.p.  58°, 
is  obtained  by  boiling  styrol  with  fuming  nitric  acid,  by  condensation 
of  benzaldehyde  with  nitro-methane  CH3(NO2)  (B.  31,  656  ;  32,  1293  ; 
A.  325,  7),  as  well  as  by  the  action  of  fuming  nitric  acid  upon  phenyl- 
iso-crotonic  acid  (B.  17,  413),  or  by  the  action  of  NO2  upon  cinnamic 
acid,  when  the  dinitro-compound  C6H5.C2H2(NO2)2.CO2H,  formed  at 
first,  decomposes  (B.  18,  2438  ;  29.  357).  It  possesses  a  peculiar  odour, 
provoking  tears,  is  readily  volatilised  in  aqueous  vapour,  and  forms 
yellow  needles.  Dilute  sulphuric  acid  decomposes  it  into  benzaldehyde, 
carbon  monoxide,  and  hydroxylamine.  It  combines  with  sodium 
methylate,  or  ethylate,  to  form  sodium  salts  C6H5CH(OR).CH  :  NOONa, 
from  which  CO2  separates  out  phenyl-methoxy-  and  ethoxy-nitro- 
ethane  in  the  form  of  yellowish  oils,  boiling  at  136°  and  137°  (12  mm.) 
(B.  38,  466).  p-Phenylene-bis-nitro-ethylene  C6H4(CH2CH.NO2)2  is 
obtained  from  terephthalic  aldehyde  with  nitro-methane  (B.  32, 1295). 


406  ORGANIC   CHEMISTRY 

Phenyl-vinyl-amine,  co-amido-styrol  C6H5.CH  :  CHNH2,  is  very 
unstable.  It  is  obtained  by  heating  a-amido-cinnamic  acid  (B.  17, 
1622),  and  from  oj-nitro-styrol  (B.  26,  R.  677). 

B.  Styrols  substituted  in  the  Benzene  Nucleus. — The  three   nitro- 
styrols  are  produced  by  the  action  of  a  cold  soda  solution  upon  the 
nitro-phenyl-bromo-lactic  acids,  or  by  boiling  the  j3-lactones  of  the 
phenyl-bromo-lactic  acids  with  water  (B.  16,  2213  ;   17,  595). 

0-,  m-,  and  p-Nitro-styrols  NO2C6H4CH  :  CH2  melt  at  +13°,  -5°, 
and  +29°.  o-Amido-styrol  is  a  very  unstable,  oily  body.  m-Amido- 
styrol,  b.p.  Ii2°-ii5°  (12  mm.),  is  an  oil  which  polymerises  with  ease. 
m-Azo-styrol  melts  at  38°  (B.  26,  R.  677).  p-Amido-styrol,  m.p.  81°, 
is  formed  on  heating  p-amido-cinnamic  acid,  and,  together  with 
p-amido-cinnamic  acid,  in  the  reduction  of  p-nitro-cinnamic  ester 
(B.  15,  1984). 

C.  Styrols  substituted  both  in  the  benzene  nucleus  and  in  the  side 
chain  PC15  convert  o-  and  p-nitro-aceto-phenones  into  liquid  ortho- 
and  p-nitro-a-chloro-styrol  NO2.C6H4.CC1 :  CH2,  melting  at  63°  (A.  221, 

329). 

o-Nitro-w-ehloro-styrol  NO2.C6H4.CH  :  CHC1,  melting  at  58°,  is 
obtained  from  o-nitro-cinnamic  acid  and  hypochlorous  acid  (B.  17, 
1070). 

o-Amido-ehloro-styrol,  melting  at  56°,  yields  indol  when  it  is  heated 
to  170°  with  sodium  alcoholate ;  see  also  o-oxy-o>-chloro-styrol.  o-, 
m-,  and  p,  co-Dinitro-styrol  melt  at  107°,  125°,  and  199°  respectively, 
with  decomposition  ;  see  B.  31,  657,  1294  ;  C.  1902,  II.  449. 

D.  Homologous    Olefin-benzols.  —  m-    and    p-Methyl-styrol,   vinyl- 
toluols  CH3C6H4CH  :  CH2,  b.p.  164°  and  b.p.  60°  ;  4-ethyl-styrol,  b.p.20 
86°  ;  2,  4,  5-  and  2,  4,  6-trimethyl-styrol,  m.p.  118°,  b.p.  213°  and  b.p.14 
92°  have  been  prepared  mostly  by  method  i  (B.  24,  1332  ;   31,  1007  ; 
35,  2245).     For  other  olefins  of  the  mesitylene  series,  dimethyl-styrols, 
see  B.  37,  924. 

Propenyl-benzol,  iso-allyl-benzol  C6H5.CH  :  CHCH3,  b.p.13  74°,  from 
a-chloro-propyl-benzol  with  pyridin,  from  cinnamic  alcohol  by  reduc- 
tion with  HI,  from  o>-bromo-styrol  with  CH3MgI,  and  from  a,  /3-ehloro- 
bromo-propenyl-benzol  C6H5CC1  :  CBrCH3,  a  transformation  product 
of  bromo-propionyl-benzol  C6H5.COCHBrCH3,  by  reduction  with 
sodium  in  ether  (B.  36,  3033). 

Allyl-benzol  C6H5.CH2.CH2.CH  :  CH2,  b.p.  155°,  from  benzene-allyl 
iodide  and  zinc  dust  (A.  172,  132)  or  from  C6H5MgBr  and  allyl  bromide 
(C.  1904,  II,  1038). 

Iso-propenyl-benzol,  metho-vinyl-benzol  C6H5C(CH3)  :  CH2,  b.p.  162°, 
from  aceto-phenone  or  benzoic  acid  ester  with  excess  of  magnesium- 
methyl  iodide,  or  from  C6H5C(CH3)2OMgI  with  NH3  ;  similarly,  metho- 
propenyl-,  metho-butenyl-,  and  metho-hexenyl-benzols  have  been  pre- 
pared, boiling  at  192°,  199°,  and  210°  (20  mm.)  respectively.  On  the 
elimination  of  formaldehyde  from  metho-vinyl-benzol  by  atmospheric 
oxidation,  see  C.  1902,  II.  1505.  Optically  active  metho-pentenyl- 
benzol,  b.p.9  ioo°-io3°,  [a]D  50-3°  (B.  37,  653).  to-Bromiso-propenyl- 
benzol  C6H5C(CH3)  :  CHBr,  b.p.9  106°,  from  dibromo-£-methyl- 
cinnamic  acid  with  NaHO.  With  alcoholic  potash  and  migration  of 
the  phenyl  group  it  yields  phenyl-alkylene  (C.  1907,  I.  1201). 

A2-Butenyl-benzol   C6H5CH2CH  :  CHCH3,   b.p.   176°,   D15  0-8857, 


ACETYLENE  BENZENES  407 

nD  1-5109,  from  benzyl-acetone  by  reduction  and  dehydration,  or  by 
reduction  of  phenyl-butadiene  with  sodium  and  alcohol.  On  heating 
to  180°  with  alcoholic  potash  it  passes  into  the  isomeric  A1-butenyl- 
benzol  C6H5CH  :  CH.CH2.CH3,  b.p.  189°,  D16  0-9124,  nD  1-5414,  which 
also  results  from  benzaldehyde  treated  with  propyl-magnesium  iodide, 
and  which  is  reduced  by  nitrogen  and  alcohol  to  n-butyl-benzol,  in 
contrast  with  A2-butenyl-benzol  (B.  37,  2310). 

AMso-amenyl-benzol  C6H5CH  :  CH.CH(CH3)2,  b.p.  207°.  AMso- 
amenyl-benzol  C6H5CH2.CH  :  C(CH3)2,  b.p.  205°  (B.  37,  2314). 

Ib.  ACETYLENE  BENZENES. 

Phenyl-acetylene,  acetenyl-benzene,  C6H5.C  '•  CH,  boiling  at  139°,  is 
produced  (i)  when  a-bromo-styrolene  and  (2)  aceto-phenone  chloride 
are  heated  to  130°  with  alcoholic  potash  ;  (3)  also  from  phenyl- 
propiolic  acid,  on  heating  it  with  water  to  120°,  or  upon  distilling  the 
barium  or  aniline  salt  (B.  29,  R.  797),  or  the  copper  salt  with  steam 
(A.  342,  222).  Phenyl-acetylene  is  a  liquid  with  an  agreeable  odour. 
Like  acetylene,  it  forms  a  compound  with  ammoniacal  silver  solution 
and  with  a  solution  of  cuprous  chloride,  phenyl  -  acetylene  -  silver 
C6H5.CCAg,  white  (B.  25,  1096),  and  phenyl  -  acetylene  -  copper 
C6H5.C  '•  C.Cu,  light  yellow,  which  dissolves  in  glacial  acetic  acid  with 
an  orange  coloration  and  formation  of  the  very  oxidisable  double 
salt  C6H5C :  C.Cu,  CH3COOCu,  and  of  diphenyl-butenin  (A.  342, 
193).  Phenyl-acetylene-sodium  C6H5C  '•  CNa  is  formed  by  the  action 
of  sodium  upon  an  ether  solution  of  phenyl-acetylene  ;  it  condenses 
with  aldehydes  and  ketones  to  phenyl-acetylene  alcohols,  with  formic 
ester  to  phenyl-acetylene-aldehyde,  with  homologous  acid  esters  or 
chlorides  to  phenyl-acetylene-ketones,  with  chloro-carbonic  ester 
to  phenyl-propiolic  ester,  and  with  CO2  to  phenyl-propiolic  acid. 
Treated  with  hydrated  sulphuric  acid,  phenyl-acetylene  becomes  aceto- 
phenone,  and  by  boiling  with  acetic  acid  or  alcohol,  and  zinc  dust,  it 
becomes  styrol,  with  small  quantities  of  diphenyl-butadiene  (B. 
22,  1184). 

Phenyl-chloro-acetylene  C6H5C;CC1,  b.p.14  74°.  Phenyl-bromo- 
acetylene  C6H5C  =  CBr,  b.p.15  96°.  Phenyl-iodo-acetylene  C6H5C  ;  CI, 
b.p.  22  136°,  are  converted  by  sulphuric  acid  into  the  corresponding 
phenacyl  haloids  (B.  26,  R.  20  ;  A.  308,  292).  Various  aryl-chloro- 
acetylenes  are  formed  from  the  corresponding  a,  jS-dichloro-styrols  with 
alcoholic  potash,  while  metallic  sodium  forms  aryl-acetylenes  (B.  33, 
2654,  3261). 

o-Nitro-phenyl-aeetylene  and  p-nitro-phenyl-acetylene  C6H4<^     H, 

vNC/2 

melting  at  8i°-82°  and  152°,  are  produced  on  boiling  o-  and  p-nitro- 
phenyl-propiolic  acid  with  water. 

o-Amido-phenyl-acetylene  C6H4(NH2)C  :  CH  is  an  oil  with  an  odour 
resembling  that  of  the  indigo  vat.  It  is  produced  in  the  reduction  of 
o-nitro-phenyl-acetylene  with  zinc  dust  and  ammonia,  or  with  ferrous 
sulphate  and  potassium  hydroxide,  and  in  the  decomposition  of  o-amido- 
phenyl-propiolic  acid. 

Phenyl  -  methyl  -  acetylene,  phenyl-allylene  C6H5.C ;  C.CH3,  boiling 
at  185°,  is  produced  on  boiling  phenyl-bromo-propylene  with  alcoholic 
potash  (B.  21,  276).  Phenyl-ethyl-acetylene,  boiling  at  201°,  is 


4o8  ORGANIC  CHEMISTRY 

obtained  from  sodium  phenyl-acetylide  and  ethyl  iodide,  as  well  as 
from  phenyl-iodo-acetylene  and  zinc  ethide. 

Ic.    DlOLEFIN-BENZOLS. 

A.  p-Divinyl-benzol  C6H4(CH  :  CH2)2  is  a  liquid  with  an  odour  like 
that  of  petroleum.     It  is  produced  when  p-di-a-bromo-ethyl-benzol  is 
heated  with  quinolin  (B.  27,  2528). 

B.  Phenyl-butadiene  CgHgCH  :  CH.CH  :  CH2,  m.p.    -3-5°,  b.p.18 
95°,  is  formed  by  the  action  of  excess  of  methyl-magnesium  iodide 
upon  cinnamic  aldehyde  (B.  37,  2310),  from  cinnamylidene  malonic  or 
acetic  acid  by  splitting  off  CO2  ;  also  from  the  chloride  of  styryl-methyl- 
carbinol  C6H5CH  :  CH.CHC1.CH3  by  boiling  with  pyridin.     It  poly- 
merises on  standing,  and  does  so  rapidly  on  heating  to  150°,  forming 
bimolecular  bis-diphenyl-butadiene  (C10H10)2,  b.p.17  221°  (B.  37,  2272). 
Sodium  and  alcohol  reduce  phenyl-butadiene  to  A2-butenyl-benzol. 
With  bromine  it  forms  a  1,  4-dibromide  C6H5CHBrCH  :  CH.CH2Br,  m.p. 
94°,  and  with  2Br2  a  tetrabromide  C6H5CHBrCHBr.CHBrCH2Br.     The 
dibromide  changes  with  zinc  methyl  and  ethyl  into  dimethyl  and 
diethyl-butenyl-benzol    CgHgCHfAlkJCH  :  CHCH2(Alk).     With   diazo- 
acetic  ester,  phenyl-butadiene  combines  to  form  styryl-trimethylene- 

carboxylic  ester  C6H6CH :  CH.CH</™'C°2R  (B.  37,  2101). 

An  isomeric  (P)-phenyl-butadiene  and  its  polymerisation  product 
are  formed  from  cinnamenyl-acrylic  acid  (cinnamylidene-acetic  acid)  by 
heating  with  barium  hydroxide  (B.  35,  2649,  2696  ;  36,  1404). 

Phenyl-methyl-butadiene  C6H5CH  :  CH.C(CH3)  :  CH2,  b.p.32  124°, 
and  phenyl-methyl-pentadiene  C6H5CH,:  CH.C(CH3)  :  CHCH3,  b.p.21 
133°,  from  benzal-acetone,  with  magnesium  methyl  and  ethyl  iodide 
by  method  2  (B.  35,  2651).  Phenyl-pentadiene  C6H5CH  :  CH.CH  : 
CH.CH3,  b.p.16 116°.  Phenyl-hexadiene  C6H5CH  :  CH.CH  :  CH.CH2CH3, 
b.p.16  128°,  from  cinnamic  aldehyde  and  ethyl-  or  propyl-magnesium 
iodide  respectively  (B.  40,  1768). 

Trimethyl-phenyl-allene  C6H5(CH3)C  :  C  :  C(CH3)2,  b.p.20  108°,  a 
strongly  refractive  liquid  with  an  odour  resembling  lemon,  is  formed 
by  the  action  of  C6H5MgBr  upon  mesityl  oxide.  On  oxidation  with 
KMnO  it  yields  aceto-phenone,  and  on  reduction  with  Na  and  alcohol 
A2-hexenyl-benzol  (B.  37,  2305). 

Id.  OLEFIN- ACETYLENE-BENZOLS,  like  iso-propenyl-phenyl-aeetylene 
C6H5C  C.C(CH3)  :  CH2,  b.p.7  88°,  and  iso-butenyl-phenyl-acetylene 
C6H5C  i  C.C(CH3)  :  CH.CH3,  b.p.9 103°,  have  been  prepared  from  phenyl- 
acetylene  alcohols,  by  splitting  off  water  with  sulphuric  acid  or  potas- 
sium bisulphate  (C.  1905,  II.  1018). 

Ha.  OLEFIN-PHENOLS. 

Various  representatives  of  this  class  occur  in  the  vegetable  kingdom  : 
chavicol,  chavibetol,  estragol,  anethol,  eugenol,  safrol,  asarone,  apiol, 
etc.  All  are  phenol-like  derivatives  of  allyl-  and  iso-allyl-  or  propenyl- 
benzene.  The  allyl  fatty  derivatives  occurring  in  the  vegetable  kingdom 
were  mustard  oil  (I.  423)  and  oil  of  garlic  (I.  150). 


OLEFIN-PHENOLS  409 

A.  Olefin  -monoxy-  benzols.—  o-  Vinyl  -phenol  CH2  :  CH.C6H4OH, 

m.p.  29,  b.p.15  108°,  smells  like  phenol,  and  is  formed  by  slow  distillation 
of  o-cumaric  acid  in  a  vacuum  (B.  41,  367). 

m-Vinyl-phenol  CH2  :  CH.C6H4.OH,  b.p.  115°  (16  mm.),  is  obtained 
from  m-amido-styrol.  o-,  m-,  and  p-vinyl-anisols  CH2  :  CH.C6H4.O.CH3 
boiling  at  83°  (n  mm.),  90°  (14  mm.),  and  91°  (13  mm.)  respectively, 
are  easily  polymerised  oils,  obtained  from  the  corresponding  methoxy- 
aceto-phenones  by  method  I  ;  the  o-  and  p-derivatives  have  also  been 
obtained  from  the  methoxy-cinnamic  acids  (B.  11,  515  ;  36,  3587). 

o-Oxy-co-chloro-styrol  HO[2]C6H4.CH  :  CHC1,  m.p.  54°,  is  obtained 
from  o-amido-oj-chloro-styrol.  Caustic  potash  converts  it  into  cuma- 
rone  (q.v.).  o-Thio-cu-ehloro-styrol  HS.C6H4.CH  :  CHC1,  see  Benzo- 
thiophene. 

Allyl-  and  Propenyl-phenols.  —  A  very  common  property  of  the 
allyl-phenols  is  their  rearrangement,  induced  by  hot  alcoholic  potash, 
into  isomeric-propenyl  compounds  : 


CH3O.C6H4.CH2.CH  :  CH2  --  >  CH3O.C6H4.CH  :  CH.CH3       Anethol. 

(CH30)2C6H3.CH2.CH:CH2-^(CH30)2C6H3.CH:CH.CH3   M^^ 
Safrol       (CH202)C6H3.CH2.CH  :  CH2  -  >  (CH2O2)C6H3.CH  :  CH.CH3    Iso-safrol. 


The  propenyl  derivatives  are  distinguished  from  their  allyl  deriva- 
tives by  higher  specific  gravities,  higher  melting-points,  and  greater 
refractive  power  (B.  22,  2747  ;  23,  862).  When  the  propenyl  com- 
pounds are  acted  upon  by  nitrous  acid,  in  glacial  acetic  acid,  they  yield 
di-iso-nitroso-peroxides,  derivatives  of  a-diketones  (see  Anethol).  The 
allyl-  and  propenyl-phenols,  when  carefully  oxidised  with  potassium 
permanganate,  yield  phenol-glycols  and  phenol-glyoxylic  acids  ;  and,  on 
oxidation  with  ozone,  oxy-benzaldehydes  and  oxy-phenyl-acet- 
aldehydes  (B.  41,  2751).  Mercuric  acetate  oxidises  the  propenyl  com- 
pounds to  glycols,  with  elimination  of  mercuric  acetate.  The  allyl 
bodies  form  only  addition  products,  from  which  the  allyl-phenols  can 
be  regenerated  by  decomposition  with  acids  or  by  reduction  (B.  36, 
3577  ;  C.  1906,  II.  119  ;  B.  42,  1502).  By  boiling  with  concentrated 
formic  acid  the  propenyl  compounds  are  resinified,  while  the  allyl 
compounds  remain  unchanged  (B.  41,  2185).  The  iodo-hydrins  of 
the  propenyl  compounds,  on  treatment  with  AgNO3  or  HgO,  form 
aldehydes,  with  migration  of  the  aromatic  residue.  Thus  anethol 
forms  p-methoxy-hydratropic  aldehyde  CH3OC6H4CH(CH3)CHO.  In 
the  dibromides  of  the  propenyl  compounds  the  bromine  atom  adjoining 
the  phenyl  group  is  easily  movable  ;  they  can  therefore  be  converted 
into  ketones  by  treatment  with  two  molecules  sodium  methylate,  e.g. 
anethol  dibromide  into  anisoyl-ethyl-ketone.  This  cannot  be  done  in 
the  case  of  the  allyl  dibromides. 

Chavicol,  p-allyl-phenol  CH2  :  CH.CH2[4]C6H4OH,  b.p.  237°, 
occurs  in  the  oil  obtained  from  the  leaves  of  Chavica  Betle.  Also  in  betel 
oil  and  ethereal  bay  oil.  It  is  a  colourless  oil,  with  peculiar  odour,  and 
its  aqueous  solution  is  coloured  blue  by  a  drop  of  ferric  chloride. 
Methyl-chavicol  boils  at  226°,  and  ethyl-chavicol  boils  at  232°  (B.  23,  862). 

Estragol,  methyl-chavicol,  occurs  in  tarragon  oil  and  other  ethereal 


410  ORGANIC  CHEMISTRY 

oils  (B.  27,  R.  46).  It  boils  at  215°  (compare  B.  27,  R.  46  ;  29,  544  ; 
C.  1899,  I-  1196).  Synthetically  it  is  formed  by  the  action  of  allyl 
bromide  upon  p-methoxy-phenyl-magnesium  bromide  (C.  1904,  II. 
1038).  It  changes  into  anethol  when  heated  with  alcoholic  potash. 

p-Anol,  p-propenyl-phenol  CH3.CH  :  CH[4]C6H4OH,  m.p.  92°,  is 
prepared  by  heating  anethol  with  caustic  alkali  (A.  Suppl.  8,  88)  ;  or, 
synthetically,  from  p-oxy-benzaldehyde  and  excess  of  ethyl-magnesium 
bromide  (C.  1908,  I.  1624). 

Anethol,  p-propenyl-anisol  CH3.CH  :  CH[4]C6H4.O.CH3,  m.p.  21°, 
and  b.p.  232°,  occurs  in  anise  oil,  from  the  seed  of  Pimpinella  anisum, 
in  that  from  the  seed  of  Illicium  anisatum,  in  the  fruit  of  Anethum 
faniculum,  and  in  fennel  and  tarragon  oils.  It  is  also  formed  from 
methyl-chavicol  (see  above).  It  has  been  obtained  synthetically  from 
ethyl  Mg  iodide  and  anisaldehyde  (B.  37,  4188)  and  from  /?-p-methoxy- 
phenyl-methacrylic  acid  by  heating  ;  this  would  prove  that  its  con- 
stitution is  that  of  p-propenyl-anisol  (B.  10,  1604).  Chromic  acid 
oxidises  it  to  anisic  and  acetic  acids,  while  dilute  nitric  acid  changes  it 
to  anisic  aldehyde.  Methoxy-phenyl-glyoxylic  acid  is  produced  on 
treating  it  with  potassium  permanganate  ;  anisyl-propenyl-glycol  on 
treating  it  with  mercuric  acetate  ;  and  methoxy-hydratropic  aldehyde 
by  treatment  with  iodine  and  mercuric  oxide.  With  HNO2  it  unites 
according  to  the  conditions  either  to  form  anethol-pseudo-nitrosite, 
anethol  nitrite  CH3OC6H4CH(NO).CH(NO2)CH3,  m.p.  121°,  or  p-meth- 
oxy-phenyl-methyl-glyoxime  CH3OC6H4C(NOH)C(NOH)CH3,  or  its 
peroxide.  The  anethol  nitrite  splits  off  hyponitrous  acid  on  treatment 
with  acetyl  chloride  or  sodium  methylate,  and  becomes  jS-nitro- 
anethol  CH3OC6H4CH  :  CH[NO2].CH3,  m.p.  47°,  yellow  needles. 

Anethol-nitroso-ehloride  CH3OC6H4CHC1.CH(NO).CH3,  m.p.  128° 
(A.  332,  318).  o-  and  m-Propenyl-anisol,  b.p.  220°  and  227°  (B.  29, 
R.  644  ;  36,  1188). 

o-,  m-,  and  p-iso-propenyl-anisols  boil  at  199°,  215°,  and  222°  respec- 
tively. They  are  formed  from  the  anisol-carboxylic  esters  with 
CH3MgI  (C.  1904,  II.  593  ;  1908,  I.  1624  »  H.  595).  Like  the  propenyl 
compounds,  the  iso-propenyl  compounds  are  easily  reduced  with  Na 
and  alcohol.  On  oxidation  with  KMnO4  oxy-aceto-phenones  are 
generated.  Treated  with  AgNO3  their  iodo-hydrins  yield  ketones,  with 
migration  of  the  aromatic  residue. 

B.  Olefin-dioxy-benzols. — Of  this  group  it  is  the  olefin-3,  4-dioxy- 
benzols  which  are  almost  exclusively  known.  They  usually  occur,  as 
ethers,  in  plants,  or  are  obtained  by  the  breaking  down  of  plant  acids. 

Free  vinyl-pyro-cateehin  (HO)2[3,  4]C6H2CH  :  CH2  seems  to  be 
unstable  and  easily  polymerised.  Its  carbonate  CO(O2)C6H3CH  :  CH2, 
m.p.  66°,  is  formed  by  the  dry  distillation  of  3,  4-dioxy-benzal-malonic 
carbonate  (B.  41,  4153). 

Hesperetol,  vinyl-^  ^-guaiacol  c^o[4]}C6H3'CH  :  CH2'  m-p-  57°'  is 
produced  in  the  dry  distillation  of  calcium  iso-ferulate  (B.  14,  967). 
Vinyl-3,4-pyro-catechin-methylene  ether  CH2<^?  \c6H3CH :  CH2,b.p.15 

108°,  from  piperonal  and  magnesium-methyl  iodide  (B.  36,  3595). 

Allyl-3,  4-pyro-cateehin  (HO) ,[3,  4]C6H3CH2.CH  :  CH2,  m.p.  49°, 
b.p.4  139°,  has  been  found  in  the  oil  of  Java  betel  leaves.  It  possesses 


OLEFIN-PHENOLS  411 

a  feeble  odour,  recalling  creosote  ;  its  alcoholic  solution  is  coloured 
deep  green  by  ferric  chloride  (C.  1907,  II.  1741).  More  frequently  the 
ethers  of  allyl-pyro-catechin  are  found  among  the  ethereal  oils.  Of 
these  substances,  special  mention  should  be  made  of  eugenol  and  safrol, 
the  foundation  materials  for  the  artificial  production  of  the  perfumes 
vanillin  and  heliotropin. 

Eugenol,       allyl  -  4,  3  -  guaiacol,     eugenic     acid,     carnation     acid 

3M\C6H3.CH2.CH:CH2,    is    an    aromatic    oil,    boiling    at    247°. 
CH3O[3J  J 

It  is  coloured  blue  by  ferric  chloride.  It  occurs  in  the  oil  from  Eugenia 
caryophyllata,  in  that  from  Eugenia  pimenta,  etc.  Sodium  amalgam 
reduces  coniferyl  alcohol  to  eugenol  (B.  9,  418).  Potassium  perman- 
ganate oxidises  it  to  vanillin  and  vanillinic  acid.  Heated  with  excess 
of  alcoholic  potash,  it  is  transposed  into  the  isomeric  iso-eugenol.  See 
B.  27,  2455  ;  28,  2082,  for  the  derivatives  of  eugenol. 


Chavibetol,  betel-phenol,  allyl-^^-guaiacol  J*  °j^  }c6H3.CH8.CH  :  CH2J 

^-ti3UL4j  J_ 

boiling  at  254°,  occurs  in  the  ethereal  oil  obtained  'from  the  leaves  of 
Piper  Betle  (J.  pr.  Ch.  2,  39,  349  ;  B.  23,  862). 

Eugenol-methyl  ether,  allyl-^,  ^-veratrol  (CH3O)2[3,  4]C6H3.CH2. 
CH  :  CH2,  boiling  at  244°,  is  present  in  paracoto  oil  (A.  271,  304),  in 
the  ethereal  oil  from  Asarum  europceum  (B.  21,  1060),  and  in  bay  oil. 
It  has  been  synthetically  prepared  from  pyro-catechol-dimethyl  ether, 
allyl  iodide,  and  zinc  dust  (B.  28,  R.  1055).  Chromic  acid  oxidises  it 
to  dimethyl-proto-catechuic  acid  or  vetraric  acid.  It  forms  iso-eugenol- 
methyl  ether  when  heated  with  alcoholic  potash.  It  also  results  when 
sodium  eugenol  or  potassium  chavibetol  is  treated  with  methyl  iodide 
(J.pr.  Ch.  2,39,353). 

Safrol,       shikimol,        allyl  -  3,  4  -  pyro  -  catechol  -  methylene    ether 

CH2/^3Hc6H3.CH2.CH  :  CH2,  melting   at   8°   and  boiling  at   232°,   is 
^-'i/j.j  J 

present  in  the  oil  of  Sassafras  officinalis  and  in  that  of  Illicium  religiosum 
or  Shikimino-ki.  Potassium  permanganate  oxidises  it  to  methylene- 
p,  m-dioxy-benzyl-glycol,  homo-piper  onylic  acid  and  piperonoyl-car- 
boxylic  acid,  which  are  further  oxidised  to  piperonal  and  piperonylic 
acid  (B.  24,  3488  ;  28,  2088).  Nitrosites  (see  B.  28,  R.  1004). 

Propenyl-3,  4-pyro-eateehin,  isomeric  with  allyl-3,  4-pyro-catechin,  is 
formed  in  small  quantities  by  transformation  of  proto-catechin  alde- 
hyde with  excess  of  ethyl-magnesium  bromide  (C.  1908,  I.  1624).  The 
propenyl-pyro-catechol  ethers  :  iso-eugenol,  iso-eugenol-methyl  ether  and 
iso-safrol,  isomeric  with  the  previously  described  allyl-pyro-catechol 
ethers,  are  derived  from  it. 

Iso-eugenol       **°j:4Hc6H3CH  :  CH.CH3,  boiling  at  260°,  is  formed 

J 


when  homo-ferulic  acid  is  distilled  with  lime,  and  upon  heating  eugenol 
with  caustic  potash  or  sodium  alcoholate  in  amyl  alcohol  (B.  27,  2580  ; 
C.  1897,  I.  384).  Synthetically,  from  vanillin  and  ethyl-magnesium 
bromide  (C.  1908,  I.  1625).  On  oxidation  it  yields  vanillin,  a  reaction 
which  is  used  industrially  on  a  large  scale. 

Iso-eugenol-methyl  ether,  propenyl-%,  ^-veratrol,  boiling  at  263°, 
has  been  found  in  the  oil  of  Asarum  arifolium,  and  results  upon  heating 
eugenol-methyl  ether  with  alcoholic  potash  (B.  23,  1165).  Also  from 
methyl-vanillin  and  C2H5MgBr  (C.  1908,  I.  1625).  Potassium  perman- 


4i2  ORGANIC  CHEMISTRY 

ganate  oxidises  it  to  veratroyl-carboxylic  acid  and  veratric  acid  (B.  24, 
2877).  It  yields  a  glycol,  melting  at  88°,  when  it  is  carefully  oxidised. 

Iso-safrol  CH2<^3^C6H3.CH  :  CH.CH3,  boiling  at  249°,  is  obtained 

from  safrol  by  heating  it  with  alcoholic  potash,  or  with  dry  sodium 
ethylate.  Synthetically,  from  piperonal  and  C2H5MgI  (C.  1904, 
II.  1566).  Potassium  permanganate  oxidises  it  to  a  glycol  (B.  36, 
3580),  melting  at  101°,  and  piperonoyl-carboxylic  acid.  Chromic  acid 
changes  it  to  piperonal,  artificial  heliotropine,  from  which  it  can  be 
again  re-formed  by  condensation  with  propionic  acid,  and  the  splitting 
off  of  CO  o  from  the  methylene-homo-caffeiic  acid  which  is  first  pro- 
duced (B.  29,  R.  382).  Sodium  and  alcohol  reduce  it  to  dihydro-safrol 
and  m-propyl-phenol  (B.  23, 1160) .  Pseudo-nitrosite,  m.p.  128°  (A.  332, 

331). 

C.  Olefln  -  trioxy  -  benzols. — Asarone,  propenyl  -  2,  4,  5  -  trimethoxy- 
benzene  (CH3O)3[2,  4,  5]C6H2.CH  :  CH.CH3,  melting  at  67°  and  boiling 
at  296°,  separates  from  the  ethereal  oil  of  the  root  of  Asarum  europceum, 
in  which  it  is  present  together  with  terpenes  -and  eugenol.     Also  from 
calmus  oil  (B.  35,  3190),  and  synthetically  from  asaryl-aldehyde,  pro- 
pionic anhydride,  and  sodium  propionate  (B.  32,  289). 

Potassium  permanganate  oxidises  it  to  trimethoxy-benzaldehyde 
and  a  trimethoxy-benzoic  acid,  which  breaks  down  into  CO2  and  oxy- 
hydroquinone-methyl  ether  when  it  is  distilled  with  lime  (B.  23,  2294). 

Elemicin,  ally  1-3,  4,  $-trimethoxy-benzol  (CH3O)3[3,  4,  5]C6H2CH2. 
CH  :  CH2,  b.p.10  I44°-I47°,  is  the  chief  constituent  of  Manila  elemi  oil 
(B.  41,  1768).  On  oxidation  with  ozone,  it  yields  trimethyl-homo- 
gallic  aldehyde  and  trimethyl-homo-gallic  acid ;  with  KMnO4,  in  acetone 
solution,  it  forms  trimethyl-gallic  acid.  On  heating  with  alcoholic 
potash  it  is  converted  into  the  corresponding  propenyl  compound,  iso- 
elemicin,  b.p.10  I53°-I56°,  which  is  geometrically  isomeric  with  asarone. 
Iso-elemicin  is  oxidised  by  ozone  to  trimethyl-gallic  aldehyde  or  acid 
(B.  41,  1918,  2183). 

Myristicin,    butenyl  -  3,  4,  5  -  trioxy  -  benzol  -  methyl  -  methylene    ether 

ceH2C4H7,  melting  at  30°,  results  upon  treating  the  high-boil- 
. 
ing  portions  of  nutmeg  oil  and  mad  oil  with  metallic  sodium.     It  is  also 

obtained  with  apiol  from  the  seed  of  French  parsley  (B.  36,  3451). 
Alcoholic  potash  transposes  it  into  the  propenyl  compound  iso- 
myristicin,  m.p.  45°,  which,  on  oxidation  with  permanganate,  gives  a 
methylene-methyl-pyrogallic  aldehyde  and  methylene-methyl -gallic 
acid  (B.  36,  3446).  Nitrosites,  see  C.  1905,  II.  482. 

D.  Olefln  -  tetraoxy  -  benzols. — Apiol,    allyl-apionol-dimethyl-methyl- 
ene  ester  (CH3O)2(CH2O2).C6H.CH2.CH  :  CH2,  melting  at  30°  and  boil- 
ing at  294°,  occurs  in  parsley  seeds   and   in  Petroselinum   sativum. 
Potassium  permanganate  oxidises  it  to  ethers  of  a  tetraoxy-benzal- 
dehyde  and  a  tetraoxy-benzoic  acid.     See  also  ApinoL     Boiling  alco- 
holic potash  changes  it  to  the  isomeride  isapiol,  m.p.  56°,  b.p.  304°  (B. 
25,  R.  908).     An  apiol,  b.p.  162°  (n  mm.),  differing  from  the  preced- 
ing only  in  the  relative  position  of  the  methylene  and  methyl  groups, 
occurs  in  the  oil  from  Anethum  graveolens  (B.  29,  1800),  in  sea-fennel 
oil  (C.  1909,  II.  1334), and  m  matico  oil  together  with,  parsley  apiol.     By 
alcoholic  potash  it  is  converted  into  the  isomeric  dilliso-apiol,  m.p.  44°, 


PHENYL-OLEFIN   ALCOHOLS  413 

(C.  1904,  II.  525)  l-Allyl-2, 3, 4, 5-tetramethoxy-benzol  (CH3O)4 
[2,  3,  4,  5]C6HCH2CH  :  CH2,  m.p.  25°,  has  been  isolated  from  French 
parsley  seed.  On  oxidation  with  KMnO4  it  yields  tetramethoxy-ben- 
zoic  acid  (B.  4-1,  2761). 

lib.  Aeelylene-anisol  CH  ;  CC6H4OCH3,  b.p.u  85°-88°,  from  a,  ft- 
dichloro-p-methoxy-styrol  with  sodium  (B.  36,  915). 

Acetylene-phenetol  CH  ;  C.C6H4O.C2H5  (A.  269, 13). 

Ilia.  PHENYL-OLEFIN   ALCOHOLS  WITH  THEIR  OXIDATION  PRODUCTS. 

The  chemistry  of  the  phenyl-olefin  alcohols,  aldehydes,  and  ketones 
has  not  been  fully  developed.  Their  phenol-like  derivatives  will  be 
discussed  in  immediate  connection  with  the  most  important  repre- 
sentatives of  the  class.  The  division  in  detail  of  the  material  into  poly- 
alcohols  and  their  oxidation  products,  as  was  carried  out  with  uni- 
nuclear benzene  derivatives  having  oxygen-containing  side  chains,  is 
not  feasible  with  uni-nuclear  benzene  derivatives  having  unsaturated 
oxygen-containing  side  chains,  because,  at  present,  no  representatives 
have  been  prepared  of  many  classes  of  compounds  which  can  be  de- 
duced theoretically.  The  bodies  belonging  here  will,  therefore,  be 
introduced  at  the  proper  places  in  connection  with  the  simple  phenyl- 
olefin  alcohols,  and  their  oxidation  products. 

10.  Phenyl-olefin  Alcohols. — The  two  phenyl-vinyl  alcohols, 
possible  theoretically,  are  not  known,  and  apparently  are  incapable 
of  existence.  The  a-haloid  styrols  become  aceto-phenone  upon  re- 
placing their  halogen  atom  by  hydroxyl,  while  the  j3-haloid  styrols  yield 
phenyl-acetaldehyde  : 

a-Chloro-styrol  C6H6.CC1 :  CH8    — ^£-»-  C8H6.CO.CH3    Aceto-phenone. 
w-Bromo-styrol  C6H5.CH  :  CHBr  >  C6H6.CH2CHO  Phenyl-acetaldehyde. 

However,  the  corresponding  ethyl  ethers  have  been  prepared  : 

jS-Phenyl-vinyl-methyl  ether,  b.p.  2io°-2i3°,  and  jS-phenyl-vinyl- 
ethyl  ether  C6H5.CH  :  CH.O.C2H5,  b.p.24  115°,  are  formed  from  co- 
chloro-styrol  and  from  phenyl-acetylene  by  heating  with  sodium  alcohol- 
ate  (A.  308,  270  ;  C.  1904,  I.  720). 

a-Phenyl-vinyl-methyl  ether  C6H5C(O.CH3)  :  CH2,  b.p.  197°,  from 
/2-methoxy-cinnamic  acid. 

a-Phenyl-vinyl-ethyl  ether  C6H5C(OC2H5)  :  CH2,  ,b.p.  209°,  is  ob- 
tained by  splitting  off  alcohol  from  aceto-phenone-acetal,  with  heat, 
and  is  rearranged,  by  heating  under  pressure,  into  isomeric  phenyl 
ethyl  ketone  (B.  29,  2931).     By  saponification  these  ethers  are  con- 
verted into  phenyl-acetaldehyde  and  aceto-phenone  (C.  1904,  I.  719). 

/3-Phenyl-vinyl-phenyl  ether  C6H5CH  :  CH.O.C6H5,  b.p.7  158°,  by 
distillation  of  a-phenoxy-cinnamic  acid.  On  heating  with  alcoholic 
potash  to  about  200°,  the  phenol  residue  is  displaced,  and,  among  other 
products,  jS-phenyl- vinyl-ethyl  ether  is  formed  (B.  38, 1962). 

Cinnamyl  alcohol,  styrone,  y-phenyl-allyl  alcohol  C6H5.CH  :  CH 
CH2OH,  m.p.  33°  and  b.p.  250°,  occurs  as  cinnamic  ester  in  liquid 
storax,  the  sap  of  the  Liquidambar  orientalis  tree,  found  in  the  south- 
western portion  of  Asia  Minor.  It  is  prepared  artificially  by  reduction 
of  cinnamic  aldehyde  diacetate  (C.  1905,  II.  672).  When  oxidised  it 
becomes  cinnamic  aldehyde,  cinnamic  acid,  and  benzoic  acid  ;  see 
also  Stycerine.  Styryl-amine  C6H5.CH  :  CH.CH2NH2,  b.p.  236°  (B.  26, 


414  ORGANIC  CHEMISTRY 

1858  ;  C.  1906,  II.  1420).  Styryl-iso-cyanate  C6H5CH  :  CH.NCO,  b.p.12 
107°,  see  C.  1909,  I.  1655.  a-Phenyl-allyl  alcohol  C6H5CH(OH).CH  : 
CH2,  b.p.25  114°,  from  phenyl-magnesium  bromide  and  acrolein  (B. 
39,  2554). 

Styryl-methyl-earbinol,  y-phenyl-a-methyl-allyl  alcohol  C6H5.CH  : 
CHCH(CH3)OH,  b.p.21  144°,  from  cinnamic  aldehyde,  with  magnesium- 
methyl  iodide  (B.  35,  2649,  3186). 

ib.  Oxy-phenyl-olefin  Alcohols.  —  j8-Anisyl-/?-methyl-vinyl  alcohol 
CH3OC6H4C(CH3)  :  CHOH,  m.p.  79°,  b.p.14  175°,  is  formed  from 
estragol  dibromide  by  successive  treatment  with  potassium  acetate 
and  alcoholic  potash,  with  simultaneous  molecular  transposition  (C. 
1907,  II.  1910)  : 

j  CH3OC6H4CH2CHBr.CH2Br  ^  CH3OC6H4C(CH3)  :  CHOH 

1  CH3OC6H4CH2CH(OCOCH3).CH2Br  4-  CH3OC6H4CH(CH3).CHO. 

On  distillation  at  ordinary  pressures,  and  under  the  influence  of 
acids,  the  alcohol  transposes  into  p-methoxy-hydratropic  aldehyde. 
With  sodium  methylate,  and  dimethyl  sulphate,  the  corresponding 
methyl  ethyl  is  formed,  b.p.  262°,  which  is  also  obtained  from  anethol- 
methyl-iodo-hydrin  by  treatment  with  HgO,  with  migration  of  the 
aromatic  residue  (C.  1907,  II.  1789)  : 

CH3OC6H4CH(OCH3).CHI.CH3  --  >  CH3OC6H4(CH3)  :  CHOCH3. 


Cumarone    CeH^r^X  _  _|       is   the    inner    anhydride    of    o-oxy- 

phenyl-vinyl  alcohol.  It  will  be  described  later  under  the  heterocyclic 
compounds. 

Glyco-o-eumaro-aleohol  C6HnO5.O.C6H4.CH  :  CH.CH2OH,  m.p. 
115°,  has  been  formed  from  glyco-o-cumaraldehyde  (see  below). 

Sec.  methyl-  o-eumaro-  alcohol  HO.C6H4.CH  :  CH.CH(OH)CH3, 
m.p.  47°.  See  Methyl-o-cumaro-ketone. 

Tertiary    dimethyl-    and    diethyl  -  o  -  eumaro  -  alcohol    anhydride 

fCH:CH 
C6Hj  ,   b.p.u   93°   and   b.p.15    127°,    from    cumarin    with 

\O  -  C(Alk)2 
magnesium-methyl,  and  ethyl,  iodides  (B.  37,  494). 

Coniferyl  alcohol,  m-methoxy-p-oxy-styrone  c^^4Hc6H3.CH  :  CH. 

CH2OH,  melting  at  73°,  is  formed  from  coniferin  (q.v.),  which  emulsin 
decomposes  into  glucoses  and  coniferyl  alcohol.  Vanillin  results  from 
its  oxidation,  and  eugenol  from  its  reduction. 

Cubebin  CH2^^\C6H3.CH  :  CH.CH2OH,  melting  at  125°,  is  found 

in  cubebs,  the  fruits  of  Piper  cubeba. 

ic.  Phenyl-aeetylene  alcohols  are  formed  by  the  condensation  of 
sodium-phenyl-acetylene,  in  ethereal  suspension,  with  trioxy-methylene, 
and  the  homologous  aldehydes,  or  by  the  action  of  caustic  alkali  upon 
a  mixture  of  ketones,  with  phenyl-acetylene.  Also  from  phenyl-pro- 
pargyl-aldehyde,  and  phenyl-acetylene  ketones,  with  alkyl-magnesium 
haloids:  phenyl-acetylene  alcohol  C6H5C  i  CCH2OH,  b.p.16  139°; 
phenyl-aeetylene-methyl-earbinol  C6H5C  ;  C.CH(OH)CH3,  b.p.  29  149°; 
phenyl-acetylene-dimethyl-carbinol  C6H5C  '•  C(OH)(CH3)2,  m.p.  53°; 
omanthylidene-phenyl-earbinol  CH3[CH2]4C  ;  CCH(OH)C6H5,  b.p.16 


PHENYL-OLEFIN   ALDEHYDES  415 

181°,  from  sodium-oenanthylidene  with  benzaldehyde  (B.  39,  2594  ; 
€.1901,11.25;  1902,1.619,1319;  1905,11.1018;  1907,1.561). 

2a.  Phenyl-olefln  Aldehydes.  —  Cinnamic  aldehyde,  f$-phenyl-acroleln 
C6H5.CH  :  CH.CHO,  boiling  at  247°,  forms  the  chief  constituent  of 
cinnamon  oil  from  Cinnamomum  ceylanicum,  and  the  oil  from  Persea 
Cassia,  from  which  it  can  be  extracted  with  acid  sodium  sulphite.  The 
first  product  is  the  double  derivative  C6H5.CH  :  CH.CH(OH)SO3K, 
which  combines  with  a  second  molecule  of  mono-potassium  sulphite 
to  yield  C6H5.CHSO3K.CH2.CH(OH).SO3K+2H2O,  which  dissolves 
with  difficulty  (B.  24,  1805  ;  31,  3301). 

The  aldehyde  results  from  the  oxidation  of  cinnamyl  alcohol,  in  the 
dry  distillation  of  a  mixture  of  the  lime  salts  of  cinnamic  and  formic 
acids,  and  by  the  action  of  hydrochloric  acid  gas  or  sodium  hydrate 
(B.  17,  2117),  or  sodium  ethylate  (B.  20,  657)  upon  a  mixture  of  benz- 
aldehyde and  ace  t  aldehyde. 

Cinnamic  aldehyde  is  a  colourless,  aromatic  oil,  which  distils  readily 
in  aqueous  vapour.  When  exposed  to  the  air  it  oxidises  to  cinnamic 
acid.  It  adds  chlorine  and  bromine  very  readily.  The  dihaloid  ad- 
dition products  change  with  ease  into  a-monochloro-  and  a-mono- 
bromo-cinnamie  aldehydes  C6H5.CH  :  CX.CHO,  melting  at  35°  and  72° 
(B.  24,  246). 

Cinnamic  aldehyde  chloride  C6H6CH  :  CH.CHC12,  m.p.  54°,  b.p.30 
143°,  behaves  like  an  acid  chloride,  but  combines  with  chlorine  to  the 
phenyl-tetrachloro-propane  C6H5CHC1.CHC1.CHC12,  which  is  stable  in 
water  (C.  1903,  I.  457,  1344). 

a   and  jS-Trithio-cinnamie  aldehyde  melt  at  167°  and  213°  (B.  24, 


Hydro-einnamide  (C9H8)3N2  melts  at  106°,  or  at  131°  when  anhydrous 
(C.  1898,  I.  181). 

Cinnamic  aldehyde-phenyl-hydrazone  C6H5.CH  :  CH.CH(N2H.C6H5) 
melts  at  168°.  The  syn-oxime  melts  at  138-5°. 

Iso-quinolin  is  produced  when  the  latter  is  heated  with  P2O5  (B.  27, 
2795)  .  By  the  action  of  nitrous  gases  upon  cinnamic  aldehyde  the  chief 

product  obtained  is  phenyl-nitro-isoxazol  O.N  :  C(C6H5.)C(NO2)  :  Ctl 
(A.  328,  196). 

Nitro-cinnamic  aldehydes  are  obtained  from  the  aldehydes  of  the 
nitro-phenyl-lactic  acids.  o-,  m-,  and  p-Nitro-cinnamic  aldehydes 
melt  at  127°,  116°,  and  141°  (B.  18,  2335). 

a-Methyl-cinnamic  aldehyde  C6H5.CH  :  C(CH3)CHO  (B.  19,  526, 
1248). 

y-Benzyl-crotonic  aldehyde  (pheno  -  pentenal)  C6H5CH2CH2CH  : 
CHCHO,  b.p.13  139°,  from  hydro-cinnamic  aldehyde  with  acetaldehyde 
(B.  31,  1993). 

2b.  Oxy-phenyl-olefin  Aldehydes.—  o-Cumaric  aldehyde,  o-oxy 
cinnamic  aldehyde  HO[2]C6H4.CH  :  CH.CHO,  melting  at  133°,  is  pro- 
duced by  the  action  of  emulsin  upon  glyco-o-cumaric  aldehyde  C6H11O5. 
O.C6H4.CH  :  CH.CHO,  melting  at  199°,  the  condensation  product  of 
helicin  (q.v.)  and  acetaldehyde  (B.  20,  1931).  It  occurs  as  methyl  ether 
in  the  oil  of  cassia  (B.  28,  R.  386). 

p-Methoxy-einnamic  aldehyde,  b.p.14  170°,  has  been  found  in  tarra- 
gon oil  (C.  1908,  I.  1057). 


416  ORGANIC  CHEMISTRY 

m-  and  p-Oxy-cinnamic-aldehyde-o-acetic  acid  COOH.CH2O.C6H4. 
CH  :  CH.CHO  (B.  19,  3049). 

Piperonyl-aeroleln  (CH 2O2) [3,  4]C6H3CH  :  CH.CHO,  melting  at 
70°,  is  obtained  from  piperonal,  acetaldehyde,  and  sodium  hydroxide 
(B.  27,  2958)  ;  see  Piperic  acid. 

3.  Phenyl-diolefln  Aldehydes. — o-Nitro-cinnamylidene-acetaldehyde 
NO2C6H4.CH  :  CH.CH  :  CH.CHO  melts  at  153°  (B.  17,  2026). 

40.  Phenyl-olefln  Ketones. — The  phenyl-olefm  ketones  are  readily 
obtained  by  the  condensation  of  aromatic  aldehydes  with  aliphatic 
ketones,  which,  besides  carbonyl,  contain  CH3  or  CH2R  groups  ;  from 
mixed  ketones,  phenyl-olefin  ketones,  with  normal  C-chains,  are 
usually  obtained  on  using  NaHO  as  means  of  condensation,  whereas 
HC1  gives  a  branched  chain  (cp.  B.  35,  3088,  3549).  Excess  of  benz- 
aldehyde  yields  dibenzylidene  ketones  : 

C,H6CH  :  CHCOCH3  < CH3COCH3 >  C6H5CH  :  CHCOCH  :  CHC6H6. 

Benzal-acetone,  benzylidene  -  acetone,  styryl  -  methyl  -  ketone  C6H5. 
CH  :  CH.CO.CHg,  melting  at  41°  and  boiling  at  262°,  is  produced  in 
the  distillation  of  calcium  cinnamate  and  acetate,  as  well  as  in  the 
condensation  of  benzaldehyde  and  acetone  with  dilute  sodium 
hydroxide  (A.  223,  139).  Also  in  small  quantities  by  the  action  of 
CH3MgI  upon  cinnamic  acid  nitrite  (C.  1906,  II.  48). 

It  dissolves  with  an  orange-red  colour  in  sulphuric  aid.  With 
mercaptans,  it  combines  to  form  mercaptols,  which  add  a  third  molecule 
of  mercaptan  to  the  olefin  linkage  C6H5CH(SR)CH2C(SR)2CH3  (B.  35, 
804). 

With  alcoholic  S2Am  it  gives  a  dimeric  benzal-thio-acetone  (C10H10S)  2, 
m.p.  132°,  which,  with  water,  acids,  and  salts,  gives  well-crystallised 
addition  compounds  (B.  40,  2982). 

Benzal-aeetone-phenyl-hydrazone,  m.p.  156°,  easily  transposes  into 
i,  6-diphenyl-3-methyl-pyrazolin  (B.  20,  1099).  Oxime,  m.p.  115° 
(B.  20,  923).  On  boiling  with  sodium  hypochlorite,  benzal-acetone  is 
broken  up  into  chloroform  and  cinnamic  acid.  On  reduction,  we  get 
benzyl-acetone  and,  by  the  junction  of  two  molecules  of  the  olefin 
ketone,  diphenyl  -  octadiones.  Similar  behaviour  is  shown  by  the 
homologues  of  benzal-acetone,  on  its  reduction  (B.  35,  968,  3089). 
Benzal-acetoxime  is  reduced  by  Na  and  alcohol  to  l-phenyl-3-amino- 
butane  C6H5CH2CH2CH(NH2)CH3,  by  zinc  dust  and  glacial  acetic  acid, 
only,  to  i-phenyl-3-amino-butene  C6H5CH  :  CHCH(NH2)CH3  (B.  36, 
2997) ;  the  latter  is  split  up  by  ozone  into  benzaldehyde  and  a-amido- 
propionic  aldehyde  (B.  37,  615). 

o-  and  p-Nitro-benzal-aeetone,  formed  by  nitrifying  benzal-acetone, 
melt  at  60°  and  110°  respectively.  The  o-body  passes  readily  into 
indigo.  a-Methyl-quinaldin  results  from  it  by  reduction.  Water  is 
simultaneously  liberated. 

p-Amido-benzal-aeetone,  m.p.  81°,  p-dimethyl-amido-benzal-acetone, 
m.p.  132°,  by  condensation  of  amido-  and  dimethyl-amido-benzalde- 
hyde  respectively  with  acetone.  Its  red  and  yellow  chloride  solutions 
colour  wool,  silk,  and  tanned  cotton  an  orange  yellow  (C.  1906,  II.  1324). 

a-  and  y-Benzylidene-methyl-ethyl-ketone  C6H5CH  :  CHCOC2H5, 
m.p.  39°,  b.p.12  142°,  and  C6H5CH  :  C(CH3)COCH3,  m.p.  38°,  b.p.12 
i27°-i3o°,  and  a-  and  y-benzylidene-methyl-propyl-ketone  C6H5CH  : 


PHENYL-OLEFIN   KETONES  417 

CHCOC3H7,  b.p.20  155°,  and  C6H5CH  :  C(C2H5)COCH3,  b.p.18  120°- 
130°,  with  benzaldehyde  and  methyl-ethyl-  and  methyl-propyl-ketone 
respectively,  by  means  of  NaHO  and  HC1  respectively.  From  benz- 
aldehyde and  phenoxy-acetone  both  NaHO  and  HC1  give  : 

a-Benzylidene-phenoxy-aeetone  C6H5CH  :  C(OC6H5)COCH3,  m.p. 
102°,  which  is  reduced  by  alkaline  hypochlorite  to  a-phenoxy-cinnamie 
acid  (B.  35,  3549). 

Cuminal-acetone  (A.  223,  147).  Benzal-pinacolin  C6H5CH  :  CH. 
COC(CH3)3,  m.p.  41°,  b.p.25  154°,  from  benzaldehyde  and  pinacolin  ; 
it  adds  malonic  acid  ester  with  formation  of  8,  y-ketonic  acid  (B. 
30,  2268). 

Phenyl-vinyl-ketone  C6H5COCH  :  CH2,  b.p.18  115°,  a  colourless  oil 
of  penetrating  odour,  formed  by  the  action  of  alcoholic  KI  solution 
upon  a,  jS-dibromo-propio-phenone,  and  by  distillation  of  triphenacyl- 
methyl-amino-chlorohydrate  with  steam  (B.  39,  2187).  It  easily 
polymerises  in  sunlight  or  on  heating.  A1C13  converts  it  into  the  iso- 
meric  a-hydrindone.  With  HC1,  alcohol,  and  sodium  bisulphite  it 
easily  combines,  with  dissolution  of  the  double  linkage  ;  with  phenyl- 
hydrazin  it  forms  i,  3-diphenyl-pyrazolin  (C.  1910,  I.  434). 

Phenyl-propenyl-ketone  C6H5COCH  :  CH.CH3,  b.p.20  135°,  is  also 
formed  from  crotonyl  chloride,  benzene,  and  A1C13. 

Allyl  -  aceto  -  phenone  C6H5.CO.CH2.CH2.CH  :  CH2,  from  allyl- 
benzoyl-acetic  acid  (B.  16,  2132),  boils  at  236°. 

46.  Oxy-phenyl-olefin  Ketones.  —  o-Oxy-benzal-aeetone,  methyl-o- 
cumaro-ketone  HO.C6H4.CH  :  CH.CO.CH3,  m.p.  139°,  is  obtained  from 
salicyl-aldehyde,  and  also  by  the  action  of  emulsin  upon  gluco-methyl-o- 
cumaro-ketone  C6HnO5.O.C6H4.CH4 :  CH.COCH3,  melting  at  192°.  The 
latter  compound  is  a  condensation  product  of  helicin  (q.v.)  and  acetone 
(B.  24,  3180).  p-Oxy-benzal-aeetone,  m.p.  103°,  from  p-oxy-benz- 
aldehyde,  acetone,  and  HC1,  besides  the  p2-dioxy-dibenzal-acetone 
occurring  as  a  chief  product  (B.  36,  134)  ;  o-,  m-  and  p-oxy-benzal- 
acetone-o-acetic  acid,  m.p.  108°,  122°,  and  177°  (B.  19,  3056).  Piper- 
onylidene  acetone  CH2O2C6H3CH  :  CHCOCH3,  m.p.  96°  (B.  28, 
R.  1009). 

5.  Phenyl-acetylene  Aldehydes. — Phenyl-propargyl  aldehyde  C6H5C 
C.CHO,  b.p.2g  128°,  from  sodium-phenyl-acetylide  with  formic  acid  in 
ether  (C.  1903,  II.  569),  or,  better,  from  its  acetal,  easily  obtained  from 
a-bromo-cinnamic-aldehyde-acetal,  by  treating  it  with  dilute  mineral 
acids,  is  split  up  by  aqueous  alkalies,  in  the  cold,  into  phenyl-acetylene 
and  formic  acid.     Its  -oxime  C6H5CC.CH  :  NOH,   m.p.   108°,  is  iso- 
merised  by  aqueous  alkali  to  phenyl-isoxazol,  and  by  sodium  ethylate 
further  to  oj-cyanaceto-phenone  C6H5CH2.CO.CN  (B.  36,  3670). 

6.  Phenyl-acetylene  Ketones  are  obtained  synthetically  from  sodium- 
phenyl-acetylide,  with  acid  esters,  chlorides,  and  anhydrides  (C.  1900, 
I.  1290;    II.  1231;    1902,  I.  404).      Acetyl-phenyl-acetylene  C6H5C 
CCOCH3,  b.p.22  130°,  gives,  with  H2SO4,  benzoyl-acetone,  and  is  split 
up  by  KHO  into  phenyl-acetylene  and  acetic  acid.     Butyryl-phenyl- 
acetylene  C3H7COC  CC6H5,  b.p.9  136°.    Benzoyl-amyl-aeetylene  C6H5 
COC  :  CC5Hn,  b.p.19  178°,  from  sodium-oenanthylidene  with  benzoyl 
chloride,  gives,  with  dilute  sulphuric  acid,  benzoyl-caproyl-methane. 

7.  Phenyl  -  diolefin    Ketones.  —  Cinnamyl  -  acetone    C6H5.CH  :  CH. 
CH  :  CH.CO.CH3,  m.p.  68°,  results  from  the  condensation  of  cinnamic 

VOL.  II.  2  E 


4i8  ORGANIC   CHEMISTRY 

aldehyde  and  acetone.  Its  oxime  yields  a  pyridine  derivative  upon 
dry  distillation  (B.  29,  613).  Piperonylene-aeetone  (CH2O2)C6H3.CH  : 
CH.CH  :  CH.CO.CHg,  m.p.  89°  (B.  28,  1193).  Benzal-mesityl  oxide 
CGH6.CH  :  CH.CO.CH  :  C(CH3)2,  b.p.  178°  (14  mm.)  (B.  14,  351). 
Piperonylene-aeetone  (CH2O2)C6H3.CH  :  CH.CH  :  CH.CO.CH3  melts  at 
89°  (B.  28,  1193). 

8.  Phenyl-olefin-carboxylie  Acids. — These  acids  arrange  themselves 
in  two  distinct  classes.  The  one  class  is  derived  from  a  saturated  acid, 
by  substituting  an  unsaturated  side  chain  for  hydrogen  attached  to 
the  benzene  nucleus — e.g.  vinyl-benzoic  acid.  The  second  class  com- 
prises the  phenylated  olefin-monocarboxylic  acids. 

A.  Phenyl-olefin-carboxylie  acids  (having  their  CO2H  group  attached 
to  the  nucleus). 

o- Vinyl-benzoic  acid  CH2 :  CH[2[C6H4.CO2H.  o- Vinyl-benzoic  acids, 
chlorinated  in  the  vinyl  residue,  and  also  in  the  benzene  residue,  have 
been  obtained  by  the  decomposition  of  chlorinated  hydrindene  and 
naphtho-quinone  derivatives  (B.  27,  2761  ;  A.  275,  347). 

m- Vinyl-benzoic  acid,  m.p.  95°,  is  formed  from  m-amido-styrol 
(B.  26,  R.  677).  o-,  m-,  and  p-Propenyl-benzoic  acids  CH2  :  C(CH3). 
C6H4.CO2H,  m.p.  60°,  99°,  and  161°  (A.  219,  270  ;  248,  64  ;  275,  160). 

o-Vinyl-phenyl-acetic  acid  CH2  :  CH.C6H4.CH2.CO2H.  Derivatives 
of  this  acid,  chlorinated  in  the  vinyl  residue,  have  also  been  obtained 
by  the  breaking  down  of  chlorinated  keto-hydro-naphthalenes  (B. 

21,  3555). 

B.  Phenyl-olefin-carboxylie  acids  (with  the  carboxyl  group  in  the 
unsaturated  aliphatic  side  chain). 

The  true  phenyl-olefm-monocarboxylic  acids  may  be  obtained  by 
the  oxidation  of  corresponding  alcohols  and  aldehydes,  as  well  as,  by 
similar  methods,  from  the  phenyl-paramn-monocarboxylic  acids  or 
fatty  acids.  The  nuclear-synthetic  method,  however,  is  far  more 
important.  It  consists  in  the  action  of  the  sodium  salt,  and  the 
anhydride  of  a  fatty  acid,  upon  an  aromatic  aldehyde  (Perkin's  reaction). 

History. — As  early  as  the  year  1856  Bertagnini  found  that  cinnamic 
acid  was  formed  upon  heating  benzaldehyde  with  acetyl  chloride. 
In  1865  W.  H.  Perkin,  sen.,  synthesised  cumarin,  the  lactone  of 
o-oxy-cinnamic  acid,  by  heating  sodium  salicyl-aldehyde  with  acetic 
anhydride.  In  1875  Perkin  gave  this  reaction  an  entirely  different 
aspect  by  allowing  sodium  acetate  and  acetic  anhydride  to  act  upon 
salicyl-aldehyde.  In  this  modified  form  the  reaction  acquired  more 
general  application. 

Many  chemists  have  assisted  in  the  amplification  of  the  Perkin 
reaction,  which  in  consequence  has  become  one  of  the  most  fruitful 
synthetic  methods. 

The  course  of  the  reaction  has  been  made  clear  by  the  researches 
of  v.  Baeyer  and  O.  R.  Jackson,  Conrad  and  Bischoff,  Oglialoro,  and 
especially  by  those  of  Fittig  and  his  students,  Jayne  and  Slocum 
(A.  215,  97,  116  ;  227,  48)  : 

(1)  In  the  condensation  of  aromatic  aldehydes  and  fatty  acids  the 
carbon  atom,  combined  with  the  carboxyl  group,  unites  with  the  carbon 
of  the  aldehyde  group. 

(2)  It  is  doubtful  whether  the  reaction  takes  place  between  the 
aldehyde  and  the  Na  salt,  or  the  anhydride  of  the  fatty  acid,  since, 


PHENYL-OLEFIN-CARBOXYLIC  ACIDS  419 

on  using  a  mixture  of  anhydride  and  Na  salt  of  two  different  acids, 
we  obtain  various  mixtures  of  the  two  possible  phenyl-olefin-carboxylic 
acids,  according  to  circumstances  ;  cp.  B.  34,  918. 

(3)  The  condensation  proceeds  in  two  stages  :  (a)  the  union  of  the 
aldehyde  and  the  sodium  salt,  as  in  the  formation  of  aldol,  with  the 
production  of  the  /?-oxy-acid  ;  (b)  the  exit  of  water  from  the  j3-oxy- 
acid,  resulting  in  the  formation  of  the  olefin-carboxylic  acid.  In 
many  instances  the  reaction  was  arrested  in  the  first  stage  : 

(a)  C6H5.CHO+CH3.C02H  -          ->  C6H5.CH(OH).CH2.CO2H. 

(b)  C6H5.CH(OH)CH2.CO2H-::5^->  C6H5.CH  :  CH.CO2H. 

A  second  nucleus-synthetic  method  for  the  preparation  of  phenyl- 
olefin-carboxylic  acids  consists  in  the  condensation  of  benzaldehydes 
with  fatty-acid  esters  by  means  of  sodium  ethylate  or  metallic  sodium 
(Claisen,  B.  23,  976)  : 

C6H5.CHO+CH3.CO.O.C2H5  -^^  —  >  C6H5.CH  :  CH.CO2.C2H5. 

Phenyl-acrylic  Acids.  —  According  to  the  structural  theory  there 
are  two  possible  isomerides,  the  a-  and  j8-acids,  which  are  also  known 
in  cinnamic  and  atropic  acids  : 


/5-Phenyl-acrylic  acid,        r  «   ru    rw  rn  w          a-  Phenyl-acrylic  acid,      r  „  r 

cinnamic  acid,  C.H..CH  :  CH.CO,H  atropic  acid,  *    s    \CH 

Cinnamic  acid,  f$-phenyl-acrylic  acid,  acidum  cinnamylicum  C6H5. 
CH  :  CH.CO2H,  melting  at  133°  and  boiling  at  300°,  occurs  in  Peru 
and  tolu  balsams,  in  storax,  and  in  some  benzoin  resins  ;  also,  together 
with  a-  and  jS-truxillic  acids,  the  natural  iso-cinnamic  and  allo-cinnamic 
acids,  in  the  decomposition  products  of  the  associated  alkaloids  of 
cocain. 

Formation.  —  It  is  produced  (i)  by  the  oxidation  of  its  alcohol  and 
its  aldehyde  ;  (2)  by  the  reduction  of  phenyl-propiolic  acid  with  zinc 
dust  and  glacial  acetic  acid  (B.  22,  1181)  ;  (3)  nuclear  synthesis  —  from 
benzaldehyde  :  (a)  with  sodium  acetate  and  acetic  anhydride,  (b)  with 
acetic  ester  and  sodium  ethylate  (see  above)  ;  (4)  upon  heating  benzyl 
chloride  with  sodium  acetate.  The  latter  reaction  serves  for  the 
commercial  preparation  of  cinnamic  acid  (B.  15,  969)  ;  (5)  by  heating 
benzal-malonic  acid  ;  (6)  its  phenyl  ester  is  produced  when  phenyl- 
fumaric  ester  is  heated  ;  (7)  by  splitting  off  water  from  synthetic 
j8-phenyl-hydracrylic  acid. 

Properties  and  Behaviour.  —  Cinnamic  acid  crystallises  from  hot 
water  in  fine  needles,  from  alcohol  in  thick  prisms.  It  is  soluble  in 
3500  parts  of  water  at  17°,  and  readily  in  hot  water.  It  may  be  purified 
by  distillation  under  greatly  reduced  pressure,  or  by  crystallisation 
from  petroleum  benzin  (A.  188,  194). 

Ferric  chloride  produces  a  yellow  precipitate  in  solutions  of  the 
cinnamates. 

Nitric  acid  and  chromic  acid  oxidise  it  to  benzaldehyde  and  benzoic 
acid.  It  is  converted  into  phenyl-glyceric  acid  by  potassium  perman- 
ganate. Fusion  with  caustic  potash  decomposes  it  into  benzoic  and 
acetic  acids. 

Being  an  unsaturated  acid,  cinnamic  acid  can  readily  take  up 
hydrogen,  hydrogen  bromide,  hydrogen  iodide,  bromine,  chlorine,  and 


420  ORGANIC  CHEMISTRY 

hypochlorous  acid,  with  the  .production  of  hydro-cinnamic  acid, 
jS-bromo-,  /?-iodo-hydro-cinnamic  acid,  phenyl-a,  j3-dichloro-,  a,  jS-di- 
bromo-propionic  acid,  or  cinnamic  acid  dichloride,  cinnamic  acid 
dibromide,  and  j3-phenyl-a-chloro-lactic  acid. 

Cinnamic  Acid  Derivatives. — Methyl  ester  melts  at  33°  and  boils  at 
263°.  It  is  contained  in  some  Alpinia  varieties.  Ethyl  ester  boils  at 
271°.  Phenyl  ester  melts  at  72°  and  boils  at  206°  (15  mm.)  ;  see  Cin- 
namic acid.  Pyro-cateehol  ester  melts  at  129°  (B.  11, 1220 ;  18,  1945  ; 
25,  3533).  Benzyl  ester,  m.p.  30°,  also  found  in  the  oil  of  Peruvian 
balsam  (B.  2,  180). 

Styryl  ester,  stymcin,  melts  at  14°.  The  chloride  melts  at  35°  and 
boils  at  154°  (25  mm.).  The  anhydride  melts  at  130°  (B.  27,  284). 
The  amide  melts  at  141°.  The  anilide  melts  at  151°.  The  nitrile  melts 
at  11°  and  boils  at  254°  (B.  15,  2544  ;  27,  R.  262). 

Unstable  and  Polymeric  Modifications  of  Cinnamic  A  cid. — As  in  the 
jS-alkyl-acrylic  acids  (Vol.  I.),  so  also  in  the  j3-phenyl-acrylic  acids, 
besides  the  ordinary  stable  forms,  the  corresponding  unstable  stereo- 
isomeric  forms  have  been  discovered,  and  have  been  termed  "  allo- 
cinnamic  "  acids.  Allo-cinnamic  acid  itself  has  the  noteworthy  pro- 
perty of  being  able  to  occur  in  three  crystalline  forms  which  are  chemi- 
cally identical  but  structurally  different.  These  can  be  converted 
into  one  another  by  the  simple  process  of  melting  or  crystallisation 
(Biilmann,  B.  42,  182,  1443). 

The  modification,  m.p.  42°,  formerly  called  Erlenmeyer's  iso-cin- 
namic  acid,  is  the  most  unstable,  much  more  so  than  the  modification 
melting  at  58°  (formerly  Liebermann's  iso-cinnamic  acid),  and  the  modi- 
fication melting  at  168°  (formerly  Liebermann's  allo-cinnamic  acid). 

But  it  is  the  acid  which,  with  certain  precautions,  can  always  be 
obtained  from  the  mixture  of  the  three  liquid  acids,  or  of  the  three 
acids,  in  solution,  on  precipitation  with  acid  (B.  42,  4659  ;  43,  411). 
In  all  reactions  which  give  rise  to  allo-cinnamic  acid  it  is  the  primary 
product,  but  it  is  extremely  easily  transformed  into  the  other  acids, 
especially  the  stable  acid  melting  at  68°,  on  contact  with  the  slightest 
traces  of  crystals  of  the  other  acids.  Allo-cinnamic  acid  is  obtained 
in  one  or  other  of  its  three  forms  (i)  by  semi-reduction  of  phenyl- 
propiolic  acid  with  hydrogen  and  colloidal  palladium  (B.  42,  3930)  ; 
(2)  by  reduction  of  allo-a-  and  allo-jS-bromo-cinnamic  acid  with  zinc 
dust  in  an  alcoholic  solution  ;  (3)  by  the  action  of  ultra-violet  light 
upon  an  alcoholic  solution  of  ordinary  cinnamic  acid  (B.  42,  4869)  ;  (4) 
by  heating  benzal-malonic  acid,  whereby  also  much  ordinary  cinnamic 
acid  is  formed. 

The  acid  melting  at  58°  was  first  discovered  in  the  acids  resulting 
from  the  breaking  up  of  the  secondary  cocai'n  alkaloids,  together  with 
ordinary  cinnamic  acid. 

Allo-cinnamic  acid,  m.p.  68°,  forms  an  aniline  salt,  m.p.  83°, 
sparsely  soluble  in  ligroin.  With  chlorine  and  bromine  it  yields 
addition  products  differing  from  cinnamic  dichloride  and  allo-cinnamic 
acid  dibromide. 

On  distillation  at  ordinary  pressure  by  concentrated  sulphuric  acid 
and  by  illumination  in  benzene  solution  with  the  addition  of  a  little 
iodine,  allo-cinnamic  acid  is  converted  into  ordinary  cinnamic  acid 
(B.  28,  1446).  On  oxidation  with  potassium  permanganate  it  forms 


PHENYL-OLEFIN-CARBOXYLIC  ACIDS  421 

phenyl-glycerine  acid  melting  at  21°.  On  treating  with  fuming 
sulphuric  acid  it  splits  off  water  and  easily  polymerises  into  tmxone, 
in  contrast  with  ordinary  cinnamic  acid  (B.  31,  2095).  On  account  of 
this  behaviour,  but  especially  of  their  generation  from  phenyl-propiolic 
acid  and  jS-bromallo-cinnamic  acid  respectively,  allo-cinnamic  acid  is 
regarded  as  the  maleinoid  or  cis-form,  and  ordinary  cinnamic  acid  as 
the  fumaroid  or  trans-iorm,  of  j8-phenyl-acrylic  acid  : 

H— C— C6H5  H— C— C«H5 

HOoC— C— H  H— C— CO2H 

Ordinary  cinnamic  acid  Allo-cinnamic  acid. 

This  view  agrees  with  the  behaviour  of  the  oxy-cinnamic  acids, 
in  which  the  spatial  configuration  can  be  deduced  from  the  more  or 
less  marked  tendency  towards  splitting  off  H2O.  It  is  also  confirmed 
by  the  power  of  allo-cinnamic  acid,  in  contrast  with  cinnamic  acid, 
to  form  with  mercuric  salts  an  additive  compound  of  the  formula 

C<}H5CH(OH)CHHg.COO,  a  power  which,  according  to  observations 
with  other  cis-trans-isomeric  olefin-dicarboxylic  acids,  can  only  be 
ascribed  to  the  maleinoid  forms  (B.  43,  568). 

By  the  action  of  light,  in  the  solid  condition  cinnamic  acid  is  poly- 
merised into  the  so-called  a-truxillie  acid  (C6H5C2H2COOH)2  (B.  35, 
2908,  4128),  also  found  in  the  secondary  alkaloids  of  cocai'n  together 
with  jS,  y,  and  8-truxillic  acid.  On  distillation  these  acids  are  split  up 
into  ordinary  cinnamic  acids.  They  are,  perhaps,  diphenyl-tetra- 
methylene-dicarboxylic  acids.  As  the  heat  of  combustion  is  unchanged, 
the  transformation  of  cinnamic  into  truxillic  acid  involves  no  change 
of  energy,  which  is  noteworthy  (Z.  physik.  Ch.  48,  345). 

Haloid  Cinnamic  Acids  substituted  in  the  Side  Chain. — (a)  Phenyl- 
monohaloid-aerylic  Acids. — The  structural  theory  provides  for  two 
isomeric  monochloro-acrylic  acids,  but  there  are  really  two  modifica- 
tions for  each  of  these  structural  isomerides.  It  is  customary  to  dis- 
tinguish them  as  a-  and  j8-chloro-cinnamic  acid  and  allo-a-  and  allo- 
j3-chloro-cinnamic  acid  (B.  22,  R.  741  ;  A.  287,  i). 

a-ChlcTO-eiimamie  acid  C6H5.CH  :  CC1.CO2H,  m.p.  137°,  is  formed 
(i)  by  the  action  of  alcoholic  potash  or  phenyl-a-,  j3-dichloro-propionic 
acid ;  (2)  from  benzaldehyde,  sodium  monochloro-acetate,  and  acetic 
anhydride  ;  (3)  from  phenyl-a-chloro-lactic  acid,  by  means  of  acetic 
anhydride,  and  sodium  acetate  ;  (4)  by  the  action  of  CrO3  upon  aldehyde 
(B.  24,  249). 

Allo-a-chloro-cinnamic  acid,  m.p.  111°,  is  produced,  together  with 
a-chloro-cinnamic  acid,  according  to  method  i. 

/3-Chloro-cinnamie  acid  C6H5.CC1  :  CH.CO2H,  m.p.  132-5°,  and 
allo-^-ehloro-cinnamic  acid,  m.p.  142°,  are  formed  by  the  addition  of 
hydrochloric  acid  to  phenyl-propionic  acid. 

a-Bromo-einnamie  acid,  C6H5.CH  :  CBr.CO2H,  m.p.  130°,  and 
allo-a-bromo-ciimamic  acid,  m.p.  120°  (Glaser's  jS-bromo-cinnamic 
acid),  result  when  phenyl-a,  /3-dibromo-propionic  acid  is  acted  upon 
with  alcoholic  potash.  The  latter,  when  heated,  changes  to  the  higher- 
melting  a-bromo-cinnamic  acid.  When  it  is  treated  with  zinc  dust 
in  alcoholic  solution  it  yields  allo-cinnamic  acid.  Both  yield  benz- 
aldehyde upon  oxidation. 


422  ORGANIC  CHEMISTRY 

j8-Bromo-cinnamic  acid  C6H5.CBr  :  CH.CO2H,  m.p.  133°,  and  allo- 
j8-bromo-cmnamie  acid,  m.p.  158-5°,  are  formed  simultaneously  upon 
the  addition  of  hydrogen  bromide  to  phenyl-propiolic  acid.  The 
second  acid,  upon  heating,  changes  to  the  lower-melting  j8-bromo- 
cinnamic  acid,  and  upon  reduction  yields  not  only  cinnamic  acid, 
but  also  allo-cinnamic  acid. 

jS-Iodo-cinnamic  acid  CeH6CI  :  CHCOOH  is  obtained  by  iodina- 
tion  of  cinnamic  acid  in  pyridin  solution  (C.  1899,  II.  527). 

(b)  Phenyl-dihaloid-acrylic  acids  result  from  the  addition  of  halogens 
to  phenyl-propiolic  acid.  Dichloro-einnamic  acid  C6H5.CC1 :  CC1.CO2H, 
m.p.  120°  (B.  25,  2665).  a-  and  /3-Dibromo-cinnamie  acids  melt  at 
139°  and  100°  (B.  25,  2665).  Di-iodo-cinnamie  acid  melts  at  121° 
(B.  24,  4113). 

a-Amido-cinnamic  acid  C6H5.CH  :  C(NH2).CO2H  decomposes,  when 
rapidly  heated,  at  24O°-25o°,  with  the  production  of  phenyl-vinyl- 
amine.  Its  hydrochloride  is  produced  upon  heating  its  benzoyl-amido- 
cinnamic  anhydride  with  hydrochloric  acid  to  120°.  The  acid  itself 
may  be  liberated  from  the  hydrochloride  by  means  of  sodium  acetate 
or  soda.  The  amide  of  an  isomeric  (?)  a-amido-cinnamic  acid,  m.p.  160°, 
is  formed  by  the  action  of  ammonia  upon  phenyl-dibromo-propionic 
ester  or  a-bromo-cinnamic  ester  (B.  29,  R.  795). 

a-Acetamido-cinnamic  acid  C6H5.CH  :  C(NHCO.CH3).CO2H+2H2O 
melts,  when  anhydrous,  at  190°  with  decomposition.  It  is  formed 
when  sodium  hydroxide  acts  upon  the  anhydride. 

CO — O 

a-Aeetamido-einnamic  anhydride  ,    melting    at 

C6H5CH  :  C.N  :  CCH3 

146°,  results  from  the  action  of  acetic  anhydride  upon  a-amido- 
phenyl-lactic  acid,  and  from  glycocoll,  benzaldehyde,  sodium  acetate, 
and  acetic  anhydride. 

a-Benzoyl-amido-cinnamic  anhydride  melts  at  165°.  It  is  produced 
in  the  condensation  of  hippuric  acid  and  benzaldehyde  with  acetic 
anhydride  and  sodium  acetate.  When  heated  with  dilute  alkalies 
the  lactimide  changes  to  a-benzoyl-amido-cinnamic  acid  C6H5CH  : 
C(NHCOC6H5)COOH,  which  decomposes  at  275°  with  the  formation  of 
phenyl-acetaldehyde  and  is  split  up  by  excess  of  alkali  into  benzamide 
and  phenyl-racemic  acid  (B.  33,  2036).  p-Oxy-benzoyl-amido-cinnamie 
acid  anhydride,  m.p.  173°,  from  p-oxy-benzaldehyde,  hippuric  acid  ; 
the  corresponding  acid  is  reduced  by  sodium  amalgam  to  benzoyl- 
ty  rosin. 

Cinnamic  acids  substituted  in  the  benzene  nucleus  are  isomeric  with 
the  corresponding  mono-cinnamic  acid  derivatives,  having  side-chain 
substitutions. 

1.  Mono-haloid    Cinnamic  Acids  have  been  made  from  the  three 
nitro-cinnamic  acids  as  bases  (B.  16,  2040  ;  18,  961  ;  25,  2109). 

o-,  m-,  and  p-Chloro-cinnamic  acids  melt  at  200°,  176°,  and  241°. 

o-  and  m-Bromo-cinnamic  acids  melt  at  212°  and  178°. 

o-,  m-,  and  p-Iodo-cinnamic  acids  melt  at  213°,  181°,  and  255°. 

2.  Nitro-cinnamic  Acids. — The  introduction  of  cinnamic  acid  into 
nitric  acid  of  specific  gravity  1-5  leads  to  the  formation  of  the  ortho- 
(60  per  cent.)  and  para-nitro-acids.    To  separate  them,  cover  the  acid 
mixture  with  8-10  parts  of  absolute  alcohol,  and  conduct  hydrochloric 


PHENYL-OLEFIN-CARBOXYLIC  ACIDS  423 

acid  gas  rapidly  into  the  liquid,  until  complete  solution  ensues.  On 
cooling,  the  para-ester  separates.  The  pure  esters  are  saponified  with 
sodium  carbonate  or  with  dilute  sulphuric  acid,  when  the  pure  acids 
result  (A.  212,  122,  150  ;  221,  265). 

The  three  isomeric  acids  can  be  prepared  from  the  corresponding 
nitro-benzaldehydes  by  means  of  Per  kin's  reaction  : 

o-,  m-,  and  p-Nitro-cinnamic  acids,  m.p.  240°,  197°,  286°. 
o-,  m-,  and  p-Nitro-cinnamic  ethyl  esters,  m.p.  44°,  78°,  138°. 

Oxidation  converts  the  three  nitro-cinnamic  acids  into  the  three 
nitro-benzaldehydes  and  nitro-benzoic  acids. 

Further  nitration  of  o-,  m-,  and  p-nitro-cinnamic  acids  produces 
dinitro-cinnamic  acids,  containing  an  NO2  group  in  the  side  chain  ; 
o,  p-dinitro-cinnamic  acid  (NO2)[2,  4]C6H3CH  :  CHCOOH,  m.p.  179°, 
is  obtained  from  o,  p-dinitro-benzaldehyde  by  means  of  Perkin's 
reaction  (M.  23,  534).  m-  and  p-nitro-cinnamic  acids  are  decomposed 
at  230°  and  220°  respectively  (C.  1904,  II.  1498). 

Cinnamic  Acids  substituted,  both  in  the  Benzene  Residue  and  the  Side 
Chain,— a,  m-Dinitro-einnamie  acid  NO2[3]C6H4.CH  :  C(NO2)COOH, 
from  m-nitro-cinnamic  acid  ester,  with  nitro-sulphuric  acid  (A.  229, 
224).  a,  p-dinitro-cinnamic  acid,  p-nitro-phenyl-a-nitro-acrylic  acid, 
from  p-nitro-cinnamic  acid  (A.  229, 224).  See  also  a),  p-Dinitro-phenyl- 
ethylene  and  p-Amido-phenyl-alanin.  a-  and  /J-Nitro-o-amido-cin- 
namic  acid,  m.p.  240°  and  254°,  from  o-amido-cinnamic  acid. 

3.  Amido-cinnamic  Acids  can  be  prepared  by  reducing  the  three 
mononitro-cinnamic  acids  with   tin  and  hydrochloric  acid.     The  re- 
duction is  better  effected  with  ferrous  sulphate  in  an  alkaline  solution 
(B.  15,2294;  A.  221,266). 

o-,  m-,  and  p-Amido-cinnamic  acids  melt  at  158°,  181°,  and  176°. 
When  the  diazo-bodies  are  boiled  with  haloid  acids,  the  haloid  cinnamic 
acids,  described  above,  are  produced  ;  but  when  they  are  acted  upon 
with  boiling  water,  the  products  are  o-,  m-,  and  p-cumaric  acids. 

Carbostyril  Formation. — Free  o-amido-cinnamic  acid  differs  from 
o-amido-hydro-cinnamic  acid  in  behaviour,  in  that,  when  heated  alone, 
it  does  not  give  rise  to  an  inner  anhydride  formation  ;  it  behaves  like 
o-cumaric  acid.  The  anhydride  formation  occurs,  however,  when 
o-amido-cinnamic  acid  is  heated  with  hydrochloric  acid  (B.  13,  2070), 
or  with  50  per  cent,  sulphuric  acid  (B.  18,  2395).  The  resulting  an- 
hydride is  carbostyril,  discovered  in  1852  by  Chiozza,  when  he  reduced 
o-nitro-cinnamic  acid  with  ammonium  sulphide.  It  can  be  viewed 
both  as  a  lactime  and  a  lactame  : 

Lactame  formula.  C.H.{gJ£:  ™      Lactime  formula,  C.H4{W^H  : 

According  to  the  second  formula,  carbostyril  is  nothing  more  than 
a-oxy-quinolin  ;  hence  it  will  be  discussed  later,  in  conjunction  with 
quinolin.  This  will  also  be  done  with  the  alkyl  compounds  derived 
from  both  formulae. 

o-Ethyl-amido-cinnamic  acid,  m.p.  125°  (B.  15,  1423).  Its  nitros- 
amine  melts  at  150°  with  decomposition,  and,  on  reduction,  is  con- 
densed to  ethyl-isindazol-acetic  acid. 

4.  o-Hydrazin-cinnamic   acid  NH2.NH.C6H4.CH  :  CH.CO2H,  m.p. 


424  ORGANIC  CHEMISTRY 

/CH.NH 
171°  with  decomposition  into  indazol  C6H4<J  (q.v.),  and  acetic 

.w  — 
acid. 

o  -  Sulpho  -  hydrazin  -  cinnamic  acid  SO3H.NH.NH.C6H4CH  : 
CH.CO2H  is  formed  when  sodium  sulphite  acts  upon  the  hydro- 
chloride  of  o-diazo-cinnamic  acid.  Hot  hydrochloric  acid  breaks 
it  down  into  o-hydrazin-cinnamie  acid  and  the  lactame  of  this  acid 

^{SSS^00'  m'p- 127° (A" 221' 274)' 

5.  Sulpho-cinnamic  Acids  are  produced  when  fuming  sulphuric  acid 
acts  upon  cinnamic  acid  (A.  173,  8).  The  m-derivative  has  been  ob- 
tained by  a  nuclear  synthesis  from  m-benzaldehyde-sulphonic  acid. 
p-Sulpho-cinnami'c  acid,  on  reduction,  splits  off  the  sulpho-groups, 
and  produces  hydro-cinnamic  acid  (B.  33,  2014  ;  C.  1903,  II.  438). 

Homologous  Cinnamic  Acids. — Cinnamic  acids  containing  alkyl 
groups  in  the  benzene  residue  are  produced  when  alkylated  benzalde- 
hydes  are  condensed  with  sodium  acetate  and  acetic  anhydride.  The 
three  tolyl-aldehydes  yield  o-,  m-,  and  p-methyl-cinnamic  acids,  j8,  o-, 
m-,  and  p-tolyl-acrylic  acids,  melting  at  169°,  115°,  and  196°.  Cuminol 
yields  p-cumenyl-acrylic  acid  (CH3)2CH[4]C6H4.CH  :  CH.CO2H,  melting 
at  158°.  When  the  latter  is  nitrated  it  yields  not  only  the  p-nitro-acid, 
but  also  o-nitro-cumenyl-acrylic  acid,  which  manifests  the  same  re- 
action transpositions  as  o-nitro-cinnamie  acid  (B.  19,  255). 

a- Alky  I  substituted  cinnamic  acids  are  produced  in  the  condensation 
of  benzaldehyde  with  sodium  propionate,  capronate,  or  butyrate  and 
acetic  anhydride  (A.  227,  57  ;  B.  34,  918). 

a-Methyl  -  cinnamic  acid,  a-benzal-propionic  acid,  p-phenyl- 
methacrylic  acid  C6H5.CH  :  C(CH3)CO2H,  melting  at  78°  and  boiling 
at  288°,  is  also  formed  from  benzyl-propionic  ester  and  metallic  sodium 
(B.  20,  617).  Also  from  a-methyl-jS-phenyl-ethylene-lactic  acid  by 
splitting  off  water  (C.  1898,  I.  674  ;  B.  20,  617). 

Phenyl-angelica  acid,  a-ethyl-cinnamic  acid,  a-benzal-n-bntyric  acid 
C6H5.CH  :  C(C2H5)CO2H  melts  at  104°  (B.  23,  978). 

j8-Alkyl-substituted  cinnamic  acids  are  obtained  by  detaching  H2O 
from  )3-aryl-alkyl-hydracrylic  acids,  the  condensation  products  of  aro- 
matic ketones  with  bromacetic  ester,,  and  zinc,  or  iodo-acetic  ester, 
and  magnesium,  respectively  (B.  40,  1589  ;  41,  5). 

j8-Methyl-cinnamie  acid,  j3-phenyl-erotonic  acid  C6H5C(CH3)  : 
CHCOOH,  m.p.  98°,  b.p.  167° ;  anilide,  from  dypnone  oxime  by  Beck- 
mann's  transformation  (B.  37,  733).  j8-Ethyl-,  j8-n-propyl-,  and  /Mso- 
butyl-einnamic  acids  melt  at  95°,  94°,  and  86°  respectively. 

Higher  cD-phenyl-n-olejin-carboxylic  acids  are  produced  by  heating 
the  lactone-carboxylic  acids,  when  carbon  dioxide  is  expelled,  and 
in  the  reduction  of  phenyl-diolefin-dicarboxylic  acids. 

Phenyl-iso-crotonic  acid,  p-benzal-propionic  acid  C6H5.CH  :  CH. 
CH2.CO2H  melts  at  86°  and  boils  at  302°  with  partial  decomposition 
into  water  and  a-naphthol.  It  is  formed  also  by  expelling  CO2  and 
rearranging  phenyl-paraconic  acid,  as  well  as  from  phenyl-trimethylene- 

/  P  M  f**  O  O  "H" 

tricarboxylic  acid  C6H5C(COOH)Q^°*  (B.  25,  1155),  by  heat- 
ing*; also  by  heating  phenyl-acetaldehyde,  malonic  acid,  and  pyridin 
from  the  benzal-malonic  acid  first  formed  by  detaching  CO2,  and  dis- 


PHENYL-OLEFIN-CARBOXYLIC  ACIDS  425 

placing  the  double  linking  (A.  345,  244).  With  HBr  it  combines  to 
y-phenyl-y-bromo-butyric  acid,  which,  with  soda  solution,  forms 
phenyl-butyro-lactone,  into  which  phenyl-iso-crotonic  acid  can  also 
be  partly  converted,  by  means  of  dilute  sulphuric  acid  or  HC1  ; 
concentrated  HC1  condenses  phenyl-iso-crotonic  acid  to  a  polymeric 
unibasic  lactonic  acid,  melting  at  179°  (B.  23,  3520). 

a-  and  /?-Methyl-phenyl-iso-crotonic  acids  melt  at  110°  and  112° 
(A.  255,  262).  A2-Dihydro-cinnamenyl-acrylic  acid  C6H5.CH2.CH  : 
CH.CH2.CO2H,  melting  at  31°,  is  formed  when  sodium  amalgam  acts 
upon  cinnamenyl-acrylic  acid,  and  also  by  heating  A2-  and  Aa-cinna- 
mylidene-malonic  acid.  a-Benzyl-erotonie  acid  C6H5CH2C(  :  CH.CH3) 
COOH,  m.p.  99°,  by  detaching  water  from  a-benzyl-/?-oxy-butyric  acid. 

The  behaviour  of  these  phenyl-olefin-carboxylic  acids  towards 
alkalies  is  worthy  of  note.  While  the  aliphatic  /?,  y-unsaturated  acids 
are  transposed  by  alkalies  into  the  isomeric  a,  jS-unsaturated  acids 
(Vol.  I.),  the  aromatic  olefin-car  boxy  lie  acids  show,  at  the  same  time, 
a  tendency  to  place  the  double  linking  in  the  neighbourhood  of  the 
phenyl  group  (cp.  A2-  and  A1-styrols).  Thus,  the  A2-dihydro-cinna- 
menyl-acrylic  acid,  with  caustic  soda,  gives  a  mixture  of  the  A1-  and 
A3-acids  (B.  38,  2742).  Phenyl-crotonic  acid,  on  mere  heating  with 
pyridin,  passes,  almost  completely,  into  the  phenyl-iso-crotonic  acid, 
a  reaction  which  can  be  partly  reversed  by  boiling  with  caustic  soda 
(A.  283,  309).  a-Benzyl-crotbnic  acid  gives,  on  fusing  with  KHO, 
phenyl-angelica  acid  (/.  pr.  Ch.  2,  74,  334  ;  cp.  also  A.  319,  144). 

C6H5CH  :  CH.CH2.CH2.CO2H  «—        -  C,H5CH2.CH  :  CH.CH2CO2H  v 

A3-acid,  m.p.  90°  A2-Dihydro-cinnamenyl-acrylic  acid 

CGH5CH2.CH2CH  :  CHCO2H 
A1-acid,  m.p.  104°. 

C8H5CH  :  CH.CH2.COOH   <  x  C6H5CH2CH  :  CH.COOH 

Phenyl-iso-crotonic  acid,  m.p.  86°        Phenyl-crotonic  acid,  m.p.  65°. 

C6H5CH2C(  :  CHCH3)COOH  -        -^  C6H5CH  :  C(CH2.CH3)COOH 
a-Benzyl-crotonic  acid,  m.p.  99°  Phenyl-angelica  acid,  m.p.  105°. 

The  A3-dihydro-cinnamenyl-acrylic  acid  has  also  been  obtained  by 
distillation  of  8~phenyl-S-valero-lactone-y-carboxylic  acid. 

Atropie  acid,  a-phenyl-acrylic  acid   c6H5.c^°2H  melts  at   106°. 

This  acid,  structurally  isomeric  with  ordinary  cinnamic  acid,  results 
from  tropic  acid  and  atro-lactinic  acid  when  they  are  heated  with 
concentrated  hydrochloric  acid  or  with  baryta  water.  It  is  sparingly 
soluble  in  cold  water,  easily  in  ether,  carbon  disulphide,  and  benzene, 
and  distils  with  aqueous  vapour.  Chromic  acid  oxidises  it  to  benzoic 
acid  ;  when  fused  with  caustic  alkali  it  yields  formic  and  a-toluic  acids  ; 
sodium  amalgam  converts  it  into  hydrb-atropic  acid,  and  hydrochloric 
and  hydrobromic  acids  change  it  to  a-  and  /Mialogen  hydro-atropic 
acids. 

Protracted  fusion,  or  heating  with  water  or  hydrochloric  acid,  con- 
verts atropic  acid  into  two  polymeric  isatropic  acids,  diatropic  acids 
(C9H8O2)2  (melting  at  237°  and  206°),  which  bear  the  same  relation  to 
atropic  acid  that  the  truxillic  acids  sustain  to  cinnamic  acid  (B.  28, 137). 


426  ORGANIC   CHEMISTRY 


Methyl-atropie   acid    C6H5.C\3,  m.p.  135°,  is  obtained  from 

phenyl-acetic   acid    and    paraldehyde   by   the    action   of    acetic    an- 
hydride (B.  19,  R.  251). 

Phenyl-allyl-acetic  acid  C6H5.CH(CHa.CH  :  CH2)COOH,  b.p.  200°, 
has  been  obtained  from  phenyl-allyl-malonic  acid,  and  its  nitrite  from 
benzyl  cyanide,  allyl  iodide,  and  caustic  soda  (B.  29,  2601). 

Illb.   OXY-PHENYL-OLEFIN-CARBOXYLIC   ACIDS. 

A.  Monoxy-phenyl-olefln-carboxylie  Acids.  —  Formation  :  —  They  are 
obtained  (i)  from  the  corresponding  amido-phenyl-olenn-carboxylic 
acids  upon  boiling  the  diazo-compounds  with  water  (B.  14,  479)  ; 
(2)  by  a  nuclear  synthesis,  when  the  phenol-aldehydes  are  heated 
with  the  sodium  salts,  and  anhydrides,  of  the  fatty  acids  (Perkin's 
reaction)  . 

The  following  nuclear  syntheses  (von  Pechmann)  lead  to  the  inner 
anhydrides  or  S-lactones  of  the  o-oxy-cinnamic  acids,  the  so-called 
cumarins  :  (3)  The  action  of  sulphuric  acid  upon  phenol  and  malic  acid, 
when  it  is  very  probable  that  the  first  product  is  the  semi-aldehyde  of 
malonic  acid,  which  condenses  with  the  phenol. 

(4)  When  sulphuric  acid  is  allowed  to  act  upon  phenol,  and  aceto- 
acetic  ester,  or  monoalkyl-aceto-acetic  esters. 

Phenol  itself,  with  aceto-acetic  ester,  gives  but  a  small  yield  of 
methyl-cumarin.  Polyvalent  phenols  give  cleaner  reactions  in  this 
respect  than  simple  phenols,  and  the  best  are  those  containing  two  OH- 
groups  : 

,    r  K  /H+C02H.CH(OH).CH,  PM/[i]CH:CH  r 

C*H*  \OH  •    '        '  '  HOCO""      '        *     o—  Co 


H+CH3.CO.CH2  _   r  „  /[i]C(CH3)  :  CH     tf-Methyl- 
C2H60:CO  C6H4l[2]0  __  CO       cumarin. 


The  first  members  of  this  series  are  the  monoxy-cinnamic  acids 
obtained  by  method  I  from  the  three  amido-cirmamic  acids.  o-Oxy- 
cinnamic  acids  are  especially  important.  They,  like  the  cinnamic 
acids,  occur  in  two  stereo-isomeric  forms  :  o-cumaric  acids,  correspond- 
ing to  the  stable  trans-ioTm  ;  and  cumarinic  acids,  corresponding  to 
the  unstable  a's-form.  The  cumarinic  acids  are  in  general  unstable 
in  the  free  state,  spontaneously  detaching  water,  and  passing  into  the 
corresponding  8-lactones,  the  so-called  "  cumarins."  But  salts  and 
ethers,  both  mono-  and  dialkyl  ethers,  of  the  cumarinic  acids,  are 
known,  which  are  isomeric  with  the  corresponding  compounds  of  the 
o-cumaric  acids. 

The  salts  and  ethers  of  cumarin  are  also  designated  as  a-cumarates, 
and  those  of  o-cumaric  acid  as  the  j8-cumarates  —  salts  and  ethers. 

When  the  hydrogen  atom  in  cumarin,  occupying  the  o-position 
with  reference  to  phenol-oxygen,  is  replaced  by  the  nitro-group,  free 
nitro-cumarinic  acid  may  be  liberated  from  the  salts. 

This  acid  is  distinguished  from  free  3-nitro-cumaric  acid  in  that 
by  the  exit  of  water  it  reverts  to  3-nitro-cumarin.  In  order  to 
account  for  the  different  removability  of  water  in  o-cumaric  acid  and 


MONOXY-PHENYL-OLEFIN-CARBOXYLIC   ACIDS     427 

cumarinic  acid  respectively,  the  following  space  formulae  have  been 

proposed  : 

HC.COOH  THC.COOH    1  ^  HC CO 

HOC6H4.CH  LHC.C6H4OHJ  *  HC.CaH46 

o-Cumaric  acid  Cumarinic  acid  Cumariii. 

As  in  the  case  of  cinnamic  acid,  the  stable  o-cumaric  acids 
and  their  derivatives  may  easily  be  transformed  into  the  unstable 
cumarinic  acids  by  means  of  ultra-violet  light,  i.e.  by  supplying 
energy  in  a  suitable  form.  In  this  action  o-cumaric  acid  yields 
cumarin  direct  (B.  44,  637).  By  boiling  with  dilute  mineral  acids, 
or  by  the  action  of  iodine  in  CS2  solution,  the  o-alkyl-cumarinic  acids 
can  be  transposed  into  the  more  infusible  o-alkyl-cumaric  acids 
C.  (1907,  I.  636). 

By  the  action  of  light  in  the  solid  state  the  o-cumaric  acids  are 
transformed  into  bimolecular  bis-cumaric  acids,  corresponding  to  the 
truxillic  acids  (B.  37,  1383). 

o-Oxy-cinnamic  acid,  o-cumaric  acid  HO[2]C6H4<:H  :  CH.CO2H, 
melting  at  208°,  and  isomeric  with  hydro-cumarilic  acid,  phenyl-pyro- 
racemic  acid,  etc.,  occurs  in  Melilotusofficinalis,  together  with  o-hydro- 
cumaric  acid,  and  in  the  leaves  of  Angrcecum  fragrans.  Nitrous  acid 
converts  o-amido-cinnamic  acid  into  cumaric  acid.  It  is  most  readily 
prepared  by  boiling  cumarin  for  some  time  with  concentrated  potassium 
hydroxide,  or,  better,  with  sodium  ethylate  (B.  18,  R.  28  ;  22,  1714). 
Its  acetyl  derivative  is  obtained  from  salicylic  aldehyde  and  sodium 
acetate. 

Ortho-cumaric  acid  is  very  easily  soluble  in  hot  water  and  in  alcohol. 
It  does  not  volatilise  with  steam.  The  free  cumaric  acid  heated  alone 
does  not  yield  cumarin,  but  only  when  treated  with  acetic  chloride  or 
anhydride.  Sodium  amalgam  converts  it  into  melilotic  acid,  and  fusion 
with  potassium  hydroxide  into  salicylic  and  acetic  acids. 

2 -Methoxy- cinnamic  acid  (0)  CH3O[2]C6H4[i]CH  :  CH.CO2H, 
melting  at  182°,  is  produced  by  the  action  of  sodium  acetate  and  acetic 
anhydride  upon  salicyl-aldehyde-methyl  ether,  and  by  the  rearrange- 
ment of  methyl-cumarinic  acid.  Sodium  amalgam  reduces  it  to 
melilotic  acid  methyl  ether,  while  bromine  changes  it  to  methyl-ether- 
dibromo-melilotic  acid.  o-Cumaric  dimethyl  ether  (jB)  CH3O[2]C6H4 
[i]CH  :  CH.CO2CH3,  boiling  at  293°,  is  obtained  from  the  previously 
described  acid  chloride  by  means  of  methyl  alcohol.  Aeeto-o-eumaric 
acid  CH3.CO.O[2]C6H4.CH  :  CH.CO2H,  m.p.  149°,  is  obtained  from 
salicyl-aldehyde,  acetic  anhydride,  and  sodium  acetate  (B.  20,  284). 
See  Cumarin. 

3-Nitro-cumaric  acid  (j8)  NO2[3]C6H3[2](OH)CH  :  CH.CO2H  is 
formed  by  the  protracted  heating  of  the  dimethyl  ether  with  sodium 
hydroxide.  It  suffers  no  change  when  heated  with  water,  alcohol,  or 
hydrogen  bromide  (distinction  from  3-nitro-cumarinic  acid).  The 
methyl-ether  acid,  m.p.  193°,  is  formed  from  3-nitro-salicyl-aldehyde- 
methyl  ether,  and  from  the  dimethyl  ether,  m.p.  88°,  by  the  action  of 
soda  (see  above).  This  latter  ether  is  produced  when  methyl  iodide 
acts  upon  the  silver  salt  of  the  methyl-ether  acid  (B.  22,  1710). 

f  r —  "1/^TT  .  f^TT 

Cumarin   C6H4|  ,   m.p.    70°   and    b.p.    290°,    occurs    in 

( [2]0— CO 


428  ORGANIC  CHEMISTRY 

Asperula  odorata,  in  the  Tonka  beans  (from  Dipterioc  odor  at  a),  and 
in  Melilotus  officinalis.  It  is  artificially  prepared  (i)  by  heating  aceto- 
o-cumaric  acid  (B.  10,  287),  the  reaction  product  resulting  from  acetic 
anhydride  and  sodium  salicyl-aldehyde  (A.  147,  230),  or  from  the 
action  of  acetic  anhydride  and  sodium  acetate  upon  salicyl-aldehyde 
(Perkin,  sen.,  B.  8,  1599) ;  (2)  from  phenol  with  malic  acid  and  sul- 
phuric acid  ;  (3)  by  reduction  of  /2-chloro-  or  /?-bromo-cumarin. 

It  has  the  agreeable  odour  of  Asperula,  and  is  applied  in  perfumery 
for  the  preparation  of  the  Asperula  essence. 

Cumarin  dissolves  rather  easily  in  hot  water,  and  very  readily  in 
alcohol  or  in  ether.  It  dissolves  in  caustic  potash  with  a  yellow  colour, 
the  first  product  being  potassium  cumarinate,  from  which  carbon 
dioxide  separates  cumarin.  Boiling  concentrated  caustic  potash 
changes  it  to  potassium  cumarate.  In  aqueous  solution  it  is  reduced 
by  sodium  amalgam  to  melilotic  acid,  while  sodium  and  alcohol  reduce 
it  to  oxy-hydro-cinnamic  alcohol  (B.  39,  2856). 

When  it  is  digested  with  an  aqueous  alcoholic  solution  of 
potassium  cyanide,  hydrocyanic  acid  is  added,  and,  upon  subsequent 
saponification,  o-oxy-phenyl-succinic  acid  is  formed  (A.  293,  366). 
Concerning  the  action  of  alkyl-magnesium  haloids  upon  cumarin, 
see  B.  37,  489. 

Cumarin-monomethyl-ester  acid,  m.p.  88°,  and  cumarinic  dimethyl 
ester,  b.p.  275°,  result  when  sodium  cumarin  is  heated  to  150°  with 
methyl  iodide.  When  heated,  both  compounds  change  to  the  corre- 
sponding o-cumaric  acid  derivatives,  from  which  they  can  be  recovered 
by  means  of  ultra-violet  light. 

Cumaroxime,  m.p.  131°  (B.  19,  1662),  is  produced  when  hydroxyl- 
amine  acts  upon  thio-cumarin. 

Cumarin  bromide  C9H6O2Br2,  m.p.  105°,  is  produced  when  bromine 
acts  upon  cumarin  in  carbon-disulphide  solution.  Alcoholic  potash 

(  [i]CH:CBr 

converts  it  into  a-bromo-cumarin  C6HJ  I     .    Boiling  alcoholic 

I  [2jo— do 

potash    changes    both    of    these    bodies    into    cumarilic    acid    (q.v.). 
( [i]CH :  CH 

Thio-cumarin  C6H44  |    ,  m.p.   101°,   consists   of  golden-yellow 

I  [2]0— CS 

needles.  It  is  obtained  from  cumarin  or  o-cumaric  acid  by  the  action 
of  P2S5  (B.  19,  1661). 

3-Nitro-cumarinic   acid   NO2[3]C6H3/W^:CH-COOH    melts    when 

L  [2JOH 

rapidly  heated,  with  the  exit  of  water,  at  150°,  and  passes,  on 
gentle  warming  with  water  or  alcohol,  into  the  anhydride,  3-nitro- 
cumarin,  from  which  it  is  obtained,  upon  boiling  with  soda.  It  forms 
long  yellow  prisms.  The  silver  salt  and  methyl  iodide  yield  3-nitro- 
cumarinic  dimethyl  ether. 

Cumarin  Homologues. — Following  method  2  (p.  426),  and  using 
propionic,  butyric,  and  iso-valerianic  anhydrides,  with  their  sodium 
salts,  the  products  are  a-alkyl-cumarins.  The  fi-alkyl-ciimarins  are 
produced  from  phenols,  aceto-acetic  ester,  and  sulphuric  acid  (B.  17, 
2188)  by  method  4.  P2S5  converts  the  a-alkyl-cumarins  into  a-alkyl- 
thio-cumarins,  which  hydroxylamine  changes  to  a-alkyl-cumarin 
oximes  (B.  24,  3459). 


DIOXY-PHENYL-OLEFIN-CARBOXYLIC  ACIDS        429 
a-Methyl-cumarin  ^H1™3^  m-P-  9°°.     jS-Methyl-cumarin 


For  other  homologous  cumarins,  see  B.  39,  871  ;  41,  830  ;  A.  367, 
232  ;  C.  1906,  I.  933  ;  1908,  II.  790  ;  1909,  I.  373. 

p-Amido-jS-methyl-cumarin,  mono-  and  dimethyl-amido-j3-methyl- 
cumarin,  m.p.  230°,  123°,  and  143°,  from  amido-,  monomethyl-,  and 
dimethyl-amido-phenol  with  aceto-acetic  ester  (B.  30,  277  ;  32,  3690). 

m-Cumaric  acid  HO[3]C6H4.CH  :  CH.CO2H,  melting  at  191°,  has 
been  formed  from  m-amido-cinnamic  acid  and  from  m-oxy-benz- 
aldehyde  (B.  15,  2049,  2297)- 

Nitro-m-cumaric  acids,  see  B.  22,  292. 

o-Amido-m-cumaric  acid  has  been  obtained  electrolytically  from 
o-nitro-cinnamic  acid  (B.  27,  1936). 

p-Cumarie  acid  HO[4]C6H  .CH  :  CH.CXXH,  melting  at  206°,  is 
obtained  from  p-amido-cinnamic  acid  and  from  p-oxy-benzaldehyde  ; 
also  on  boiling  the  extract  of  aloes  with  sulphuric  acid  (preparation, 
B.  20,  2528),  and  by  the  decomposition  of  the  glucoside  naringin  (q.v.). 

Methyl-p-eumarie  acid,  from  anisic  aldehyde,  melts  at  154°.  The 
phenol-alkyi  ethers  of  the  cumaric  acids  yield  ethers  of  unsaturated 
phenols  (see  o-  and  p-vinyl-anisol),  just  as  styrol  is  obtained  from  /?- 
bromo-hydro-cinnamic  acid  by  the  action  of  hydrogen  bromide,  and  then 
a  soda  solution,  when  carbon  dioxide  is  eliminated. 

jS-p-Methoxy-phenyl-methacrylic  acid  CH3O[4]C6H4.CH  :  C(CH3). 
COOH,  melting  at  154°,  is  obtained  from  anisic  aldehyde  and  propionic 
acid.  It  breaks  down,  when  heated,  into  carbon  dioxide  and  anethol. 

B.  Dioxy-phenyl-olefin-earboxylic  Acids.  —  Caffeic  acid,  or  3,  4~di- 
oxy-cinnamic  acid,  corresponding  to  proto-catechuic  acid  and  umbellic 
acid,  or  2,  4-dioxy-cinnamic  acid,  are  the  most  important  of  the  known 
dioxy-cinnamic  acids,  because  they  themselves,  or  their  simple  deriva- 
tives, occur  in  plants  or  appear  as  decomposition  products  of  vegetable 
substances,  and  3-methyl-caffeic  acid,  or  ferulic  acid,  can  be  changed 
to  the  valuable  vanillin. 

Caffeic  acid,  jS-3,  ^-dioxy-phenyl-acrylic  acid,  3,  ^-dioxy-cinnamic 
acid,  and  its  methyl-  and  methylene-ester  acids,  when  reduced,  become 
hydro-caffeic  acid  and  its  ether  acids.  Oxidation  yields  proto-catechuic 
acid  and  its  ethers.  When  the  aceto-derivatives  of  the  two  methyl- 
caffeic  acids  are  oxidised  with  potassium  permanganate,  the  first 
products  are  the  aceto-derivatives  of  the  two  methyl-ether-proto-cate- 
chuic  aldehydes.  The  caffeic  acids  and  their  ether  acids  can  be 
synthesised  from  proto-catechuic  aldehyde  and  its  ethers  with  the  aid 
of  the  Perkin  reaction.  When  fused  with  caustic  potash,  caffeic  acid 
and  its  ether  acids  yield  proto-catechuic  acid  and  acetic  acid  : 


f  [i]CO  :  CH.CO2H  /  [i]CH  :  CH.CO2H  f  [i]CH  :  CH.CO,H 

C6H3     [3]OH  C6H3  \  [3]OCH3  C6H3-|  [3]OH 

l[4]OH  l[4]OH  l[4]OCH3 

Cafifei'c  acid,  m.p.  213°          Ferulic  acid,  m.p.  169°  Iso- ferulic  acid,  m.p.  228° 

(yields  vanillin)  (yields  iso vanillin) . 


Caffeic  acid  is  produced  when  coffee  tannic  acid  is  boiled  with 
potassium  hydroxide.     It  occurs  in  Cicutavirosa  (B.  17, 1922).     Ferric 


430  ORGANIC  CHEMISTRY 

chloride  produces  a  green  coloration  in  its  solutions,  which  sodium 
carbonate  changes  to  a  dark-red  colour. 

Ferulic  acid,  m-methoxy-p-oxy-cinnamic  acid,  occurs  in  the  resin  of 
asafcetida,  and  has  been  obtained  from  vanillin  as  well  as  from  m- 
methoxy-p-nitro-cinnamic  acid,  the  product  resulting  from  the  action 
of  nitric  acid  upon  m-methoxy-cinnamic  acid  ether  (B.  18,  R.  682). 
Its  aceto-compound  melts  at  196°. 

Iso-ferulic  acid,  m-oxy-methoxy-cinnamic  acid,  hesperitinic  acid,  was 
first  obtained  from  the  glucoside  hesperidin  (q.v.).  Both  methyl 
ethers  can  also  be  prepared  by  a  partial  methylation  of  caffeic  acid, 
when  the  chief  product  will  be  iso-ferulic  acid.  Its  aceto-derivative  melts 
at  199°. 

Dimethyl-eaffeie  acid  (CH3O)2[3,  4]C6H3.CH  :  CH.CO2H,  melts  at 
181°  (B.  14,  959). 

Piperonyl-aerylic  acid  (CH2O2)[3,  4]C6H3.CH  :  CH.CO2H  melts  at 
232°  (B.  13,  757). 

Diaceto-caffeic  acid  (CH3CO2)2[3,  4]C6H3.CH  :  CH.CO2H  melts  at 
190°  (B.  11,  686). 

a-Homo-caffeic  acid,  3,  4-dioxy-a-methyl-cinnamic  acid,  melts  at 
193°.  Its  monomethyl-ether  acid,  homo-ferulic  acid  (CH3O)(OH)[3,  4] 
C6H3.CH  :  C(CH3).COOH,  melting  at  168°,  yields  iso-eugenol  when  it 
is  heated  with  lime  (B.  15,  2063). 

a-Hydro-piperie  acid  (CH202)[3,  4]C6H3CH2.CH  :  CH.CH2.CO2H, 
melting  at  78°,  is  formed  when  sodium  amalgam  acts  upon  piperic  acid. 
When  boiled  with  caustic  soda  it  changes  to  jS-hydro-piperic  acid 
(CH202)[3,  4]C6H3.CH2.CH2.CH  :  CH.CO2H,  melting  at  131°.  Sodium 
amalgam  converts  the  j3-acid  into  piper-hydronic  acid  (CH2O2)[3,  4] 
C6H3[CH2]4CO2H,  melting  at  98°. 

Umbellic  acid,  2,  4-dioxy-cinnamic  acid  (HO)2[2,  4]C6H3.CH  :  CH. 
CO2H,  decomposes  about  240°.  It  is  produced  on  boiling  umbelliferone 
with  KHO  ;  the  2,  4-dimethoxy-cinnamic  acid,  m.p.  184°,  is  formed 
from  dimethyl-resorcyl-aldehyde  by  Perkin's  synthesis  (C.  1903,  I.  580  ; 
1904,  I.  724). 

(  rTld-T  •  CTT 


Umbelliferone,    4-oxy-cumarin    HO[4]C6H34  I    ,   melting    at 

([2]0 CO 

240°,  is  found  in  the  bark  of  Daphne  mezereum,  and  is  obtained  by  dis- 
tilling different  resins,  such  as  galbanum  and  asafcetida.  It  is  obtained 
synthetically  from  j8-resorcyl-aldehyde  by  method  2  ;  and  also  by  the 
condensation  of  resorcin  with  malic  acid  according  to  method  3.  It 
has  an  odour  resembling  that  of  cumarin,  and  behaves  similarly 
with  caustic  potash.  Its  alkyl  ethers  show  isomeric  phenomena 
analogous  to  those  developed  under  o-cumaric  acid  and  cumarin 
(B.  19,  1778). 

j8  -  Methyl-umbelliferone,    4  -  oxy  -  B  -  methyl-cumarin,    resocyanin, 

r[i]C(CH3):CH 

si 


HO[4]C6H3-]  I    ,  melting  at  185°,  is  formed  when  sulphuric  acid 

( [2]0— CO 

acts  upon  resorcin  and  aceto-acetic  ester  or  acetyl-cyanacetic  ester 
(B.  26,  R.  314).  Also  from  p-amido-methyl-cumarin  (B.  26,  R.  314)  ; 
on  melting  with  potash  it  gives  resaceto-phenone.  Nitro-  and  amido- 
methyl-umbelliferone,  see  B.  34,  660. 

a,  0-Dimethyl-umbelliferone  melts  at  256°  (B.  16,  2127). 


TRIOXY-CINNAMIC   ACIDS  431 

The  corresponding  bodies  have  been  prepared  from  orcin  according 
to  methods  3  and  4  (B.  17,  1649,  2188) 

2,  5-Dioxy-cinnamie  acid,  m.p.  207°,  from  o-cumaric  acid  by  oxida- 
tion with  KMnO4  in  alkaline  solution  (C.  1907,  II.  901). 

3-Oxy-cumarin,  melting  at  28o°-285°  with  decomposition,  and 
5-oxy-cumarin,  melting  at  249°,  are  produced  when  pyro-catechol  and 
hydroquinone  are  treated  with  malic  acid  and  sulphuric  acid  (B.  18, 

R.  333). 

5-Oxy-/3-methyl-cumarin,  m.p.  243°,  from  hydroquinone,  aceto- 
acetic  ester,  and  sulphuric  acid  (B.  40,  2731). 

C.  Trioxy-cinnamic  Acids. — Inner  anhydrides,  8-lactones  of  trioxy- 
cinnamic  acids,   are   daphnetin,  3,  4-dioxy-cumarin,   melting  at  255°, 
and  aesculetin,  4,  $-dioxy-cumarin,  the  aromatic  decomposition  pro- 
ducts of  the  isomeric  glucosides  daphnin  and  aesculin.     Synthetically 
they  have  been  obtained  from  pyrogallic  aldehyde,   or  oxy-hydro- 
quinone-aldehyde,  acetic  anhydride,  and  sodium  acetate  (B.  32,  287). 

/Esculetinic  and  daphnetic  acids  are  the  trioxy-cinnamic  acids  corre- 
sponding to  these  dioxy-cumarins.  They  are  only  known  as  ether 
acids  and  ether  esters.  Potassium  permanganate  oxidises  the  triethyl 
ethers  to  triethoxy-benzoic  acids,  which  become  triethoxy-benzols 
through  the  loss  of  carbon  dioxide  (B.  15,  2082  ;  17,  1086  ;  20,  1119). 

Methyl-aesculetin,  ^-oxy-^-methoxy-cumarin,  m.p.  203°,  is  identical 
with  gelseminic  acid  from  Gelsenium  sempervivens,  and  also  with 
chrysatropic  acid  from  Atropa  belladonna  (C.  1898,  II.  635  ;  B. 
31/1189). 

jS-Methyl-aesculetin,  4,  5-dioxy-j8-methyl-cumarin,  m.p.  270°,  from 
oxy-hydroquinone  triacetate  with  aceto-acetic  ester,  and  sulphuric 
acid  (B.  34,  423). 

Sinapinic  acid,  oxy-dimethoxy-cinnamic  acid  (CH3O)2[3,  5]  (OH)  [4] 
C6H2CH  :  CHCOOH,  m.p.  192°,  has  been  obtained  from  white  mustard 
seeds,  and,  synthetically,  from  syringa  aldehyde  by  Perkin's  reaction 
(B.  36,  1031).  Methyl-sinapinic  acid,  3,  4,  ^-trimethoxy-cinnamic  acid, 
m.p.  124°,  from  trimethyl-gallic  aldehyde  (B.  41,  2536).  4,  6-Dioxy- 
cumarin,  m.p.  273°,  from  phloro-glucin-aldehyde  by  Perkin's  reaction. 
On  methylation  it  yields  eitroptene,  limettin,  4,  6-dimethoxy-cumarin, 
m.p.  147°,  from  the  ethereal  oils  of  certain  species  of  Citrus  (C.  1904, 

ii.  105). 

D.  Tetraoxy-cinnamic    Acids. — Fraxetin,    melting    at    227°,    the 
aromatic  decomposition  product  of  the  glucoside  of  fraxin  (q.v.),  con- 
tains the  monomethyl  ether  of  a  trioxy-cumarin.     Isomerides  of  fraxetin 
have  been  prepared  synthetically  (B.  27,  R.  130  ;   29,  R.  293). 

E.  Phenyl  -  acetylene  -  earboxylic    Acids. — Phenyl  -  propiolie     acid 
C6H5.C  ;  C.CO2H,  m.p.  136°,  is  obtained  by  boiling  a-  and  £-bromo- 
cinnamic  acids  with  alcoholic  potash,  by  acting  upon  sodium  phenyl- 
acetylene  with  carbon  dioxide  (1870,  Glaser,  A.  154,  140),  and  when 
the  latter,  and  sodium,  act  upon  cu-bromo-styrol.     It  is  prepared  by 
boiling  the  dibromide  of  cinnamic  acid,  or  its  ethyl  ester,  with  alcoholic 
potash  (B.  34,  3647  ;  36,  902).     Heated  in  water  to  120°,  it  decomposes 
into  phenyl-acetylene  and  CO2.      On  heating  with  acetic  anhydride, 
or  by  the  action  of  POC13,  phenyl-propiolic  acid  passes  into  the  anhy- 
dride   of    i-phenyl-naphthalin-2, 3-dicarboxylic    acid    (B.    40,    3372  ; 
C.  1908,  II.  1357).     Similarly,  phenyl-propiolic  ester  polymerises,  on 


432  ORGANIC   CHEMISTRY 

heating  to  200°,  to  form  phenyl-naphthalin-dicarboxylic  ester  (B.  40, 
3839  ;  see  the  formation  of  trimesinic  acid  from  propiolic  acid). 

On  adding  hydrogen,  by  means  of  sodium  amalgam,  it  becomes 
hydro-cinnamic  acid  ;  treated  with  zinc  dust  and  glacial  acetic  acid,  or 
sodium  and  alcohol,  it  becomes  cinnamic  acid  (B.  22,  1181)  ;  with 
hydrogen  in  the  presence  of  colloidal  palladium,  allo-cinnamic  acid  ; 
and,  by  addition  of  HC1  and  HBr,  it  yields  j3-halogen  and  allo-j8- 
halogen-cinnamic  acid.  It  unites  with  halogens  to  form  phenyl- 
dihalogen-acrylic  acids;  with  hydrazin  hydrate  and  phenyl-hydrazin 
it  forms  3-phenyl-pyrazolone  and  i,  3-diphenyl-pyrazolone  (B.  27, 
783).  Similarly,  phenyl-propiolic  acid  unites  with  other  amine  bases 
(C.  1900,  I.  547  ;  1908,  I.  233),  as  well  as  the  sodium  compound  of 
j8-diketones,  aceto-acetic  ester,  and  malonic  ester.  In  the  last- 
mentioned  reaction  a  tricarboxylic  acid  is  obtained  which,  on  dis- 
carding CO2,  becomes  phenyl-glutaconic  acid  (B.  27,  R.  163  ;  C.  1899, 
II.  608).  On  digesting  with  sodium  alcoholates  one  or  two  molecules 
of  alcohol  are  attached,  and  jS-alkoxy-cinnamic  ester  is  formed,  or 
dialkyl  acetals  of  benzoyl-acetic  ester  (C.  1904,  I.  659  ;  1906,  I.  1551). 
Phenyl-propiolic-acid  nitrile  unites  with  one  molecule  of  a  primary  or 
secondary  amine  to  form  j8-alkyl-amido-cinnamic-acid  nitriles,  such  as 
C6H5C(NHCH3)  :  CH.CN,  which,  with  acids,  regenerate  the  amine  and 
form  benzoyl-aceto-nitrile  (C.  1906,  II.  1842). 

Phenyl-propiolic  ethyl  ester  C6H5C  ;  C.CO2C2H5,  b.p.22  153°,  is  also 
formed  from  sodium-phenyl-acetylide,  with  chloro-carbonic  ester.  It 
easily  transforms  into  benzoyl-acetic  ester  by  hydration  (A.  308,  280). 
Phenyl-propiolic  acid  nitrile  C6H5C  :  CCN,  m.p.  39°,  is  formed  from  the 
amide  with  P2O5  ;  from  sodium-phenyl-acetylide  with  gaseous  HCN  ; 
and  from  phenyl-propargyl-aldoxime  with  acetic  anhydride  (B.  36, 
3671).  Chloride,  b.p.25  131°;  amide,  m.p.  102°  (B.  25,  3537;  29, 
R.  795  ;  C.  1906,  I.  651). 

o-Nitro-phenyl-propiolic  acid  decomposes  at  156°.  It  is  obtained 
when  alcoholic  potash  acts  upon  the  dibromide  of  o-nitro-cinnamic 
acid  (Baeyer,  A.  212,  140).  When  boiled  with  water  it  decomposes 
into  carbon  dioxide  and  o-nitro-phenyl-acetylene.  When  boiled  with 
alkalies  it  yields  isatin. 

It  dissolves  in  concentrated  sulphuric  acid,  with  conversion  into 
the  isomeric  isatogenic  acid,  which,  at  once,  forms  carbon  dioxide  and 
isatin.  Its  silver  salt  explodes  with  great  violence  when  it  is  heated. 

If  digested  with  alkaline  reducing  agents  (grape-sugar  and  potassium 
hydroxide,  ferrous  sulphate,  hydrogen  sulphide,  potassium  xanthate), 
it  readily  changes  to  indigo  blue  (Baeyer,  1880  ;  B.  13,  2259). 

The  ethyl  ester  of  the  acid  is  obtained  by  conducting  hydrochloric 
acid  gas  into  a  mixture  of  the  acid  and  alcohol.  It  melts  at  6o°-6i°. 
When  it  is  dissolved  in  sulphuric  acid  it  changes  to  the  isomeric  isato- 
genic ester.  Ammonium  sulphide  reduces  it  to  the  indoxylic  ester 
(B.  14,  1741)  : 


Isatogenic  ester  o-Nitro-phenyl-propiolic  ester  Indoxylic  ester. 

p-Nitro-phenyl-propiolic  acid,  m.p.  198°,  is  formed  from  the  p-nitro- 
cinnamic  ester  after  the  same  manner  as  the  ortho-acid.  When  boiled 
with  water  it  breaks  up  into  carbon  dioxide  and  p-nitro-phenyl-acety- 


PHENYL-DIOLEFIN-CARBOXYLIC  ACIDS  433 

lene.  It  yields  p-nitro-aceto-phenone  if  digested  at  100°  with  sul- 
phuric acid. 

The  ethyl  ester,  m.p.  126°,  when  digested  with  sulphuric  acid  at 
35°,  forms  p-nitro-benzoyl-acetic  acid. 

c-Amido-phenyl-propiolic  acid  melts  at  129°  with  decomposition 
into  CO  2  and  o-amido-phenyl-acetylene.  It  is  obtained  by  reducing 
o-nitro-phenyl-propiolic  acid  with  ferrous  sulphate  and  ammonia 
(B.  16,  679).  It  separates  as  a  yellow  crystalline  powder.  When 
boiled  with  water  it  yields  o-amido-aceto-phenone. 

y-Chloro-carbo-styril  results  when  the  acid  is  boiled  with  hydro- 
chloric acid,  and  y-oxy-carbo-styril  upon  heating  it  with  sulphuric 
acid  (B.  15,  2147)  : 

fCCl:CH\              +HCI            ;[i]CEEC.C02H                fC(OH) :  CH\ 
C'H«\N— —  /C01    *Ili^- C«HH[2]NH2  »C«H«\N- ^C 

Sodium  nitrite  converts  the  hydrochloride  into  the  diazo-chloride, 
which  at  70°  yields  cinnolin-oxy-carboxylic  acid. 

m-Methyl-phenyl-propiolic  acid  CH3[3]C6H4C  :  C.  CO2H  melts  at 
109°  (B.  20,  1215). 

F.  Phenyl-diolefln-carboxylic  acids  have  been  prepared  from  cin- 
namic  aldehyde  by  means  of  the  Perkin  reaction.  Cinnamylidene- 
acetic  acid,  cinnamenyl-acrylic  acid  CgHg.CH  :  CH.CH  :  CH.CO6H 
melts  at  165°,  from  cinnamic  aldehyde,  pyridin,  and  malonic  acid  with 
heat,  by  decomposition  of  the  cinnamylidene-malonic  acid  first  formed 
together  with  the  stereo-isomeric  allo-cinnamylidene-acetic  acid,  m.p. 
138°  ;  on  overheating  it  discards  CO2  and  passes  into  phenyl-butadiene 
(B.  35,  2696). 

The  nitrile,  boiling  at  285°,  is  obtained  from  cinnamenyl-cyano- 
acrylic  acid.  The  o-  and  p-nitro-acids,  melting  at  217°  and  271°,  were 
obtained  from  o-  and  p-nitro-cinnamenyl-acetone  by  the  action  of 
NaQO  (A.  253,  356).  The  o-amido-acid  melts  with  decomposition  at 
176°  (B.  18,  2332).  Cinnamenyl-crotonic  acid  and  cinnamenyl-angelica 
acid  melt  at  157°  and  126°  (C.  1906,  I.  349). 

Piperic  acid,  3,  ^-methylene-dioxy-cinnamenyl-acrylic  acid  (CH2O2) 
[3, 4]C6H3.CH  :  CH.CH  :  CH.CO2H,  melting  at  217°,  is  produced, 
together  with  piperidin,  when  piperin  is  boiled  with  alcoholic  potassium 
hydroxide.  It  can  be  synthesised  by  aid  of  the  Perkin  reaction, 
from  piperonyl-acrolein,  and  from  piper onylene-malonic  acid  (B.  28, 
1190).  Sodium  amalgam  converts  it  into  two  isomeric  hydro-piperic 
acids,  a  and  /?.  It  combines  with  four  atoms  of  bromine.  It  is  oxidised, 
in  dilute  solution  by  potassium  permanganate  at  o°,  to  piperonal  and 
racemic  acid  (B.  23,  2372).  When  fused  with  potassium  hydroxide  it 
breaks  down  into  acetic,  oxalic,  and  proto-catechuic  acids.  Its  chloride 
and  piperidin  form  piperin  (q.v.). 

History. — Fittig  and  Mielck  (1874)  determined  the  constitution  of 
piperic  acid.  Ladenburg  and  Scholtz  (1894)  effected  its  synthesis 
(B.  27,  2958). 

a-Methyl-  and  a-ethyl-piperic  acids,  melting  at  208°  and  179°,  were 
synthesised  just  like  piperic  acid  (B.  28,  1187). 

j8-Cinnamylidene-propionic  acid  C,H6CH  :  CH.CH  :  CH.CH2COOH, 
m.p.  112°,  is  formed,  in  small  quantities,  on  condensation  of  cinnamic 
aldehyde  and  sodium  succinate  with  acetic  anhydride  (A.  331,  162). 
VOL.  II.  2  F 


434  ORGANIC  CHEMISTRY 

IV.  COMPOUNDS  WHICH  MAY  BE  VIEWED  AS  OXIDATION  PRODUCTS  OF 

MONONUCLEAR-AROMATIC    POLYALCOHOLS    WITH    UNSATURATED 

SIDE  CHAINS. 

The  domain  of  the  aromatic  poly  alcohols  having  unsaturated  side- 
chains  has  been  even  less  completely,  and  even  more  irregularly, 
developed  than  that  of  the  polyhydric  aromatic  paraffin  alcohols  and 
their  oxidation  products.  At  present  the  alcohols  and  aldehydes  are 
wholly  lacking  ;  from  them  the  carboxylic  acids  and  their  derivatives 
belonging  here  can  be  theoretically  deduced.  Consequently  the 
material  in  this  section  will  not  be  sharply  differentiated,  although, 
in  the  main,  the  classification  is  the  same  as  that  observed  with  the 
oxidation  products  of  the  aromatic  polyparamn  alcohols. 

i.  Phenylene-oxy-olefin-carboxylic  Acids. — Methylene-phthalide  and 
iso-cumarin  are  inner  anhydrides,  or  lactones,  of  the  possible  o-vinyl- 
alcohol-benzoic  acids.  They  are  not  known  in  a  free  state.  Cumarin 
is  isomeric  with  them. 

Methylene-phthalide  C6H4(  2,  m.p.  59°,  is  formed  in  the 

l[2]COO 
distillation  of  phthalyl-acetic  acid.    Its  dibromide  melts  at  98°.    Mono- 

,[i]C=CHBr 

bromo-methylene-phthalide  C6H4{      \  is  produced  by  the  action 

l[2]CO.O 

of  bromine  upon  o-aceto-phenone-carboxylic  acid.    Diehloro-methylene- 

phthalide  C6H4{  *  \~      2  melts  at  128°.     It  is  formed,  together  with 
l[2]COO 

,CC1.CC13 
tetraehloro-methyl-phthalide  C6H4{  \        ,  melting  at  93°,  upon  con- 

VCOO 

ducting  chlorine  into  a  mixture  of  glacial  acetic  acid  and  phthalyl- 
chloracetic  acid  (A.  255,  383  ;  268,  294). 

Bromo-methylene-phthalide,  m.p.  140°,  from  aceto-phenone-o-car- 
boxylic  acid,  with  bromine.  Dibromo-methylene-phthalide,  m.p.  140°, 
from  a-dibromaceto-phenone-o-carboxylic  acid  on  heating  with  con- 
centrated sulphuric  acid  (B.  40,  83). 

r[i]C=CH2 
Derivatives  of   methylene-phthalimidin  C6HJ        ~--^    have   been 

l[2]CO.NR 

prepared  by  the  action  of  amines  and  amino-acids  upon  o-aceto- 
phenone-carboxylic  acid  (B.  29,  2518). 

fC=CHNO2 
Nitro-methylene-phthalide     C6H4{  \  ,   m.p.   207°   with   de- 

vco.o 

composition,  from  phthalic  anhydride  and  nitro-methane,  is  split  up 
by  alkali  to  nitro-phenaeyl-o-carboxylie  acid  NO2CH2COC6H4COOH, 
m.p.  121°  (B.  36,  570). 

{Ti~lC=CH  CH 

Ethylidene-phthalide  C6H4<  3  melts  at  64°  (B.  19,  838). 

( [2]COO 

Propylidene-  and  iso-butylidene-phthalides,  boiling  at  170°  (12  mm.) 
and  melting  at  97°,  are  obtained  by  condensing  phthalic  anhydride 
with  the  sodium  salts  and  anhydrides  of  propionic,  butyric,  and  iso- 
valeric  acids.  Water  and  carbon  dioxide  are  eliminated  (B.  29,  1436). 

These  alkylidene  phthalides  are  transposed  by  sodium  ethylate 
into  the  isomeric  diketo-hydrindenes.  B}'  alkaline  hydrates,  they  are 


PHENYLENE-OXY-OLEFIN-CARBOXYLIC  ACIDS       435 

split  up  into  o-ketone-carboxylic  acids.  Ethylene-phthalide  gives  rise 
to  propio-phenone-o-carboxylic  acid. 

r      -IpfT__QTT 

Iso-cumarin    C8H4|L  J      ~  i     ,    melting    at    47°   and   boiling    at 

285°,  is  formed  in  the  distillation  of  silver  iso-cumarin-car  boxy  late.  It 
readily  volatilises  with  steam.  When  digested  with  soda  it  becomes  : 
Anhydro-o-oxy-vinyl-benzoic  acid  O(CH  :  CH[2]C6H4.CO2H)2, 
melting  at  183°.  When  this  body  is  heated  with  hydrochloric  acid  to 
160°  the  anhydride  O(CH  :  CH[2]C6H  .CO)2O,  melting  at  234°,  results. 
The  imide  O(CH  :  CH[2]C6H4CO)2NH,  melting  at  285°,  is  produced 
when  alcoholic  ammonia  acts  upon  the  anhydride  at  170°  (B.  27,  207). 

_  rT~i(~>~H[ CH 

Iso-carbo-styril    C6H4/ L  J     ^\     ,    melting    at    208°,    is   isomeric 

with  carbo-styril,  the  lactame  corresponding  to  iso-cumarin.  It  is 
formed  when  iso-cumarin  is  heated  to  130°  with  alcoholic  ammonia,  and 
upon  heating  iso-carbo-styril-carboxylic  acid  or  its  silver  salt.  It  yields 
iso-quinolin  when  distilled  with  zinc  dust  (B.  27,  208). 

3-Methyl-iso-cumarin    C^^^=_^C^>    melting    at    118°,    is 

/[i]C=C(02CCH3)CH3 
formed  when  \L-diacetyl-cyano-benzyl-cyanide  C6HJ       \ 

l[2]CNCN 

melting  at  135°,  is  heated  to  180°  with  hydrochloric  acid.  This  latter 
body  results  from  the  action  of  sodium  acetate  and  acetic  anhydride 
upon  o-cyano-benzyl  cyanide  (B.  27,  831).  Similarly,  o-cyano-benzyl 
cyanide  furnishes  an  additional  series  of  homologues  of  iso-cumarin, 
all  of  which  are  characterised  by  their  ready  transposition  into  iso- 
carbo-styrils  (see  B.  29,  2543,  etc.). 

Ammonia  converts  3-methyl-iso-cumarin  into  the  corresponding 
3-methyl-iso-carbo-styril,  melting  at  211°  (B.  25,  3563). 

By  boiling  in  KHO  methyl-iso-cumarin  is  transformed  into  methyl- 
benzyl-ketone-o-carboxylic  acid. 

CH=CH^  CCH=CH 

Bergaptene  Lc6H(OCH3H  I      (?),    melting    at    188°, 

1 o    J  [O CO 

appears  to  be  a  derivative  of  oxy-vinyl-cumarin.  It  separates,  on 
standing,  from  raw  bergamot  oil,  which  is  obtained  by  pressing  out  the 
fresh  rinds  of  Citrus  Bergamia,  Risso  (B.  26,  R.  234). 

2 .  Phenylene  -  aldehydo  -  carboxylic    A  cids. — p  -  Aldehyde  -  cinnamic 
acid  CHO[4]C6H4.CH  :  CH.C02H,  melting  at  247°,  is  obtained  from 
terephthal-aldehyde  by  the  Perkin  reaction  (A.  231,  375  ;  B.  34,  2784). 

3.  Phenylene -dicarboxylic     Acids. — o  -  Cinnamyl  -  carboxylic    acid 
CO2H[2]C6H4.CH.CH.CO2H,  m.p.  174°,  reverts  again  to  phthalidacetic 
acid.     It  is  produced  when  phthalidacetic  acid  is  digested  with  alkalies, 
and  by  carefully  oxidising  j3-naphthol  with  potassium  permanganate 
(B.   21,   R.  654).     More  energetic  oxidation   produces  carbo-phenyl- 
glyoxylic  acid. 

o-Cyano-cinnamie  acid  CN[2]C6H4CH  :  CH.CO2H,  m.p.  252°,  is 
produced  when  sodium  acetate  and  acetic  anhydride  act  upon  a-cyano- 
benzal  chloride,  and  also  from  o-amido-cinnamic  acid  (B.  24,  2574  ; 
27,  R.  262).  Its  formation  from  the  Na  salt  of  jS-nitroso-naphthol 

fC(NO)  :C(OH) 
C8H4 -j  I          by  heating  to  250°  is  worthy  of  note  (C.  1901, 1.  69). 

1 CH -       CH 


436  ORGANIC  CHEMISTRY 

p-Cinnamyl-carboxylic  acid  is  obtained  from  terephthal-aldehydic 
acid  and  sodium  acetate.  It  is  an  insoluble,  infusible  powder  (A.  231, 

369). 

o  -  Phenylene  -  diaerylie  acid  C6H4[i,  2](CH  :  CH.CO2H)2  melts 
above  300°.  It  is  produced  when  alcoholic  potash  acts  upon 
o-xylylene-dichloro-dimalonic  ester,  or  from  o-phthal-aldehyde  by 
Perkin's  reaction  (B.  19,  435  ;  A.  347,  117). 

p-Phenylene-diaerylic  acid  is  obtained  from  p-aldehydo-cinnamic 
ester  with  sodium  acetate  and  acetic  anhydride  (A.  231,  377),  and  from 
p-xylylene-dibromo-dimalonic  ester  (B.  34,  2784). 

4.  Phenyl-olefin-ketols. — Oxy  -  methylene  -  aceto  -  phenone  C6H5.CO. 
CH  :  CH.OH,  when  separated  from  its  sodium  compound,  is  a  very 
unstable  oil.     Its  sodium  derivative  is  formed  when  sodium  ethylate 
acts  upon  formic  ester  and  aceto-phenone.     Formerly,  oxy-methylene- 
aceto-phenone  was  considered  to  be  benzoyl-acetaldehyde.     As  to  the 
constitution   of   the   oxy-methylene   compounds,  see   Vol.    I.      With 
phenyl-iso-cyanate  it  yields   an   O-carbanilido-derivative,  m.p.  125°, 
which,  by  the  action  of  potassium  carbonate,  is  easily  transposed  to 
the  isomeric  C-carbanilide,  m.p.  94°  (B.  37,  4631).     Phenyl-hydrazin 
converts  it  into  diphenyl-pyrazol  (q.v.)  ;    hydroxylamine  unites  with 
it   to   form    benzoyl-acetaldoxime.     See   also   Benzylidene   phenoxy- 
acetone. 

5,  6.  Phenyl  -  oxy  -  olefin  -   and   diolefin  -  carboxylic    Acids.  —  Oxy- 
methylene-phenyl-acetic  ester  C6H5C(CO2C2H5)  :  CHOH— see  Fonnyl- 
phenyl-acetic  ester. 

j8-Methoxy-einnamic  ester  C6H5C(OCH3)  :  CHCO2C2H5,  b.p.14  155°, 
and  j8-ethoxy-einnamic  ester,  b.p.16  168°,  are  formed  from  phenyl- 
propiolic  acid  ester  with  sodium  alcoholate,  and  from  benzoyl-acetic 
ester  with  ortho-formic  acid  ether.  The  corresponding  acids  melt  at 
180°  and  162°  respectively,  discarding  CO2  and  forming  j8-phenyl- 
vinyl-methyl  and  ethyl  ethers  (B.  29,  1005  ;  C.  1904,  I.  659,  719). 
j3-Phenoxy-cinnamic  ester  C6H5C(OC6H5)  :  CHCOOC2H5,  m.p.  76°, 
b.p.10  265,  is  obtained  by  attaching  sodium  phenolate  to  phenyl-pro- 
piolic  acid  ester ;  the  acid,  m.p.  143°,  yields  on  heating  CO2  and  j8-phen- 
.oxy-styrol  C6H5C(OC6H5)  :  CH2  (C.  1900,  II.  247  ;  1901,  II.  410,  1052  ; 
1906,  I.  1551).  a-Phenoxy-einnamic  acid  C6H5CH  :  C(OC6H6)COOH, 
m.p.  181°,  is  obtained  from  benzaldehyde,  sodium  phenoxy-acetate, 
and  acetic  anhydride  by  synthesis  ;  also  from  benzylidene-phenoxy- 
acetone  with  alkali  hypochlorite  by  disintegration  (B.  35,  3555).  On 
heating  it  partly  decomposes  into  CO2  and  a>-phenoxy-styrol,  partly 
into  CO  and  phenyl-acetic  phenyl  ester  (B.  38,  1958). 

y-Phenyl-a-oxy-crotonie  acid,  styrol-a-oxy-acetic  acid  C6HgCH  : 
CH.CH(OH)COOH,  m.p.  137°,  is  prepared  by  saponifying  its  nitrile, 
cinnamyl-aldehyde  cyano-hydrin,  m.p.  74°,  with  cold  concentrated 
hydrochloric  acid  ;  or  by  reduction  of  cinnamyl-formic  acid  with  Na 
amalgam.  On  boiling  with  hydrochloric  acid  the  acid  is  readily  re- 
arranged to  benzoyl-propionic  acid  (B.  37,  3124),  whereas  by  boiling 
with  NaHO  benzyl-pyro-racemic  acid  is  formed.  Heated  alone  or 
with  acetic  anhydride,  benzoyl-propionic  acid  yields  y-phenyl-A2- 

croto-lactone   CpH5t  :  CH.CH2COO,    m.p.  91°,   from   which   benzoyl- 
propionic  acid  is  easily  regenerated.     Another  derivative  of  phenyl- 


PHENYL-OXY-OLEFIN-CARBOXYLIC   ACIDS  437 

a-oxy-crotonic  acid  is  probably  trichloro  -  methyl  -  styrol  -  carbinol 
CC13CH(OH)CH  :  CHC6H5,  m.p.  67°,  obtained  from  cinnamic  aldehyde 
with  chloroform,  which,  on  heating  with  water,  or  alkalies,  also  yields 
benzoyl-propionic  acid  (A.  299,  i  ;  C.  1900,  II.  238). 

/CH2  —  CO 
jS-Benzyl-angelica-lactone    C6H5.CH2C/  \   is  obtained-  in  the 


distillation  of  benzyl-lsevulinic  acid. 

j3-0xy-eumarin  C6H4{[*(^_^,  m.p.  206°,  is  formed  from  its 

carboxylic  ester  by  saponification  and  detachment  of  CO2.  In  its 
properties,  solubility  in  alkaline  carbonate,  formation  of  an  oximido- 
compound  with  sodium  nitrite,  capacity  of  condensation  with  aldehydes, 
etc.,  it  resembles  the  aliphatic  tetronic  acids,  and  it  has  therefore  also 
been  called  benzo-tetronic  acid.  On  heating  with  concentrated  alkalies, 
oxy-aceto-phenone  is  formed  (A.  379,  333).  j3-Ethoxy-eumarin,  m.p. 
174°,  is  formed,  from  the  silver  salt,  with  IC2H5.  With  PC15  and  PBr5, 
j8-oxy-cumarin  gives  j3-chloro-  and  jS-bromo-cumarin,  m.p.  92°  and  91° 
respectively,  which  are  reduced  with  zinc  dust  and  alcohol  to  cumarin. 
Methylene-bis-benzo-tetronic  acid  (c6H4{^  |j_£o)  CH2,  m.p. 

about  206°,  and  ethylidene-bis-benzo-tetronic  acid,  m.p.  165°,  from 
benzo-tetronic  acid  with  formaldehyde  and  acetaldehyde  respectively 
(A.  367,  169).  Homologous  and  substituted  /2-oxy-cumarins  have  been 
prepared  by  starting  from  the  corresponding  substituted  salicylic 
chlorides  (A.  367,  219  ;  368,  23). 

S-Oxy-einnamylidene-aeetie  Acid.—  Its  lactone  is  phenyl-cumalin 
C8H5.C  :  CH.CH  :  CH.CO 

I  I  ,  melting  at  68°,  and  found  in  coto  bark  (B.  29, 

2659  ;  R.  1116). 

From  a  phenyl-oxy-triolefin-carboxylic  acid  we  derive  cinnamyli- 

dene  -  dimethyl  -  eroto  -  lactone  c6H6CH  :  CH.CH  :  C.C(CH3)  :  C(CH3)>  m-P- 
153°,  obtained  by  condensation  of  phenyl-iso-crotonic  acid  and  pyro- 
cinchonic  anhydride  (A.  306,  242). 

7.  Phenyl-dioxy-olefin-carboxylic  Acids.  —  Oxy-methylene-phthalide 

(  [i]C=CHOH 
C6H44  f  m.p.  148°,  from  o»-bromo-aceto-phenone-o-carboxylic 

l[2]CO.O 

acid  on  boiling  with  water  ;  with  hydroxylamine  and  phenyl-hydrazin, 
it  reacts  in  the  desmotropic  form  as  formyl-phthalide,  with  the  forma- 
tion of  an  oxime,  m.p.  152°,  and  a  phenyl-hydrazone,  m.p.  180°  with 
decomposition  (B.  40.  74). 

8,  9.  Phenyl-olefin-  and  diolefin-a-keto-carboxylic  Acids  result  from 
the  condensation  of  aromatic  aldehydes  with  pyro-racemic  acid. 

Cinnamyl-formie  acid  C6H5.CH  :  CH.CO.CO2H,  a  light  yellow 
rubber-like  mass,  from  benzaldehyde,  pyro-racemic  acid,  and  HC1. 
With  XaHO  we  obtain  the  acid  in  bright  flakes  -f  H2O,  melting  at 
57°  when  anhydrous  ;  on  reduction  with  a  sodium  amalgam  it  gives 
y-phenyl-a-oxy-crotonic  acid  (B.  36,  2527).  The  syrupy  acid  is  also 
formed  from  its  nitrile,  cinnamyi  cyanide  C6H5.CH  :  CH.CO.  CN,  m.p. 
114°  (B.  14,  2472). 

o-Nitro-einnamyMormic  acid  NO2[2]C6H4.CH  :  CH.CO.COOH,  m.p. 


438  ORGANIC   CHEMISTRY 

135°,  from  o-nitro-benzaldehyde  with  pyroracemic  acid.  It  is  con- 
verted into  indigo  by  alkalies  in  the  cold,  discarding  oxalic  acid. 

3,4-  Methylene  -  dioxy  -  cinnamyl  -  formic  acid  (CH  2O  2)  [3 ,  4]  C6H3 . 
CH  :  CH.CO.CO2H,  m.p.  149°,  and  piperonylene-pyro-racemic  acid 
(CH2O2)[3,  4]C6H3CH  :CH.CH.CH.CO.CO2H,  m.p.  166°,  are  formed 
from  piperonal  and  piperonyl-acrolein. 

Cinnamylidene-pyro-raeemic  acid  C6H5CH  :  CH.CH  :  CH.COCOOH, 
m.p.  107°,  from  cinnamic  aldehyde  and  pyro-racemic  acid,  is  reduced  by 
sodium  amalgam  to  the  corresponding  a-oxy-acid,  which  is  trans- 
formed, by  boiling  with  HC1,  into  S-benzal-lsevulinic  acid  (B.  37,  1318). 

10.  Phenyl-olefin-fi-ketone-carboxylic  Acids  result  from  the  con- 
densation of  aceto-acetic  ester,  and  aromatic  aldehydes,  with  hydro- 
chloric acid  gas,  or,  better,  with  primary  or  secondary  amines  in  the 

cold  (B.  29, 172).     Benzal-aceto-acetic  ester  C6H5.CH :  c<(^°^H5,  m.p. 

59°,  b.p.  181°  (17  mm.)  (A.  281,  63).  The  m-mVro-ester  melts!at  112° 
(B.  26,  R.  448).  y-Benzal-diethyl-aeeto-acetic  ester  C6H5.CH  :  CH.COC 

(C,H5)2.C02C2H5,  m.p.   101°.     Acetyl-cumarin  C6H4{[^^OCO  :H«, 

m.p.  124°,  from  aceto-acetic  ester,  salicyl-aldehyde,  and  acetic  anhy- 
dride. It  has  feebly  acid  qualities;  see  Cumarin  and  nitro-cumarin 
(B.  35,  1153  ;  37,  4497).  See  also  Acetyl-oxy-cumarin. 

Allyl-benzoyl-  acetic     ester    C6H5.CO.CH/£°2C***5  melts    at 

\L/rl2.Url  :  U±l<> 

122°  (B.  16,  2132).  

y-Phenyl-a-acetyl-erotonie  lactone  C6H5C  :  CH.CH(COCH3)COO, 
m.p.  113°,  from  aceto-phenone-aceto-acetic  ester  on  boiling  with 
alcoholic  KOH  (B.  39,  1809). 

IT.  Phenyl-olefin-  and  diolefm-y-ketone-carboxylic  Acids  result  by 
the  condensation  (i)  of  aldehydes  and  ketone-carboxylic  acids  with 
acids  or  alkalies ;  (2)  of  olefm-dicarboxylic  anhydrides — e.g.  male'ic- 
acid  anhydride,  citraconic  anhydride,  and  benzols  with  aluminium 
chloride. 

j8-Benzoyl-aerylic  acid  C6H5.CO.CH  :  CH.CO2H  melts  at  96°  when 
anhydrous.  It  results  from  the  action  of  sulphuric  acid  upon  maleic 
anhydride  (see  above),  as  well  as  from  phenyl-y-keto-a-oxy-butyric 
acid.  Also  from  bromo-benzoyl-propionic  acid  with  potassium  acetate, 
and  from  phenyl-iso-crotonic  acid  with  sodium  hypo-iodide  (C.  1908,  I. 
1175  ;  1909,  I.  530). 

Trichloro-ethylidene-aceto-phenone  C6H5.CO.CH  :  CH.CC13,  melting 
at  102°,  is  produced  when  sulphuric  acid  acts  upon  chloral-aceto- 
phenone.  jS-Benzoyl-crotonicacidC6H5.CO.C(CH3)  :  CH.CO2H, melting 
at  113°,  is  obtained  from  citraconic  anhydride  (B.  15,  891). 

/r"O  PT-T 

jS-Benzal-laevulinic    acid  C6H5.CH :  <\£jj^»  R,  melting  at  125°, 

is  produced  by  the  condensation  of  benzaldehyde  and  laevulinic  acid  in 
acid  solution.  It  parts  with  water  upon  distillation  and  forms  3-aceto- 
i-naphthol.  Phenyl-itaconic  acid  is  formed  by  its  oxidation,  and 
j8-benzyl-laevulinic  acid  by  its  reduction.  Hydroxylamine  produces 

the  neutral   lactoxime,    benzal-lcevoxime    C6H5.CH :  c<^HzC<:     melting 

CH3/C  :  K0 
at  94°. 


PHENYL-OLEFIN-  AND  DIOLEFIN-CARBOXYLIC  ACIDS     439 

When  benzaldehyde  and  laevulinic  acid  condense  in  alkaline  solution 
the  product  is  : 

S-Benzal-laevulmie  acid  C6H5CH  :  CH.CO.C2H4.CO2H,  melting  at 
120°.  It  yields  benzal-angelic  lactone,  melting  at  90°  (B.  24,  3202),  upon 
distillation. 

8-Cinnamal- laevulinic  acid  C6H5CH  :  CH.CH  :  CH.CO.CH2.CH2. 
CO2H,  m.p.  161°,  sulphur-yellow  crystals,  from  cinnamic  aldehyde, 
laevulinic  acid,  and  pyridin  (B.  38, 1113). 

12,  13.  Phenyl-olefin-  and  diolefin-dicarboxylic  Acids. — Benzal- 
malonie  acid  C6H5.CH  :  C(CO2H)2,  melts  with  production  of  cinnamic 
acid  and  allo-cinnamic  acid.  It  is  formed  in  the  condensation  of  benzal- 
dehyde, malonic  acid,  and  glacial  acetic  acid.  By  heating  a  mixture 
of  benzylidene-aniline,  and  similar  bodies,  with  malonic  acid,  cinnamic 
acid  is  obtained  at  once  (B.  31,  2596).  Its  ethyl  ester,  boiling  at  198° 
(13  mm.),  is  obtained  from  benzaldehyde,  malonic  ester,  and  hydro- 
chloric acid.  It  adds  to  itself  more  readily  than  the  free  acid.  Aniline 
as  well  as  phenyl-hydrazin  converts  the  methyl  ester  into  j3-anilido- 
and  /2-phenyl-hydrazido-benzyl-malonie  methyl  ester,  melting  at  117° 
and  94°  (B.  29,  813).  When  substituted  benzaldehydes  are  used,  sub- 
stituted benzal-malonic  acids  result — e.g.  nitro-benzal-malonie  acid, 
which  is  reduced  by  ferrous  sulphate  and  ammonia  to  j8-carbo-styril- 
carboxylic  acid  (B.  21,  R.  253). 

a  -  Cyano  -  cinnamic     acid,    semi  -  nitrile    of   benzal  -  malonic   acid 

C6H5.CH :  <X^2H,  melting   at   180°,   is   obtained    by    the    action    of 

cyano-acetic  acid  in  the  heat  upon  benzaldehyde,  or  when  it  is  boiled 
with  cyano-acetyl  chloride.  When  heated  it  passes  into  the  nitrile  of 
cinnamic  acid.  The  methyl  and  ethyl  esters  melt  at  70°  and  50°.  A 
large  number  of  semi-nitriles  of  unsaturated,  aromatic  malonic  acids 
of  related  constitution  have  been  obtained  by  the  union  of  readily  ac- 
cessible, aromatic  aldehydes  with  cyano-acetic  acid  (B.  27,  R.  262). 
Nitrile~acid  amide,  dinitrile,  and  diamide  of  benzal-malonic  acid,  melt- 
ing at  123°,  87°,  and  190°,  have  also  been  synthesised  by  the  conden- 
sation of  benzaldehyde  with  cyano-acetamide,  malonitrile,  and  malon- 
amide  (B.  28,  2251  ;  35,  1320). 

Benzal-barbituric  acid  C6H5.CH :  c^coNH/"00  is  easil>T  formed 
from  benzaldehyde  and  malonyl-urea  (B.  34, 1340). 

f[i]CH:C.CO2H 
j8-Carbo-styrii-a-carboxylic    acid    C6HJ  is     formed 

( [2]NH .  CO 

from  o-amido-benzaldehyde  upon  heating  it  with  malonic  acid  to  120°, 
and  also  from  o-nitro-benzal-malonic  acid  (B.  21,  R.  353).  Its  silver 
salt,  when  heated,  yields  carbo-styril. 

f[i]CH:C.C02H 
Cumarin-a-earboxylic    acid   C6HJ  ,  melting  at  187°, 

l[2]O CO 

breaks  down  at  290°  into  carbon  dioxide  and  cumarin.  It  is  obtained 
from  salicyl-aldehyde,  malonic  acid,  and  glacial  acetic  acid  or  amine 
bases  (B.  31,  2593,  2597),  as  well  as  from — 

f[i]CH:C.CN 
a-Cyano-eumarin  C6H44  melting  at  182°.    This  latter 

([2]O CO 

body  may  be  prepared  by  the  action  of  dilute  sulphuric  acid  upon 


440  ORGANIC   CHEMISTRY 

o-oxy-benzal-dicyano-aeetic  ester  HO[2]C6H4CH[CH(CN)CO2C2H5]2+ 
JH2O,  melting  at  140°.  This  is  a  condensation  product  of  salicyl- 
aldehyde  and  cyano-acetic  ester  (B.  27,  R.  576). 

a-Cumarin-carboxylie  amide,  m.p.  269°.  Anilide,  m.p.  250°  (C.  1906, 
II.  724).  Cp.  also  j8-0xy-eumarin-a-carboxylic  ester. 

Cinnamylidene  -  malonic  acid,  phenyl-butadiene-dicarboxylic  acid 
C6H5.CH  :  CH.CH  :  C(COOH)2,  m.p.  208°,  has  a  yellow  colour,  but,  on 
illumination,  it  passes  into  a  colourless,  dimeric  modification  which 
on  oxidation  yields  a-truxillic  acid,  and  therefore  probably  also 
contains  the  tetramethylene  ring.  Concentrated  sulphuric  acid  restores 
the  yellow,  monomolecular  form  (B.  35,  2411 ;  C.  1902,  II.  1047).  On 
heating,  cinnamylidene-malonic  acid  splits  off  CO2  and  gives  a  mixture 
of  linkage-isomeric  forms  of  cinnamylidene-acetic  acid.  Methyl  and 
ethyl  ester,  m.p.  67°  and  36°.  Reduced  with  Na  amalgam,  the  acid  gives 
i,  4-hydro-cinnamylidene-malonic  acid  C6H5CH2CH  :  CH.CH  (COOH)2, 
m.p.  107°  with  decomposition,  which,  on  heating  with  NaHO,  passes 
into  the  isomeric  3,  4-hydro-cinnamylidene-malonic  acid  C6H5CH2CH2 
CH:C(COOH)2,  m.p.  116°  with  decomposition  (A.  306,  259).  Cin- 
namylidene-cyano-aceticacidC6H5.CH  :  CH.CH  :  C(CN)CO2H,m.p.2i2°. 

Piperonylene  -  malonic  acid  (CH2O2) [3,  4]C6H3.CH  :  CH.CH  : 
C(CO2H)2  melts  at  205°  with  decomposition  into  CO2  and  piperic  acid 
(B.  28, 1190).  Phenyl-allyl-malonie  acid  C6H5C(CH2.CH  :  CH2) (COOH)2 
melts  with  decomposition  at  145°.  Its  ester  is  formed  when  allyl 
iodide  acts  upon  phenyl-malonic  ester  (B.  29,  2600). 

CH.CO2H 

Phenyl - maleic    acid  ||  ^changes   below   100°   into  its 

C8H6.C.CO2H 

anhydride,  melting  at  119°,  which  is  produced  when  bromine  and  PBr3 
act  upon  phenyl-succinic  acid,  and  the  reaction  product  is  treated  with 
water.  Phenyl-malic  acid  is  formed  simultaneously  (B.  23,  R.  573). 

Cumarin-jS-earboxylic  acid  caH4{^(COOH) :  ^g,  m.p.  180°,  is  de- 
composed into  CO 2  and  cumarin,  during  the  dry  distillation  of  its 
silver  salt  ;  its  ethyl  ester,  m.p.  78°,  is  formed  from  phenol,  oxalic-acid 
ester,  and  sulphuric  acid  (B.  34,  422)  ;  from  resorcin,  oxalic-acid  ester, 
and  sodium  alcoholate  we  obtain  umbelliferone-jS-carboxylic  acid, 

resorcyl-male'inic   lactone  HO[4]C,H3  <[^        J_™,  m.p.  248°  (B.  34, 

38i). 

C,H5.CH  :  C.CO2H 
Phenyl-itaconic   acid  ,  m.p.  172°,  is  formed  (i) 

CHa.C02H 

from  succinic  ester,  benzaldehyde,  and  sodium  ethylate  ;  (2)  from 
phenyl-paraconic  ester  and  sodium  ethylate.  When  fused,  particularly 
under  reduced  pressure,  it  separates  into  water  and  its  anhydride,  melt- 
ing at  i63°-i66°,  which,  in  every  fusion,  changes  in  a  slight  degree  to 
isomeric  phenyl-citraconic  anhydride,  melting  at  60°.  Water  changes  the 
latter  to  phenyl-citraconic  acid,  melting  at  iO3°-io6°.  If  phenyl-citra- 
conic acid  in  chloroform  solution,  to  which  a  little  bromine  is  added,  be 
exposed  to  sunlight,  it  becomes  phenyl-mesaconic  acid,  melting  at  212°. 
On  boiling  with  NaHO  these  isomeric  acids  are  partly  transformed 

C6H5CH 
into  a  fourth  isomeric   acid,  phenyl-aticonic   acid  || 

HO2C.C.CH2COOH 


PHENYL-OLEFIN-  AND  DIOLEFIN-CARBOXYLIC  ACIDS     441 

m.p.  i49°-i5i°,  which  is  stereo-isomeric  with  phenyl-itaconic  acid. 
By  the  action  of  concentrated  sulphuric  acid  it  easily  discards  water 

and  passes  into  indone-acetic  acid  c6H4|^)c.CH2CO2H,  the  phenyl- 
itaconic  acid  only  furnishing  the  corresponding  anhydride.  From  this 
the  a's-position  of  the  phenyl  and  carboxyl  in  phenyl-aticonic  acid 
has  been  deduced  (cp.  Vol.  I.  and  A.  304,  130  ;  305,  35  ;  330,  292  ;  B. 
41,  3983). 

Cumarin-propionic  acid  C«H4{££^££H  :H3)C°2H,  m.p.  171°,  is 

formed,  together  with  o-oxy-phenyl-methyl-iso-crotonic  acid,  from 
salicyl-aldehyde,  sodium  pyro-racemate,  and  acetic  anhydride.  It 
passes  into  a-ethyl-cumarin  when  it  is  distilled  (A.  255,  285). 

Methyl-phenyl-itaeonie  acid  C6H5C(CHj)=C(CO?H)CH8.CO2H  melts 
with  decomposition  at  i6i°-i63°.  It  is  obtained  from  succinic 
ethyl  ester,  aceto-phenone,  and  sodium  ethylate  in  ether.  Its  anhy- 
dride melts  at  114°.  This  acid  may,  like  phenyl-itaconic  acid,  be  trans- 
formed into  several  isomerides  (B.  37, 1619). 

Styril-succinie  acid,  cinnamenyl  succinic  acid  C6H5CH  :  CH.CH 
(COOH).CH2COOH,  m.p.  173°,  is  obtained  by  saponifying  the 
resultant  product  of  the  action  of  alcoholic  potassium  cyanide 
upon  cinnamylidene  malonic  ester  (cp.  phenyl-succinic  acid,  and 
A.  306,  254). 

Cinnamylidene-succinic  acid,  styril-itaconic  acid,  cinnamenyl-itaconic 
acid  C6H5CH  :  CH.CH  :  C(COOH)CH2COOH,  m.p.  2i5°-2i8°  with 
decomposition,  from  cinnamic  aldehyde,  succinic  ester,  and  sodium 
ethylate,  is  reduced  by  sodium  amalgam  to  phenyl-ethylidene-pyro- 
tartaric  acid  C6H5CH2CH  :  CHCH(COOH)CH2COOH,  m.p.  112°.  This 
latter  acid  transposes,  on  boiling  with  NaHO,  to  phenyl-ethyl-itaconic 
acid  C6H5CH2CH2CH  :  C(COOH).CH2COOH,  m.p.  153°  (B.  34,  2188  ; 
cp.  A.  331,  151). 

Phenyl-glutaconic  acid  C6H5.C(CH2.COOH)  :  CH.COOH,  m.p.  154°, 
has  been  obtained  from  the  condensation  product  formed  in  the  union 
of  phenyl-propiolic  ester  with  sodium-malonic  ester.  Its  ester,  b.p.n 
187°,  is  converted  by  ammonia  into  y-phenyl-a,  c^-dioxy-pyridin 
(C.  1899,  I.  1081  ;  B.  27,  R.  163  ;  A.  370,  72). 

Benzal-glutaric  acid  C6H5.CH  :  C(CO2H)CH2.CH2.COOH  (A.  282, 
338)  melts  at  177°  (B.  31,  2004). 

Benzyl-glutaconic  ester  C6H5.CH2.CH(COOH)CH  :  CH.COOH  melts 
at  145°  (A.  222,  261).  Its  ethyl  ester,  boiling  at  203°  (10  mm.),  when 
treated  with  aqueous  ammonia  at  100°,  forms  benzyl-dioxy-pyridin 
(B.  26,  R.  318). 

Cinnamenyl-glutarie  acid  C6H5CH  :  CH.CH(CH2CO2H)2,  m.p.  135°, 
is  obtained  from  the  condensation  product  of  cinnamenyl-acrylic 
ester  and  sodium-malonic  ester,  or  by  oxidation  of  cinnamenyl-dihydro- 
resorcin  with  sodium  hypochlorite  (A.  345,  206). 

14.  Phenyl-olefin-tricarboxylic  Acids. — Phenyl-carboxy-aconitic  ester 
C6H5C(C02C2H5)  2C(C02C2H5)  :  CHCO2C2H5      and      benzyl  -  earboxy  - 
aconitic  ester  from  phenyl-  and  benzyl-malonic  esters,  with  chloro- 
fumaric  ester  (C.  1902,  II.  888). 

15.  Phenyl  -oxy-  olefin  -  dicarboxylic  A  cids. — Cinnamenyl-paraconic 

acid  CCH5CH  :  CH.dH.CH(CO2H)CH2.COO,  m.p.  145°,  from  cinnamic 


442  ORGANIC  CHEMISTRY 

aldehyde  and  succinic  acid.  On  boiling  with  water  it  yields  cinna- 
menyl-crotonic  acid  (C.  1906,  II.  515). 

jS-Oxy-eumarin-a-earboxylie   ethyl  ester  C8H4|C(QH)  :  CH.coac,H^ 

m.p.  101°,  is  formed  by  the  condensation  of  acetyl-salicylic-acid 
chloride  with  sodium-malonic  ester,  and  detachment  of  NaCl  and 
acetic  ester.  In  a  similar  manner  we  obtain  /?-oxy-a-eyano-cumarin, 
m.p.  242°,  and  jS-oxy-a-acetyl-cumarin,  m.p.  134°,  from  acetyl- 
salicylic  chloride  and  sodium  cyano-acetic  ester  or  aceto-acetic  ester 
(A.  367,  169). 

16.  Phenylene-oxy-olefin-dicarboxylic   Acids.  —  Phthalyl-acetic    acid 
and  iso-cumarin-carboxylic  acid  have  the  same  relation  to  each  other 
that   methylene-phthalide   sustains   to   iso-cumarin.      Phthalyl-acetic 
acid  and  its  homologues  have  been  obtained  by  applying  the  Perkin 
reaction  to  phthalic  anhydride  : 

J/~*  _  C^T-T  f~*(~\    TT 
-------  „  ------------  6_5k  melts   with    decomposition 

(coo 

above  260°.  When  distilled  under  greatly  diminished  pressure  it 
breaks  down  into  carbon  dioxide  and  methylene-phthalide.  Salts  of 
benzoyl-aceto-carboxylic  acid  are  obtained  by  dissolving  it  in  alkalies. 
When  it  is  heated  with  water  to  200°  it  breaks  down  into  carbon 
dioxide  and  o-acetyl-benzoic  acid.  When  heated  with  ammonia  it 
forms  phthalimide-acetic  acid.  The  alkylamines  react  analogously. 

Sodium  ethylate  converts  phthalyl-acetic  acid  into  the  sodium  salt 
of  diketo-hydrindene-carboxylic  acid  (q.v.)  (B.  26,  953). 

f[i]CH=C—  CO2H 
Iso-cumarin-carboxylic  acid  C6H4J  ,  melting  at  237°, 

(  [2]CO—  C 

is  formed  when  o-carbo-phenyl-glyceric-acid  lactone  is  heated  to  160° 
with  hydrochloric  acid  ;  see  Iso-cumarin.  Ammonia  converts  it  quite 

{[i]CH=CCO,H 
'    ,  melt- 
[2]CO—  NH 

ing  at  320°  (B.  25,  1138).  Boiling  caustic  potash  decomposes  it  into 
o-toluic  acid  and  oxalic  acid  (B.  28,  R.  770). 

On  the  formation   of   y-oxy-iso-carbo-styril-carboxylic  ester  from 
phthalyl-glycocollic  ester,  see  the  latter. 

Oxy-methylene-homophthalic  ethyl  ester  C6H4/C<  :  CHOH).co2c2H6  a 

UCO2C2H5 

colourless  oil  of  strong  acid  reaction,  obtained  by  the  condensation  of 
homophthalic  ester  with  formic  ester.  On  heating  to  100°  it  passes 
into  iso-eumarin-4-carboxylie  ethyl  ester  c6H4/c^c°2C2H^  :CH)  m.p. 

V.  C^U'"    '  ------  '  •  "  '"  ----  '\J 

68°,  which  is  split  up  again  into  formic  acid  and  homophthalic  acid  by 
alkalies.  Ammonia  converts  the  ester  into  iso-carbo-styril-4-ear- 
boxylic  ethyl  ester  C6H4{C(CQ2C2H5)  :  CH^  m  p  ^  (R  ^  ^^ 

17.  Phenylene  -  oxy  -  olefin  -  tricarboxylic    A  cids.  —  Phthalyl-malonic 

f[i]C=C(C02C2H5)2 
ester  C0H4J        \  ,  melting  at  74°,  is  formed,  together  with 

I  [2]  COO 
phthalyl-dimalonic  ester,  from  phthalyl  chloride  and  sodium-malonic 


f[i]C=C 
ester  (A.  242,  46).    Phthalyl-cyano-acetic  ester  ceHJ 

I  [2]COO 


HYDRO-AROMATIC   HYDROCARBONS  443 

melting  at  175°,  is  made  from  phthalyl  chloride  and  sodium-cyano-acetic 
ester  (B.  26,  R.  370). 

B.  Hydro-aromatic  Substances  with  Single-nucleus,  Hydro-benzol 

Derivatives. 

It  was  shown  in  the  introduction  to  the  carbocyclic  compounds  that 
the  treatment  of  the  hydro-aromatic  derivatives  presupposed  a  know- 
ledge of  the  aromatic  bodies.  Indeed,  numerous  reactions  which  led 
to  the  hydro-aromatic  compounds,  especially  the  additions,  were 
described  in  connection  with  the  aromatic  substances.  Many  bodies 
discussed  under  the  aromatic  derivatives — e.g.  the  quinones — are 
rather  to  be  viewed  as  derived  from  the  hydro-aromatic  hydrocarbons. 
And  synthetic  reactions  were  also  studied  in  the  discussion  of  the  fatty 
bodies  which  will  again  be  encountered. 

The  methods  of  ring  formation  in  cyclo-paraffins,  discussed  at  the 
commencement  of  this  volume,  are  also  used  to  some  extent  in  the 
building  up  of  hydro-aromatic  substances.  The  terpenes  and  camphor 
will  be  included  in  the  hydro-aromatic  derivatives,  as  they  are  closely 
related  to  the  hydrated  m-  and  p-cymols. 

(i)  HYDRO-AROMATIC  HYDROCARBONS. 

Hexahydro-benzol  is  the  parent  hydrocarbon  of  the  hydro-aromatic 
substances.  Tetra-  and  dihydro-benzol  bear  the  same  relation  to  it 
that  an  olefin  and  a  diolefin  show  to  the  paraffin,  having  the  same 
number  of  carbon  atoms. 

The  hexahydro-benzols,  which  are  isomerides  of  olefins  with  a  like 
number  of  carbon  atoms,  resemble  the  paraffins  in  chemical  behaviour  ; 
they  belong  to  the  cyclo-paraffins,  while  the  tetrahydro-benzols  belong 
to  the  cyclo-olefins,  the  dihydro-benzols  to  the  cyclo-diolefins,  and 
benzene  is  the  simplest  imaginable  cyclo-triolefin,  if  we  accept  the 
formula  proposed  for  it  by  Aug.  Kekule. 

The  aromatic  compounds  in  general  oppose  a  great  resistance  to 
the  attachment  of  hydrogen.  This  was  only  overcome  in  1897  by  an 
excellent  method  discovered  by  Sabatier  and  Senderens,  which  con- 
sists in  conducting  the  vapours  of  aromatic  substances,  with  excess  of 
hydrogen,  over  finely  divided  hot  nickel.  By  this  means  it  is  easy  to 
convert  aromatic  hydrocarbons,  phenols,  and  anilines  into  the  corre- 
sponding hydro-aromatic  compounds. 

Berthelot  (1867)  first  effected  the  reduction  of  benzene  to  hexa- 
hydro-benzol.  It  was  obtained  pure  by  Baeyer  (1894)  in  the  course  of 
an  investigation  in  which  he  demonstrated  how  the  simplest  repre- 
sentatives of  the  hydro-aromatic  bodies — hexahydro-benzol,  tetrahydro- 
benzol,  and  dihydro-benzol — could  be  prepared  from  p-diketo-hexa- 
methylene,  a  decomposition  product  of  succino-succinic  ester.  Before 
beginning  a  detailed  description  of  the  hydro-aromatic  hydrocarbons, 
it  may  be  well  briefly  to  present  the  steps  of  this  research  in  a 
diagram.  The  enclosed  numbers  following  the  names  refer  to  the 
formulae  of  the  diagram. 

p-Diketo-hexamethylene  (i)  yields  quinite  (2)  by  reduction,  which 
hydrogen  bromide  changes  to  p-dibromo-hexamethylene,  and  hydrogen 
iodide  into  the  mono-iodo-hydrin  (4)  of  quinite,  along  with  p-di-iodo- 


444  ORGANIC  CHEMISTRY 

hexamethylene.  Quinite  mono-iodo-hydrin,  when  reduced,  yields  oxy- 
hexamethylene  (5),  obtained  more  easily  from  pimelin-ketone  and 
cyclo-hexanone.  Hydrogen  bromide  and  iodide  convert  oxy-hexa- 
methylene  (6)  into  bromo-  and  iodo-hexamethylene  (6,  7).  When  p-di- 
bromo-hexamethylene  and  monobromo-hexamethylene  are  heated  with 
quinolin,  the  latter  yields  tetrahydro-benzol  (8)  and  the  former  dihydro- 
benzol  (9) ;  whereas  mono-iodo-hexamethylene  is  reduced  by  zinc  dust 
and  glacial  acetic  acid  to  hexahydro-benzol  (10)  : 


\CH..CH 


(7) 

CH  /CH2.CH2\ 

CHs  XCH..CH, /C 

The  following  values  (V)  and  differences  (D)  were  observed  by 
Stohmann  in  determining  the  heats  of  combustion  and  the  boiling- 
points  of  benzene,  the  three  hydro-benzols,  and  hexane  : 

Approximately. 

QH.    (V)  =779-8  |D=68.2Cal  b.p.8o.4°          lD  =  +5° 

C.H8     „   =848-0 1     =44.Q  „     84°-86* 

CSH10    „   =892.o{         .  „     82°-84°     J     =_ 

C6H12    „   -993-2  {'  „     790-79-5°{ 

C.HM    „   =991  -2}"  =58-c-     „  M     69o  }„  = 

The  differences  calculated  from  these  numbers  would  have  to  be 
equal  if  the  changes  were  of  like  character.  The  magnitude  of  these 
differences  expresses,  therefore,  the  magnitude  of  the  changes  involved 
in  the  reduction  (A.  278,  115). 

(10)  CYCLO-HEXANES,  HEXAHYDRO- BENZOLS  (NAPHTHENES). 

Hydro-aromatic  hydrocarbons  constitute  the  chief  portion  of 
Caucasian  petroleum  (I.  88)  (Beilstein  and  Kurbatow,  B.  13,  1818). 
Markownikow  has,  therefore,  designated  them  naphthenes. 

The  simplest  naphthene,  hexahydro-benzol,  is  also  called  hexa- 
naphthene,  and  its  homologues  are  called  heptanaphthene,  octo- 
naphthene,  nononaphthene,  etc.  Besides  these  hexahydra-benzols,  we 
also  find  in  Caucasian  petroleum  the  isomeric  alkyl  pentamethylenes 
(cp.  B.  31,  1803  ;  Ch.  Zeitung,  22,  900  ;  A.  324,  i).  Hexahydro- 
benzols  have  also  been  discovered  in  the  tar  from  bituminous  coal  and 
in  that  from  certain  shales,  as  well  as  in  the  resin  oils  obtained  from  the 
distillation  of  colophonium. 

Finally,  a  nononaphthene,  hexahydro-pseudo-cumol,  has  been  found 
in  coal-tar  (C.  1908,  II.  402).  Artificially,  the  hexahydro-benzols  are 
prepared  from  their  halogen  substitution  products  by  reduction,  or 
by  transposition  with  alkyl-magnesium  haloids.  They  are  obtained 
most  easily  by  reduction  of  the  benzene  hydrocarbons,  on  passing  the 
latter,  in  the  gaseous  state,  mixed  with  hydrogen,  over  finely  divided 


CYCLO-HEXANES,   HEXAHYDRO-BENZOLS  445 

nickel  at  temperatures  of  180°  to  250°.  In  the  benzol  homologues, 
with  lengthy  side  chains,  this  is  accompanied  by  a  partial  breaking  up 
of  the  latter.  Thus,  from  propyl-benzol  we  obtain,  besides  propyl- 
cyclo-hexane,  a  small  quantity  of  ethyl-  and  methyl-cyclo-hexane.  At 
temperatures  above  300°  the  cyclo-hexanes  are  broken  up  by  the 
nickel,  particularly  in  the  hydrogen  and  the  corresponding  benzene 
hydrocarbons  (C.  1901,  I.  502,  817  ;  II.  201).  They  have  been  made 
artificially  by  reducing  aromatic  hydrocarbons  with  hydriodic  acid 
at  high  temperatures.  Hexahydro-benzol  resists  decomposition  by 
means  of  hydrogen  very  strongly  (A.  278,  88).  The  hexahydro-benzols 
are  more  easily  obtained  by  reducing  their  halogen  substitution 
products. 

When  hydro-iodic  acid  is  used  as  a  reducing  agent,  under  certain 
circumstances  alkyl-pentamethylenes  appear  to  form  by  a  process  of 
isomerisation  ;  these  are  isomeric  with  the  hexamethylenes.  Thus 
methyl-pentamethylene  is  formed  together  with  hexamethylene  (B.  30, 
1214;  A.  324,6). 

The  hexahydro-benzols  are  distinguished  from  the  olefins  isomeric 
with  them  by  their  higher  specific  gravity,  and  their  inability  to  take 
up  bromine.  Like  the  paraffins,  they  are  first  changed  by  chlorine  or 
bromine  into  monohalogen  substitution  products. 

Heating  with  dilute  nitric  acid  produces  nitro-substitution  products  ; 
tertiary  H  atoms  are  replaced  by  the  NO2  group  with  particular  ease 
(A.  30i,  154  ;  302,  i  ;  C.  1899,  I.  176  ;  1910,  II.  1376).  With  nitro- 
sulphuric  acid  small  quantities  of  nitrified  benzol  hydrocarbons  are 
produced.  The  action  of  bromine  and  aluminium  bromide  converts 
the  hexahydro-benzols  into  substitution  products  of  aromatic  hydro- 
carbons : 

Cyclo-hexane,  hexahydro-benzol  .          .     m.p.  6-4 
Methyl-cyclo-hexane,  hexahydro-toluol 
1, 1-Dimethyl-cyclo-hexane      .... 
1,  2-Dimethyl-cyclo-hexane,  hexahydro-o-xylol     . 
1,  3-Dimethyl-cyclo-hexane,  hexahydro-m-xylol   . 
1,  4-Dimethyl-cyclo-hexane,  hexahydro-p-xylol    . 
Ethyl-cyclo-hexane  .... 

1,  2-Methyl-ethyl-cyclo-hexane 

n-Propyl-cyclo-hexane          .... 
1,  3,  5-Trimethyl-cyclo-hexane,  hexahydro-mesitylene 
1,  3,  4-Trimethyl-cyclo-hexane,  hexahydro-pseudo-cumol 
1,  3,  5-Dimethyl-ethyl-cyclo-hexane 


b.p.  81°  D20  0-7788 

„  100°  ,,    0-7697 

„  120°  D15  0-7864 

„  126°  D20  0-7733 

,,  121°  „  0-7736 

,,  I2O°  ,,   0-7690 

„  I300  „   0-7772 

„  I5I°  „  0.7845 

„  156°  „   0-7865 

„  138°  „   0-7867 

„  143°  „   0-7807 

,,  169°  „   0-7929 


1, 4-Methyl-iso-propyl-cyclo-hexane,  hexahydro-cymol       „     167°    seeTerpene. 

Literature. — x  B.  34,  2799.  2  A.  341,  129.  3  C.  1905,  II.  1673.  4  C.  1901, 
II.  201.  5  C.  1909,  I.  851.  «  B.  34,  2035.  '0.1899,1.176. 

Of  these  hydrocarbons,  cyclo-hexane  (B.  28,  1234  >  A.  302,  2), 
methyl-,  i,  3-dimethyl-,  I,  3,  4-trimethyl-,  and  I,  3,  5-dimethyl-ethyl- 
cyclo-hexane  have  been  found  in  the  naphtha  of  Caucasian  petroleum, 
while  methyl-,  propyl-,  i,  3-dimethyl-,  and  i,  4-methyl-iso-propyl- 
cyclo-hexane  have  been  found  in  resin  oil.  Most  of  these  have  also 
been  prepared  by  reduction  of  the  corresponding  benzene  derivatives 
by  the  methods  above  named. 

Cyclo  -  hexane,       hexahydro  -  benzol,       naphthene,       hexamethylene 


446  ORGANIC  CHEMISTRY 


H2,    results    from    the    reduction    of    benzene    or   of 

iodo-cyclo-hexane  (see  above)  ;  or  by  the  action  of  sodium  upon 
synthetic  hexamethylene  bromide.  Pure  hexamethylene  is  a  liquid 
smelling  like  benzine.  Heated  with  bromine  to  150°,  it  yields  sym. 
tetrabromo-benzol  ;  digesting  with  nitric  acid  oxidises  it  to  adipinic 
acid  (A.  324,  3). 

Methyl-cyclo-hexane,  hexahydro-toluol,  heptanaphthene,  has  also 
been  made  from  suberyl  alcohol  by  the  action  of  HI  at  140°  (B.  25, 
R.  858),  as  well  as  from  synthetic  methyl-hexamethylene-ketone  by 
means  of  the  corresponding  alcohol  (B.  29,  731).  Bromine  and  alumi- 
nium bromide  convert  it  into  pentabromo-toluol,  melting  at  282°. 

1,  3-Dimethyl-cyelo-hexane,  hexahydro-m-xylol,  octonaphthene,  is 
obtained  from  camphoric  acid,  from  heptanaphthene-carboxylic  acid 
by  means  of  HI  (A.  225,  no  ;  B.  24,  2718  ;  25,  920  ;  C.  1905,  I.  1392), 
and  from  2,  6-dimethyl-cyclo-hexanol  ;  this  substance  has  been 
obtained  from  optically  active  I,  3-dimethyl-cyclo-hexanol,  in  a  feebly 
dextro-rotatory  form,  [a]D=o-8°  (B.  35,  2680).  1,  4-Dimethyl-eyclo- 
hexane  has  been  obtained  synthetically  from  dimethyl-succinylo- 
succinic  ester  (B.  31,  3206). 

1,  3,  4-Trimethyl-cyclo-hexane,  hexahydro  -  pseudo  -  cumol,  nono- 
naphthene,  from  2,  3,  6-trimethyl-cyclo-hexanol  (B.  29,  215)  ;  when 
acted  upon  with  bromine  and  aluminium  bromide,  it  yields  tribromo- 
pseudo-cumol. 

n-Propyl-eyclo-hexane  has  also  been  formed  from  chloro-cyclo- 
hexane,  propyl  iodide,  and  zinc. 

1,  3-Methyl-iso-propyl-cyclo-hexane,  sym.  menthane,  b.p.  167°,  is 
formed  by  the  reduction  of  its  iodine  substitution  product. 

[1,  3]-Diethyl-cyelo-hexane,  b.p.  170°,  sp.  gr.  07957  (22°),  from 
2,  6-diethyl-cyclo-hexanol. 

Halogen  Substitution  Products  of  the  Hexahydro-benzols.  —  Forma- 
tion :  —  (i)  From  the  hexahydro-benzols  by  the  introduction  of  chlorine. 
(2)  By  the  addition  of  halogens  and  halogen  hydrides  to  di-  and  tetra- 
hydro-benzols.  (3)  By  the  addition  of  halogens  to  benzols  and  halogen 
benzols.  (4)  From  cyclo-hexanols  through  the  exchange  of  hydroxyl 
groups  for  halogens,  by  means  of  H  haloids  or  P  haloids. 

The  third  method  has  brought  to  light  some  peculiar  isomeric 
phenomena.  Two  isomeric  benzene  hexachlorides,  and  two  isomeric 
chloro-benzol  hexachlorides,  have  been  found.  The  disposition  on  the 
part  of  chemists  is  to  ascribe  the  cause  of  this  isomerism  to  the  different 
positions  of  the  attached  chlorine  atoms  with  reference  to  the  plane 
of  the  carbon  ring,  as  in  the  case  of  the  isomeric  trithio-aldehydes  and 
the  isomeric  tri-,  tetra-,  and  pehtamethylene-dicarboxylic  acids. 

Of  the  dihalogen  cyclo-hexanes  and  the  monohalogen  alkyl-cyclo- 
hexanes,  cis-trans-  isomeric  forms  have  also  been  discovered  : 


Chloro-cyclo-hexane         .  .     b.p.     143° 

Bromo-cyclo-hexane        .  .       „       163° 

Iodo-cyclo-hexane   .         .  b.p."    69° 

1, 1-Methyl-chloro-cyclo-hexane  b.p.40    54° 

1,  2-Methyl-chloro-cyclo-hexane  b.p.    156° 

1, 3-Methyl-chloro-cyclo-hexane  ,,       160° 

1, 4-Methyl-chloro-cyclo-hexane  „      158° 

Literature.—1  C.  1898,  I.  1294.  2  C.  1905,  II.  1429.     3  A.  302,  xx  ;   B.  34,  2801.     4  C.  1905,  I.  1242  ; 
B.  40,2062.     *  A.  278,  94-     6  B.  40,  2067.     '  B.  40,  4865. 


1, 2-Dichloro-cyclo-hexane    .  b.p.  190° 

1, 2-Dibromo-cyclo-hexane    .  b.p.100  146° 

1, 4-Dibromo-cyclo-hexane    .  m.p.  113° 

1, 4-Di-iodo-cyclo-hexane      .                „  145° 

Hexahydro-benzyl  chloride  b.p.100  98° 

Hexahydro-benzyl  iodide  b.p.29  103° 


CYCLO-HEXANES,   HEXAHYDRO-BENZOLS  447 

Various  di-,  tri-,  and  tetrachloro-cyclo-hexanes  have  been  obtained, 
besides  monochloro-cyclo-hexane,  by  the  chlorination  of  cyclo-hexane 
at  o°.  With  KHO  they  yield  cyclo-hexane,  chloro-cyclo-hexane, 
chloro-hexadiene,  benzene,  and  chloro-benzol  (C.  1903,  II.  664). 

The  halogen  derivatives  of  the  cyclo-hexanes  cannot,  like  the  ali- 
phatic halogen  alkyls,  be  converted  into  the  corresponding  alcohols, 
cyanides,  mercaptans,  etc.,  by  transformation  with  alkali  salts,  and 
other  substances  of  basic  reaction  like  KCN,  KSH,  Ag2O,  NH3, 
sodium-malonic  ester,  etc.  Instead,  they  split  off  halogen  hydride 
and  form  tetra-  or  dihydro-benzols.  On  the  other  hand,  the  cyclo- 
hexyl  magnesium  haloids  are  easily  formed,  and  from  these  we  may 
obtain,  with  oxygen,  cyclo-hexanols  ;  with  CO2,  the  cyclo-hexane- 
carboxylic  acids  ;  with  aldehydes  and  ketones,  extra-cyclic  alcohols. 

a-  or  trans-Benzene  hexachloride  C6H6C16,  melting  at  157°  and  boil- 
ing at  218°  (345  mm.),  decomposes  into  3HC1  and  unsym.  trichJoro- 
benzol.  £-  or  cis-Benzene  hexachloride  melts  and  sublimes  near  310°. 
a-Benzene  hexachloride  was  made  by  the  action  of  chlorine  upon 
benzene  in  sunlight  (1825,  Faraday  ;  1835,  Mitscherlich,  Pogg.  A.  35, 
370).  a-  and  ft- Benzene  hexachloride s  are  produced  when  chlorine  is 
conducted  into  boiling  benzene  (1884,  Meunier  ;  B.  18,  R.  149  ;  19,  R. 
348),  or,  better,  into  a  mixture  of  benzene  and  I  per  cent,  sodium 
hydroxide.  The  a-body  is  separated  by  distillation  in  steam  from  the 
less  volatile  jS-derivative  (B.  24,  R.  632),  or  by  means  of  chloroform 
from  the  more  sparingly  soluble  /2-compound.  The  latter  is  the  more 
resistant  of  the  two  modifications.  When  heated  with  alcoholic 
potash  it  is  converted  with  greater  difficulty  than  the  a-body  into 
unsym.  trichloro-benzol.  It  is  not  affected  by  alcoholic  potassium 
cyanide,  but,  when  boiled  with  this  reagent,  the  a-variety  is  converted 
into  unsym.  trichloro-benzol.  Zinc  in  alcoholic  solution  changes  the 
a-modification  into  benzene  (Z.  f.  Ch.  1871,  N.F.  7,  284,  293). 

a-  and  j8- Chloro-benzol  hexachloride  C6H5C17,  melting  at  146°  and 
260°,  yield  I,  2,  3,  5-tetrachloro-benzol  with  alcoholic  potash  (A.  141, 
101 ;  B.  25,  373).  1,  2,  4-Trichloro-benzol  hexachloride  C6H3C19  melts 
at  95°. 

o-Xylol  hexachloride  C6H4(CH3)2C16,  m.p.  194°,  b.p.  26o°-265° 
(C.  1898,  I.  1019). 

a-Benzene  hexabromide  C6H6Br6,  melting  at  212°,  results  from  the 
action  of  bromine  upon  benzene  in  sunlight,  and  when  bromine  acts 
upon  boiling  benzene.  When  it  splits  off  HBr,  i,  2,  4-tribromo-benzol 
is  formed  (Pogg,  A.  35,  374).  It  is  isomorphic  with  a-benzene  hexa- 
chloride (B.  18,  R.  553). 

(ib)  CYCLO-HEXENES,  TETRAHYDRO-BENZOLS,  NAPHTHYLENES. 

Tetrahydro-toluol  has  been  found  together  with  hexahydro-toluols 
and  allied  hydrocarbons  in  the  essence  of  resin. 

Cyclo-hexenes  are  produced  artificially  (i)  from  the  halogen  cyclo- 
hexanes  by  withdrawing  the  hydrogen  haloid  by  means  of  alkali  or 
tertiary  amines,  especially  quinolin.  (2)  From  amido-cyclo-hexanes, 
by  dry  distillation  of  their  chlorohydrates  or  phosphates.  (3)  From 
the  cyclo-hexanols  by  extracting  water  by  means  of  SO4HK,  P2O5, 
ZnQ2,  A1C13,  or  by  heating  with  aqueous  oxalic  acid  (B.  34,  3249), 


448  ORGANIC   CHEMISTRY 

or  phthalic  anhydride.  In  order  to  avoid  possible  transpositions 
during  the  extraction  of  water  from  cyclo-hexanols,  these  are  trans- 
formed by  the  action  of  CS2  upon  their  sodium  or  potassium  salts,  and 
by  methylation  of  the  resulting  xanthogenates  into  the  corresponding 
xanthogenic  methyl  esters,  which,  on  distillation  at  ordinary  pressure, 
decompose  into  COS,  mercaptan,  and  the  corresponding  cyclo-hexene  : 

-  CwHaw_2+COS+CH8SH. 


This  method  is  particularly  suitable  for  the  higher  molecular 
alcohols,  and  has  been  very  serviceable  for  preparing  terpenes.  Those 
alkylidene-cyclo-hexanes  which  contain  a  semi-cyclic  linkage  are  iso- 
meric  with  alkyl-cyclo-hexenes  (compare  ethylidene-cyclo-hexane,  etc.). 
These  hydrocarbons,  which  are  of  special  importance  in  the  chemistry 
of  terpenes,  are  generated  by  discarding  CO2  from  the  cyclo-hexene 
and  cyclo-hexylidene  fatty  acids  obtained  by  condensation  of  cyclo- 
hexanones  with  bromo-aliphatic  esters  and  zinc,  with  dehydration. 
They  differ  from  the  isomeric  cyclo-hexenes,  with  unsaturated  rings, 
by  their  higher  specific  gravities,  higher  boiling-points,  and  abnormal 
molecular  refraction  (A.  360,  36).  On  heating  with  alcoholic  sulphuric 
acid,  they  easily  shift  the  double  linkage  and  become  true  tetrahydro- 
benzols.  A  similar  capacity  for  transposing  into  hydrocarbons  of  the 
same  linkage,  especially  under  the  influence  of  acids,  is  shown,  to  some 
extent,  by  all  alkyl-cyclo-hexenes,  so  that  the  preparation  of  a  perfectly 
uniform  hydrocarbon,  apart  from  cyclo-hexene  itself,  has  probably 
not  yet  been  accomplished.  Characteristic  of  the  cyclo-hexenes  are 
their  addition  products  with  NOC1,  N2O3  and  N2O4,  the  so-called 
nitroso-chlorides,  nitrosites,  and  nitrosates  (compare  terpenes). 

Cyclo-hexene,  tetrahydro-benzol  CH2/™2—  OF  VH,  boiling  at  82°- 

\Uxj.2  -  txttj/ 

84°,  is  produced  on  distilling  monobromo-  and  monochloro-cyclo- 
hexane  with  quinolin  or  alcoholic  potash  (A.  302,  27),  and  from  cyclo- 
hexanol  by  heating  with  oxalic  acid  (B.  34,  3252)  or  HKSO4  (C.  1905, 
I.  1014).  It  is  a  colourless  liquid,  resembling  petroleum.  It  has  less 
of  the  leek  odour  than  dihydro-benzol.  It  is  coloured  yellow  by  con- 
centrated sulphuric  acid. 

With  ozone  it  yields  a  very  stable  ozonide  C6H10O3,  which  can  be 
recrystallised  from  alcohol,  m.p.  75°.  Water  decomposes  this,  with 
formation  of  adipin-dialdehyde  and  adipinic  acid  (B.  42,  694).  The 
nitroso-chloride  melts  at  152°.  The  nitrosate  NO.C6H10.O.NO2  melts  at 
150°  with  decomposition  (A.  343,  49). 

Methyl-cyelo-hexenes,  tetrahydro-toluols  C6H9.CH3.  Three  methyl- 
cyclo-hexenes  are  possible,  isomeric  by  the  position  of  the  double 
linkage.  The  most  stable  of  these  is  — 

AMHethyl-cyelo-hexene  *    CHzc(^—^\cu2,   b.p.     io6°-io8°, 


D17  0-799.     The  isomeric  hydrocarbons  easily  pass  into  this  substance. 
with  displacement  of  the  double  linkage.     It  is  formed,  nearly  pure, 

*  A1,  A2,  A3,  etc.  indicates  the  situation  of  a  double  linkage  of  the  C-atom 
i,  2,  3,  etc.  reckoned  with  reference  to  the  next  higher  number.  It  is  sometimes 
preferable  to  affix  the  number  indicating  the  double  linkage  to  the  name,  e.g. 
"  methyl-cyclo-hexene-i."  The  same  notation  is  sometimes  used  to  indicate  the 
position  of  the  hydroxyl  or  keto-group  in  the  alcohols  and  ketones,  e.g.  "  i-methyl- 
cyclo-hexanone-3  .  '  ' 


CYCLO-HEXENES,  TETRAHYDRO-BENZOLS  449 

from  i,  I-  and  I,  2-methyl-cyclo-hexanol.  It  is  formed,  practically 
pure,  from  i,  i-  and  i,  2-methyl-cyclo-hexanol  by  elimination  of  water 
(see  also  A.  359,  287).  An  apparently  fairly  uniform  A3-methyl-eyclo- 
hexene,  b.p.  103°,  D15  0-841,  [a]D+no°,  has  been  obtained  by  heating 
acid  phthalic  ester,  or  the  methyl-xanthogenate  of  the  optically  active 
i,  3-methyl-cyclo-hexanol .  On  oxidation  with  KMnO4,  it  yields  j3- 
methyl-adipinic  acid  (C.  1904, 1.  1346, 1213).  A2-Methyl-cyelo-hexene, 
b.p.  103°,  D27  07937,  [a]D-f  81-47°,  from  i,  3-methyl-iodo-cyclo-hexane 
(B.  34,  3252  ;  35,  2493). 

Synthetically,  a  methyl-cyclo-hexene  has  been  obtained  from 
perseite  (Vol.  I.)  by  heating  with  HI  (B.  25,  R.  503). 

Isomeric  with  the  tetrahydro-toluols  is  methene-cyclo-hexane 
CH2:C<^2— ^2^>CH2,  b.p.  106°,  D20  0-8020,  nD=i-45i6,  from  cyclo- 

hexene-ac£tic  acid,  and  from  hexahydro-benzyl  iodide,  with  alcoholic 
potash  (A.  359,  291  ;  B.  40,  4863).  It  yields,  on  oxidation  with 
KMnO4,  besides  cyclo-hexanone,  a  glycol  C7H12(OH)2,  m.p.  77°,  which, 
on  heating  with  dilute  H2SO4,  passes  into  hexahydro-benzaldehyde. 
On  boiling  with  alcoholic  sulphuric  acid,  it  is  transposed  into  A^methyl- 
cyclo-hexene.  Nitrole-piperidide,  m.p.  127°. 

Several  homologous  tetrahydro-benzols  have  been  obtained,  mostly 
by  elimination  of  water  from  the  corresponding  cyclo-hexanols.  As 
regards  their  uniformity  the  above  remarks  apply. 

1,  2-Dimethyl-cyelo-hexerie,  b.p.  132°,  is  formed  from  the  2,  2-di- 
methyl-cyclo-hexanol,  by  dehydration  and  migration  of  a  methyl 
group  (reversal  of  the  pinacolin  transposition,  see  Vol.  I.)  ;  it  easily 
yields  crystalline  dibromide  melting  at  about  138°  (private  communi- 
cation of  H.  Meerwein).  1,  3-Dimethyl-cyclo-hexene,  b.p.  124°.  1,4- 
Dimethyl-cyclo-hexene-l  (B.  41,  2632).  1, 1-Dimethyl-cyelo-hexene, 
b.p.  117°,  from  dimethyl-dihydro-resorcin,  yields,  on  oxidation  by 
KMnO4,  a  mixture  of  a,  a-  and  j8,  j3-dimethyl-adipinic  acid  (C.  1907, 
I.  239).  A^ethyl-,  propyl-,  and  iso-propyl-cyclo-hexenes  boil  at  135°, 
155°,  and  156°  respectively  ;  they  are  formed  by  linkage  displacements 
from  ethylidene-,  propylidene-,  and  iso-propylidene-eyclo-hexane,  b.p. 
138°,  158°,  and  161°  (A.  360,  44).  Allyl-eycio-hexane  C6HU.CH2.CH  : 
CH2,  b.p.  149°,  from  cyclo-hexyl-magnesium  bromide  and  allyl  bromide 
(C.  1910,  II.  387).  a-Cyelo-geraniolene,  i,  3,  •$-trimethyl-cydo-hexene-s 

^CHCH^CH02'  b'p'  I39°-I4i°J  is  formed,  besides  the  isomeric 
j3-cyclo-geraniolene,  from  the  olefinic  terpene  geraniolene  by  treating 
with  sulphuric  acid.  It  is  also  formed  from  the  synthetic  dimethyl- 
heptinol  (CH3) 2C(OH).CH2.CH2.CH  :  C(CH3)2  by  boiling  with  phosphoric 
acid  (B.  37,  848),  and  by  the  action  of  zinc  chloride  upon  dihydro- 
iso-aceto-phorol  or  3,  5,  5-trimethyl-cyclo-hexanols,  it  yields  a  sparsely 
soluble  nitroso-chloride  and  nitrosate  (A.  324,  97,  112). 

Special  interest  attaches  to  A1-  and  A3-i,  4-methyl-iso-propyl-cyclo- 
hexene,  the  so-called  carro-menthene  and  menthene,  which  are  closely  re- 
lated to  the  terpenes,  and  are  therefore  treated  among  hydro-terpenes. 

(ic)    DlHYDRO-BENZOLS    [CYCLO-HEXADIENES], 

Very  probably  some  of  the  naturally  occurring  terpenes  belong  to  the 
dihydro-benzols.     The  artificially  prepared  representatives  of  the  di- 
VOL.  II.  2  G 


450  ORGANIC   CHEMISTRY 

hydro-benzols  are  very  similar  in  behaviour  to  them.  The  method  of 
preparing  the  simplest  of  the  hydrocarbons  in  this  class — dihydro- 
benzol — from  succino-succinic  ester  has  already  been  discussed.  Mono- 
alkyl  and  di-p-alkyl-dihydro-benzols  were  made  in  like  manner  from 
mono-  and  di-alkyl-succino-succinic  esters  (B.  26,  232). 

The  other  methods  of  preparing  dihydro-benzols  are  quite  analogous 
to  this  for  cyclo-hexenes.  They  are  formed  (i)  from  the  cyclo-hexane 
diols  which  are  obtained  mostly  by  reduction  of  the  easily  synthesised 
dihydro-resorcins  as  well  as  from  cyclo-hexenols  by  dehydration  ;  (2) 
from  the  dibromides  of  the  cyclo-hexenes  by  heating  with  quinolin 
(compare  B.  42,  693)  ;  (3)  by  distillation  of  the  phosphates  of  diamido- 
cyclo-hexanes  in  a  stream  of  CO2,  if  necessary  under  diminished 
pressure  (A.  328,  88  ;  C.  1909,  II.  356). 

The  dihydro-benzols  mostly  have  a  penetrating  odour  like  that  of 
leeks.  They  are  easily  polymerised  and  resinified.  With  alcoholic 
sulphuric  acid  and  aceto-anhydride  and  sulphuric  acid,  they  give  char- 
acteristic red  or  purple  colours.  By  oxidising  agents  they  can  usually 
be  easily  transformed  into  benzene  derivatives. 

The  situation  of  the  double  linkages,  and  especially  their  uniformity, 
is  in  most  cases  more  doubtful  in  the  dihydro-benzols  than  it  is  even 
in  the  tetrahydro-benzols.  The  physical  data  communicated  there- 
fore only  apply  to  a  mixture  of  hydrocarbons  which,  according  to  its 
transformations,  consists  mostly  of  the  cyclo-hexadiene  in  question. 
On  the  utilisation  of  molecular  refraction  for  determining  the  con- 
stitution of  dihydro-benzols,  see  B.  43,  3076. 

A1'3- Cyclo-hexadiene,  dihydro-benzol  CH\£H~CH  /CH-  b-P-  8l'5°> 
from  i,  3-diamido-hexamethylene  phosphate  by  distillation,  from 
i,  3-dichloro-  and  i,  2-dibromo-cyclo-hexane  by  heating  with  quinolin 
besides  some  cyclo-hexene  and  small  quantities  of  the  isomeric  A1'4- 

dihydro-benzol  CH\cH~ZcH2!)CH'  b'p>  8l'5°'  which  is  the  chief  Product 
formed  from  i,  4-diamido-cyclo-hexane.  The  i,  4-cyclo-hexadiene 
easily  yields  a  tetrabromide,  m.p.  188°,  whereas  the  i,  3-cyclo-hexadiene 
yields  chiefly  a  dibromide,  m.p.  109°,  probably  i,  4-dibromo-A2-cyclo- 
hexene,  which,  on  heating  with  quinolin,  becomes  benzene.  The 
dihydro-benzol  formed  from  i,  4-dibromo-hexamethylene  is  a  mixture 
of  both  isomers  (A.  328, 105  ;  B.  41,  2479  ;  42,  693  ;  C.  1904,  II.  1736). 

A^-Dihydro-toluol  C?H7.CH3,  b.p.  111°,  from  m-diamido-hexahydro- 
toluol  phosphate,  on  oxidation  with  KMnO4  gives  methyl-dioxy-hexa- 
methylene-ketone  or  methyl-cyclo-hexanone-diol,  and  then  succinic 
and  oxalic  acids,  which  determine  its  constitution.  But  this  hydro- 
carbon also  lacks  uniformity  (B.  41,  1698).  Aa'4-Dihydro-toluol,  b.p. 
106°,  D20  0-8274  (B.  41,  2484).  A2>6-Dihydro-toluol,  b.p.  109°,  D20 
0-8292  (B.  41,  2630). 

1, 1-Dimethyl-cyclo-hexadiene  (see  B.  36,  2692  ;  C.  1909,  II.  356). 

Dihydro-o-xylol,  cantharene,  b.p.  135°,  is  produced  when  cantharic 
acid  C10H12O4,  a  rearrangement  product  of  cantharidin,  is  distilled 
with  caustic  lime.  Its  odour  is  like  that  of  a  terpene,  and  it  resinifies 
on  exposure  to  the  air  (Piccard,  1878  ;  B.  25,  2453  ;  A.  328,  115). 

A3'5-Dihydro-m-xylol,  b.p.  129°,  D18  0-8203,  from  3, 5-diamido- 
1, 3-dimethyl-cyclo-hexane  and  from  1, 3-dimethyl-5-chloro-eyelo- 


RING-ALCOHOLS  OF  HYDRO-AROMATIC  CARBONS    451 

hexadiene-3,  5,  the  product  of  the  action  of  PC15  upon  i,  3-dimethyl- 
cyclo-hexenone,  by  reduction  (B.  43,  3111). 

A2,4-Dihydro-m-xylol,  b.p.  129°,  D20  0-8225  (see  B.  41,  2631).  A 
mixture  of  hydrocarbons  containing  a  dihydro-m-xylol,  besides  m- 
xylol  and  tetrahydro-m-xylol,  has  been  obtained  from  methyl- 
heptenone  (CH3)2C :  CH.CH2.CH2COCH3  by  condensation  with  ZnCl2 
(C.  1909,  II.  357)- 

A1»3-Dihydro-p-xylol,  b.p.  I35°-I38°,  D19  0-8314,  has  been  obtained 
by  a  peculiar  reaction  on  boiling  dichloro-a,  j3-pulenenone  with  alcoholic 
potash ;  it  polymerises  easily.  Oxidation  with  KMnO4  produces 
acetyl-acetone,  which  proves  its  constitution  (B.  41,  1816  ;  42,  2404). 
A2'4-Dihydro-p-xylol,  b.p.  133°  (B.  41,  2633).  Dihydro-p-diethyl- 
benzol,  b.p.  i8o°-i85°. 

Addendum  :  Cyclo-hexyl-acetylenes. — While  steric  conditions  mili- 
tate against  the  possibility,  or  at  least  the  stability,  of  combinations  of 
cyclo-hexane  with  an  acetylene  binding  in  the  nucleus,  as  well  as  of 
combinations  with  two  double  linkages  in  the  allene  position,  cyclo- 
hexyl-acetylenes  with  the  acetylene  binding  in  the  side  chain  have 
been  obtained  by  the  methods  usual  in  aliphatic  series. 

Cyelo-hexyl-acetylene  C6HnC ;  CH,  b.p.  131°,  from  cyclo-hexyl- 
chlor-ethylene  with  KHO  ;  it  gives  a  Na  salt,  which  with  CO2  forms 
hexahydro-phenyl-propiolic  acid  (C.  1909,  II.  2081).  Cyclo-hexyl- 
allylene  C6HnCH2.C  •  CH,  b.p.  i65°-i7o°  (see  C.  1910,  II.  387). 

(20)  RING-ALCOHOLS  OF  THE  HYDRO-AROMATIC  CARBONS. 

In  this  group  are  included  quercite  and  inosite,  formerly  classed 
with  the  sugars,  as  well  as  the  ring-alcohols  of  the  terpane  or  men  thane 
group  among  the  terpenes,  while  other  members  have  been  obtained 
by  the  reduction  of  aromatic  or  hydro-aromatic  compounds,  but  chiefly 
from  the  corresponding  ketones,  which  yield,  by  reduction,  secondary 
ring-alcohols,  and,  by  transformation  with  magnesium-alky  1-iodides 
(Vol.  I.),  tertiary  ring-alcohols  (B.  34,  2877  ;  Ann.  Chim.  Phys.,  8,  10, 
527).  Cyclo-hexanols  have  also  been  obtained  by  the  action  of  oxygen 
upon  cyclo-hexyl-magnesium  haloids,  from  the  ring  amines  with  HNO2, 
by  the  attachment  of  water  to  cyclo-hexenes,  by  heating  with  glacial 
acetic  acid  and  concentrated  H2SO4.  Many  alkyl-cyclo-hexanols 
occur  in  stereo-isomeric  forms. 


Name. 

M.P. 

B.p. 

D. 

Cyclo-hexanol 

15° 

160° 

0-9471  (22°) 

1-Methyl-cyclo-hexanol 

13° 

157° 

0-9387  (12°) 

(  B.  34,  2880 
\C.  1904,  II.  219 

2-Methyl-cyclo-hexanol 

165° 

0-936     (14°) 

C.  1909,  I.  850 

3-Methyl-cyclo-hexanol 
4-Methyl-cyclo-hexanol 

•• 

172* 
174° 

0-926     (12°) 
0-924     (14°) 

|c.  1905,  I.  742 

1-Ethyl-cyclo-hexanol 
1,  2-Dimethyl-cyclo-hexanol 

33° 

z66° 
166° 

0-926     (14°) 

C.  1904,  II.  219 
C.  1905,  II.  483 

1,  3-Dimethyl-cycl>hexanol 
1,  4-Dimethyl-cyclo-hexanol 

50°' 

169° 
170° 

0-9II      (14°) 

C.  1907,  I.  1606 
C.  1906,  I.  1096 

2,  2-Dimethyl-cyclo-hexanol 
2,  4-Dimethyl-cyclo-hexanol 
2,  5-Dimethyl-cyclo-hexanol 

6-5° 

63°  (18  mm.) 
179° 

0-9073  (16°) 
0-9073  (16°) 

j-C.  1906,  I.  1248 

2,  6-Dimethyl-cyclo-hexanol 
3,  3-Dimethyl-cyclo-hexanol 
3,  4-Dimethyl-cyclo-hexanol 
3,  5-Dimethyl-cyclo-hexanol 

12° 

174-5° 
78°  (15  mm.) 
189° 
187° 

0-9129  '15°) 
0-9119  (16°) 
0-9019  (16°) 

B.  28,  78i 
C.  1907,  I.  964 
C.  1906,  I.  1248 
A.  297,  160 

452  ORGANIC  CHEMISTRY 


Cyelo-hexanol,  hexahydro-phenol  CH,2~  ;2:HOH  is  formed 

\v_/iri  2  —  v-/  x"  1  2 

(i)  from  cyclo-hexanone  by  reduction  with  sodium  and  aqueous  ether 
(B.  34,  2800)  ;  (2)  from  p-iodo-hexahydro-phenol,  the  product  of  the 
action  of  HI  upon  quinite,  by  reduction  with  zinc  dust  and  glacial  acetic 
acid  ;  (3)  from  amido-hexamethylene  and  from  pentamethylene- 
methyl-amine  with  nitrous  acid  (A.  302,  20)  ;  (4)  by  passing  gaseous 
phenol  and  hydrogen  over  reduced  nickel  at  about  170°  (C.  1904,  I.  454, 
727  ;  1905,  I.  1243)  ;  (5)  by  the  action  of  oxygen  upon  cyclo-hexyl- 
magnesium  chloride  (C.  1907,  I.  1695).  It  smells  like  fusel-oil,  and  is 
more  soluble  in  water  than  the  aliphatic  alcohols  with  6  C  atoms  (B. 
26,  229).  Its  acetyl  compound  melts  at  104°.  With  HBr  it  forms  a 
bromo-cyclo-hexane.  On  oxidation  with  nitric  acid  (density  1-2),  or 
KMnO4,  it  gives  a  good  yield  of  adipinic  acid  (for  method  of  preparing 
this  acid,  see  B.  41,  575  ;  C.  1908,  1.  1835).  Cyclo-hexanol-methyl  ether 
C6HUOCH3,  b.p.  I35°'5i  from  sodium-cyclo-hexanol  and  ICH3,  or  by 
reduction  of  anisol  with  Irydrogen  and  nickel.  For  the  ester  of  cyclo- 
hexanol,  see  C.  1905,  I.  1014.  Cyclo-hexyl  ether  C6Hn.O.C6Hu,  b.p. 
276°,  from  diphenyl  ether  with  hydrogen  and  nickel  (B.  41,  1001). 

3-Methyl-eyelo-hexanol  has  also  been  obtained  in  its  laevo-rotatory 
form  [a]D=-3°  40'  by  reduction  of  the  optically  active  3-methyl-cyclo- 
hexanone  (B.  30,  1534). 

1-Methyl-eyclo-hexanol  is  produced  by  nuclear  synthesis  in  the 
action  of  I,  5-magnesium-dibromo-pentane  upon  acetic  ester  (C.  1907, 
II.  681). 

3-Methyl-6-propyl,  3-methyl-6-iso-butyl-,  and  3-methyl-6-iso-amyI- 
cyclo-hexanol,  b.p.22  112°,  m.p.  69°,  and  b.p.23  137°  respectively,  are 
obtained  synthetically  by  heating  3-methyl-cyclo-hexanone  with 
sodium  and  propyl-iso-butyl-  and  iso-amyl-alcohol  to  about  220°  (C. 
1905,  I.  872,  noo).  3,  6,  6-Trimethyl-eyclo-hexanol,  "  pulenol,"  b.p. 
188°  (see  A.  329,  87). 

Hexahydro-thymol  and  hexahydro-earvaerol  (see  Menthol  and  Carvo- 
menthol). 

Polyvalent  Ring-alcohols  are  produced  (i)  by  reduction  of  poly- 
keto-cyclo-hexanes  ;  (2)  from  polyvalent  phenols,  by  reduction  with 
hydrogen  and  nickel  (C.  1908,  II.  240)  ;  (3)  from  cyclo-hexenes  by 
gentle  oxidation  with  KMnO4,  or  by  transformation  of  the  correspond- 
ing halogen  hydrins. 

trans-  Cyclo-hexane-1,  2-diol,  o-dioxy-hexahydro-benzol  C6H10[i,  2] 
(OH)  2,  m.p.  100°,  b.p.  225°,  is  obtained  from  tetrahydro-benzol  with 
KMnO4  (A.  302,  21)  or  by  reduction  of  pyro-catechin.  The  isomeric 
cis-i,  2-cyclo-hexane-diol,  m.p.  104°,  b.p.  236°,  is  produced  from  the 
iodo-hydrin,  o-iodo-cyclo-hexanol  C6H10I(OH),  m.p.  42°,  obtained  from 
cyclo-hexene  with  iodine  and  mercury,  and  yielding,  with  silver  oxide 
and  KHO,  at  first  a  cyclo-hexene  oxide  C6H10>  O,  b.p.  131°,  resem- 
bling ethylene  oxide.  This  combines  with  water  to  form  cis-cyclo- 
hexane-diol,  with  bisulphite  to  cyclo-hexanol-sulphonic  acid  C6H10 
(OH)SO3H,  with  ammonia  to  o-amino-cyclo-hexanol  C6H10[i,  2](NH2) 
(OH),  m.p.  66°,  b.p.  219°  (C.  1905,  II.  1337). 

i-Methyl-cyclo-hexane-i,  2-diol,  m.p.  67°,  from  A^methyl-cyclo- 
hexene  ;  on  heating  with  oxalic  acid  it  yields  i,  2-methyl-cyclo- 
hexanone. 


RING-ALCOHOLS   OF   HYDRO-AROMATIC  CARBONS      453 

4-Methyl-eyclo-hexene-l,  2-oxide,  b.p.  146°,  from  the  chloro  hydrin 
of  A3-methyl-cyclo-hexene  with  KOH  (A.  336,  310). 

Gyclo-hexane-1,  3-diol,  m.p.  65°,  by  reduction  of  resorcin  with  H 
and  Ni  at  130°  (C.  1908,  II.  240). 

Quinite  [Cyclo-hexane-i,  4-*diot]    HOCH/^2~  ;2a\:HOH,    m.p. 

NL-Hg — Ori2/ 

144°,  is  formed  from  p-diketo-hexamethylene,  when  treated  with 
sodium  amalgam,  in  the  presence  of  carbon  dioxide,  or  by  reducing 
hydroquinone  with  H  and  Ni.  This  was  demonstrated  by  A.  v. 
Baeyer  in  1892.  It  tastes  sweet  at  first,  then  bitter,  and  is  readily 
soluble  in  water  and  in  alcohol.  Chromic  acid  oxidises  it  to  quinone 
(B.  25,  1038  ;  34,  506).  Quinite  serves  for  the  preparation  of  the 
simple  hydride  derivatives  of  benzene  (B.  26,  229).  Hydriodic  acid 
converts  it  into  p-iodo-eyelo-hexanol  and  p-di-iodo-cyclo-hexane.  By 
reduction  the  first  yields  hexahydro-phenol,  the  second  cyclo-hexane. 
p-Dibromo-cye!o-hexane  passes  readily  into  dihydro-benzol  (B.  26, 
230).  2, 5-Dimethyl-quinite  is  formed  from  the  corresponding  di- 
ketone  (B.  25,  2122). 

Phloro-glucite,    s-trioxy-hexamethylene,    cyelo-hexane-1, 3, 5-trioI 

HOCH<^;**2~"  ;!?{°J5\:Ha+2HaO,  melts  when  anhydrous  at  184°.     It 

\Cri2 — CM  (OH)/ 

is  formed  when  phloro-glucin  is  reduced  in  an  approximately  neutral 
solution  with  sodium  amalgam  (B.  27,  357). 

Cyelo-hexane-1,  2,  3-triol,  a-form,  m.p.  108° ;  j8-forai,  m.p.  124°, 
from  A2-ethoxy-cyclo-hexene  with  KMnO4,  and  saponification  of  the 
resulting  ethoxy-cyclo-hexane-diol  with  concentrated  HBr  (C.  1910, 
1.  2017). 

Quercite,  cyclo-hexane-pentol  CH2<^|^|-™|^j)cH(OH),  m.p. 

235°,  [a]D— -f  24-16°,  occurs  in  acorns.  The  aqueous  extract  of 
the  latter  can  be  freed  of  glucoses  by  fermentation  with  beer-yeast. 
Also  from  the  leaves  of  Chamfer  ops  humilis  (C.  1908, 1.  267).  Quercite 
does  not  ferment  with  yeast.  Hydriodic  acid  converts  it  into  benzene, 
hexane,  phenol,  quinone,  and  hydroquinone  (Prunier).  Nitric  acid 
oxidises  it  to  mucic  acid  and  trioxy-glutaric  acid  (see  Vol.  I.).  A 
solution  of  potassium  permanganate  converts  it  chiefly  into  malonic 
acid,  although  oxalic  acid  and  carbonic  acid  are  formed  simultaneously 
(B.  29,  1762).  A  laevo-rotatory  quercite,  m.p.  (anhydrous)  174°, 
[a]D=  —  73-9°,  has  been  discovered  in  the  leaves  of  Gym-nemo,  silvestre. 
Penta-acetyl  compound,  m.p.  125°  (C.  1904,  II.  329). 

Inosite,  hexahydro-hexaoxy-benzol,  cyclo-hexane-hexene  C6H6(OH)6, 
has  seven  possible  optically  inactive,  and  two  optically  active,  modifi- 
cations, as  well  as  a  racemic  form  (cp.  Vol.  I.).  The  only  modifica- 
tions known  with  certainty  are  one  inactive  and  two  active  forms,  and 
the  racemic  form. 

i-Inosite,  phaseomannite,  dambose  C6H6(OH)6+2H2O,  melts  at  225° 
when  anhydrous.  It  occurs  in  the  muscles  of  the  heart  and  in  the  urine 
when  there  has  been  an  excessive  consumption  of  water  ;  also  in 
unripe  beans  (Phaseolus  vulgaris)  and  peas.  If  heated  to  170°  with 
hydriodic  acid,  it  yields  phenol,  di-iodo-phenol,  and  traces  of  benzene 
(Maquenne).  Concentrated  nitric  acid  oxidises  it  to  di-  and  tetra- 
oxy-quinones,  and  to  rhodizonic  acid  (B.  20,  R.  478  ;  23,  R.  26  ;  C. 
1908, 1. 269).  It  yields  furfurol  on  heating  with  P2O5  (C.  1908, 1.  2152). 


454  ORGANIC  CHEMISTRY 

Dambonite  C6H6(OH)4(OCH8)2+3H2O  is  the  dimethyl  ether  of 
i-inosite.  It  occurs  in  the  rubber  from  Gabon.  i-Inosite  hexa-acetate 
melts  at  211°. 

d-Inosite,  melting  at  247°,  [a]D=-f-65°,  from  pinite  by  the  action 
of  hydriodic  acid,  behaves  like  i-inosite  with  nitric  acid.  Pinite,  mate- 
zite  CeH6(OH)5(OCH3),  melting  at  186°,  [a]D=+65-5i°,  is  present  in 
the  juice  of  Pimts  Lambertiana,  also  m  the  rubber  from  Mateza  roritina 
of  Madagascar. 

1-Inosite,  melting  at  238°,  [a]D= — 55°,  from  quebrachite  by  means 
of  hydriodic  acid,  behaves  towards  nitric  acid  just  like  i-inosite. 
Quebrachite  C6H6(OH)5OCH3,  melting  at  186°,  [a]D=—  80°,  occurs  in 
the  quebracho  bark.  Racemic  inosite  melts  at  253°. 

Scyllite  C6H12O6,  m.p.  about  340°,  probably  a  second  inactive 
inosite,  was  discovered  by  Staedeler  in  1856.  It  is  found  in  the  organs 
of  various  plagiostomes,  e.g.  Scyllium  canicula,  but  most  plentifully  in 
the  kidneys  of  roach  and  pike  (?),  from  which  it  is  separated  by  means 
of  its  slightly  soluble  lead  salt  (B.  40,  1821). 

Gocosate  C6H12O6,  m.p.  345°-350°,  from  the  leaves  of  Cocos  nucifera 
and  Cocos  plumosa,  is  very  similar  to  inosite  in  its  behaviour,  and  is 
oxidised,  like  the  latter,  to  rhodizonic  acid  by  H2O2.  The  hexa-acetyl 
compound  melts  about  300°  (C.  1908,  I.  267). 

Phenose  C6H6(OH6)  (?)  is  an  amorphous,  readily  soluble  substance, 
deliquescing  in  the  air.  It  has  a  sweet  taste  and  reduces  Fehling's 
solution,  but  is  not  capable  of  fermentation.  It  has  been  obtained  by 
the  action  of  a  soda  solution  (A.  136,  323)  upon  the  addition  product 

of  benzene  with  three  molecules  of  hypochlorous  acid  C6H6  /  /  2 
(2b)  RING  ALCOHOLS  OF  TETRAHYDRO-BENZOL. 

A3-Cyelo-hexanol,  tetrahydro-phenol  CH\^  ZCH^H°H'  b'p<  l63°' 
is  formed  when  p-iodo-cyclo-hexanol  is  distilled  with  quinolin. 

A2-Cyclo-hexanol-methyl  and  ethyl  ether  C6H9OAlk,  b.p.  139°  and 
154°  respectively,  from  the  methyl  and  ethyl  iodo-hydrins  of  cyclo- 
hexane,  the  results  of  the  action  of  iodine  and  HgO  upon  an  alcoholic 
solution  of  cyclo-hexene,  by  boiling  with  alcoholic  potash.  From  the 
corresponding  dibromides  we  obtain,  by  saponification  and  reduction 

with  zinc  dust  and  alcohol,  A2-cyelo-hexenol  CH2<^         X?\CHOH, 

\utij — C/HJ/ 

b.p.  165°  with  decomposition.  The  urethane  melts  at  108°  (C.  1905, 
II.  1339)  ;  the  A^cyclo-hexenol  acetate,  b.p.  i8o°-i82°,  is  formed 
by  heating  cyclo-hexanone  with  acetic  anhydride  and  sodium  acetate 
(B.  41,  564). 

Numerous  A2-cyclo-hexenols  have  been  obtained  by  reduction  of 
the  3-alkyl-A2-cyclo-hexenones,  e.g.  3-methyl-A2-eyelo-hexenol,  b.p. 
176°  (A.  289,  i3f). 

Dihydro-eumin  alcohol  C9H13.CH2OH,  b.p.5  93°,  has  been  found  in 
ginger  grass  and  peppermint  (?)  oil  (B.  44,  466).  It  is  also  produced 
from  a-phellandrene-glycol,  on  heating  with  dilute  H2SO4. 

(20)  EXTRA-CYCLIC  HYDRO-AROMATIC  ALCOHOLS. 
These  have  been  obtained  (i)  by  transformation  of  cyclo-hexyl- 
magnesium   haloids  with   aldehydes   and   ketones ;     (2)   from   cyclo- 


RING-AMINES  OF  HYDRO-AROMATIC  HYDROCARBONS     455 

hexane-carbocyclic  esters,  and  extra-cyclic  hydro-aromatic  ketones  by 
reduction,  or  by  the  action  of  alkyl-magnesium  haloids  ;  (3)  by  oxida- 
tion of  alkylidene-cyclo-hexanes  with  dilute  permanganate  : 

Cyclo-hexyl-carbinol          .  .  .  C,HU.CH,OH  b.p.    181°  D0  0-944  ,C.  1904,  II.  704. 

Cyclo-hexyl-methyl-carbinol  .  .  C.Hn.CH(OH)CH,  ,,     189°  D0  0-946  { C.  1907, 1.  1695- 

Cyclo-hexyl-dimethyl-carbinol  .  .  C.HnC(OH)(CH,)t  b.p.,.    96°  D0  0-938  IB.  40, 4165. 

/3-Cyclo-hexyl-ethyl-alcohol  .  .  C,HUCH,.CH,OH  b.p.    206°                     B.  41, 2628. 

1-Methyl-cyclo-hexane-l,  7-diol  C6H10(OH).CH2OH,  m.p.  77°,  by 
oxidation  of  methylene-cyclo-hexane  with  KMnO4 ;  with  acids  it 
yields  hexahydro-benzaldehydes  (A.  347,  331). 

1-Iso-propyl-cyclo-hexane-l,  7-diol  C6H10(OH).C(OH)(CH3)2,  m.p. 
83°,  from  i,  i-cyclo-hexanol-carboxylic  ester  and  CH3MgI  ;  on  heating 
with  dilute  H2SO4  it  undergoes  pinacolin  transposition  and  yields 
i-methyl-i-acetyl-cyclo-hexane  (C.  1910,  II.  466). 

(zd)  SULPHUR  DERIVATIVES  OF  HYDRO-AROMATIC  ALCOHOLS. 

Cyclo-hexyl  mercaptan,  hexahydro-thio-phenol  C6HnSH,  b.p.  158°- 
1 60°,  a  colourless,  highly  refractive  oil  of  penetrating  odour  of  mercap- 
tan, is  obtained  in  small  quantities  by  transformation  of  halogen-cyclo- 
hexanes  with  KSH  ;  and,  more  easily,  by  splitting  up  cyclo-hexyl- 
xanthogenic  ester  C6HnS.CSOC2H5,  b.p.]6  152°,  with  ammonia.  It  is 
also  prepared  by  the  action  of  sulphur  upon  cyclo-hexyl-magnesium 
chloride  (C.  1910,  I.  1830),  or  by  reduction  of  cyclo-hexane-sulphonic 
acid  chloride,  b.p.15  127°,  with  tin  and  HC1.  It  yields  a  sparingly 
soluble  mercury  salt.  Cyclo-hexyl-methyl  sulphide  C6HnS.CH3,  b.p. 
180°,  from  the  Na  salt  with  ICH3.  Dicyclo-hexyl  disulphide  (C6Hn)2S2, 
b.p.  288°,  from  the  Na  salt  with  iodine  (B.  39,  392  ;  40,  2220). 

(30)  RING-AMINES  OF  HYDRO-AROMATIC  HYDROCARBONS. 

These  are  formed  (i)  by  reduction  of  nitro-hexahydro-benzols  with 
zinc  or  tin  and  HC1,  or  of  the  oximes  of  the  corresponding  ketones 
with  sodium  in  alcoholic  solution  ;  m-diamines,  especially,  have  been 
obtained  by  reducing  the  hydroxylamine  oximes,  the  addition  products 
of  hydroxylamine  with  cyclo-hexenone  oximes  ;  (2)  by  reduction  of 
anilines  with  Ni  and  H  (C.  1904,  I.  884  ;  B.  41,  991)  ;  (3)  by  heating 
cyclo-hexanones  with  ammonium  formate,  or  the  formates  of  organic 
bases  (A.  343,  54)  ;  (4)  from  the  cyclo-hexane-carboxylic  amides  by 
decomposition  with  bromine  and  alkali  (B.  40,  2061). 

Amido-cyclo-hexane,  cy do-he xylamine  C6HUNH2,  a  strong  base, 
boiling  at  134°,  smells  of  coniin  ;  but  slightly  soluble  in  water.  It  is 
prepared  from  cyclo-hexanone  oxime,  or  from  the  nitro-hexamethylene 
C6HnNO2,  b.p.  206°.  On  conducting  aniline  vapour  with  hydrogen 
over  reduced  nickel  at  190°,  we  obtain — besides  cyclo-hexyl-amine — 
cyclo-hexyl-aniline  C6HUNHC6H5,  b.p.30  71°,  and  dicyclo-hexyl- 
amine  (C6Hn)2NH,  b.p.30  145°  (C.  1904,  I.  884).  Acetamido-eyelo- 
hexane,  m.p.  104°.  Its  benzol  compound  melts  at  147°,  and  is  also 
obtained  by  transposition  of  a-hexahydro-benzo-phenone  oxime  (q.v.) 
(B.  30,  2863).  Phenyl-urea  derivative,  m.p.  180° ;  phenyl-thio-urea 
derivative,  m.p.  147°  (A.  302,  22).  Cyclo-hexyl-methyl-,  -ethyl-,  and 
-dimethyl-amine,  b.p.  145°,  164°,  and  165°,  are  formed  by  hydrogenating 
the  alkyl-anilines  with  H  and  Ni  (C.  1904,  II.  105). 


456  ORGANIC   CHEMISTRY    . 

1,  1-Amido-methyl-cyelo-hexane  C6H10(CH3)NH2,  b.p.  143°,  from 

I,  i-nitro-methyl-cyclo-hexane,  b.p.40  110°,  and  by  method  4  (C.  1910, 

II.  1377).     Benzoyl  compound,  m.p.  101°. 

1,  2-Amido-methyl-cyclo-hexane,  b.p.  150°  ;  benzoyl  compound, 
m.p.  147°. 

1,  3-Amido-methyl-cyclo-hexane,  b.p.  152°  ;  benzoyl  compound, 
m.p.  163°,  from  methyl-cyclo-hexanone  oxime,  and  from  i,  3-nitro- 
methyl-cyclo-hexane,  b.p.  ^  120°,  by  reduction,  is  converted  into 
methyl-cyelo-hexyl-hydrazin  C6H10(CH3)NHNH2  by  treating  its  bromyl 
compound  with  Ag2O  (C.  1900,  I.  653). 

1,  4-Amido-methyl-cyclo-hexane,  b.p.  151°;  benzoyl  compound, 
m.p.  181°. 

o-Diamido-cyelo-hexane  C6H10[i,  2](NH2)2  is  an  oil,  boiling  at  183°- 
185°.  It  results  when  the  amide  of  hexahydro-anthranilic  acid  is 
treated  with  sodium  hypobromite  and  then  with  hydrochloric  acid. 
Like  the  aromatic  o-diamines,  it  unites  with  benzaldehydes,  forming 
aldehy  dines  (A.  295,  187). 

m-Diamido-cyclo-hexane,  boiling  at  193°,  smells  like  ethylene- 
diamine.  It  is  soluble  in  water.  Nitrous  acid  decomposes  it  into 
nitrogen  and  dihydro-benzol  (A.  228,39).  The  diaceto-compound  melts 
at  256°. 

p-Diamido-cyclo-hexane  C6H10[i,  4](NH2)2  is  a  liquid  (B.  27,  1449). 

m-Diamido-hexahydro-toluol  C6H9[i,  3,  3](CH3)(NH2)2,  b.p.17  85°- 
89°,  m-diamido-hexahydro-xylol,  b.p.27  io3°-io5°,  m-diamido-hexa- 
hydro-m-cymol,  b.p.10  I03°-I05°,  from  the  corresponding  hydroxyl- 
amine  oximes,  gem-dimethyl-3,  5-diamido-cyelo-hexane,  b.p.10  103°- 
105°  (A.  328,  105).  Cp.  also  the  ring  amines  of  the  terpane  and 
menthane  groups,  discussed  among  the  terpenes. 


EXTRA-CYCLIC  HYDRO-AROMATIC  AMINES. 

Cyclo-hexyl-methyl-amine,  hexahydro-benzyl-amine  CCH11.CH2NH2, 
b.p.  163°,  benzoyl  compound,  m.p.  108°,  from  cyclo-hexyl-acetamide 
with  sodium  hypo-bromite,  and  by  reduction  of  hexahydro-benzo- 
nitrile  (A.  353,  298).  With  HNO2  it  is  partly  transformed  into  suberyl- 
alcohol  with  ring  expansion  (A.  353,  326). 

jS-Cyelo-hexyl-ethyl-amine  C6Hn.CH2.CH2NH2,  b.p.  188°,  by  reduc- 
tion of  cyclo-hexyl-aceto-nitrile  (A.  353,  297). 

(4)    RlNG-KETONES   OF  THE  HYDRO-AROMATIC   HYDROCARBONS. 

(a)  Ring-ketones  of  Hexahydro-benzols.  —  These  belong  to  the  most 
easily  accessible  hydro-aromatic  substances,  starting  from  which 
numerous  other  compounds  can  be  prepared,  and  which  have,  there- 
fore, been  studied  in  detail. 

Methods  of  Formation.  —  (i)  By  oxidation  of  the  corresponding 
cyclo-hexanols  with  chromic  acid,  or  by  conducting  their  vapours 
over  finely  divided  metallic  copper  at  300°  (C.  1903,  1.  1212).  (2)  From 
cyclo-hexene-glycols  with  dilute  acids.  (3)  By  nuclear  synthesis  from 
pimelinic  acid  and  its  alkyl  substitution  products  by  distillation  of 
their  calcium  salts  or  anhydrides  (C.  1907,  II.  685).  (4)  From  the 
synthetic  cyclo-hexanone-carboxylic  esters  and  their  alkylation  pro- 
ducts by  saponification  and  elimination  of  CO2.  (5)  By  the  action  of 


KETONES   OF  HYDRO-AROMATIC  HYDROCARBONS     457 

NaNH2  and  halogen  alkyl  upon  I,  3-methyl-cyclo-hexanone  ;  an  H 
atom  in  the  neighbourhood  of  CO  can  be  replaced  by  alkyl  (C.  1905, 
I.  605).  (6)  Several  i,  2-alkyl-cyclo-hexanones  have  been  obtained 
from  the  Mg-compound  of  i,  2-chloro-cyclo-hexanone  by  transposition 
with  halogen  alkylene  (C.  1906,  II.  126). 

Behaviour. — (i)  Like  the  aliphatic  ketones,  cyclo-hexanones  combine 
with  hydroxylamine,  phenyl-hydrazin,  semi-car bazide,  prussic  acid, 
etc.,  some  also  with  sodium  bisulphite.  (2)  Reduction  with  N  a  and 
moist  ether  produces  cyclo-hexanols.  (3)  Sodium  ethylate  or  gaseous 
HC1 — they,  like  acetone,  undergo  self-condensation  with  combination 
of  two  or  three  molecules  and  elimination  of  water.  (4)  Cyclo-hexa- 
nones condense  with  benzaldehyde,  forming  characteristic  mono-  or 
di benzyl  compounds  by  joining  up  two  methylenes  adjoining  the  CO 
group  (C.  1908,  I.  638).  (5)  With  acetic  ester,  and  sodium,  they  form 
i,  2-acetyl-cyclo-hexanones,  with  oxalic  ester  and  sodium  ethylate 
i,  2-cyclo-hexanone-oxalic  esters  (A.  348,  91),  with  NaNH2  and  CO2 
i,  2-cyclo-hexanone-carboxylic  acids  (C.  1910,  II.  1378).  (6)  With 
PC15  unstable  dichlorides  are  first  formed,  which  decompose  into  HC1 
and  chloro-cyclo-hexenes.  (7)  KMnO4  and  NHO3  oxidise  them 
clearly  to  adipinic  acids  with  the  grouping  — CO.CH2 — .  (8)  By 
means  of  Caro's  acid  some  have  been  split  up  into  lactones  (B.  33,  858). 
(9)  Cyclo-hexanone-oximes  are  converted  into  €-lactames  of  concen- 
trated H2SO4  or  PClg,  and  into  the  nitriles  of  unsaturated  aliphatic 
acids  by  P2O5  with  ring  opening  (A.  312,  173  ;  346,  266).  (10)  Sun- 
light and  water  partly  convert  cyclo-hexanones  into  saturated  fatty 
acids,  and  the  corresponding  unsaturated  aldehydes  (B.  41,  1071). 


B.p. 

D. 

Cyclo-hexanone 

155-4° 

0-9471 

(22°) 

2-Methyl-cyclo-hexanone  . 

163° 

0-9246 

1  8°) 

( 

3-Methyl-eyclo-hexanone  . 

168° 

0-9111 

18°) 

1  C.  1905,  I.  742 

4-Methyl-cyclo-hexanone  . 

169° 

0-9332 

0°) 

1 

2,  2-Dimethyl-cyclo-hexanone 

170° 

0-9141 

20°) 

A.  376,  159 

3,  3-Dimethyl-cyclo-hexanone 

174° 

.  . 

C.  1907,  I.  964 

3,  4-Dimethyl-cyclo-hexanone 

187° 

.  . 

C.  1906,  I.  1248 

2,  6-Dimethyl-cyclo-hexanone 
2,  4-Dimethyl-cyclo-hexanone 

175° 
176-5° 

0-9124 

(16°) 

B.  27,  594 

C.  1906,  I.  1248 

3,  5-Dimethyl-cyclo-hexanone 

182° 

0-8994 

(17°) 

W.  297,  163 

2,  5-Dimethyl-cyclo-hexanone 

176° 

0-9083 

13°) 

/C.  1906,  I.  1248 
\A.  357,  202 

Cyclo-hexanone-pimelin-ketone,  keto  -  hexameihylene 
2~~  **2\CO    is  an  oil  with  an   odour  like  peppermint.      It 

/ 


results  (i)  by  the  oxidation  of  cyclo-hexanol  ;  (2)  in  the  reduction  of 
phenol  with  alternating  currents  ;  (3)  in  the  distillation  of  calcium 
n-pimelinate  or  pimelinic  anhydride  (Vol.  I.)  ;  (4)  by  the  action  of  CO2 
upon  i,  5-dibromo-pentane  magnesium  (C.  1907,  II.  681)  ;  (5)  from 
nitro-hexamethylene  by  treatment  with  glacial  acetic  acid  and  zinc 
dust  (A.  302,  18). 

Upon  reduction  it  yields  cyclo-hexanol,  while  nitric  acid  oxidises 
it  to  adipinic  acid  (B.  39,  2202  ;  C.  1905,  I.  1243).  By  sodium  ethylate 
or  HC1  two  or  three  molecules  of  cyclo-hexanone  are  condensed,  with 


458  ORGANIC   CHEMISTRY 

formation  of  cyclo-hexylidene-cyclo-hexanone  (C6H8O)  :  (C6H10),  di- 
cyclo-hexylidene-cyclo-hexanone  (C6H10)  :  (C6H6O)  :  (C6H10),  b.p.  214°- 
217°,  and  dodeka-hydro-triphenylene  (B.  40,  153). 

Illumination  of  an  aqueous-alcoholic  solution  of  cyclo-hexanone  pro- 
duces capronic  acid  and  A5-hexene-aldehyde.  Cyclo-hexanone-oxime 
is  transposed  by  concentrated  H2SO4  in  e-capro-lactame  (see  Vol.  I.). 

Its  phenyl-hydrazone,  melting  at  74°-77°,  when  acted  upon  by 
mineral  acids  loses  ammonia  and  passes  into  tetrahydro-carbazol 
(A.  278,  100). 

With  benzaldehyde,  cyclo-hexanone  condenses  to  a  mono-  and  a 
dibenzylidene  compound  C6H5CH  :  (C6H8O),  m.p.  53°  (B.  40,  71),  and 
C6H5CH  :  (C6H6O)  :  CHC6H5,  m.p.  117°.  Under  special  conditions,  it 
was  found  possible  to  isolate  the  intermediately  formed  mono  acid 
di-aldols,  m.p.  102°  and  162°  (C.  1908,  I.  638).  With  nitrous  acid  we 
obtain  di-iso-nitro-cyclo-hexanone  HON  :  (C0H6O)  :  NOH,  m.p.  200° 
with  decomposition  (C.  1909,  II.  1549).  Chlorine  and  bromine  easily 
produce  substitution,  with  formation  of  I,  2-chloro-  and  i,  2-bromo- 
cyclo-hexanone  respectively,  b.p.10  82°  and  b.p.14  89°.  With  excess  of 
Br  a  tetrabromide  is  formed,  m.p.  120°,  which,  on  heating,  splits  off 
HBr  and  forms  2,  6-dibromo-phenol  (A.  343, 40  ;  /.  pr.  Ch.  2,  80, 487). 

3  -  Methyl  -  cyclo  -  hexanone  CO/^2—CH((;!^)\CH2    has  been  ob- 

M_/rl2 Url2/ 

tained  in  an  optically  active  dextro-form  of  [a]D=  4-12-5°  by  splitting 
up  the  natural  pulegone  (B.  30,  23;  /.  pr.  Ch.  2,  61,  477).  It  is  the 
most  accessible  hydro-aromatic  ketone.  On  oxidation  with  HNO3  we 
obtain  simultaneously  a-  and  j8-methyl-adipinic  acid  (A.  336,  299). 
Its  oxime,  m.p.  44°  (A.  332,  337),  is  transposed  by  concentrated  H2SO4 
into  a  mixture  of  j8-  and  S-methyl-e-capro-lactame  (A.  346, 253) .  On  its 
conversion  into  m-cresol,  see  B.  32,  3338.  From  3-methyl-cyclo- 
hexanone  the  action  of  NaNH2  and  alkyl  iodide  produces  1-methyl- 
4-ethyl-  and  l-methyl-4-propyl-cyclo-hexanone,  b.p.18  84°  and  98° 
respectively,  as  well  as  numerous  homologous  cyclo-hexanones  (see 
synthesis  of  menthone,  below). 

2, 2-Dimethyl-cyclo-hexanone  is  formed  from  i-iso-propyl-cyclo- 
pentane-i,  6-diol  by  pinacolin  transformation  and  simultaneous  ring 
extension. 

3,  5,  5-Trimethyl-cyclo-hexanone,  dihydro-iso-aceto-phorone,  b.p. 
189°,  has  been  obtained  from  dihydro-iso-aceto-phorol,  the  reduction 
product  of  iso-aceto-phorone,  by  oxidation  with  chromic  acid  mixture. 
For  transposition  of  the  oximes,  see  A.  346,  256.  2,  4,  4-Trimethyl- 
cyclo-hexanone,  b.p.  191°,  from  2,  4,  4-trimethyl-cyclo-hexenone  (A. 
324,  97).  3,  6,  6-Trimethyl-cyclo-hexanone,  see  Pulenone. 

Ring-ketols.— 1,2-Cyelo-hexanolone    co<^(OH)-™2\CH2,    m.p. 

\Uri2 (_/rl2/ 

113°,  sublimes  very  easily,  and  is  formed  from  i,  2-chloro-cyclo-hexa- 
none  with  alkalies.  It  yields  on  oxidation  with  KMnO4  adipinic  acid 
(C.  1906,  II.  125 ;  /.  pr.  Ch.  2,  80,  488).  Methyl-1,  2-cyelo-hexanolone 
CH3C6H,O(OH),  b.p.12  86°,  from  methyl-bromo-cyclo-hexanone  (B.  35, 
2695).  3-Methyl-l,  2, 3-cyelo-hexanone-diol  CH3C6H7O(OH)2,  m.p.  65°, 
is  formed  from  the  synthetic  methyl-cyclo-hexenone  and  from  A1-3- 
dihydro-toluol,  by  oxidation  with  KMnO4  ;  on  boiling  with  dilute  sul- 
phuric acid  it  yields  methyl-cyclo-hexane-dione  (B.  35,  1176).  i,  3- 


KETONES   OF  HYDRO-AROMATIC   HYDROCARBONS     459 

Cyclo-hexanolones  must  be  assumed  as  intermediate  products  in  the 
formation  of  cyclo-hexenones  from  i,  5-diketones  of  the  formula 

<££§•  some  of  which  ma^  be  C<^(°O^>CH;  <A'  323'  83  '•  B- 
36,  2118). 

Diketo-hexamethylenes,  Cydo-hexane-diones. — Theory  indicates  three 
isomeric  diketo-hexamethylenes,  two  of  which,  the  I,  3-  and  the  i,  4- 
diketo-hexamethylene,  are  known,  while  of  the  o-diketo-hexamethylene, 
up  to  now  only  a  methyl  derivative,  l-methyl-2, 3-diketo-hexa- 
methylene  CH3.C6H7O2,  m.p.  65°,  has  been  prepared  ;  it  is  formed  from 
methyl-cyclo-hexanone-diol  by  discarding  water,  and  smells  strongly 
of  quinone  (B.  35,  1178). 

Dihydro-resorcin,  i,  3-cy  do-he  xane-dione,  m-diketo-hexamethylene 
CH/CH..CO  \co  or  CO/^^C^/011*  melts  wit*1  decomposition 

\Crl2-^Al2/  \UH2 -Cxi^/ 

at  I04°-io6°.  It  is  a  feeble  acid,  and  probably  therefore  an  un- 
saturated  ketone  alcohol  of  ring  formation.  It  is  produced  upon 
introducing  pure  sodium  amalgam  into  a  boiling  aqueous  resorcin 
solution  while  carbon  dioxide  is  being  conducted  into  it.  It  may  be 
synthesised  by  the  condensation  of  y-acetyl-butyric  ester  with  sodium 
ethylate.  Dihydro-resorcin  dissolves  readily  in  water,  alcohol,  and 
chloroform,  but  with  difficulty  in  ether.  It  reacts  acid,  and  decom- 
poses the  alkali  and  alkaline  earth  carbonates.  It  can  be  directly 
esterified  with  alcohol  and  HC1. 

It  also  forms  a  dioxime  C6H8(NOH)2-f  2H2O.  This  melts  at  154°- 
157°  when  it  is  anhydrous  ;  when  reduced  it  becomes  m-diamido- 
hexamethylene.  m-Dioxy-hexahydro-iso-phthalo-nitrile  (A.  278,  20) 
is  formed  by  adding  prussic  acid  to  dihydro-resorcin  (A.  308,  184). 
PC13  produces  chloro-keto-tetrahydro-benzol  C6H7OC1,  b.p.24  104°, 
whereas  PC15  produces  diehloro-dihydro-benzol  C6H6C12,  b.p.29  89° 
(C.  1903,  I.  1352)  ;  bromine  gives  2-bromo-hydro-resorein  C6H7O2Br. 
NaOBr  and  bleaching-lime  decompose  hydro-resorcin  into  glutaric  acid 
and  chloroform  (A.  322,  245) ;  by  heating  with  baryta  water  to  150°- 
160°  it  is  broken  up  into  acetyl-butyric  acid  (A.  294,  269). 

Homologues  of  dihydro-resorcin  are  similarly  formed  in  the  con- 
densation of  like  S-ketone-carboxylic  esters,  as,  for  example,  in  the 
addition  of  malonic  esters  to  alkylidene-aceto-acetic  ester.  When 
the  latter  is  condensed  with  malonic  ester,  through  the  agency  of  sodium 
ethylate,  and  the  product  then  saponified,  carbon  dioxide  is  eliminated, 
and  there  results  methyl-dihydro-resorcin,  m.p.  126°  (A.  289, 137  ;  294, 
253)  : 

CH3                                                 CH3  CHS 

C02RCH.CH.CHC02R y  CO2RCH.CH.  CHCO2R  v  CH2.CH.CH, 

CO.CH3C02R  CO.CH2.CO  CO.CH2.CO 

Iso-propyl-dihydro-resorcin  (CH3)2CH.C6H7O2,  m.p.  82°  (C.  1902,  II. 
115).  Phenyl-dihydro-resorcin  (C6H5)C6H7O2,  m.p.  184°.  1,  2-Di- 
phenyl-dihydro-resorcin,  m.p.  160°,  from  phenyl-acetic  ester,  benzal- 
acetone,  and  sodium  ethylate  (B.  42,  4498). 

Cinnamenyl-dihydro-resorem  (C6H5CH  :  CH)C6H7O2,  from  cinna- 
mylidene-acetone  and  Na-malonic  ester,  is  changed,  by  bleaching-lime, 
into  cinnamenyl-glutaric  acid  (A.  345,  206). 


460  ORGANIC  CHEMISTRY 

Dimethyl-hydro-resorcin  (CH3)2C  :  [CH2CO]  :  CH2,  m.p.  150°,  from 
mesityl  oxide,  and  sodium-malonic  ester,  gives,  with  NaOBr  and 
bleaching-lime,  jSjjS-dimethyl-glutaric  acid  (A.  368,  135).  For  halogen 
derivatives  of  dimethyl-hydro-resorcin,  see  A.  322,  239.  For  the  trans- 
formation of  dimethyl-dihydro-resorcin  into  dimethyl-di-  and  tetra- 
hydro-benzol,  see  C.  1908,  I.  1779.  Trimethyl-dihydro-resorcin,  m.p. 
100°  (C.  1-900,  I.  1069  ;  1901,  I.  567). 

The  homologous  dihydro-resorcins  react  like  simple  dihydro-resorcin, 
both  as  diketones  and  as  unsaturated  oxy-ketones. 

1,  4-Cyclo-hexane-dione,    tetrahydroquinone,    p-diketo-hexamethylene 

</""*TT  f^T-T    \ 

^TT2    ^TT  2/co>  m-P-  78°,  results  upon  saponifying  succino-succinic 
.C/xig  —  (--.rig/ 

ester  with  concentrated  sulphuric  acid,  when  it  loses  carbon  dioxide 
(Baeyer),  or  when  the  same  body  is  boiled  with  aqueous  alcoholic 
hydrochloric  acid.  On  heating  succinyl-succinic  ester  with  methyl 
or  ethyl  alcohol  to  200°,  acetals  of  p-diketo-hexamethylene  are  formed, 
methyl  acetal,  m.p.  81°,  ethyl  acetal,  m.p.  89°  (B.  34,  1344).  In  small 
quantities,  p-diketo-hexamethylene  is  also  produced  by  distillation  of 
calcium  succinate. 

It  unites  with  sodium  bisulphite  to  form  a  dioxime,  melting  at  192°  ; 
the  latter  is  changed  by  chlorine  into  p-dichloro-dinitroso-hexa- 
methylene  (ON)CC1(CH2.CH2)2CC1(NO),  deep-blue  crystals,  m.p.  108°, 
changed  by  glacial  acetic-hydrochloric  acid  into  a  colourless  form 
melting  at  I28°-I3O°  with  decomposition  (B.  35,  3101).  With  benz- 
aldehyde  and  HC1  p-diketo-hexamethylene  forms  benzyl-hydroquinone 
(B.  37,  3486).  It  forms  quinite  upon  reduction  ;  see  also  a-Dioxy-hexa- 
hydro-terephthalic  acid. 

p-Dimethyl-p-diketo-hexamethylene,  2,  5-dimethyl-i,  ^-cyclo-hexane- 
dione,  m.p.  93°,  is  obtained  from  p-dimethyl-succino-succinic  ester 

(B.  25,2122). 

Cyclo-hexane-triones.  —  Phloro-glucin  yields  derivatives  which  can  be 
deduced  from  the  formula  of  I,  3,  5-trioxy-benzol,  and  others  which 
can  be  obtained  from  the  formula  of  i,  3,  5-triketo-hexamethylene. 
It  was  discussed  at  the  conclusion  of  pyrogallol  and  oxy-hydroquinone, 
as  were  the  hexa-alkyl  derivatives  of  phloro-glucin. 

Triquinoyl  C6O6-[-8H2O,  described  with  the  quinones,  is  probably 
hexaketo-hexamethylene. 

Halogen  Substitution  Products  of  the  Ring-ketones  of  Hexahydro- 
benzol  are  formed  in  the  continuous  action  of  chlorine  and  bromine 
upon  phenols,  quinones,  and  oxy-quinones.  Several  of  the  keto- 
chlorides  can  be  readily  rearranged  into  halogen  keto-pentene  deriva- 
tives, and  be  decomposed  into  highly  chlorinated  fatty  bodies  :  ketones, 
ketonic  acids,  and  fatty  acids. 

Heptachloro-resorcin,    heptachloro  -  1,  3-cyclo-hexane-dione 

C0^CH2^a)>CH2'  m'p'  5°°'  b>p>25  I7°°'  from  resorcin  and  C1  in 
chloroform  (B.  24,  912). 

Quinone     tetrabromide,     2,3,5,6-  tetrabromo  -  cyclo  -  hexane  -  dione 

Hexachloro-triketo-R-hexylene,     hexachloro- 


,  3,  S-cyclo-hexane-trione  CO/^J2~    Ncci2,  m.p.  48°,  b.p.  268°,  from 

— 


phloro-glucin  with  Cl  in  chloroform  (B.  22,  1473). 


KETONES  OF  HYDRO-AROMATIC  HYDROCARBONS     461 


Pentabromo-diketo-oxy-cyclo-hexenol  co^co  /CBr  +H!!O  ' 
m.p.  119°  with  decomposition.  It  is  produced  when  bromine  in  water 
acts  upon  phloro-glucin.  It  forms  amber-yellow-coloured  crystals.  It 
is  a  strong  acid. 

Hexabromo-triketo-cyclo-hexane   C6Br6O3  melts  at    147°   (B.   23, 

I729)« 

Tri-  and   tetrachloro  -  tetraketo  -  cyclo  -  hexanes  co 

They  are  obtained  from  chloranilic  acid  and  chlorine.  The  correspond- 
ing bromine  derivatives  are  made  from  bromanilic  acid  (B.  25,  845). 

(b)  Ring-ketones  from  the  Tetrahydro-benzenes  can  be  synthesised 
by  condensing  aceto-acetic  ester,  acetone-dicarboxylic  ester,  and  ana- 
logous compounds  with  aldehyde  iodides,  like  methylene  iodide,  or  with 
aldehydes  in  the  presence  of  small  quantities  of  bases,  such  as  diethyl- 
amine  or  piperidin,  to  i,  5-diketone-carboxylic  esters  —  e.g.  methylene-, 
ethylidene-,  iso-butylidene-diaceto-acetic  ester  and  methylene  bis- 
acetone-dicarboxylic  ester.  When  the  latter  are  treated  with  hydro- 
chloric acid  in  ether,  they  first  form  a  ring  and  become  carboxylic  esters 
of  A2-keto-R-hexenes,  and  then,  when  acted  upon  with  alkalies  or 
dilute  acids,  are  saponified,  split  off  C02,  and  change  to  the  ketones 
themselves  (A.  289,  131)  : 

C02.C2H5.CH.CO.CH3  C02.C2H5.CH.C.CH3  CH2.C.CH3 

CH2  -  '-+  CH2CH       -  >  CH2CH 

CO2.C2H5.CH.CO.CH3  CO2.C2H5.CH.CO  CH2.CO 

From  acetyl-acetone  with  aldehydes  we  obtain  82-tetraketone 
(CH3COCH)2CHR(CHCOCH3)2,  which,  on  twofold  ring  condensation, 
yields  dicyclic  systems  whose  structure  has  still  to  be  determined 
(B.  30,  2136). 

From  the  nitroso-chlorides  of  some  cyclo-hexenes  A2-cyclo-hexe- 
nones  have  been  prepared  by  splitting  oft  HC1  by  means  of  sodium 
ethylate  or  sodium  acetate  and  glacial  acetic  acid,  and  breaking  up  the 
resulting  oxides  with  oxalic  acid  or  phthalic  anhydrides. 

By  reduction  with  sodium  and  alcohol  we  obtain  from  A2-cyclo- 
hexenones  the  saturated  cyclo-hexanols.  But  if  we  reduce  with  sodium 
amalgam  in  acid  solution,  two  molecules  are  combined  and  we  obtain 
derivatives  of  diketo-perhydro-diphenyl.  3-Methyl-A2-cyclo-hexenone 
CH2<(^2-CHa\C(CH3).q^^  By  the  action  of  two 

molecules  of  hydroxylamine,  oximes  are  formed.  Thus,  from  3- 
methyl-A2-cyclo-hexenone  we  get  3-methyl-3-hydroxylamino-cyclo- 
hexanone-oxime  (B.  32,  1315). 

A2-Cyelo-hexenone    co/c         3HN)CH2,   b.p.14  63°,    bromo-cyclo- 

\CH2  —  CH2  / 

hexanone,  on  boiling  with  aniline,  or  from  I,  2-cyclo-hexanolone  with 
anhydrous  oxalic  acid.  Its  unstable  dibromide  easily  passes  into  phenol 
by  splitting  off  HBr.  The  oxime  melts  at  75°  and  yields  aniline  on 
boiling  with  acetic  anhydride.  Oxamine  oxime,  m.p.  50°  (/.  pr.  Ch. 
2,  80,  487). 

3-Methyl-A2-eyclo-hexenone  co^     =c(CrI5)  \CH2,  b.p.  200°,  forms 


462  ORGANIC  CHEMISTRY 

a  mobile  liquid  of  pleasant  odour.  Its  bromine  addition-product  de- 
composes spontaneously  into  BrH  and  m-cresol.  It  seems  to  exist  in 
two  isomeric  forms,  one  of  which  can  be  mixed  with  water,  while  the 
other  is  difficult  to  dissolve.  They  are  of  identical  chemical  behaviour, 
and  both  are  oxidised  by  permanganate  to  y-acetyl-butyric  acid  (B. 
40,  2482).  The  oxime,  m.p.  89°,  gives,  on  boiling  with  acetic  anhydride, 
m-toluidin  (A.  322,  382).  The  hydroxylamino-oxime,  m.p.  84°,  gives, 
by  oxidation  with  mercuric  oxide,  a  nitroso-oxime.  By  heating  with 
concentrated  potash,  the  3-methyl-A2-cyclo-hexenone  is  changed  into 
a  polymerisation  product  resembling  an  aldol,  melting  at  113°  (B.  32, 
423  ;  A.  297,  142).  With  sodium-aceto-acetic  ester  it  combines  to 
form  5-diketone-carboxylic  ester,  which  by  ring-condensation  passes 
into  a  bicyclic  ketone-alcohol  (B.  37,  1671). 

2-Methyl-A2-cyclo-hexenone  co?^£H3)  =^  >CH2,  b.p.  179°,  from 

\(_,H2 U.H.2/ 

the  nitroso-chloride  of  A^methyl-cyclo-hexene  (A.  359,  303). 

4-Iso-propyl-A2-cyclo-hexenone  co/^  =c?\:H.CsH7f  b.p.la  94°, 

\Cri2 — C.H.2/ 

semi-carbazone,  m.p.  185°,  is  formed  by  heating  sabina-ketone  and 
nopinone  with  dilute  sulphuric  acid  and  by  the  self-oxidation  of  j3- 
phellandrene.  It  polymerises  very  easily,  especially  in  the  presence  of 
alkali.  With  methyl-magnesium  iodide  water  is  split  off  and  a-phel- 
landrene  is  formed  (A.  359,  270). 

4-Iso-propyl-A3-eyclo-hexenone  co<f^3~~cTf  V.QH,,  b.p.12  95°, 

\CH  2 — C  H  2  / 

semi-carbazone,  m.p.  170°,  is  formed  from  the  HC1  addition  product  of 
sabina-ketone  by  heating  with  dimethyl-aniline.  Mineral  acids  trans- 
pose it  into  the  A2-ketone.  With  methyl-magnesium  iodide  it  yields 
terpinenol-i  (A.  362,  280). 

1,  4-Iso-propylidene-eylo-hexanone    co^CH*—cu*\c :  c/01^   b.p. 

NCH2 — CH2/  \CH3 

220°,  semi-carbazone,  m.p.  200°,  from  the  corresponding  carboxylic 
ester  (C.  1907,  II.  1975).  1,  4  -  Iso  -  propenyl  -  cyclo  -  hexanone 

C°<CHlIcH2>CH'C\CH^  b-P'300  I85°  (C  I9°4'  IL  33I)' 

3,  5-Dimethyl-A2-eyelo-hexenone,  b.p.  211°.  Its  dibromide  easily 
passes  into  sym.  xylenol  (A.  281,  121)  ;  its  oxime,  m.p.  68°-74°,  is 
transposed,  by  heating  with  HC1,  into  sym.  xylidene  (A.  322,  381). 

5, 5-Dimethyl-A2-cyclo-hexenone,  b.p.32  85-5°,  from  dimethyl- 
chloro-cyclo-hexanone,  the  product  of  the  action  of  PC13  upon  dimethyl- 
dihydro-resorcin,  by  reduction  with  zinc  dust.  With  permanganate 
it  gives  a-oxy-jSjjS-dimethyl-glutaric  acid  and  unsym.  dimethyl- 
succinic  acid  (C.  1907,  I.  1039). 

3,  5,  5-Trimethyl-A2-cyclo-hexenone,  iso-aceto-phorone,  iso-phorone 
C9H140=CO<^  =C£™\  ^>CH2,  boiling  at  89°  (10  mm.),  is  produced 

\Ura2 — M^^S/2' 

in  the  condensation  of  mesityl  oxide  with  aceto-acetic  ester,  saponifica- 
tion,  and  elimination  of  carbon  dioxide  from  the  carboxylic  ester 
formed  at  first.  It  also  results  from  the  condensation  of  acetone 
by  means  of  lime  or  sodium  ethylate.  It  is  isomeric  with  phorone, 
camphor-phorone,  iso  -  camphorone,  nopinone,  camphenilone,  and 
fencho-camphorone.  Upon  reduction  with  sodium  and  alcohol  it 
forms  dihydro-iso-phorol  C9H17(OH),  which  by  loss  of  water  becomes 


KETONES   OF  HYDRO-AROMATIC  HYDROCARBONS     463 

trimethyl-cyclo-hexene,  and  by  the  reduction  of  its  iodide  yields 
trimethyl-cyclo-hexane.  When  oxidised  with  potassium  permangan- 
ate the  ring  is  ruptured  and  various  acids  result  :  yy-dimethyl- 
a,  2-diketo-heptylic  acid  CSH14O4,  y-acetyl-j3j3-dimethyl-butyric  acid 
CSH14O3,  and  unsym.  dimethyl-succinic  acid  (C.  1909,  I.  853). 

The  iso-phorone  gives  two  isomeric  oximes  melting  at  75°  and  100° 
respectively  (A.  297,  187  ;  299,  165,  193),  which  are  transposed,  by 
heating  with  HC1  to  170°,  into  i-amido-3,  4,  5-trimethyl-benzol  (A. 
322,  379).  Besides  iso-phorone,  we  find  among  the  condensation  pro- 
ducts of  acetone  more  highly  condensed  ketones,  the  so-called  xyli- 
tones  C12H18O,  probably  formed  by  condensation  of  a  further  molecule 
of  acetone  with  iso-phorone  ;  the  xylitones  produced  by  different  con- 
densation agents,  such  as  lime,  sodium  ethylate,  and  HC1,  seem  all  to 
differ  from  one  another.  An  identically  situated  xylitone,  which,  how- 
ever, is  not  identical  with  any  of  the  others,  and  melts  at  133°  (12  mm.), 
has  been  obtained  by  the  addition  of  sodium-aceto-acetic  ester  and 
phorone.  By  boiling  with  formic  acid  it  is  split  up  into  acetone  and 
iso-phorone  (B.  39,  3441). 

2,  4,  4-Trimethyl-A2-eyclo-hexenone,  b.p.  196°,  by  transformation 
of  a-cyclo-geraniolene  nitroso-chloride  (A.  324,  97). 

3-Methyl-5-iso-propyl-A2-cyclo-hexenone 


boils  at  244°.  Its  dibromide  passes  readily  into  sym.  carvacrol  (B.  26, 
1089  ;  27,  2347  ;  A.  288,  357). 

3-Methyl-5-iso-butyl-     and     3-methyl-5-hexyl-A2-eyclo-hexenones 

boil  at  147°  and  at  167°  (22  mm.)  (B.  288,  336,  344). 

Those  chemists  who  consider  the  quinones  to  be  ketones  regard 
rhodizonic  acid  as  a  tetraketo-tetrahydro-benzol  derivative. 

4-Methyl-  and  2,  4-dimethyl-A2-eyclo-hexenones,  b.p.  192°  and  194°, 
are  found  among  the  ketones  of  wood-tar  (C.  1901,  I.  611). 

Halogen  Substitution  Products  of  Ring-ketones  of  Tetrahydro-benzols 
result  when  chlorine  acts  upon  phenols,  anilines,  oxy-benzoic  acids,  etc. 
They  can  be  very  readily  broken  up. 

Heptachloro  -  keto  -  tetrahydro  -  benzols   cci/^f.          \x>     and 

\OHC1  —  CCi2/ 

CC1\CHci^CCl2^C0'  the  a'body  melting  at  98°  and  the  ^-modification 
at  80°,  result  from  the  action  of  chlorine  upon  m-chloraniline 
(B.  27,  547)- 

Octo  -  chloro  -  keto  -  tetrahydro  -  benzol     cci,/c  '  Nco,      or 

\V-/  v/1  2  -  V^x-'l  2  * 

CC1\CC1~^CC1^X°'  melting  at  103°,  result  from  the  action  of  chlorine 

upon  pentachloro-phenol  in  glacial  acetic  acid,  and  from  perchloro-m- 
oxy-benzoic  acid.  Reducing  agents  change  it  into  pentachloro-phenol 
(B.  27,550). 

Hexachloro  -  o  -  diketo-tetrahydro-benzol   cci^001*^00  ^>co  +2Hao 

melts  at  93°  with  decomposition.  It  is  formed  when  chlorine  acts 
upon  pyro-catechol  and  o-amido-phenol  chlorohydrate  dissolved  in 
acetic  acid.  Stannous  chloride  reduces  it  to  cyclo-benzo-quinone. 
Homologous  o-diketo-chlorides  have  been  obtained  from  o-diamido- 
methyl-benzols  (B.  27,  560). 


464  ORGANIC   CHEMISTRY 


Pentaehloro  -  m  -  diketo-tetrahydro-benzol  cocQ^H/^ccl2'  m'p' 
92°  and  b.p.  160°  (25  mm.),  results  when  chlorine  acts  upon  resorcin 
in  chloroform  (B.  23,  3777). 

Hexachloro  -  m  -  diketo-tetrahydro-benzol  co<^°~  ;^2\:ci2,   m.p. 

\OG1  —  GC1  / 

115°   and  b.p.  159°  (14  mm.),  is  produced  when  chlorine  acts  upon 
3,  5-dioxy-benzoic  acid  dissolved  in  glacial  acetic  acid  (B.  25,  2688). 

Hexachloro  -  p  -  diketo-tetrahydro-benzol   co<^ccl^7ccl2^>co,    m.p. 

89°  and  b.p.  184°  (45  mm.),  is  formed  when  chlorine  acts  upon  p-amido- 
phenol  hydrochloride  in  glacial  acetic  acid  (A.  267,  16). 

(c)  Ring-ketones  of  the  Di  hydro-benzols.  —  There  are  two  possible 
dihydro-benzols,  and  from  each  one  monoketone  can  be  obtained.  Both 
bodies  are  not  yet  known,  but  in  tetrachloro-keto-dihydro-benzol 

m<-   I06°'  WC  have  chlorine 


derivatives  of  one  or  of  both  keto-dihydro-benzols.  The  first  body 
is  formed  from  trichloro-phenol  and  chlorine,  and  the  second,  most 
conveniently,  by  heating  (B.  27,  546)  the  heptachloro-keto-tetra- 
hydro-benzol,  melting  at  98°,  and  by  treating  phenol,  anisol,  and  penta- 
chloraniline  with  chlorine  (B.  28,  R.  63). 

Among  the  ring-ketones  of  the  dihydro-benzols  we  must  also  include 
a  series  of  substances  obtained  as  by-products  in  the  action  of  chloro- 
form and  alkali,  or  of  carbon  tetrachloride  and  aluminium  chloride 
upon  o-  and  p-alkylated  phenols,  e.g.  : 

/CH=CH\     /R  /CH=CH\     /R  /CH-COX     /R 

\CH=CH/     \CHC12'          \CH=CH/    \CC13'  \CH=CH/     \CHC12 

Thus,  compounds  which  are  reconverted  into  the  original  phenols 
by  reduction  with  zinc  dust  and  glacial  acetic  acid,  and  reduction  of 
CH2C12  or  CHC13,  react  with  phenyl-hydrazin,  hydroxylamine,  and  semi- 
carbozide  like  ketones  (B.  36,  1861).  Special  interest  attaches  to  the 
further  transformations  of  these  ketones  with  alkyl-magnesium  com- 
pounds. The  ketones  (i)  derived  from  the  p-alkyl-phenols  yield 
normal  tertiary  alcohols  (2)  which  easily  split  off  water  and  become 
unstable  alkylidene-dihydro-benzols  (3),  and  change  into  true  benzol 
derivatives  (4)  on  heating  at  ordinary  temperatures  with  migration  of 
the  CHC12  group  or  the  CC13  group  (A.  352,  219). 

(i) 

CH3\    /CH=CH\  CH,Mgl  CH3\     /CH=CH\     /OH 

C12CH/    \CH=CH/  /    C12CH/    \CH=CH/     \CH3 

(3) 

CH3\     /CH=CH\ 
C12CH/C\CH=CH/ 

Different  behaviour  is  shown  by  the  ketones  derived  from  the 
o-alkyl-phenols.  These  (5)  attach  the  alkyl-magnesium  compounds  to 
the  carbon  double  link  and  form  higher  homologous  j8,  y-unsaturated 
ketones  (6),  which,  by  the  action  of  concentrated  sulphuric  acid,  dis- 
place the  double  link  and  pass  into  the  isomeric  a,  j3-unsaturated 
ketones  (7).  The  latter,  on  heating  with  alcoholic  potash,  yield 


KETONES  OF  HYDRO-AROMATIC  HYDROCARBONS    465 

I,  4-dialkyl-cyclo-hexadienes   (8),   by   a  curious  reaction  with  inter- 
mediate formation  of  p-dialkyl-dihydro-benzoic  acids  (B.  42,  2404) : 

(5)  (6) 

CH3\^  /CO— CH\          CH.Mgi          CH3\r /CO— CH. 
C12CH/^\CH-CH/  /    C12CH/    \CH=CH 

(7)  /  (8) 


CH3\    /CO— CH\ 
C12CH/C<\CH-CH2/CCH3 


By  using  iso-propyl-magnesium  iodide  we  get  a  synthesis  of  a- 
terpinene  (Auwers). 

l-Methyl-4-dicnloro-methyl-keto-dihydro-benzol,  m.p.  55°,  changes, 
under  the  action  of  PC15,  with  intermediate  formation  of  an  unstable 
tetrachloride  and  migration  of  the  methyl  group,  into  trichloro-o-xylol 
Cl[5]C6H3[i]CH3[2]CHCl2.  With  CH3MgI  it  forms  1,  4-dimethyl-4- 
dichloro-methyl-oxy-dihydro-benzol  (2),  m.p.  96°,  which  easily  decom- 
poses into  water  and  l-methylene-4-methyl-4-dichloro-methyl-dihydro- 
benzol  (3),  a  yellowish  oil.  On  heating,  the  latter  transposes  into 
l-methyl-4-(j8)-dichlorethyl-benzol  (4),  which,  with  concentrated 
H2SO4,  passes  into  m-xylol-aldehyde,  with  migration  of  the  methyl 
group. 

4-M  ethyl  -  4-  trichloro-  methyl  -keto-dihydro-benzol 

ca'X^cH-cH^00'  m'p'  I05°'  oxime'  m'p-  I34°'  from  P-cresol>  CQ2> 
and  A1C13,  behaves  like  the  corresponding  dichloro-compound  (B.  41, 
897). 

2-Methyl-2-dichloro-methyl-keto-dihydro-benzol  (5),  m.p.  33°,  b.p.9 
113°,  gives,  with  CH3MgI,  3,  6-dimethyl-6-dichloro-methyl-A4-cyclo- 
hexenone,  dichloro-f$,  y-pulenone  (6),  b.p.  124°  (15  mm.),  which  is  con- 
verted by  H2SO4  into  the  isomeric  3,  6-dimethyl-6-dichloro-methyl-A2 
cyclo-hexenone,  dichloro-afi-pulenone  (7),  m.p.  41°,  b.p.15  151°  ;  the 
latter,  with  alcoholic  potash,  gives  A1'3-dihydro-p-xylol  (8),  and  by 
reduction  with  Na  and  alcohol  3,  6,  6-trimethyl-cyelo-hexanol  or 
pulenol. 

The  methylene-quinones  and  qitinols,  discussed  in  connection  with 
phenol  alcohols,  are  probably  also  monoketones,  derivable  from 
A^-dihydro-benzol  : 


/CH=CH\  /CH=CH\     /R 

\CH=CH/  \CH=CH/    \OH' 

Each  of  the  possible  dihydro-benzols  also  yields  a  diketone  : 
CH\CH-CH2)>CH2  AU-Dihydr°-benzo1     CH2<(.cH-CH/>CH2  AM-Dihydr°-benzo1 


o-Benzo-quinone,         rO</=TO          p-Benzo-quinone. 
H—  CH/  o-diketo-dihydro-benzol  \CH—  CH/  p-diketo-dihydro-benzol 

If  the  diketone  formula  is  preferred  for  the  benzo-quinones,  pre- 
viously discussed  with  the  phenols,  then  p-benzo-quinone  is  p-diketo- 
dihydro-benzol,  and  its  numerous  derivatives  are  also  deducible  from 
the  latter  compound.  o-Benzo-quinone  would  be  o-diketo-dihydro- 
benzol. 

VOL.  II.  2  H 


466  ORGANIC  CHEMISTRY 

(5)  HYDRO-AROMATIC  ALDEHYDES. 

Concerning  the  production  of  hydro-aromatic  aldehydes,  which  is 
connected  in  general  with  well-known  reactions,  we  must  remark 
that  their  production  from  the  calcium  salts  of  the  hydro-aromatic 
carboxylic  acids,  by  distillation  with  calcium  formate,  is  not  a  straight- 
forward reaction,  and  is  often  accompanied  by  transpositions.  On 
the  other  hand,  the  conversion  of  the  hydro-aromatic  carboxylic  acids 
into  the  corresponding  aldehydes,  by  the  transformation  of  the  acid 
anilides  into  the  anilide  chlorides  (i),  and  diphenyl-amidines  (2),  the 
reduction  of  the  latter  with  sodium  and  alcohol  (3),  and  the  splitting 
up  of  the  resulting  alkylidene-dianilines  with  dilute  sulphuric  acid  (4), 
can  be  successfully  carried  out  (B.  41,  2064). 

RCONHC6H6  -  —  ->  RCC12NHC6H5  — Q- 

(3)/ 

NHC6H5      (4) 


Hexahydro-benzaldehyde  C6Hn.CHO,  b.p.  162°,  is  formed  (i)  by 
oxidising  cyclo-hexyl-carbinol  with  chromic  acid  ;  (2)  from  the 
glycol  of  methene-cyclo-hexane  with  dilute  H2SO4  (A.  347,  331)  ;  (3) 
from  the  synthetic  cyclo-hexyl-glycidic  ester  by  saponification  and 
CO  2  rejection  (C.  1906,  I.  1423).  It  smells  of  oil  of  bitter  almonds 
and  valeraldehyde,  and  polymerises  readily  to  meta-hexahydro-benz- 
aldehyde  (C7H12O)2,  m.p.  202°  (B.  40,  3050).  Oxime,  m.p.  91°  ;  semi- 
carbazone,  m.p.  174°.  By  methods  2  and  3  numerous  homologous 
aldehydes  have  been  obtained  :  o-,  m-,  and  p-hexahydro-tolyl-alde- 
hydes  CH3.C6H10CHO,  b.p.15  61°,  60°,  and  63°.  2,  6,  6-Trimethyl-hexa- 
hydro-benzaldehyde,  b.p.10  59°,  by  reduction  of  j8-cyclo-citral  with  H 
and  colloidal  palladium  (B.  42,  1635). 

A1-Tetrahydro-benzaldehyde  C6H9.CHO,  an  oil  smelling  strongly  of 
benzaldehyde,  formed  by  HC1  rejection  from  the  nitroso-chloride  of 
methene-cyclo-hexane,  by  means  of  sodium  acetate  and  glacial  acetic 
acid.  Oxime,  m.p.  58°.  Semi-carbazone,  m.p.  212°.  In  a  similar 
manner  the  tetrahydro-tolyl-aldehydes  are  formed  (A.  359,  292). 
A3-Tetrahydro-benzaldehyde,  b.p.17  58°,  from  A3-bromo-cyclo-hexene- 
magnesium  and  orthoformic  ester  (B.  43,  1040). 

2,  6,  6-Trimethyl  -  tetrahydro  -  2  -  benzaldehydes,  cyclo  -  citrals.  —  Of 
these  aldehydes,  important  for  the  synthesis  of  violet  perfumes,  all 
four  linkage  isomers  are  known  : 


CH3CH3 

V  V  Y               Y 

H2C     CCHO  H2C     CH.CHO  H2C     CH.CHO  ttC     CH.CHO 

HaC     CCH3  H2C     CCH3  HC     CH.CH3  HC     CH.CH3 

CHa  CH  CH                                 CH2 

A1-  or  A2-  or  A3-cyclo-citral  A4-cyclo-citral. 

/3-cyclo-citral  a-cyclo-citral 


HYDRO-AROMATIC  ALDEHYDES  467 

a-Cyclo-citral,  b.p.20  90°-95°,  D  0-925,  semi-carbazone,  m.p.  204°, 
and  £-eyclo-citral,  b.p.10  88°-9i°,  D20  0-957,  semi-carbazone,  m.p. 
167°,  are  obtained  together  from  the  a-cyclic  terpene-alcohol  citral  by 
changing  the  latter  into  aniline,  and  then  condensing  to  a  ring  by  means 
of  sulphuric  and  phosphoric  acids  (C.  1901,  II.  716).  See  also  B.  33, 
3720.  They  are  also  produced  by  the  oxidation  of  cyclo-geraniol. 
a-  and  £-Cyclo-citral  oxidise  in  air  to  the  corresponding  cyclo-geranic 
acids.  With  acetone  and  sodium  alcoholate  a-cyclo-citral  condenses 
to  a-ionone,  and  /2-cyclo-citral  to  j8-ionone. 

For  the  synthesis  of  A3-  and  A4-cyclo-citrals  we  start  from  iso- 
phorone-carboxylic  ester  (i),  which,  by  reduction  with  Na,  yields  a 
mixture  of  cis-trans-isomeric  oxy-acids  (2),  which,  on  discarding  water, 
pass  into  A3-cyclo-geranium  acids  (3)  .  PC15  changes  the  iso-phorone- 
carboxylic  ester  into  S-chloro-cyclo-geraniol-adiene-car  boxy  lie  acid  (4), 
from  which,  by  reduction,  together  with  the  A2-  and  A3-acids,  A4-cyclo- 
geranium  acid  (5)  is  obtained  : 

CH,  CH,  CH,  CH.  CH,  CH,  CH,  CH,  CH,  CH, 

V  V  V  V  V 

(5)    C  (4)    C  (i)     C  (2)     C  (3)     C 


/\ 
HC        CH.CO,H<  —  HC        CH.CO2H«  —  H,C       CH.CO,R  —  >  H,C       CH.CO,H  —  >-H,C       CH.COaH 

HC        CH.CH3  C1C        CCH,  OC       C.CH,  HOHC        CH.CH,  HC       CH.CH, 

\y  \s  \/-  \s  \/ 

CH,  CH  CH  CH,  CH 

The  A3-  and  A4-cyclo-geranium  acids  so  obtained  are  changed  by 
the  method  given  above  into  A3-cyelo-eitral,  b.p.12  76°,  and  A4-cyclo- 
citral.  With  acetone  the  A3-cyclo-citral  condenses  to  a-irone,  and 
the  A4-cyclo-citral  to  j3-irone,  which  is  identical  with  the  irone  ex- 
tracted from  violet  roots  (Merling  and  Welde,  A.  366,  119).  Isomeric 
trimethyl-tetrahydro-benzaldehydes,  see  C.  1903,  II.  78. 

Dihydro-benzaldehyde  C6H7.CHO,  b.p.120  122°,  is  formed  from 
anhydro-ecgonin  dibromide  (q.v.)  with  sodium  carbonate.  By  gentle 
oxidation  with  Ag2O  it  gives  A^-dihydro-benzoic  acid  (B.  26,  454  ; 

31,  1545). 

Dihydro-cumin-aldehyde  C3H7.C6H6.CHO,  semi-carbazone,  m.p. 
202°  ;  oxime,  m.p.  43°  ;  by  reduction  of  nitro-fi-phellandrene  (A. 
340,3). 

(6)  EXTRA-CYCLIC  HYDRO-AROMATIC  KETONES. 

Among  these  compounds  we  have  the  important  violet  perfumes, 
irone  and  the  ionones. 

Preparation.  —  (i)  Oxidation  of  extra-cyclic  secondary  alcohols  ;  (2) 
from  a-alkyl-cyclo-hexyl-glycidic  esters  by  saponification  and  rejection 
of  CO  2  ;  (3)  by  condensation  of  cyclo-hexanone  with  acetic  ester  and 
sodium  ;  (4)  ring-unsaturated  ketones  are  obtained  from  the  nitroso- 
chlorides  of  alkylidene-cyclo-hexanes  by  deprivation  of  HC1  and  split- 
ting up  the  resulting  oximes  (A.  360,  39). 

Hexahydro-aceto-phenone  C6Hn.COCH3,  b.p.12  68°,  by  methods 
i  and  2,  and  from  the  synthetic  a-acetyl-cyclo-hexane-car  boxy  lie  ester. 
2-,  3-  and  4-Methyl-hexahydro-aceto-phenone  CH3.C6H10.COCH3,  b.p.]8 
78°,  b.p.38  99°,  and  b.p.14  75°,  by  method  2  (C.  1907,  II.  332). 

1,  1-Methyl-acetyl-eyelo-hexane    CH2™cH3,    b.p.18 


468  ORGANIC  CHEMISTRY 

83°,  from  iso-propyl-cyclo-hexane-i,  7-diol  with  dilute  SO4H2  (C.  1910, 
II.  466). 

Hexahydro-propio-phenone  C6Hn.CO.CH2.CH3,  b.p.  196°,  by  oxida- 
tion of  cyclo-hexyl-ethyl-carbinol,  or  by  action  of  zinc  ethyl  upon 
hexahydro-benzoyl-chloride  (B.  42,  2230). 

Cyclo-hexyl-aeetone  C6H11.CH2.CO.CH3,  b.p.  196°,  from  cyclo- 
hexyl-aceto-acetic  ester  (B.  42,  2236). 

2-Acetyl-cyclo-hexanone  C6H9O.COCH3,  b.p.18  m°,  by  method  3. 
Alkalies  break  it  up  into  acetyl-capronic  acid.  It  can  be  alkylated 
by  means  of  sodium  and  alkyl  iodide  (C.  1906,  I.  252). 

3,  6-Methyl-acetyl-cyclo-hexanone  C6H8O[3,  6](CH3)(COCH3),  b.p.J4 

122°  (C.  1901,  I.  683).     2-Propionyl-eyclo-hexanone  C6H9O.COC2H5, 

'b.p.21  123°,  is  formed  by  nuclear  synthesis  from  z-ketononylic  ester 

and  Na  ethylate  (C.  1909,  II.  119). 


A^Tetrahydro-aeeto-phenone    CH.*~c.COCaJ  b.p.  201°, 

M_,ri2  —  Cri2 

from  the  nitroso-chloride  of  ethylidene-cyclo-hexane,  and  by  the  action 
of  acetyl  chloride  and  A1C13  upon  cyclo-hexene.  Oxime,  m.p.  99° 
(C.  1910,  I.  1785). 

4-Methyl-A1-tetrahydro-aceto-phenone,  b.p.  213°.  An  isomeric 
4-methyl-A3-tetrahydro-aceto-phenone,  b.p.  206°,  has  been  obtained 
by  the  oxidation  of  j8-terpineol  (A.  324,  89). 

Irone  (formula  below),  b.p.  144°,  D20  0-939,  [a]D=+44°,  was 
obtained  by  Tiemann  and  Kriiger  (B.  26,  2675)  from  the  etheric 
oil  of  so-called  violet  root  of  Iris  florentina,  Iris  germanica,  and 
Iris  pallida.  When  diluted,  it  possesses  an  intense  smell  of  violets. 
On  boiling  with  HI  and  P,  irone  splits  off  water  and  forms  irene, 
a  hydrated  naphthalene  hydrocarbon,  which  can  be  broken  up  by 
a  series  of  oxidations  into  dehydro-irene,  iregenone-di-  and  tri- 
carboxylic  acid,  ion-iregene-tricarboxylic  acid,  and  dimethyl-homo- 
phthalic  acid  : 


CH3CH3 

C     CH 

/\/\ 
HC      CH  CH >  HCO2C     CH 

II        II  II       I 

HC      CH  CO.CH3       HC      CH  C.CH3          HCO2C      CCO2H 


CH2CH3  CH2CH  CO  CH  HCO2CH 

Irone  Irene  Iregenone-  Dimethyl- 

tricarboxylic  acid      homo-phthalic 
acid. 

a-Ionone,  b.p.12  127°,  D20  0-9301,  and  /Monone,  b.p.10  127°,  D20 
0-9442  (Tiemann,  B.  26,  2691  ;  31,  808),  possess  an  intense  odour 
of  violets  closely  approaching  that  of  irone,  and  they  are  therefore 
made  on  a  large  scale.  Their  occurrence  in  the  vegetable  kingdom 
has  not  yet  been  established  with  certainty.  They  are  formed  by 
condensation  of  a-  and  j3-cyclo-citral  with  acetone  and  sodium  ethylate, 
or  by  inversion  of  pseudo-ionone  by  means  of  concentrated  sulphuric 
acid,  phosphoric  acid,  or  by  heating  with  aqueous  salt  solutions  to 
190°  under  pressure  (C.  1905,  I.  783). 

In  the  latter  case  we  obtain  a  mixture  of  various  quantities  of 


HYDRO-AROMATIC   CARBOXYLIC  ACIDS  469 

a-  and  jS-ionone,  the  formation  of  which  can  be  explained  by  the 
successive  attachment  and  rejection  of  water  : 

CH,  CH, 

H,C    NC.CH  :  CH.COCH, 
CH,  CH3  CH,  CH, 


HC       CH.CH  :  CH.COCH,  HSC       CH,.CH  :  CHCOCH, 


H,C       C.CH, 


CH, 


/3-Ionone 


CH,  CH, 

V 

I,C       CH.( 


H,C       CH.CH  :  CHCOCH, 

->  I       ! 

H.C       C.CH, 


H±C       C.CH,  H,C       C(OH).CH, 

CH,  CH, 

Pseudo-ionone  Pseudo-ionone  hydrate 


CH 

a-Ionone. 

The  pseudo-ionone  hydrate,  assumed  as  an  intermediate  product, 
has  been  isolated  (C.  1906,  II.  723).  The  constitution  of  the  two 
ionones  follows  from  their  decomposition  products  :  a-ionone  gives, 
on  oxidation,  j8j3-dimethyl-adipinic  acid  ;  j8-ionone  gives  aa-dimethyl- 
adipinic  acid. 

(7)  HYDRO-AROMATIC  CARBOXYLIC  ACIDS. 

Attached  to  the  hydro-aromatic  hydrocarbons,  alcohols,  amines, 
aldehydes,  and  ketones  are  numerous  hydro-aromatic  carboxylic  acids. 
In  addition  to  the  simple  carboxylic  acids,  oxy-  and  keto-carboxylic 
acids  are  also  known.  S/M&IWIC  and  quinic  acids  belong  to  the  first 
class,  while  in  the  second  class  we  find  succino-succinic  ester  and  other 
important  ketone-carboxylic  esters,  which  are  of  great  value  in  the 
synthesis  of  the  simple  hydro-aromatic  derivatives. 

i.  HYDRO-  AROMATIC  MONOCARBOXYLIC  ACIDS. 

A  direct  introduction  of  the  carboxyl  group  into  the  nucleus  of 
hydro-aromatic  substances  can  be  brought  about  by  the  action  of 
CO  2  upon  the  cyclo-hexyl-magnesium  haloids  : 

C.HUI  -^->  CeHnC02MgI  -J*U  C6HHC02H. 

But  the  transposition  of  halogen-cyclo-hexanes  with  KCN  or  Na 
malonic  ester  either  does  not  succeed  at  all,  or  is  uneconomic,  since 
cyclo-hexenes  are  mostly  formed  and  H  haloids  split  off  : 

1-Methyl-cyclo-hexane-l-carboxylicacid  m.p.  39°,  b.p.  234°    (B.  40,  2069) 

trans-Hexahydro-o-toluylic  acid  .  .  m.p.  51°.  b.p.  24l0lm  41  2679) 

cis-Hexahydro-o-toluylic  acid  .  .  liquid,  b.p.  236°  / 

Hexahydro-m-toluylic  acid  .  .  liquid,  b.p.  240° 

a-Hexahydro-p-toluylic  acid  .  .  m.p.  no0,  b.p.  246° 

/'-Hexahydro-p-tomylic  acid  .  .  liquid 

2,  4-Hexahydroxylylic  acid  .  .  m.p.  77°,  b.p.40  156° 

3,  4-Hexahydroxylylic  acid  .  .  liquid,  b.p.  251° 

2,  6-Hexahydroxylylic  acid  .         .      m.p.  72°.    b.p.     251° 

3,  5-Hexahydroxylylic  acid  .      liquid,         b.p.     139° 

Hexahydro-cuminic  acid       •         •       m.p.  96°. 


470  ORGANIC  CHEMISTRY 

Hexahydro  -  benzole      Acids,     hexamethylene  -  carboxylic      acids, 

naphthenic  acids,  have  been  obtained  by  the  reduction  of  boiling  amyl 
or  capryl  solutions  of  benzoic  acid  and  its  homologues  with  metallic 
sodium,  or  by  reducing  the  solution  of  sodium  benzoate  with  sodium 
in  an  atmosphere  of  CO2  (B.  24,  1865  ;  25,  3355).  So  far  as  present 
experience  warrants,  they  are  isomeric  and  not  identical  (B.  27,  R.  195, 
197)  with  the  "  natural  naphthenic  acids  "  occurring  in  the  oil  which 
issues  from  the  earth  in  and  about  Baku.  Just  as  fatty  acids  have  been 
prepared  from  malonic  acids,  so  hexamethylene-monocarboxylic  acids 
have  been  obtained  by  heating  hexamethylene- 1,  i-dicarboxylic  acids. 
The  latter  bodies  have  been  prepared  synthetically. 

The  hexamethylene-carboxylic  acids  are  weak  acids.  They  are 
reduced,  when  heated  with  hydriodic  acid,  to  hexahydro-aromatic 
hydrocarbons — naphthenes,  containing  a  like  number  of  C-atoms  in 
the  molecule.  Hence  they  are  also  designated  as  naphthenic  acids. 

Hexahydro-benzoic  acid,  naphthenic  acid  CeH^.COaH,  melting  at 
28°  and  boiling  at  232°,  results  from  the  reduction  of  benzoic  acid, 
A2-tetrahydro-benzoic  acid  (A.  271,  261),  p-dimethyl-amido-benzoic 
acid  (B.  27,  2829),  and  cyclo-hexanol-i -carboxylic  acid  (B.  27,  1231)  ; 
also  by  heating  hexamethylene- 1,  i-dicarboxylic  acid,  and  from  chloro-, 
bromo-,  and  iodo-cyclo-hexane  with  Mg  and  CO2  (B.  35,  2688).  The 
calcium  salt  (C7H11O2)2Ca+5H2O.  The  methyl  ester  boils  at  182°. 
The  ethyl  ester  boils  at  194°,  and  the  amide  melts  at  185°.  The  chloride 
boils  at  179°  (B.  30,  1941). 

The  acids  are  prepared  partly  by  the  reduction  of  the  corresponding 
benzol-carboxylic  acids,  and  partly  by  the  action  of  Mg  and  CO2  upon 
the  halogen-cyclo-hexanes.  Hexahydro-o-toluic  acid  is  formed  from 
2-methyl-cyclo-hexane-i,  i-acetyl-carboxylic  ester  and  I,  i-dicar- 
boxylic  ester.  The  liquid  cis-acid  has  been  obtained  by  reduction  of 
its  bromine  substitution  product.  The  liquid  p-hexahydro-toluic 
acid  has  been  obtained  from  tropilidene-carboxylic  acid  (/.  pr.  Ch.  2, 
57,  102  ;  B.  32,  1167  ;  C.  1899,  n-  387)- 

a-Monobromo-hexahydro-benzoic  acid,  melting  at  63°,  and  a-Mono- 
bromo-hexahydro-p-toluic  acid,  melting  at  71°,  are  produced  by  acting 
with  bromine  upon  the  chlorides  of  the  corresponding  hexahydro-acids. 
From  hexahydro-m-toluic  acid  two  isomeric  monobromo-derivatives 
are  obtained,  melting  at  118°  and  142°  respectively  (B.  32,  1167). 

a-Amido-hexahydro-benzoic  acids  have  been  obtained  by  action 
of  ammonium  cyanide  upon  cyclo-hexanones  and  saponification  of  the 
resulting  a-amido-acid  nitriles  (B.  41,  2925). 

a-Amido-hexahydro-benzoie  acid  C5H10>  C(NH2)COOH,  m.p.  335°. 

Hexahydro  -  anthranilic  acid,  o  -  amido  -  hexahydro  -  benzoic  acid 
NH2[2]C6H10.CO2H  melts  with  decomposition  at  274°.  It  is  formed 
along  with  pimelic  and  hexahydro-benzoic  acids  in  the  reduction  of 
anthranilic  acid  with  Na  and  amyl-alcohol  (B.  27,  2470  ;  A.  295,  187). 
Hexahydro-m-amido-benzoic  acid,  m.p.  269°,  ethyl  ester,  b.p.u  123°, 
from  m-amido-benzoic  acid  by  reduction  with  Na  and  ethyl-  or  amyl- 
alcohol,  together  with  other  bodies  (A.  319,  324).  Hexahydro-p- 
dimethyl-amido-benzoic  acid  (B.  27,  2831). 

Derivatives  of  o-amido-hexahydro-phenyl-acetic  acid  and  propionic 
acid  result  on  oxidising  dekahydro-quinolin  compounds  with  potassium 
permanganate. 


HYDRO-AROMATIC   MONOCARBOXYLIC  ACIDS        471 

(CH2.CH2 
Octohydro-carbostyril  caH10j         I       melting  at  151°,  is  poisonous 

(B.  27,  1472).  Numerous  further  amido-cyclo-hexane-carboxylic  acids 
have  been  obtained  from  the  oximes  of  the  cyclo-hexanone-  and  cyclo- 
hexenone-carboxylic  ester  by  reduction  with  Na  and  alcohol  (B.  40,  4167). 
trans-Die  thy  1-hexahydro-benzyl-amine-o-carboxylic  acid  (C2H5)2N 
CH2[2]C6H10COOH,  m.p.  101°,  from  o-diethyl-benzyl-amine-carboxylic 
acid,  by  reduction  with  sodium  and  amyl-alcohol.  By  heating  with 
alkalies  it  is  transposed  into  the  more  strongly  basic,  betain-like,  oily 
cis-acid,  which  is  easily  decomposed  into  diethyl-amine  and  o-methylol- 
hexahydro-benzoie  acid  HOCH2.C6H10COOH,  m.p.  112°.  This  latter 

<f*T_T     V 
CO/°    (A'    3°°' 

161). 

For  hexahydro-p-benzyl-amine-  and  p-diethyl-benzyl-amine-car- 
boxylic  acids,  see  A.  310,  189. 

Tetrahydro-benzoic  Acids  can  be  obtained  from  the  monoxy- 
and  monobromo-cyclo-hexane-carboxylic  acids  by  splitting  off  H2O 
or  HBr,  and  also  by  the  reduction  of  the  benzoic  acids  and  dihydro- 
benzoic  acids  (B.  26,  457). 

A^Tetrahydro-benzoie   acid   CH2<^22  ™2!/c-co2H.  m-P-  29°>  b-P- 

\V^/  il  2  •  V^  -H-  2 

240°,  is  formed  from  a-bromo-hexahydro-benzoic  acid  and  from  A4«6-di- 
hydro-benzoic  acid.  Also  from  A2-tetrahydro  benzoic  acid  by  boil- 
ing with  alcoholic  potash  (B.  33,  3455). 

A2-Tetrahydro-benzoic    acid,  benzolelnic  acid  C 


CO2H,  is  a  liquid  boiling  at  234°  (A.  271,  234  ;  B.  27,  2471).     It  is 
formed  from  benzoic  acid. 


A3-Tetrahydro-benzoic   acid   CH^??  "^  ^NaiCOOH,  m.p.   about 

\CH2  —  C/H.J/ 

13°,  b.p.  237°,  from  3-  and  4-bromo-cyclo-hexane-carboxylic  acid, 
and  by  the  action  of  CO2  and  Mg  upon  A3-bromo-cyclo-hexene  (C. 
1907,  I.  1408  ;  B.  43,  1039). 

Of  the  tetrahydro-toluic  acids,  the  following  seven  are  known,  which 
are  all  obtained  from  the  various  bromo-methyl-cyclo-hexane-car- 
boxylic  acids  by  HBr,  regenerative  by  means  of  quinolin,  pyridin,  etc.  : 

Ai-Tetrahydro-o-toluic  acid         CH2-CH2-—  C  CO2H      m'p>    87V 
A^Tetrahydro-m-toluic  acid         CH'-^CH^C  CO  H       liquid      b-p'"   I5°°'2 


A^etrahydro-m-toluicacid  ,         b.P. 


.20 


/^TT    . 

A3-Tetrahydro-m-toluic  acid        £H  _H  _^H2CO  H        »         b.p.100  185°.* 

A«-Tetrahydro-m-toluioacid        C^. 

k,  _,  CH,CH  —  CH2  --  CH 

A^Tetrahydro-p-toluic  acid         CH2—  CH2  __  C.CO2H       m>P-  I33 


1  C.  1905,  II.  766.  a  C.  1905,  II.  767.  3  C.  1907,  I.  1409.  *  C.  1909,  I.  172  ; 
6  C.  1905,  II.  767.  6  A.  880,  159  ;  C.  1906,  II.  342.  7  C.  1909,  I.  170. 


472  ORGANIC  CHEMISTRY 

The  A1-  and  A2-tetrahydro-p-toluic  acids  and  the  A2-tetrahydro- 
m-toluic  acid  have  been  split  up  into  their  optically  active  constituents 
by  means  of  their  brucin  and  strychnin  salts.  Starting  from  A2-tetra- 
hydro-m-toluic  acid,  sylvestrene  and  carvestrene  (q.v.)  have  been  built 
up,  and,  starting  from  A3-tetrahydro-toluic  acid,  a-terpineol  and  di- 
pentene  (see  below)  (Per  kin,  jun.).  A1-Tetrahydro-2,  6-xylylic  acid, 
m.p.  90°  (C.  1899,  II.  387). 

a  -  Cyclo  -  geranic    acid,    2,  6,  6-trimethyl-k?-tetrahydro-benzoic    acid 

CH2<\CH^C(CH33J2/CHC°2H'  m'p-  Io6°'  k'P'i1  I38°>  is  formed>  together 
with  the  isomeric  j3-cyelo-geranic  acid,  m.p.  94°,  from  geranic  acid  with 
concentrated  sulphuric  acid  ;  its  constitution  is  proved  by  its  disintegra- 
tion into  a-acetyl-dimethyl-adipinic  ester  acid,  and  j3/2-dimethyl-adi- 
pinic  acid  (B.  31,  828,  881  ;  33,  3713).  A3-Cyclo-geranie  acid,  2,  6,  6- 
trimethyl-k?-tetrahydro-benzoic  acid,  m.p.  (a)  76°,  (j8)  84°,  from  oxy- 
dihydro-cyclo-geranic  acid,  used  for  preparing  A3-cyclo-citral  (B.  41, 
2066).  From  the  cyano-hydrin  of  dihydro-iso-aceto-phorone  we  obtain 
by  saponification  and  elimination  of  H2O,  a  3,  3,  5-trimethyl-tetra- 
hydro-benzoic  acid,  m.p.  140°,  b.p.16  154°  (C.  1903,  1.  1245). 

Dihydro-benzoic  Acid  s.  —  A1-3-  Dihydro-benzoie  acid 
CH^™  -™  ^C.C02H,  m.p.  94°,  is  produced  in  the  oxidation  of 

dihydro-benzaldehyde,  boiling  at  I2i°-i22°,  with  silver  oxide.  A 
different  dihydro-benzoic  acid,  melting  at  73°,  is  obtained  from  A2- 
tetrahydro-benzoic  acid  dibromide  (B.  24,  2622).  Dihydro-cumie  acid, 
p-iso-propyl-dihydro-benzoic  acid  C6H6(C3H7)COOH,  m.p.  I3O°-I33°, 
is  formed  when  nopic  acid,  an  oxidation  product  of  j3-pinene,  is  boiled 
with  sulphuric  acid  (B.  29,  1926). 

Hexa-,  Tetra-,  and  Dihydro-phenyl  Aliphatic  Acids.  Hexa- 
hydro-phenyl-acetic  acid  C6HU.CH2.COOH,  m.p.  33°,  b.p.  244°,  from 
cyclo-hexyl-malonic  acid  or  from  hexahydro-benzyl  chloride  and  iodide 
with  Mg  and  CO2  (B.  40,  2067).  Hexahydro-phenyl-propionie  acid 
C6Hn.CH2.CH2COOH,  b.p.n  143°,  from  hexahydro-benzyl-malonic  acid. 
Amide,  m.p.  120°  (B.  41,  2676). 

Tetrahydro-phenyl  fatty  acids  are  formed  by  detaching  water  from 
the  corresponding  i,  i-cyclo-hexanol  fatty  acids,  or  their  esters,  ob- 
tained by  the  action  of  bromo-aliphatic  esters  and  zinc  upon  cyclo- 
hexanones.  According  to  the  dehydrating  agents  used,  whether  P2O5 
and  HKSO4  or  acetic  anhydride,  we  obtain  either  the  ring-unsaturated 
cyclo-hexene  fatty  acids  or  the  isomeric  cyclo-hexylidene  fatty  acids, 
with  semi-cyclic  double-binding  : 

/CH2—  CH2\  (CH,.co)2o          /CH2—  CH2\    /OH 

CH2\CH2-CH2/C  '  CH-CO*H  «-  CH2\CH2-CH2/C\CH2C02H 

S04HK  |  rw  /CH2—  CH  \ 


On  heating,  both  series  of  acids  split  off  CO2,  and  change  into  alkyli- 
dene-cyclo-hexanes  (A.  365,  255). 

From  the  easily  synthesised  cyclo-hexenones  we  immediately  obtain 
with  zinc  and  bromo-acetic  ester,  instead  of  oxy-acids,  cyclo-hexadiene- 
carboxylic  acids,  which  probably  contain  both  double  linkings  in  the 
ring,  and  which,  on  heating,  split  off  CO2  and  yield  dihydro-benzol 
derivatives  (A.  323,  136). 


HYDRO-AROMATIC   MONOCARBOXYLIC  ACIDS        473 

A^Cyelo-hexene-acetic  acid,  m.p.  38°,  on  oxidation  with  KMnO4, 
probably  forms  first  an  aldehyde-ketonic  acid  A^acetyl-cyclo-pentene 
(B.  42, 145),  and  then  A2-eyelo-hexene-aeetic  acid,  m.p.  12° ;  see  C.  1909, 
II.  2146.  4-Methyl-A1-cyclo-hexene-acetic  acid,  m.p.  42°  (C.  1909,  I. 
286).  A^Cyelo-hexene-iso-butyric  acid,  m.p.  72°. 

Cyclo-hexylidene-acetic  acid  (CH2)5  :  C  :  CH.CO2H,  m.p.  92°.  The 
4-methyl-eyclo-hexylidene-aeetic  acid,  m.p.  66°  (inactive),  has  a  special 
theoretical  interest,  since,  without  containing  an  unsym.  carbon  atom, 
it  can  be  split  up,  by  means  of  its  brucin  salts,  into  two  optically  active, 
mirror-isomeric  acids,  m.p.  52°,  [a]D=+8i°.  The  acids  owe  their 
optical  activity  to  the  existence  of  an  enantiotropic  molecular  structure. 
In  fact,  the  molecule  of  4-methyl-cyclo-hexylidene-acetic  acid, 

CH3\     /CH2— CH2\C C/H  CH3\r C/CH2— CH2\     ,-CH3 

HX     \CH2— CH,/  \CO2H         HCO2/  \CH2— CH2/       H     ' 

in  which  the  links  in  the  plane  of  the  paper  are  indicated  by  solid  lines, 
and  the  links  at  right  angles  to  the  paper  by  dotted  lines,  contains  no 
plane  of  symmetry  ;  in  other  words,  object  and  mirror  image  can  be 
brought  to  coincide  (A.  371, 180  ;  cp.  also  Vol.  I.). 

1, 3-Methyl-cyclo-hexadiene-acetie  acid  CH3C6H6CH2CO2H,  m.p. 
171°,  from  3-methyl-cyclo-hexenone. 

1,  3,  5-Dimethyl-cyclo-hexadiene-acetic  acid  (CH3)2C6H5CH2CO2H, 
m.p.  151°,  b.p.15  170°,  from  3,  5-dimethyl-cyclo-hexenone. 

Addendum. — Hexahydro-phenyl-acetylene-carboxylic  acids  : 

Hexahydro-phenyl-propiolie  acid  C6HnC  ;  C.CO2H,  b.p.16  139°,  from 
hexahydro-phenyl-acetylene  sodium  and  CO2  (C.  1909,  II.  208).  Hexa- 
hydro-phenyl-tetrolie  acid  C6Hn.CH2.C ;  CO2H,  m.p.  75°,  from  cyclo- 
hexyl-allylene  (C.  1910,  II.  387). 

Hexahydro  -  oxy-benzoic  A  cids. — a  -  Oxy  -  cyclo  -  hexane  -  carboxylic 
acid,  a-oxy-hexahydro-benzoic  acid,  cy do-he  xanol-i-carboxylic  acid 
CH2<^  2  2Nc<^  2  ,  melting  at  106°,  is  formed  when  cyclo- 

hexanone,  in  ether,  is  treated  with  prussic  and  hydrochloric  acids 
(C.  1909,  II.  1869).  a-Oxy-3-methyl-cyclo-hexane-carboxylic  acid, 
b.p.12  164° ;  see  C.  1907,  I.  1407.  2-,  3-,  and  4-Oxy-cyclo-hexane-car- 
boxylic  acids  are  formed  by  reduction  of  the  oxy-benzoic  acids  or  the 
cyclo-hexane-carboxylic  acids  with  sodium  and  alcohol.  They  usually 
occur  in  cis-trans-isomeric  forms,  out  of  which  the  cis-forms  of  3-  and 
4-oxy-cyclo-hexane-carboxylic  acids  pass  easily  into  lactones  with 
elimination  of  water. 

Hexahydro  -  salicylic  acid,  (j5-)  hexahydro -o- oxy-benzoic  acid 
CH2/CH2.CH(OH)\  CR  COaH)  m.p.  in0,  results  when  nitrous  acid  acts 


upon  hexahydro-anthranilic  acid  and  by  reducing  jS-keto-hexamethylene- 
carboxylic  ester  (B.  27,  2472,  2476). 

Hexahydro-m-oxy-benzoic  acid,  m.p.  cis-  132°,  trans-  120°,  is  ob- 
tained by  the  reduction  of  m-oxy-benzoic  acid  with  sodium  in  ethyl 
alcohol  (B.  29,  R.  549  ;  C.  1907,  I.  1408). 

Hexahydro-p-oxy-benzoie  acid,  m.p.  121°,  from  i,  4-cyclo-hexanone- 
carboxylic  acid  (C.  1904,  I.  1082). 

2-,  4-,  5-,  and  6-Methyl-3-oxy-eyclo-hexanone-carboxylie  acids  have 
been  obtained  from  the  corresponding  oxy-toluic  acids  (C.  1910, 1.  270). 


474  ORGANIC   CHEMISTRY 

3-Methyl-oxy-eyclo-hexane-carboxylic  acids,  cis-  m.p.  140°,  trans- 
m.p.  116°,  from  the  corresponding  ketonic  acids  (C.  1909,  I.  172). 

4-Methyl-4-oxy-cyclo-hexane-carboxylic  acids,  m.p.  153°,  lactone 
m.p.  70°,  from  i,  4-cyclo-hexanone-carboxylic  ester  and  CH3MgI  (C. 
1904,  I.  1604). 

Oxy-dihydro-cyclo-geranic  acid,  S-oxy-cyclo-geraniolane-carboxylic 
acid  CH(OH)/CH^H(CH3)\CH .co2H,  cis-  (a)  m.p.  145°,  trans-  (a) 

\U±12 — U(Uil3)2   / 

m.p.  155°,  lactone  m.p.  58°,  cis-  (j3)  m.p.  158°,  trans-  (]8)  m.p.  38°,  is 
formed  in  two  stereo-isomeric  pairs  each  by  reduction  of  iso-phorone- 
carboxylic  ester  with  Na  and  alcohol.  By  the  action  of  dehydrating 
agents,  all  of  these  pass,  more  or  less  easily,  into  A3-cyclo-geranic  acid 
(A.  366,  151). 

3, 5, 5-Trimethyl-hexahydro-salieylic  acid,  m.p.  180°,  b.p.10  204°, 
from  trimethyl-j8-keto-hexamethylene-carboxylic  acid  (C.  1903,  II.  78). 

Hexahydro-dioxy-benzoic  acid  is  obtained  from  AMetrahydro- 
benzoic  dibromide  (A.  271,  280). 

Dihydro-shikimic  acid,  hexahydro-trioxy-benzoic  acid  (HO)3C6H8. 
CO2H,  m.p.  175°,  results  when  shikimic  acid  is  reduced  with  sodium 
amalgam. 

Quinic  acid,  hexahydro-tetraoxy-benzoic  acid  (HO)4.C6H7.CO2H, 
m.p.  162°,  optically  active,  is  present  in  cinchona  bark,  in  coffee  beans, 
in  bilberry,  and,  in  small  quantities,  in  hay  and  sugar-beet.  It  is  ob- 
tained as  a  secondary  product  in  the  preparation  of  quinine,  by  ex- 
tracting the  quinia  bark.  When  its  calcium  salt  has  been  purified  by 
recrystallisation,  the  acid  is  liberated  by  oxalic  acid.  Upon  distilla- 
tion, the  acid  breaks  down  into  phenol,  hydroquinone,  benzoic  acid, 
and  salicyl-aldehyde.  When  boiled  with  water  and  lead  peroxide  it 
changes  to  hydroquinone,  while  manganese  peroxide  and  sulphuric 
acid  convert  it  into  quinone.  Proto-catechuic  acid  is  formed  when  it 
is  melted  with  caustic  potash  or  soda.  Ferments  decompose  calcium 
quinate  into  proto-catechuic  acid.  If  air  is  excluded  while  the  fermen- 
tation takes  place,  the  products  are  formic  acid,  acetic  acid,  and  pro- 
pionic  acid.  Quinic  acid  is  reduced  by  hydriodic  acid  to  benzoic  acid. 
The  calcium  salt  has  the  formula  (C7Hn06)2Ca+ioH2O.  The  methyl 
ester,  m.p.  120°.  Amide,  m.p.  132°.  Tetracetyl-ethyl  ester  C6H7 
(O.COCH3)4.CO2C2H5  melts  at  135°  (B.  22, 1462). 

Inactive  quinic  acid  is  produced  when  its  lactone,  quinide,  is  boiled 
with  milk  of  lime.  Calcium  salt  (C7H11O6)2Ca+4H2O. 

Quinide  C7H10O5,  m.p.  198°,  optically  inactive,  results  upon  heating 
ordinary  optically  active  quinic  acid  to  22O°-240°  (B.  24, 1296). 

Dioxy-dihydro-shikimic  acid,  hexahydro-pentaoxy-benzoic  acid 
(HO)5C6H6.CO2H,  melts  at  156°  with  the  elimination  of  water.  It  is 
optically  inactive,  and  is  obtained  from  the  bromo-lactone,  melting  at 
235°,  which  is  formed  in  the  action  of  baryta  water  (B.  24,  1294)  upon 
dibromo-shikimic  acid. 

Shikimic  acid,  trioxy-tetrahydro-benzoic  acid  (HO)3C6H6.CO2H, 
m.p.  184°,  occurs  in  the  fruit  of  Illicium  religiosum.  Its  transposition 
products,  dihydro-  and  dioxy-dihydro-shikimic  acids,  have  been 
previously  described. 

Hexahydro-oxy-phenyl  Fatty  Acids. — 1, 1-Cyclo-hexanol-aeetic  acid 
C$Hlo  :  C(OH).CH2CO2H,  m.p.  63°.  1,  4-Methyl-cyclo-hexanol-acetic 


HYDRO-AROMATIC   MONOCARBOXYLIC   ACIDS        475 

acid  CH3.C5H9  :  C(OH).CH2.CO2H,  a-acid,  m.p.  141°,  0-acid,  m.p.  90°. 
1,  4-Methyl-cyclo-hexanol-propionic  acid  CH3.C5H9 :  C(OH).CH(CH3). 
CO2H,  m.p.  110°.  These  esters  are  produced  by  condensation  of 
cyclo-hexanones  with  bromo-aliphatic  esters  and  zinc  (A.  360,  26 ;  365, 
261). 

Hexahydro-mandelic  acid  C6Hn.CH(OH).COOH,  m.p.  166°,  from 
hexahydro-phenyl-acetaldehyde-cyano-hydrin  (B.  41,  2677). 

Cyelo-hexyl-glycidic  esters  like  [CH2]5 :  C.O.CH.CO2C2H5,  b.p.17 128°, 

and  [CH2]5  :  C.O.(':(CH3)CO2C2H5,  b.p.^  155°,  are  formed  by  condensa- 
tion on  cyclo-hexanones  and  chloracetic  esters  or  chloro-propionic  ester 
with  sodium  ethylate. 

The  glycidic  acids  produced  by  saponification  easily  break  up  into 
CO2  and  aldehydes  or  ketones  (C.  1906,  I.  1423  ;  1907,  II.  332). 

Keto-hydro-monocarboxylic  Acids,  I,  2-cyclo-hexanone-carboxylic 
acids  and  their  esters  are  produced  (i)  by  cyclic  aceto-acetic-ester 
condensation  of  pimelinic  ester  and  its  alkyl-substitution  products  by 
means  of  sodium  (A.  317,  27)  ;  (2)  from  cyclo-hexanone  oxalic  esters, 
the  condensation  products  of  the  cyclo-hexanones  with  oxalic  ester, 
on  heating  with  rejection  of  carbon  monoxide  (A.  350,  211)  ;  (3)  by 
the  action  of  sodium  amide  and  CO2  upon  cyclo-hexanones  in  ether 
solution  (C.  1910,  II.  1378). 

1,  2-Cyelo-hexanone-earboxylic  acid  CH2<^*^°^>cH.CO2H,  m.p. 

80°,  with  rejection  of  CO2.  The  ethyl  ester  boils  at  107°  (n  mm.), 
and  is  formed  by  the  above  methods.  Like  the  j3-keto-pentamethylene- 
carboxylic  ester,  it  is  a  cyclic  analogue  of  aceto-acetic  ester.  It  is 
broken  up  by  dilute  sulphuric  acid  into  cyclo-hexanone,  and  by  boiling 
with  alcoholic  potash  into  pimelinic  acid.  With  sodium  alcoholate 
and  methyl  iodide  it  gives  1-methyl-l,  2-cyclo-hexanone-carboxylic 
ester,  b.p.  108°.  It  is  split  up  by  alcoholic  potash  to  a-methyl-pime- 
linic  acid  ;  with  ammonia  the  I,  2-cyclo-hexanone-carboxylic  ester 
produces  tetrahydro-anthranilic  ester  C6H8(NH2)CO2R,  m.p.  74°  (A. 
317,  93).  Special  interest  attaches  to  the  4-methyl-l,  2-cyclo-hexa- 
none-carboxylic ester  CH3.CH<^2~^2VHCO*C2H5>  b.p.13  123°,  from 

NL/xlj — L/U  / 

j3-methyl-pimelinic  ester  or  I,  3-methyl-cyclo-hexanone-oxalic  ester  ; 
with  sodium  and  iso-propyl  iodide  it  gives  4-methyl-l-iso^propyl-l,  2- 
cyclo-hexanone-carboxylic  ester  CH3CH<(^^^2)>c<(^  R  ,  b.p.14 

146°,  from  which,  by  saponification  with  dilute  sulphuric  acid,  methone 
is  formed  (A.  342,  198). 

3,  5,  5-Trimethyl-l,  2-cyclo-hexanone-carboxylic  acid,  m.p.  111° 
with  decomposition,  is  formed  from  dihydro-iso-aceto-phorone  by 
treatment  with  CO2  and  Na  in  ether  (C.  1902,  II.  1372). 

1,  3-Cyclo-hexanone-carboxylic  acid  CH2<(^°-™*\CH.coztt,  m.p. 

XL-rlj.Urlj/ 

74°,  from  tetrahydroxy-terephthalic  acid  by  heating  to  115°  or  by 
boiling  with  water,  or  by  oxidation  of  m-oxy-hexahydro-benzoic  acid 
in  the  form  of  its  ester  "with  sodium  bichromate  (B.  29,  R.  550  ;  C. 
1910,  I.  533). 

1,  4-Cyclo-hexanone-carboxylic  acid 


476  ORGANIC   CHEMISTRY 

m.p.  68°,  is  formed  synthetically  by  the  action  of  acetic  anhydride 
upon  a,  y,  €-pentane-tricarboxylic  acid  and  subsequent  distillation. 
The  acid  is  useful  as  a  starting-point  for  the  synthesis  of  a-terpineol 
and  dipentene  (C.  1904,  I.  1082).  3-Methyl-l,  4-cyclo-hexanone- 
carboxylic  acid,  m.p.  94° ;  see  C.  1909,  I.  172. 

Numerous  y-keto-carboxylic  acids  have  been  obtained  by  reducing 
the  corresponding  i,  4-cyclo-hexanone-carboxylic  esters  with  hydrogen 
and  colloidal  palladium  (B.  42,  1627).  2-Methy  1-1,  4-cyclo-hexanone- 
carboxylic  ethyl  ester,  b.p.15  128°,  dihydro-iso-phorone-carboxylic  ester, 
occurs  in  two  cis-trans-isomeric  forms  :  a-form,  m.p.  44°,  b.p.9  125°  ; 
/J-form,  liquid,  b.p.12  137°  ;  and  the  free  acids,  a-form,  m.p.  127°, 
j8-form,  m.p.  119°,  are  produced  by  oxidation  of  the  oxy-dihydro- 
cyclo-geranic  acids,  passing  into  the  trans-forms  of  these  acids,  by 
reduction  with  sodium  and  alcohol. 


1-Acetyl-cyclo-hexane-carboxylic  ester  ci 

b.p.  24i°-245°,  is  formed  from  i,  5-dibromo-pentane  and  sodium  aceto- 
acetic  ester  ;  on  boiling  with  alcoholic  potash  it  yields  hexahydro- 
aceto-phenone  (B.  40,  3945).  Similarly,  we  obtain  2-methyl-l-acetyl- 
cyclo-hexane-carboxylic  ester  from  i,  5-dibromo-hexane  and  sodium 
aceto-acetic  ester  (B.  21,  737). 

Hexahydro-benzoyl-acetic  ester  CpHij.CO.CH^COaCgHg,  b.p.18 136°, 
from  hexahydro-benzoic  ester,  acetic  este**  and  sodium  (C.  1908,  II. 
1687). 

Cyclo-hexyl-aceto-acetic  ester  C6HnCH(COCH3)CO2C2H5,  b.p.14 
126°,  obtained  in  small  quantities  from  iodo-cyclo-hexane  and  sodium- 
aceto-acetic  ester  (B.  42,  2232). 

A6  - 1,  2  -  Cyclo  -  hexenone  -  carboxylic  acid,  dihydro  -  salicylic  acid 
CH/^2— C0\c  C02H)  m.p.  128°,  its  ethyl  ester,  b.p.12  103 

\(_/.H.o — OAT.-/ 


cyclo-hexanone-carboxylic  ester  by  bromination  and  rejection  of  HBr 
from  a-bromo-i,  2-cyclo-hexanone-carboxylic  ester,  b.p.13  144°,  by 
boiling  with  aniline.  On  heating  with  soda-lime  the  acid  breaks  up 
into  CO2  and  A2-cyclo-hexanone  (/.  pr.  Ch.  2,  80,  495). 
AM,  4-Cyclo-hexenone-carboxylic  esters  like 


are  obtained  by  the  action  of  sodium  ethylate  upon  alkylidene-bis- 
aceto-acetic  ester  with  rejection  of  one  carboxyl  group.  They  contain 
the  group  of  glutaconic  ester  (Vol.  I.),  and  can  therefore,  like  the  latter, 
be  alkylated  with  sodium  alcoholate  and  alkyl  iodide.  The  esters  occur 
in  a  neutral  form  insoluble  in  alkali,  and  an  acid  form  soluble  in  alkali. 
By  means  of  sodium  ethylate,  the  former  may  be  transformed  into  the 
latter.  Reduction  with  hydrogen  and  colloidal  palladium  produces 
i,  4-cyclo-hexanone-carboxylic  esters.  The  cyclo-hexenone-carboxylic 
acids  easily  break  up  into  CO2  and  A2-cyclo-hexenones. 

2-Methyl-A2-l,4-cyclo-hexenone-carboxylie   ester 

C°<CH^>CH3C02.C2H6'  b'P'»  '55°.  from  methylene  iodide,  and 
sodium-aceto-acetic  ester,  or  by  the  action  of  sodium  ethylate  upon 
methylene-bis-aceto-acetic  ester  (B.  30,  639  ;  41,  2943)  ;  by  addition 
of  bromine  and  rejection  of  2HBr  it  yields  o-methyl-p-oxy-benzoic 
acid  (B.  38,  969). 

2,  6-Dimethyl-A2-l,  4-cyclo-hexenone-carboxylic  ester,  b.p.   140°, 


HYDRO-AROMATIC  DICARBOXYLIC  ACIDS  477 

from  ethylidene-bis-aceto-acetic  ester  (A.  342,  344).     Iso-phorone-car- 
boxylic  ester  co<(C^COtCtHtl  b.p.10  i36°-i40°,  is  formed 


by  attaching  sodium-aceto-acetic  ester  to  iso-propylidene-aceto-acetic 
ester.  On  saponification,  iso-phorone  is  produced  ;  and,  on  reduction 
with  sodium  and  alcohol,  a  mixture  of  various  isomeric  oxy-dihydro- 
cyclo-geranic  acids. 

4-Iso-propylidene-l,  2-cyelo-hexanone  -  carboxylie    ester 

*  2~  nas  been  obtained,  by  cyclic  aceto-acetic 


ester  condensation,  from  y-iso-propylidene-pimelinic  ester  (C.  1907,  II. 
1976). 

5,  5-Dimethy  1-A1-!,  3-cyclo-hexenone-acetic     ester 

b.p.22  I7I..  see  C.  I909,  I.  853. 


2.  HYDRO-AROMATIC  DICARBOXYLIC  ACIDS. 

Hexahydro-dicarboxylic  Acids.  —  These  acids,  depending  upon  the 
position  of  the  carboxyl  groups  with  reference  to  one  another,  show  the 
behaviour  of  dialkyl-malonic  acids,  sym.  dialkyl-succinic  acids,  sym. 
a-dialkyl-glutaric  acids,  and  sym.  a-dialkyl-adipic  acids. 

1,  1-Dicarboxylic  ester  and  2-methyl-cyclo-hexane-l,  1-dicarboxylic 
ester  have  been  made  by  the  action  of  sodium-malonic  ester  upon 
pentamethylene  bromide  and  methyl-pentamethylene  bromide.  The 
free  acids,  when  heated,  split  off  CO2  and  become  hexahydro-benzoic 
acid  and  hexahydro-o-toluic  acid.  2-Methyl-eyclo-hexane-l,  1-dicar- 

boxylic acid  CH,<^^^^^>C(COtH)tmeltsati4^e.     Cyclo-hexane- 

dicarboxylic  acid  and  its  esters  appear  not  to  have  been  isolated  as  yet 
(B.  21,  735  ;  26,  2246). 

Cyclo-hexane-malonic  acid  ethyl  ester  C6Hn.CH(CO2C2H5)2,  b.p.20 
164°,  and  cyclo-hexyl-cyanic  acid  ester,  b.p.23  158°,  are  obtained  in 
small  quantity  from  bromo-  and  iodo-cyclo-hexane  with  sodium-malonic 
ester  and  cyan-acetic  ester  respectively. 

Cyclo-hexyl-malonic  acid,  m.p.  177°,  breaks  up,  on  heating,  into 
CO2  and  hexahydro-phenyl-acetic  acid  (C.  1905,  II.  1430).  Hexahydro- 
benzyl-malonic  ester  C6Hn.CH2.CH(CO2C2H6)2,  b.p.12  i45°-i55°. 

Hexahydro-phthalic  Acids.  —  A.  Baeyer's  theory  (B.  23,  R.  577), 
based  upon  the  spatial  representations  of  van  Hoff  as  to  the  union  of 
the  C  atoms,  predicts  the  possibility  of  geometrically  isomeric  hexa- 
hydro-phthalic  acids.  The  latter  isomerism  is  due  to  the  different 
positions  occupied  by  the  carboxyls  relatively  to  the  plane  of  the 
hexamethylene  ring  ;  hence  the  isomerides  are  termed  cis-  and  trans- 
forms. 

eis-Hexahydro-o-phthalic  acid,  i,  z-hexamethylene-dicarboxylic  acid 
C6H10(CO2H2)  melts  at  192°,  and  its  anhydride  melts  at  32°  and  boils 
at  145°  (18  mm.)  ;  the  trans-hexahydro-o-phthalie  acid  melts  at  215°, 
and  its  anhydride  at  140°.  They  are  produced  together  when  A1-tetra- 
hydro-o-phthalic  acid  is  reduced.  The  trans-acid  is  also  obtained  by 
the  oxidation  of  o-methylol-hexahydro-benzoic  acid.  The  cis-acid  is 
more  soluble  in  water  than  the  trans-acid.  The  anhydride  of  the  latter 
is  converted  by  continuous  heating  at  2io°-220°  into  the  anhydride  of 


478  ORGANIC  CHEMISTRY 

the  cis-acid  (A.  258,  214).  The  trans-acid  has  been  broken  up  by 
means  of  its  quinine  salt  into  optically  active  components,  d-  and 
1-trans-hexahydro-phthalic  acid  [a]D2-hi8-2°  and  —18-5°,  m.p.  179°- 
183°.  Anhydride,  m.p.  164°  (B.  32,  3046). 

Hexahydro-iso-phthalie  acids  are  produced  in  the  reduction  of  iso- 
phthalic  acid  and  when  I,  I  ,3,  3-hexamethylene-tetracarboxylic  acid 
is  heated  to  200°-22O°.  The  calcium  salt  of  the  cis-acid  is  more 
sparingly  soluble.  The  cis-acid,  melting  at  162°,  when  heated  to  180° 
with  hydrochloric  acid,  changes  in  part  to  the  trans-acid,  melting  at 
1  88°.  Both  acids,  with  acetyl  chloride,  yield  the  acid  anhydride, 
melting  at  119°  (B.  26,  R.  721). 

Hexahydro-terephthalic  acids  result  on  reducing  the  hydro-bromides 
of  the  tetrahydro-terephthalic  acids  in  glacial  acetic  acid  with  zinc 
dust,  as  well  as  upon  heating  hexamethylene-i,  i,  4,  4-tetracar  boxy  lie 
acid  to  200°-220°.  In  the  latter  case  the  trans-acid,  melting  at  200°, 
predominates.  The  cis-acid,  melting  at  161°,  is  also  converted  into 
it  when  heated  with  hydrochloric  acid  to  180°.  As  regards  solubility, 
these  three  pairs  of  hexahydro-phthalic  acids  reduce  fumaric  and 
maleic  acids.  They  are  also  convertible  one  into  the  other  in  like 
manner.  They  have  also  been  distinguished,  one  from  the  other,  as 
malelnold  and  fumaroid  modifications. 

a-Bromo-substitution  products  of  these  acids  have  also  been 
prepared  from  the  acid  chlorides,  by  treatment  with  bromine.  Bromo- 
substituted  hexahydro-carboxylic  acids  have  also  been  obtained  by  the 
addition  of  hydrogen  bromide  and  bromine  to  the  corresponding  tetra- 
and  dihydro-carboxylic  acids. 

Hexahydro-homo-iso-phthalie  acid  C6Hiq[i,  3](COOH)(CH2COOH), 
m.p.  158°,  by  reduction  of  homo-iso-phthalic  acid,  gives,  on  distilling 


its   calcium   salt,    a   dicyclic   ketone   CH22.^^-         ^.   cp 

Nv^Jtio'^-tjL  -  V-/-H.O 

camphor  (B.  36,  3610). 

Tetrahydro  -  diearboxylic  Acids,  Tetrahydro-o-phthalic  Acids  — 
Depending  upon  the  point  of  double  union  there  are,  theoretically 
speaking,  four  structurally  isomeric  bodies.  The  two  modifications  in 
which  neither  of  the  two  CO2H-groups  is  attached  to  a  doubly  com- 
bined C  atom  permit  of  a  stereo-isomeric  modification  of  each. 

CH2.CH2.C.CO2H 

A^Tetrahydro-o-phthalic    acid    I  ,  melting  at   120°, 

CH2.CH2.C.C02H 

and  its  anhydride  at  74°,  is  formed  when  hydro-pyro-mellitic  acid  is 
distilled.  Potassium  permanganate  decomposes  it  into  adipic  acid 
(A.  166,  346;  258,  203). 

/-»TT    /~>TT  _  -p  PO  TT 

A2-Tetrahydro-o-phthalic  acid   \    *'         ~  \'     *      ,  melting  at  21  5°, 

CH2-CH2—  CH.C02H 

and  its  anhydride  at  78°,  has  been  obtained  by  the  decomposition  of 
sedanonic  acid,  an  o-valeryl-tetrahydro-benzoic  acid  obtained  from 
celery  oil  (B.  30,  503).  It  is  also  formed  on  boiling  the  A*-acid  with 
caustic  potash,  when  the  double  union  is  shifted,  and  by  the  reduction 
of  phthalic  acid  or  A2'6-dihydro-phthalic  acid  together  with  trans-A4- 

^   CH—  CH2—  CH.C02H 
tetrahydro-o-phthalie  acid  ||  |          '   ,  melting  at  216°,  and 

CH  .  CH2  .  CH.C02H 
its  anhydride  at    140°.     Acetyl  chloride  separates  it  from   A2-acid. 


HYDRO-AROMATIC  DICARBOXYLIC  ACIDS  479 

This  reagent  converts  it  alone  into  its  corresponding  anhydride 
(A.  258,  211). 

cis-A4-Tetrahydro-o-phthalic  acid  melts  at  174°.  It  is  produced 
when  the  A2'4-dihydro-acid  is  reduced,  as  well  as  from  its  anhydride, 
melting  at  58°.  The  latter  anhydride  is  formed  when  the  anhydride 
of  the  trans-  A4-acid  is  heated  (A.  269,  202). 

Tetrahydro-iso-phthalie  Acids.  —  The  three  theoretically  possible 
structure-isomeric  acids  are  all  known,  one  of  them  even  occurring  in 
a  stereo-isomeric  modification  (C.  1905,  I.  1320  ;  II.  474). 


A^A^Tetrahydro-iso-phthalic  acid  2^ZH~Cii2'  m'p- 
1  68°,  is  obtained  by  the  reduction  of  iso-phthalic  acid  with  sodium 
amalgam  at  45°.  Its  anhydride,  m.p.  78°,  is  also  formed  from  the 
A3-  and  A4-acid  by  heating  with  acetic  anhydride. 

A3-Tetrahydro-iso-phthalic  acid  H°2C  '^^z~  ^C°2  'H>  m-P-  244°, 
from  the  A2-  and  A4-acid  on  boiling  with  concentrated  potash. 

cis-A4-Tetrahydro-iso-phthalic  acid  H°aC  '£^3^—  CHC°2H'  m'p' 
165°,  is  formed  together  with  the  A2-acid  by  reducing  iso-phthalic  acid 
with  sodium  amalgam.  On  heating  with  HC1  to  170°,  it  is  converted 
into  trans-AMetrahydro-iso-phthalic  acid,  m.p.  226°. 

Tetrahydro-terephthalic  Acids  are  theoretically  possible  in  two 
structurally  isomeric  forms,  depending  upon  the  position  of  the  double 
union  ;  one  of  these  can  occur  in  two  stereo-isomeric  modifications. 

A2-Tetrahydro-terephthalic   acid   CO.H.CH/^  \CH.co2.H   is 


produced  in  two  isomeric  modifications  by  the  reduction  of  A1'3- 
and  A1'5-dihydro-terephthalic  acids.  The  trans-acid  melts  at  about 
300°.  The  cis-acid  melts  at  150°.  The  latter  is  much  more  readily 
soluble  in  water  than  the  former.  Potassium  permanganate  oxidises 
them  to  succinic  acid.  Boiling  sodium  hydrate  changes  the  two  acids, 
like  /?y-hydro-muconic  acid,  into  ajS-hydro-muconic  acid. 

A^Tetrahydro-terephthalic  acid  co2H.CH/™2—  CE  V.CO2H  melts 

\CH2  —  CH2/ 

above  300°  and  sublimes  (A.  258,  7). 

Dihydro-dicarboxylic  Acids.  —  Dihydro-o-phthalic  acids  are  possible, 
according  to  the  position  of  the  double  union,  in  six  structurally  isomeric 
forms,  one  of  which  can  occur  in  two  stereo-isomeric  modifications. 

CH.CH2.C.CO2H 

A1'4-Dihydro-o-phthalic   acid    ||  ,  melting  at  153°   (its 

CH.CH2.C.CO2H 

anhydride  at  134°),  is  produced  on  boiling  A2»4-dihydro-phthalic 
acid  with  acetic  anhydride  (A.  269,  204). 

CH.CH2.CH.CO2H 

A2-4-Dihydro-o  -  phthalic  acid  \\  ,  melting  at  179°  (its 

CH.CH.C  .  C02H 

anhydride  at  103°),  is  produced  when  the  acid  is  acted  upon  in 
the  cold  with  acetic  anhydride. 

The  acid  is  produced,  further,  on  boiling  A2j6-dihydro-o-phthalic 
acid  dihydro-bromide  with  methyl-alcoholic  potash. 

C"T~f    fT-f  •  C  CO  TT 

A2'6-Dihydro-o-phthalic  acid    I  melts  at  215°,  and 

CH2.CH  :  C.C02H 
its  anhydride  at  83°.     The  acid  results  by  reducing  phthalic  anhydride 


480  ORGANIC   CHEMISTRY 

with  sodium  amalgam  in  alkaline  solution,  and  by  boiling  the  A2-4-  and 
A3»5-acid  with  sodium  hydrate  (see  also  B.  27,  3185). 

CH  :  CH.CH.CO2H 

trans-A3'5-Dihydro-phthalic  acid    I  ,  melting  at  210°. 

CH  :  CH.CH.C02H 

is  produced  by  reducing  phthalic  anhydride  with  sodium  amalgam  in 
acetic  acid  solution.  The  acid  has  been  split  up  into  its  optically 
active  components  by  means  of  its  strychnin  salt.  On  passing  into 
the  A2)6-acid  by  boiling  with  sodium  hydrate,  or  into  the  cis-A3>5-acid 
by  heating  with  acetic  anhydride,  the  optical  activity  disappears,  the 
resulting  acids  containing  no  unsym.  carbon  atom  (C.  1907,  I.  565). 

cis-A3>5-Dihydro-phthalie  acid  melts  at  174°.  Its  anhydride,  melt- 
ing at  99°,  is  formed  when  the  trans-A3«5-acid  is  acted  upon  with  acetic 
anhydride. 

Dihydro-terephthalic  Acids.  —  Depending  upon  the  points  of  double 
union,  there  are  four  possible  structural  isomerides.  One  of  these,  the 
A2«5-acid,  appears  in  two  stereo-isomeric  forms.  All  the  modifications 
are  known. 

A^-Dihydro-terephthalie    acid    COZH.C<^H  -C^:  \c.Co2H    is  pro- 

\L/rl2.Orl2/ 

duced  on  digesting  a,  c^-dibromo-hexahydro-terephthalic  acid  and 
A2-tetrahydro-terephthalic  acid  dibromide  with  alcoholic  potash 
(A.  258,  23).  The  dimethyl  ester  melts  at  85°. 

A^-Dihydro-terephthalic  acid  CO2H.c<^H.c^\c  CO2H   is  formed 

by  reducing  terephthalic  acid  with  sodium  amalgam,  by  boiling  the 
isomeric  dihydro-terephthalic  acids  with  sodium  hydrate  (A.  251,  272), 
and  by  reducing  p-dichloro-A1>4-dihydro-terephthalic  acid,  the  result 
of  the  action  of  PC16  upon  succinyl-succinic  ester,  with  sodium  amalgam 
(B.  22,  2122). 

The  dimethyl  ester  melts  at  130°.  It  condenses  by  means  of  its 
CH2  groups  with  oxalic  ester  and  with  benzaldehydes  in  the  presence 
of  sodium  alcoholate  to  terephthalic  acid  derivatives  :  phthalide-dicar- 
boxylic  acid,  the  lactone  of  the  acid  (HOOC)2C6H3CH(OH)COOH,  and 
benzyl-terephthalic  acid  (HOOC)2C6H3CH2C6H3  (B.  36,  842). 

A1'5-Dihydro-terephthalie  acid  results  on  boiling  trans-A2'5-dihydro- 
terephthalic  acid  with  sodium  hydroxide  ;  the  dimethyl  ester  resinifies 
on  exposure  to  the  air  (A.  258,  18). 

A2'5-Dihydro-terephthalie    acids    co2H.CH/™  :  ^\CH.CO,H,    cis- 


acid  and  trans-acid,  are  formed  in  the  reduction  of  terephthalic  acid. 
See  also  A1»5-dihydro-terephthalic  acid.  The  trans-diphenyl  ester  melts 
at  146°.  The  cis-dimethyl  ester  melts  at  77°  (A.  258,  17).  This  ester 
breaks  up  into  terephthalic  and  hexahydro-terephthalic  esters,  on 
heating  in  a  CO2  atmosphere  in  the  presence  of  palladium  black 
(B.  36,  2857). 

Oxy-   and    k  e  t  o  -  h  y  d  r  o  -  benzol  -  dicarboxylic    Acids.  —  a-Oxy- 

hexahydro-iso-  phthalic  acid  c^^^)^<^   is  obtained 
from  m-keto-hexahydro-benzoic   acid  by  the  action  of  prussic   acid 
and  hydrochloric  acid  (B.  22,  2186  ;   C.  1904,  I.  1082). 
m-Dioxy-hexahydro-iso-phthalie    acid    CH2/ 

\v 


HYDRO-AROMATIC  DICARBOXYLIC  ACIDS  481 

melts  with  decomposition  at  217°.  Its  anhydride  melts  at  175°.  The 
acid  is  obtained  from  its  nitrile,  the  product  of  the  addition  of  prussic 
acid  to  dihydro-resorcinol  (A.  278,  49). 

a,  a^Dioxy-hexahydro-terephthalic  acid 

is  formed  when  its  dinitrile,  melting  with  decomposition  at  180°,  is 
boiled.  This  dinitrile  results  on  adding  prussic  acid  to  p-diketo-hexa- 
methylene  with  hydrochloric  acid  (B.  22,  2176). 

Hexahydro-2,5-dioxy-terephthalie  acid  C6H8(OH)2(COOH)2,  ethyl 
ester,  m.p.  136°,  formed  besides  tetrahydro-p-dioxy-terephthalie  acid, 
ester,  b.p.14  219°,  by  reduction  of  succinyl-succinic  ester  with  sodium 
amalgam.  The  dioxy-hexahydro-terephthalic  ester,  on  distillation, 
partly  splits  off  H2O  and  passes  into  A1'4-dihydro-terephthalic  acid 
ester  (B.  33,  390). 

A1-Tetrahydro-2-oxy-terephthalic  acid,  or  2-keto-hexamethylene-i,  4- 
dicarboxylic  acid 

.CO.H,  or  C 

results  from  the  reduction  of  oxy-terephthalic  acid.  When  heated  to 
60°  with  water,  it  splits  off  carbon  dioxide  and  becomes  m-keto-hexa- 
hydro-benzoic  acid,  the  oxime  of  which  is  obtained  from  tetrahydro- 
oxy-terephthalic  acid  by  means  of  hydroxylamine  hydrochloride 
(B.  22,  2187). 

Keto-tetrahydro-benzol-polycarboxylic  esters  and  m-diketo-hexahydro- 
benzol-carboxylic  esters,  or  hydro-resorcylic  esters,  have  been  prepared 
synthetically  in  great  numbers  from  I,  5-diketone-  and  S-ketone- 
carboxylic  esters,  respectively,  by  the  elimination  of  water  or  of  alcohol. 
A  series  of  keto-R-hexenes,  dihydro-resorcins,  tetrahydro-benzols, 
dihydro-benzols,  etc.,  has  been  built  up  from  these  bodies  as  the 
foundation  substances. 

Several  alkylidene-bis-aceto-acetic  esters  are  to  be  regarded  as 
cyclo-hexanolone-dicarboxylic  esters. 

Cyelo-hexanone-2,  4-dicarboxylic     ethyl     ester 

,  ,-tricar- 


boxylic  ester  by  cyclic  aceto-acetic  ester  condensation  (C.  1907,  I.  344). 
Cyelo-hexanone-2,  6-dicarboxylic    methyl    ester 

CH2/^;H2—  CH>cc£°2™3,  keto-form  melting  at  125°,  enol-form  liquid 

\CH2  —  CH  -  CO2Cri3 

from  pentane-cu-tetracarboxylic  ester,  with  sodium  ethylate  and  elimi 
nation  of  carbonic  acid  ester   (H.  Meerwein).     2-Methyl-cyclo-hexa- 
none-2,  6-dicarboxylic  ethyl  ester,  b.p.10  160°,  see  A.  350,  214. 

Succino-succinic  acid   co2H.CH/^.CH2\CH  COaH    results   upon 

\UH2.CU/ 

saponifying  its  diethyl  ester  with  a  calculated  amount  of  normal 
sodium  hydroxide,  and  by  treating  2,  5-dioxy-terephthalic  ester  with 
sodium  amalgam.  The  dry  acid  breaks  down  into  two  molecules  of 
carbon  dioxide  and  p-diketo-hexamethylene  when  heated  to  200° 
(B.  22,  2168). 

Succino-succinic  diethyl  ester,  m.p.  126°,  is  produced  by  the  con- 
densation of  two  molecules  of  succinic  ester  through  the  action  of 
potassium,  sodium,  or  sodium  ethylate  upon  succinic  ester  (A.  211, 
VOL.  II.  2  I 


482  ORGANIC   CHEMISTRY 

306)  or  bromaceto-acetic  ester  (A.  245,  74),  as  well  as  by  the  interaction 
of  silver  cyanide  and  iodo-aceto-acetic  ester  (A.  253,  182),  and  by  the 
reduction  of  2,  5-dioxy-terephthalic  ester  with  zinc  and  hydrochloric 
acid  (B.  19,  432). 

Succino-succinic  ester  behaves  like  phloro-glucin.  It  also  mani- 
fests many  reactions  of  a  ketone,  corresponding  to  formula  I.  of  2,  5- 
diketo-hexamethylene-carboxylic  ester  ;  whereas  it  also  conducts 
itself  like  a  phenol,  corresponding  then  to  formula  II.  of  2,  5-dioxy- 
dihydro-terephthalic  acid  (B.  24,  2692)  : 

I.  C02.C2 

IL  CO-C 

The  ester  crystallises  in  bright-green  triclinic  prisms,  or  colourless 
needles.  It  is  insoluble  in  water,  dissolves  with  difficulty  in  ether, 
very  readily  in  alcohol  ;  its  solution  shows  a  bright-blue  fluorescence. 
Ferric  chloride  imparts  a  cherry-red  colour  to  it.  It  dissolves  in 
alkalies  with  a  yellow  colour,  yielding  metallic  derivatives  by  the 
replacement  of  two  hydrogen  atoms.  It  does  not  unite  with  phenyl 
iso-cyanate,  whereas  the  structurally  similar  jS-keto-hexamethylene- 

carboxylic  ester  combines  with  it  to  form  CH.™ 


(A.  317,  104). 

With  hydroxylamine  (in  alkaline  or  acid  solution)  succino-succinic 
ester  splits  off  CO2  and  yields  quinone-dioxime-carboxylie  ester 
C6H3(N.OH)2.CO2R,  melting  at  174°  (B.  22,  1283). 

With  phenyl-hydrazin  it  forms  a  phenyl-hydrazin  derivative  of 
dihydro-terephthalic  acid  (B.  24,  2687  ;  26,  R.  590),  while  with  hydrazin 
it  yields  hexahydro-benzo-3,  ^-dipyrazolone  (q.v.)  (B.  27,  472)  ;  with 
Am  acetate,  di-imino-succino-succinic  ester,  m.p.  178°,  which  is  oxidised 
by  Br  to  p-diamido-terephthalic  ester  (C.  1905,  II.  1240). 

If  sodium-succino-succinic  diethyl  ester  be  treated  with  alkylene 
iodide,  it  yields  the  following  compounds  : 

Diethyl-succino-suecinic  ester  :  m-body  is  liquid  ;  trans-body  melts 

at  65°. 
Di-n-propyl-suecino-succinie  ester  :   cis-body  is  liquid  ;   trans-body 

melts  at  86°. 
Di-iso-propyl-sueeino-suceinie   ester  :    cis-body   is   liquid  ;    trans- 

body  melts  at  116°. 
Methyl-n-  and  methyl-iso-propyl-suceino-suceinic  ester  boil  at  195°- 

200°  (25  mm.). 

p-Dichloro-hydroquinone-dicarboxylie  ester  C6C12O2(CO2C2H5)2, 
melting  at  195°,  consists  of  yellowish-green  crystals  (B.  21,  1761). 
When  reduced  with  zinc  dust  and  glacial  acetic  acid,  it  becomes  p-di- 
ehloro-hydroquinone-dicarboxylie  ester  C6C12H2O2(C02C2H5)2,  crystal- 
lising in  two  different  forms  —  colourless  needles  and  yellow-green 
plates  (B.  20,  2796  ;  21,  1759  ;  23,  260).  Similar  behaviour  is  shown 
by  dibromo-  and  di-iodo-hydroquinone-dicarboxylic  esters  (B.  32,  1742). 
Compare  the  two  forms  of  2,  5-dioxy-terephthalic  ester. 

p-Dioxy-quinone-dlcarboxylic  ester  C602(OH)2(CO2C2H5)2,  melting 


HYDRO-BENZOL-TRICARBOXYLIC  ACIDS  483 

at  151°,  may  be  prepared  by  shaking  dichloro-hydroquinone-dicarboxylic 
ester  with  sodium  hydroxide,  and  by  the  action  of  nitrous  acid  upon 
dioxy-terephthalic  ester  (B.  19,  2385).  It  crystallises  in  pale-yellow 
flakes  and  intense  greenish-yellow  prisms  (B.  20,  1307).  It  reacts  acid, 
and  forms  salts  with  two  equivalents  of  the  metals.  It  does  not  form 
a  dioxime  with  hydroxylamine,  but  an  oxy-ammonium  salt,  and  with 
phenyl-hydrazin  a  phenyl-hydrazin  salt  (B.  22,  1290).  Further- 
more, it  does  not  react  with  phenyl  iso-cyanate  (B.  23,  265).  Boiling 
hydrochloric  acid  decomposes  the  ester  into  carbon  dioxide  and  dioxy- 
quinone.  By  the  absorption  of  two  atoms  of  hydrogen  (by  reduction 
with  sulphurous  acid)  the  ester  becomes  : 

Tetroxy-terephthalie  ester  C6(OH)4(CO2R2),  or  dioxy-quinone-di- 
hydro-carboxylie  ester  C6H2(O2)(OH)2(CO2R)2.  It  crystallises  in 
golden-yellow  flakes,  and  melts  at  178°  (B.  20,  2798).  Its  alkaline 
solution  oxidises  on  exposure  to  the  air  (giving  up  two  hydrogen  atoms) 
to  dioxy-quinone-dicarboxylic  ester  ;  hence  it  yields  the  same  products 
with  hydroxylamine  and  phenyl-hydrazin  (B.  22,  1291).  It  forms  a 
tetracarbanilido-derivative  (B.  23,  267)  with  four  molecules  of  phenyl 
iso-cyanate. 

Phloro  -  gluein  -  diearboxylie  ester  ^Z5     CO'  m'p' 


104°,  is  formed  by  the  condensation  of  three  molecules  sodium-malonic 
acid  ester  on  heating  to  I2O°-I45°,  with  rejection  of  carbonic  acid  ester, 
with  acetone-tricarboxylic  ester  as  an  intermediate  product  ;  also  by 
the  condensation  of  acetone-dicarboxylic  ester  and  malonic  ester  with 
sodium  ethylate  (B.  29,  R.  1117  ;  41,  4171).  It  behaves  like  succino- 
succinic  ester,  dissolves  without  change  in  alkalies,  and  is  coloured  a 
cherry-red  by  ferric  chloride.  With  acetic  anhydride  it  forms  a  tri- 
acetyl  derivative  with  hydroxylamine  or  trioxime  (B.  21,  176),  with 
phenyl  iso-cyanate  or  tricarbanilido-derivative  (B.  37,  4637).  Fused 
with  caustic  potash,  it  forms  phloro-glucin. 

3.  HYDRO-BENZOL-TRICARBOXYLIC  ACIDS. 

Among  these  we  have  the  dioxy-phenyl-aeetic-dicarboxylie  esters 
C02RCH/<;    C(C02R)VCH2C02R,   condensation   products   of    acetone- 

\Lx(J.  \^t±2  -  / 

diearboxylie  ester  (C.  1900,  II.  963),  and  the  analogous  — 

Dihydro-oxy-phenyl-aeetic-diearboxylie       ester 

.H..    m.p.   82°,    obtained    by 


condensing  glutaconic  ester  by  means  of  sodium  ethylate  free  from 
alcohol  (B.  37,  2113). 

Dlhydro-methyl-trimesime    acid    CH/WHHCH         fa 


formed  from  pyro-racemic  acid  by  heating  with  sodium  hydroxide. 
The  acid  is  the  intermediate  product  of  the  synthesis  of  uvitinic  acid 
with  pyro-racemic  acid.  On  heating  with  concentrated  sulphuric  acid 
it  splits  off  CO  2  and  2H,  and  passes  completely  into  uvitinic  acid  ;  on 
fusing  it  yields  uvitinic  acid  besides  dihydro-uvitinie  acid  C6H5(CH3) 
(COOH)2,  m.p.  236°,  and  several  tetrahydro-uvitinic  acids.  On  reduc- 
tion with  Na  amalgam  we  obtain  tetrahydro-methyl-trimesinic  acid 
C6H6(CH3)(COOH)3,  m.p.  221°  -with  decomposition  (A.  305  125). 


484  ORGANIC  CHEMISTRY 

4.  HYDRO-BENZOL-TETRACARBOXYLIC  ACIDS. 

Acids  having  two  carboxyl  groups  attached  to  the  same  carbon 
atom  have  been  obtained  synthetically  in  the  action  of  trimethylene 
bromide  upon  the  disodium  compound  of  methylene-dimalonic  ester, 
as  well  as  from  the  interaction  of  methylene  iodide  and  disodium- 
trimethylene-dimalonic  ester  :  hexamethylene-i,  i,  3,  3-tetracarboxylic 
ester,  and  from  n-butane-tetracarboxylic  ester  with  ethylene  bromide  : 
hexamethylene-i,  i,  4,  4-tetracarboxylic  ester  (Perkin,  jun.)  : 
(C02C2H5)2  (C02C2H5)2 


(C02.C2H5)2  (C02.C2H5)2. 

1,  1,  3,  3-Hexamethylene-tetraearboxylic  acid  decomposes  at  220° 
with  the  elimination  of  2CO2  into  hexahydro-iso-phthalic  acid  (B.  25, 
R.  159,  274). 

Terpenes. 

The  volatile  or  ethereal  oils,  obtained  mostly  by  the  distillation  of 
various  plants  (chiefly  Coniferae  and  Citrus  species)  with  steam,  more 
rarely  by  pressing  them,  or  by  extraction  with  volatile  solvents  or 
fats,  contain,  along  with  different  compounds,  certain  hydrocarbons 
having  the  formula  C10H16,  which  are  called  terpenes. 

Terpenes  C10H16,  being  the  important,  and  often  the  chief,  compo- 
nents of  many  ethereal  oils  of  great  value  in  perfumery,  demand 
particular  attention.  They  are  more  or  less  closely  related  to  p-cymol 
or  p-iso-propyl-methyl  benzol,  and  a  few  to  m-cymol. 

Their  classification,  and  the  possibility  of  distinguishing  the  indi- 
vidual true  terpenes,  are  mainly  due  to  the  painstaking  researches  of 
O.  Wallach,*  who  has  brought  order  and  system  out  of  this  chaotic 
mass  of  hydrocarbons  of  the  most  varying  origin. 

The  terpenes  can  be  divided  into  two  groups  according  to  their 
behaviour.  The  first  group  contains  the  doubly  unsaturated  mono- 
cyclic  terpenes,  which  can  add  four  quadrivalent  atoms,  or  atomic 
groups,  and  which  can  be  regarded  as  true  dihydro-p-cymols.  To 
these  belong  limonene,  dipentene,  terpinolene,  terpinene,  and  phellan- 
drene.  To  these  must  be  added  sylvestrene  and  carvestrene,  which 
also  contain  two  double  bindings,  but  are  derived  from  m-cymol. 

Terpenes  of  the  second  group  are  chiefly  distinguished  from  these 
dihydro-cymols  by  adding  only  two  univalent  atoms  or  atomic  groups, 
which  indicates  that  they  must  contain  a  double  carbon  ring.  The 
most  important  representatives  of  these  bicyclic  terpenes  are  camphene, 
pinene,  fenchene,  and  sabinene.  Some  members  of  both  groups  are 
related  to  each  other  by  transitional  reactions.  Completely  saturated 
tricyclic  terpenes  have  not  been  found  up  to  the  present  among  the 
ethereal  oils.  Quite  recently  terpenes  of  the  formula  C10H16  have 
become  known,  which  contain  no  closed  carbon  chain,  and  are 
therefore  distinguished  from  the  real  cyclic  terpenes  by  calling  them 
acyclic  or  olefinic  terpenes  (B.  24,  682). 

Beside  the  terpenes  proper,  we  often  find,  among  ethereal  oils,  hydro- 

"  O.  Wallach,  Terpene  und  Campher,  Leipzig,  1909. 


TERPENES  485 

carbons  of  higher  boiling-points,  having  the  same  percentage  composi- 
tion but  a  higher  molecular  weight.  Among  these  we  have  the  so- 
called  sesqui-terpenes  C15H24,  the  di-terpenes  C20H32,  and  poly-terpenes 
(C5Hj.)x.  The  same  percentage  composition  is  also  shown  by  isoprene 
C5H8,  generated  by  distillation  of  rubber  and  closely  related  to  the 
terperies,  easily  polymerised,  e.g.  into  dipentene.  Isoprene  has  there- 
fore also  been  called  hemi-terpene. 

From  the  terpenes  a  large  number  of  alcohols  and  ketones  of  the 
general  composition  C10H16O,  C10H18O,  and  C10H20O  are  derived.  These 
are  usually  found  besides  the  terpenes  in  the  ethereal  oils,  and  are  com- 
prised under  the  name  "  camphors,"  since  the  commercially  important 
common,  or  Japanese,  camphor  is  among  them.  Corresponding  to  the 
olefinic  terpenes  we  have  the  olennic  camphors,  and  corresponding  to 
sesqui-terpenes  we  have  the  sesqui-terpane  camphors.  We  must 
therefore  discuss  the  terpene  alcohols  and  terpene  ketones  with  their 
transformation  products  in  connection  with  the  terpenes  and  their 
addition  products. 

In  the  isolation  of  the  terpenes  the  same  difficulties  are  encountered 
as  are  met  with  in  the  preparation  of  dihydro-benzols.  We  nearly 
always  obtain  a  mixture  of  closely  related  link-isomeric  hydrocarbons, 
and  it  seems  doubtful  whether  a  perfectly  uniform  terpene  has,  as  yet, 
been  prepared.  The  elucidation  of  the  constitution  of  the  terpenes 
has,  therefore,  been  a  matter  of  special  difficulty,  but  since  the  works 
of  Baeyer,  Perkin  jun.,  Sellner,  Wagner,  and  especially  Wallach,  have 
appeared,  the  structure  of  the  majority  of  terpenes,  and  their  relations 
to  each  other,  appear  to  be  settled.  In  many  cases,  as  in  dipentene, 
terpinene,  sylvestrene,  and  carvestrene,  a  complete  synthesis  has  been 
carried  out,  while  in  other  cases,  as  in  pinene,  phellandrene,  camphene, 
and  fenchene,  at  least  a  partial  synthesis  has  been  effected.  The  isola- 
tion and  the  purification  of  the  camphors  are  much  easier.  Many  of 
them  are  distinguished  by  their  ready  crystallisation,  while  others  may 
be  easily  regenerated  in  a  pure  state  from  characteristic  derivatives. 
Here  also  the  elucidation  of  the  constitution  has  been  followed  by 
numerous  total  syntheses,  e.g.  camphor,  menthone,  a-terpineol,  etc. 
The  synthesis  has  here  taken  a  step  further,  as  also  in  some  of  the 
terpenes,  by  preparing  new  compounds,  not  yet  found  among  ethereal 
oils,  but  closely  related  in  their  constitution  and  behaviour  to  the 
natural  products,  and  thus  creating  new  types  of  terpenes  and 
camphors. 

The  question  of  the  constitution  of  the  sesqui-terpenes  and  poly- 
terpenes,  as  well  as  the  oxygen-containing  derivatives,  is  almost  com- 
pletely unsolved  up  to  the  present. 

Properties. — The  true  terpenes,  when  pure,  are  colourless,  strongly 
refracting  liquids.  Camphene  alone  is  a  solid.  They  boil,  without 
decomposition,  at  i55°-i8o°.  They  are  very  volatile  with  steam,  and 
have  a  pleasant  odour.  Many  are  optically  active.  Some,  indeed, 
exist  in  two  optically  active  forms  with  equal  but  opposite  rotatory 
power.  Dipentene  is  a  racemic  terpene. 

Behaviour. — (i)  Terpenes  polymerise  very  readily.  (2)  Acids  trans- 
pose many  terpenes  very  easily  into  linkage-isomeric  terpenes.  (3) 
Many  are  oxidised  by  the  oxygen  of  the  air  (compare  a-pinene  and 
j3-phellandrene).  They  then  manifest  a  tendency  to  resinify  (see  B.  29, 


486  ORGANIC  CHEMISTRY 

R.  658).  The  formation  of  benzene  derivatives  by  oxidising  terpenes 
is  very  important.  Thus,  turpentine  oil  with  iodine  yields  p-cymol ; 
with  nitric  acid,  p-toluic  acid  and  terephthalic  acid.  (4)  The  signifi- 
cance of  the  addition  reactions  for  the  classification  of  the  terpenes  has 
already  been  pointed  out  above  : — (a)  By  addition  of  hydrogen  the  ter- 
penes form  hydro-terpenes  (B.  36,  1033).  (b)  The  addition  of  chlorine 
and  bromine,  as  well  as  of  hydrogen  haloids,  in  glacial  acetic  acid  at 
low  temperatures,  gives  rise  to  haloid  hydro-terpenes.  Some  of  these 
are  well-crystallised  compounds,  which  can  be  used  for  differentiating 
the  terpenes.  (c)  Nitrosyl  chloride  NOC1  (Tilden),  or  an  alkyl  nitrite, 
glacial  acetic  acid,  and  hydrochloric  acid  acting  upon  terpenes  give 
rise  to  well-defined  terpene  nitroso-chlorides.  With  primary  and 
secondary  bases,  these,  usually  unstable,  nitroso-chlorides  form  stable 
terpene-nitrol-amines,  or,  with  rejection  of  HC1,  nitroso-terpenes, 
which  are  useful  for  characterisation.  The  latter  make  a  transition 
from  the  terpenes  to  the  terpene  ketones  (see  Limonene  nitroso-chloride) . 
(d)  Several  terpenes  unite  with  N2O4,  forming  nitrosates  C10H16(NO). 
O.NO2>  and  with  N2O3,  yielding  nitrosites  C10H16(NO).O.NO,  or  pseudo- 
nitrosites  (nitrites)  C10H1§(NO).NO2  (A.  332,  313).  The  nitroso- 
chlorides,  nitrosates,  and  nitrosites  are  bimolecular  in  the  solid  state, 
and  should,  therefore,  be  regarded  as  bis-nitroso-chlorides,  bis-nitro- 
sates  and  bis-nitrosites.  In  their  transformations  they  behave  as 
monomolecular  compounds  (B.  28,  648  ;  29,  10).  (e)  By  the  action 
of  ozone  the  terpenes  are  converted  into  ozonides,  while,  with  dilute 
KMnO4  solution,  they  become  glycols  by  attaching  2HO.  Both 
reactions  are  important  for  determining  the  constitution  of  the  terpenes. 

Concerning  the  addition  of  trichloro-acetic  acid  and  formaldehyde 
to  terpenes,  see  B.  29,  695  ;  32,  57. 

Nomenclature. — In  most  cases  camphor  and  the  terpenes  are 
designated  by  names  derived  from  the  plants  in  which  they  were 
first  observed,  and  which  contain  them  most  abundantly  in  their 
ethereal  oils.  Since  many  terpenes,  formerly  considered  uniform, 
have  lately  been  found  to  be  mixtures,  the  terpenes  isolated  from 
them  have  been  distinguished  from  each  other  by  prefixing  Greek 
letters,  e.g.  a-,  jS-,  and  y-terpinene. 

Baeyer,  observing  the  "  Geneva  nomenclature,"  suggested  that  the 
cyclic  terpenes  containing  the  same  carbon  skeleton  as  p-cymol,  the 
dihydro-p-cymols,  be  called  terpadienes  ;  then  the  tetrahydro-cymols 
would  be  terpenes,  and  hexahydro-cymol  terpane.  To  obtain  names 
for  the  terpenes  which  would  be  designated,  according  to  this  sugges- 
tion, as  terpadienes,  Wagner  calls  hexahydro-cymol  menthane,  the 
tetrahydro-cymols  menthenes,  and  the  dihydro-cymols  or  terpenes 
menthadienes  (B.  27,  1636,  footnote). 

The  latter  terminology  has  become  most  usual.  In  order  to 
indicate  the  constitution  of  the  dihydro-cymoles,  the  carbon  atoms 
are  designated  by  numbers  : 


65  io 

The    dihydro  -  cymol    of    the    formula    CH3.C^          ;H2\c=C(CH3)2 

\CHjj- 


OLEFINIC  TERPENE   OR  TERPENOGEN   GROUP      487 

would      be      called      A1'4'(8)-menthadiene,     the      dihydro  -  cymol 
CH3.C^™— CI**\C.CH(CH3)2,    A^-menthadiene.      The    terpenes    wiU 

N  CH-2 — CtL'y 

be  discussed  in  the  following  groups  : — 

A.  Olefinic  terpene  or  terpenogen  group. 

B.  Monocyclic  terpene  or  menthane  group. 

C.  Bicyclic  terpene  groups. 

I.  Sabinane  or  tanacetane  group. 
II.  Carane  group. 

III.  Pinane  group. 

IV.  Camphane  group. 

D.  Sesqui-terpene  and  poly-terpene  groups. 

To  the  hydrocarbons  of  each  group  must  be  added  the  alcohols  and 
ketones,  the  so-called  camphors. 

A.  OLEFINIC  TERPENE  OR  TERPENOGEN  GROUP. 

Many  olefin  hydrocarbons,  alcohols,  aldehydes,  and  acids  with 
open  carbon  chain  are  included  under  this  designation.  They  occur 
in  ethereal  oils,  or  in  the  transposition  products  obtained  from  the 
latter.  They  are  distinguished  chiefly  by  the  fact  that  they,  as 
a  rule,  are  easily  converted  into  hydro-aromatic,  terpene-like,  or 
aromatic  substances. 

i.  Olefinic  Terpenes. — Myrcene,  b.p.  67°  (20  mm.),  sp.  gr.  0-8025 
(15°),  WD =1-4673,  occurs  with  1-phellandrene  and  the  aromatic  phenols 
of  the  cinnamic  series  in  bay  oil.  Its  formula  is  C10H16=(CH3)2 
C  :  CH.CH2.CH2C(  :  CH2).CH  :  CH2  or  CH2  :  C(CH3).CH2.CH2.CH2.C 
(  :  CH2).CH  :  CH2,  b.p.20  67°,  D15  0-8025.  It  is  also  found  in  the 
ethereal  oil  of  Lippia  citriodora.  The  terpene  isolated  from  hop  oil  is 
also  probably  identical  with  myrcene  (C.  1903,  I.  1028). 

Artificially,  it  is  prepared  by  eliminating  water  from  linalool  (see 
below)  by  heating  with  KHSO4.  It  adds  4  Br  atoms.  By  reduction 
with  sodium  and  alcohol  we  obtain  dihydro-myreene  C10H18,  b.p.  172°, 
tetrabromide,  m.p.  88°,  which  is  converted  by  glacial  acetic-sulphuric 
acid  into  the  isomeric  cyclo-dihydro-myrcene  (B.  34,  3126).  By 
heating  under  pressure  to  300°,  myrcene  is  polymerised  to  dimyrcene, 
b.p.13  i6o°-2OO°,  and  to  undistillable  poly-myrcenes ;  with  N2O3 
dimyrcene  gives  a  nitrosite  (Ci0H15N3O7)  2,  apparently  identical  with  the 
nitrosite  of  the  same  composition  obtained  from  rubber  (B.  35,  3264). 

Ocimene  C10H16=(CH3)2C  :  CH.CH2.CH  :  C(CH3)CH  :  CH2  (?), 
b.p.30  81°,  Dj5  0-8031,  has  been  obtained  from  the  ethereal  oil  of 
Ocimum  basilicum.  It  differs  from  myrcene  only  by  the  position  of  a 
double  link,  since  sodium  and  alcohol  reduce  it  to  dihydro-myreene 
with  addition  of  two  H  atoms.  On  oxidation  with  ozone,  we  obtain, 
among  other  products,  acetone,  methyl-glyoxal,  and  malonic  dialdehyde 
(C.  1907,  II.  679  ;  1909,  I.  373). 

Anhydro-geraniol  C10H16,  b.p.  ij2°-iy6°,  sp.  gr.  0-8232  (20°), 
nD= 1-4835,  is  obtained  by  heating  geraniol  with  potassium  bisulphate 
to  170°.  It  can  also  take  up  six  bromine  atoms  (B.  24, 682).  Linalao- 
lene  C10H18  boils  at  i65°-i68°.  Its  specific  gravity  is  0-7882  (20°), 
nD= 1-455.  It  is  formed  in  the  reduction  of  linalool  (B.  27,  2520). 

Isoprene  C5H8,  b.p.  37°,  must  be  considered  under  the  olefinic 


488  ORGANIC  CHEMISTRY 

terpenes  or  terpenogens.  It  is  a  distillation  product  from  rubber. 
It  may  be  obtained  by  conducting  vapours  of  turpentine  oil  through 
tubes  at  a  dull-red  heat  (A.  228).  On  its  synthesis  by  disintegration  of 
jS-methyl-pyrrolidin,  see  this. 

Isoprene  very  probably  consists  in  the  main  of  methyl-divinyl, 

;H3^C  —  C=CH2.     It     can    take    up    two     molecules    of    hydrogen 
CH2^ 

bromide,  forming  dimethyl  -  trimethylene  bromide.  It  polymerises 
very  readily  to  dipentene  (/.  pr.  Ch.  2,  55,  i  ;  C.  1900,  II.  331)  : 


Under  different  conditions  isoprene  is  polymerised  to  para-rubber. 

2.  Olefinic  Terpene  Alcohols.—  d-Citronellol  C10H2aO=CH2  :  C(CH3) 
CH2.CH2.CH2CH(CH3)CH2.CH2OH  (?),  b.p.15  ii3°-ii4°,  was  first 
obtained  by  the  reduction  of  d-citronellal  ;  it  is  found  native  in  Java 
citronel.  It  is  a  colourless  oil,  smelling  agreeably  of  roses.  Its  con- 
stitution follows  from  its  connection  with  d-citronellol.  An  alcohol 
very  similar  to  d-citronellol,  but  kevo-rotatory,  l-citronellol,  1-rhodinol, 
is  found,  besides  geraniol,  in  several  species  of  rose,  geranium,  and 
pelargonium  oils.  It  is  probably  link-isomeric  with  d-citronellol  in  the 
sense  of  the  formula  (CH3)2C  :  CH.CH2.CH2CH(CH3)CH2CH2OH, 
since,  on  oxidation,  it  passes  into  an  aldehyde  isomeric  with  d-citron- 
ellal, viz.  rhodinal.  But  the  question  of  the  constitution  of  the 
citronellols  cannot  be  regarded  as  finally  decided.  An  i-citronellol, 
i-rhodinol,  b.p.10  110°,  is  formed  by  the  reduction  of  the  synthetic 
geranic  acid  (B.  29,  923  ;  30,  33  ;  C.  1904,  II.  440  ;  vgl.  B.  29,  R.  785). 

Geraniol  C10H18O=(CH3)2C  •  CH.CH2.CH2.C(CH3)  :  CH.CH2OH, 
b.p.17  I2O°-I22°,  forms  the  chief  alcoholic  constituent  of  geranium  oil, 
rose  oil,  pelargonium  oil,  palma  rose  oil,  etc.,  and  is  the  most  frequently 
occurring  aliphatic  terpene  alcohol  (B.  29,  R.  785)  ;  it  yields  a  character- 
istic crystallised  compound  with  calcium  chloride,  which  can  be  em- 
ployed for  separating  geraniol  from  ethereal  oils.  It  is  optically 
inactive,  and  has  the  same  relation  to  citral  as  citronellol  has  to  citron- 
ellal.  The  synthesis  of  geraniol  is  accomplished  with  that  of  citral. 
An  alcohol  probably  stereo-isomeric  with  geraniol  — 

Nerol,  b.p.  225°,  D15  0-880,  has  been  found  in  the  oils  of  neroli, 
petit  grain,  bergamot,  and  linaloe,  partly  in  a  free  condition,  partly 
esterified.  It  is  distinguished  from  the  otherwise  very  similar  geraniol 
by  its  inability  to  form  a  solid  calcium  chloride  compound,  and  by  the 
formation  of  a  crystalline  tetrabromide,  m.p.  119°.  Geraniol  and 
nerol  probably  stand  to  each  other  in  the  same  relation  as  citral-a  and 
citral-b,  geraniol  corresponding  to  the  former,  and  nerol  to  the  latter 
(B.  39,  1780.) 

1-Linalool,  licareol  C10H18O=(CH3)2C  :  CH.CH2.CH2.C(CH3)(OH). 
CH  :  CH2,  b.p.  I97°-I99°,  D20  0-8702,  nD=  1-4695,  is  found  in  linaloe 
oil  from  Licari  Kanali,  as  well  as  lavender,  bergamot,  limette  and 
origanum  oil. 

d-Linalool,  coriandrol,  is  found  in  coriander  oil  and  oil  of  pome- 
granates and  orange  blossoms.  By  reduction  with  Ni  and  hydrogen, 
geraniol  and  linalool,  as  well  as  ocimene,  pass  into  2,  6-dimethyl- 
octane,  which  proves  that  the  same  carbon  frame  forms  the  basis  of 


OLEFINIC  TERPENE  OR  TERPENOGEN   GROUP      489 

all  these  compounds.  Dilute  sulphuric  acid  converts  the  linalool  with 
ease  into  inactive  terpin  hydrate  ;  this  conversion  is  made  with  greater 
difficulty  with  geraniol  (B.  28,  2137).  Formic  and  glacial  acetic-sul- 
phuric acids  convert  geraniol  with  some  difficulty,  and  the  linalools  with 
greater  ease,  into  solid  a-terpineol,  m.p.  35°.  In  this  process  linalool  is 
partly  isomerised  to  geraniol,  and,  on  the  other  hand,  geraniol  can  be 
converted  into  inactive  linalool  (/.  pr.  Ch.  2,  60,  244).  Besides,  or 
instead  of,  terpin  hydrate  and  terpineol,  terpenes,  like  terpinene,  and 
terpinolene,  are  formed  by  stronger  action  of  these  agents.  By  the 
action  of  geraniol  esters  with  concentrated  acids  cyclo-geraniol  is 
formed,  the  alcohol  corresponding  to  cyclo-citral  (C.  1903,  I.  266). 

The  constitution  of  these  bodies,  as  well  as  that  of  the  correspond- 
ing aldehydes  and  acids,  has  been  mainly  deduced  from  their  conver- 
sion into  methyl-heptenone  (CH3)2C  :  CH.CH2.CH2.CO.CH3,  which  has 
been  previously  described.  Again,  this  methyl-heptenone  has  been 
employed  in  the  synthesis  of  certain  bodies  belonging  to  this  group. 
Thus  by  condensation  with  zinc  and  allyl  iodide  it  yields  homo-linalool 
(CH3)2C  :  CH.CH2.CH2C(CH3)OH.CH2.CH  :  CH2,  boiling  at  io2°-iO4° 
(14  mm.)  (B.  29, 693  ;  cp.  C.  1899, 1.  24).  a-Alkyl-geraniols  are  obtained 
from  citral  and  alkyl-magnesium  compounds  (C.  1904,  II.  624). 

3.  Olefinic  Terpene-aldehydes—Citionellal  C10H18O=CH2  :  C(CH3). 
CH2.CH2.CH2.CH(CH3).CH2.CHO  (I.)  and  (CH3)2C  :  CH.CH2.CH2.CH 
(CH3).CH2CHO  (II.),  boiling  at  205°,  is  optically  dextro-rotatory.  It  is 
found  in  citronella  oil,  in  the  oil  from  Eucalyptus  maculata,  var. 
citriodora,  etc.  (B.  29,  904).  1-Citronellal  has  hitherto  only  been  found 
in  Java  lemon  oil.  Acetic  anhydride  condenses  it  to  iso-pulegol,  a 
terpene  alcohol  very  similar  to,  yet  not  identical  with,  pulegol,  a 
reduction  product  obtained  from  pulegon  (B.  30,  22).  It  changes  to 
d-citronellol  upon  reduction. 

By  oxidation  with  KMnO4  the  acetal  of  citronellal  in  aqueous 
solution  is  split  up  into  acetone  and  the  half-aldehyde  of  ^3-methyl- 
adipinic  acid,  whereas  in  acetone  solution  it  is  converted  to  the  extent 
of  80  per  cent,  into  a  dioxy-aldehyde,  which,  on  further  oxidation  with 
CrO3,  yields  an  oxy-dialdehyde  and  finally  a  keto-aldehyde  CH3COCH2. 
CH2.CH2CH(CH3).CH2CHO  (B.  34,  2981).  Upon  oxidation  of  the 
citronellal  with  ozone,  acetone  and  j8-methyl-adipinic  acid  are  obtained, 
but  not  quantitatively.  Natural  citronellal,  therefore,  appears  to  be 
a  mixture  of  two  very  similar  aldehydes,  which  are  link-isomeric  in 
the  sense  of  the  above  formula  (B.  41,  2187). 

A  laevo-rotatory  aldehyde,  rhodinal,  closely  related  to  citronellal,  is 
formed  by  oxidation  of  citronellal.  The  formula  (II.)  above  is  ascribed 
to  it.  It  differs  from  citronellal  in  that  acetic  anhydride  does  not 
change  it  into  iso-pulegol,  but  into  a  cyclic  ketone,  menthone.  The 
process  may  be  represented  by  the  following  formulae  : — 

H2C=C— CH3  H2C=C— CH3  H3C— C— CH3  H3C— CH— CH3 

Cna  CH  CH  CH 

CHO  >  H2C      CHOH  H2C      CHO >  H2C      CO 

II  II  II  II 

H2C      CH2  H2C      CH2  H2C      CH2  H2C      CH2 


H2C 


CH.CH3  CH.( 


:H.CH3  CH.CH3  CH.CH3  CHCH3 

Citronellal  Iso-pulegol  Rhodinal  Menthone. 


490  ORGANIC  CHEMISTRY 

The  reverse  of  this  process  takes  place  on  illuminating  an  aqueous- 
alcoholic  solution  of  menthone.  The  ring  is  opened,  and  an  unsaturated 
aldehyde  similar  to  citronellal,  but  of  lower  b.p.,  195°,  is  formed  (B. 
40,  2421).  It  may  be  identical  with  the  aldehyde  designated  as 
mentho-citronellal,  obtained  by  splitting  up  menthone-oxime  (A.  296, 


Citral,  geranial  C^^QHCH^C  :  CH.CH2.CH2.C(CH3)  :  CH. 
CHO,  b.p.  228°-229°,  is  a  faint-yellow  oil  smelling  of  lemon.  It  is 
found  in  lemon  oil,  verbena  oil,  and  particularly  in  lemon-grass  oil  (?), 
from  which  it  is  prepared  industrially  ;  also  in  many  other  ethereal 
oils  ;  it  is  also  formed  by  the  oxidation  of  geraniol  (C.  1908,  I.  1375)  J 
synthetically,  it  can  be  prepared  by  the  distillation  of  geranium  acid 
and  calcium  formate  (B.  31,  827).  The  natural  citral  consists  of  two 
structurally  identical  stereo-isomeric  forms,  citral  a  and  b,  which  can 
be  separated  by  their  different  ease  of  condensation  with  cyano-acetic 
acid  to  eitralidene-cyano-aeetie  acids,  m.p.  122°  and  95°  (B.  33,  877). 
With  jS-naphthylamine  and  pyro-racemic  acid  citral  combines  to  form 
the  characteristic  citryl-naphtho-cinchonic  acid  (q.v.),  m.p.  197°  (B. 
31,  3195).  Like  cinnamic  aldehyde,  citral  combines  with  sulphites  not 
only  to  form  the  normal  bisulphite  compound  with  attachment  of 
2SO3HNa  to  the  olefin  links,  but  also  salts  of  eitral-dihydro-disulphonic 
acid  (B.  31,  3278).  By  boiling  with  soda  solution,  citral  is  split  up  into 
methyl-heptenone  and  acetaldehyde  (C.  1897,  1.  495).  It  is  oxidised  by 
ozone  to  acetone,  Isevulinic  aldehyde,  or  laevulinic  acid  and  glyoxal  (?) 
(B.  40,  2823).  By  treatment  with  potassium  bisulphate,  HI,  acetic 
acid,  etc.,  it  is  converted  into  cymol  with  elimination  of  H2O.  But 
if  citral  derivatives,  unconvertible  into  cymol,  like  citralidene-aniline 
(C.  1901,  II.  716),  citralidene-acetic  acid,  -cyano-acetic  acid,  -aceto- 
acetic  ester,  etc.,  are  treated  with  concentrated  H2SO4  or  H3PO4,  we 
obtain  derivatives  of  cyclo-citral,  a  trimethyl-tetra.hydro-benzaldehyde. 
Similarly,  the  so-called  pseudo-ionone  (CH3)2C  :  CH.CH2.CH2.C(CH3)  : 
CHCH  :  CHCOCH3,  b.p.12  I43°-I45°,  obtained  by  the  condensation  of 
citral  with  acetone,  forms  a  hydro-aromatic  ketone  called  ionone,  under 
the  influence  of  concentrated  H2SO4  ;  cp.  also  cyclo-dihydro-myrcene 
(above),  cyclo-geraniol,  cyclo-geranic  acid,  and  cyclo-geraniolene 
(above). 

4.  Olefinic  Terpene  Acids.  —  Citronellic  acid  (rhodinic  acid,  B.  29,  R. 
352)  CH2  :  C(CH3).CH2.CH2.CH2CH(CH3)CH2COOH  and  (CH3)2C  : 
CH.CH2.CH2CH(CH3)CH2COOH,  b.p.10  I43°-I45°,  obtained  from 
its  nitrile  formed  by  withdrawing  water  from  citronell-aldoxime, 
or  by  oxidation  of  citronellal,  to  which  it  can  be  restored  by 
distilling  its  calcium  salt  with  calcium  formate.  From  geranic 
acid  it  is  obtained  by  reduction  with  sodium  and  amyl  alcohol  (B. 
31,  2899). 

Reduction  of  its  ester  with  sodium  and  alcohol  produces  i-citronellol 
(see  above),  which  proves  the  relation  between  the  geraniol  and  citron- 
ellol  series. 

Geranic  acid  (CH3)2C  :  CH.CH2.CH2C(CH3)  :  CHCOOH,  b.p.13  153°, 
is  also  formed  from  citral.  It  has  been  prepared  synthetically  from 
methyl-heptenone  with  iodo-acetic  ester  and  bromo-acetic  ester  and  zinc 
(B.  29,  R.  222  ;  31,  825).  Sulphuric  acid  converts  it  into  isomeric 
hydro-aromatic  cyclo-geranic  acid.  By  heating  at  ordinary  pressures 


MONOCYCLIC  TERPENE  OR  MENTHANE  GROUP  491 

geranic    acid  produces    geraniolene    C9H16,   which    is  isomerised  by 
sulphuric  acid  into  cyclo-geraniolene  (A.  324,  101). 

B.  MONOCYCLIC  TERPENE  OR  MENTHANE  GROUP. 

To  this  group  belong  the  terpenes  limonene,  dipentene,  terpinolene, 
a-,  J3-,  and  y-terpinene,  a-  and  J8-phellandrene,  and  the  synthetic  A2»4- 
menthadiene,  which  must  all  be  regarded  as  dihydro-p-cymols,  also 
sylvestrene  and  carvestrene,  which  must  be  regarded  as  dihydro- 
m-cymols.  These  terpenes  are  partly  optically  active,  and  partly 
inactive,  or  racemic.  Numerous  transitions  and  transformations 
connect  the  various  terpenes,  and  several  of  them  have  been  made 
by  molecular  synthesis. 

i.  Limonene  and  Dipentene  Group.  — 

Limonene  C10H16=CH3C^  —  CH2\CHC/-CH2   js  known  in   three 

\CH2  —  CH2/  NCH/j 

modifications  —  d-limonene,l-limonene,  and  [d+1]  -limonene  or  dipentene. 

d-Limonene,  citrene,  hesperidene,  carvene,  together  with  pinene,  is 
among  the  most  widely  distributed  terpenes.  It  is  present  in  the  oil 
obtained  from  the  shell  of  Citrus  aurantium,  in  lemon  oil,  in  the  oil  of 
bergamot,  in  oil  of  dill,  in  oil  of  celery,  etc.  It  boils  at  175°  ;  [a]D= 
+  106-8°.  1-Limonene  occurs  in  the  oil  of  pine-needles,  in  oil  of  fir, 
and  in  oil  of  peppermint.  It  boils  at  175°  ;  [a]D=  —  105°.  On  the 
preparation  of  1-limonene  from  d-carvone,  see  B.  33,  735. 

Both  limonenes  are  liquids,  with  an  agreeable  lemon-like  odour. 
Their  specific  gravity  equals  0-846  (20°).  They  differ  from  each  other, 
as  do  their  derivatives,  almost  entirely  by  their  opposite  rotatory 
power  (A.  252,  144).  The  two  active  limonenes  combine  with  dry 
bromine  to  tetrabromides  melting  at  104°,  and  having  equally  large  but 
opposite  rotatory  power  of  about  [a]D=73°.  The  moist  haloid  acids 
change  the  optically  active  limonenes  to  addition  products  of  [d+1]- 
limonene  or  dipentene. 

On  conducting  dry  HC1  through  a  CS2  solution  of  limonene,  a  mono- 
chlorohydrate  is  obtained  which,  on  reduction  with  sodium  and  cold 
alcohol,  gives  carvo-menthene,  and,  on  treating  with  dilute  alkali  and 
sodium  acetate,  optically  active  a-terpineol  (B.  36,  1036  ;  A.  350,  154). 

By  gentle  oxidation  with  KMnO4  limonene  is  converted  into  the 
quadrivalent  alcohol  C10H10(OH)4.  When  the  optically  active 
limonenes  are  exposed  to  elevated  temperatures  they  become 
dipentenes. 

The  nitroso-chlorides  of  the  limonenes  deserve  particular  atten- 
tion (B.  28,  1308  ;  cp.  also  B.  29,  10).  d-Limonene  forms  two 
chemically  identical  nitroso-chlorides,  with,  however,  different  physical 
properties  : 

a,  d-  and  1-Limonene-nitroso-chioride,  m.p.  103°,  [a]D=±3i3°. 
j3,  d-  and  1-Limonene-nitroso-chloride,  m.p.  105°,  [a]D 


All  the  four  nitroso-chlorides  give,  on  heating  with  sodium 
methylate,  carvoxime,  m.p.  72°,  1-limonene  nitroso-chlorides  giving 
d-carvoxime,  and  d-limonene-nitroso-chlorides  1-carvoxime  (cp.  also 
B.  43,  519). 

[d  +1]  -Limonene,  dipentene,  cinene,  sp.   gr.   0-853   (B.  28,   2145  ; 


4Q2  ORGANIC  CHEMISTRY 

29,  4),  boils  at  175°.  It  is  associated  with  cineol  in  Oleum  cince. 
It  is  produced  by  heating  d-limonene,  1-limonene,  pinene,  and  camphene 
to  25O°-300°  ;  it  is,  therefore,  present  in  the  Russian  and  Swedish 
turpentine  oil,  obtained  by  application  of  great  heat.  It  is  derived 
also  from  the  distillation  of  rubber,  and  the  polymerisation  of  the 
isoprene  C5H8,  formed  simultaneously  (A.  227,  295).  It  is  also  produced 
on  mixing  equally  large  quantities  of  d-  and  1-limonenes,  as  well  as 
when  pinene  is  boiled  with  alcoholic  sulphuric  acid.  It  forms,  too,  on 
withdrawing  water  from  linalool,  terpine  hydrate,  terpineol,  and  cineol. 
By  nuclear  synthesis,  dipentene  is  obtained  from  the  synthetic 
a-terpineol  by  heating  with  potassium  bisulphate  (C.  1904,  I.  1604). 

It  may  be  prepared  pure  by  heating  its  hydrochloride  with  aniline 
or  sodium  acetate  in  glacial  acetic  acid  solution. 

Pure  dipentene  is  a  liquid  with  an  agreeable  odour  of  lemon. 

Although  more  stable  than  most  of  the  other  terpenes,  it  can 
yet  be  changed  into  the  isomeric  terpinene  by  alcoholic  sulphuric 
acid  or  hydrochloric  acid.  It  is  oxidised  to  p-cymol  by  concentrated 
sulphuric  acid  or  phosphorus  pentasulphide.  p-Cymol  is  also 
obtained  by  treating  its  dihydro-bromide  with  bromine  and  reducing 
(B.  31,  1402). 

The  derivatives  of  dipentene  can  be  obtained  not  only  from  the 
dipentenes,  but  also  by  mixing  the  corresponding  derivatives  of  dextro- 
and  laevo-limonene. 

trans-Dipentene-dihydro-chloride  C10H16.2HC1  boils  at  119°  (10  mm.) 
and  melts  at  50°.  eis-Dipentene-dihydro-ehloride,  m.p.  about  22°. 

The  trans-dipentene-dihydro-bromide  C]0H16.2HBr,  from  d-limonene, 
dipentene,  terpine,  and  cineol  with  hydro-bromic  acid,  melts  at  64°. 

cis-Dipentene-dihydro-bromide  C10H16.2HBr,  melting  at  37°, 
results  from  the  action  of  HBr  upon  a  well-cooled  solution  of  cineol  in 
glacial  acetic  acid  ;  see  also  cis-Terpine  (B.  26,  2864). 

Tetrahydro-dipentene  tribromide,  tribromo-terpane  C]0H17Br3,  is  de- 
rived from  trans-dipentene  dihydro-bromide  by  the  action  of  bromine 
upon  the  glacial  acetic  acid  solution  (A.  264,  25). 

Dipentene  tetrabromide  C10H16.Br4  melts  at  124°  (A.  281,  140). 

Dipentene  dihydro-iodide  C10H16.2HI  melts  at  77°-79°  (A.  239, 13). 

Dipentene  nitroso-ehloride  C10H]6(NO)C1  melts  at  102°  ;  see  Carv- 
oxime,  p.  510  (A.  270,  175). 

Terpinolene  cu^c\^~^^>c=c<^'  meltinS  at  75°  (14  mm.), 
has  not  yet  been  observed  in  ethereal  oils.  It  is  produced  when  terpine 
hydrate,  terpineol,  and  cineol  are  boiled  with  dilute  sulphuric  acid, 
and  by  heating  pinene  with  the  concentrated  acid.  Boiling  oxalic 
acid  or  anhydrous  formic  acid  also  liberate  it  from  the  terpineol  melting 
at  35°  (A.  275,  106  ;  368,  n) ;  or  anhydrous  formic  acid  (A.  368,  n) 
with  bromine  terpinolene  forms  a  dibromide  C10H16Br2,  m.p.  70° 
(B.  27,  447),  and  a  tetrabromide  C10H16Br4,  m.p.  116°,  from  which 
it  can  be  regenerated,  in  great  purity,  by  reduction  with  zinc  dust 
and  alcohol  (B.  42,  4644).  Halogen  hydride  is  added  to  it  with 
formation  of  dipentene  dihalogenides.  Terpinolene  belongs  to  the 
most  unstable  terpenes,  and  is  changed  with  especial  ease  by  acids 
displacing  the  semicyclic  double  link  into  the  nucleus  and  thus 
forming  terpinene. 


MONOCYCLIC  TERPENE  OR  MENTHANE  GROUP  493 

The  Terpinene  Group.  —  The  name  terpinene  is  used  for  designating 
the  three  following  dihydro-cymols  : 

CH3.CH.CH3  CH3.CH.CH3  CH3.CH.CH3 

C  C  C 


/\  /\ 

H2C      CH  H2C      CH  H2C      CH 

H2C      CH  HC      CH2  HC      CH2 

C  C  C 

CH3  CH2  CH3 

a-Terpinene  jS-Terpinene  y-Terpinene. 

Of  these,  the  a-  and  y-terpinenes  have  been  found  in  ethereal  oils, 
while  the  j3-  terpinene  has  hitherto  only  been  prepared  synthetically. 
Both  the  natural  terpinene  and  the  terpinene  artificially  prepared  from 
other  terpenes  or  terpene  alcohols  represent  a  mixture  of  various 
amounts  of  a-  and  y-terpinenes,  in  which  a-terpinene  usually  pre- 
dominates. The  isolation  of  a  perfectly  pure  a-  or  y-terpinene  has 
hitherto  not  been  accomplished. 

Terpinene  (a+y),  b.p.  i79°-i8i°,  D  0-846  (20°)  (B.  42,  2425),  when 
pure,  has  an  odour  resembling  lemons  and  is  optically  inactive.  It 
has  been  found  in  cardamom  oil,  elemi  oil,  coriander  oil,  ajowan  oil, 
etc.,  of  which  the  latter  is  particularly  rich  in  y-terpinene.  It  results 
on  boiling  dipentene,  terpine,  phellandrene,  cineol,  or  dihydro-carveol 
with  dilute  alcoholic  sulphuric  acid,  and  when  pinene  is  shaken  with 
a  little  concentrated  sulphuric  acid.  A  partly  pure  y-terpinene  is 
obtained  (i)  from  chloro-carvenene,  the  result  of  the  action  of  PC15 
upon  carvenone,  or  by  reduction  of  sodium  and  alcohol  (B.  40,  2471)  ; 

(2)  from   carvenylamine   by  rejection    of   ammonia   (B.   40,   1256)  ; 

(3)  from  methyl-dichloro-methyl-keto-dihydro-benzol,  with  iso-propyl- 
magnesium  iodide,  and  heating  the  resulting  compound  with  alcoholic 
potash  (B.  42,  2404,  4427).     The  last  method  of  formation  represents 
a  complete  nuclear  synthesis  of  terpinene. 

j3-Terpinene,  b.p.  i73°-i74°,  specific  gravity  0-838,  has  been 
obtained  from  the  condensation  product  of  sabina-ketone  with  brom- 
acetic  ester  and  zinc  by  rejection  of  water  and  distillation  of  the 
resulting  unsaturated  acid,  C9H14  :  CHCO2H,  m.p.  68°.  It  unites  with 
bromine  to  form  a  crystallised  tetrabromide,  m.p.  155°,  while  a-  and 
y-terpinenes  only  yield  liquid  bromine  addition  products  (A.  362,  285). 

All  three  terpinenes  unite  with  two  molecules  of  halogen  hydride  to 
form  well-defined  terpinene  dihalogenides,  from  which,  on  heating 
with  aniline  or  alcoholic  potash,  a  mixture  of  a-  and  y-terpinene  is 
regenerated.  On  shaking  up  with  dilute  alkali,  dihalogen  hydrates 
are  converted  into  terpinene-terpin  and  terpinenol  (q.v.),  compounds 
which  are  isomeric  with  the  analogous  conversion  products  of  the 
dipentene  halogenides,  terpin  and  terpineol. 

Especially  characteristic  of  a-terpinene  is  the  formation  of  terpinene 
nitrosite  C10H16(NO).O.NO  or  C10H15(N.OH)O.NO,  m.p.  155°, 
formed  by  the  action  of  potassium  nitrite  upon  terpinene  dissolved  in 

flacial  acetic  acid,  and  used  for  discovering  terpinene  in  ethereal  oils. 
t  is  insoluble  in  alkali,  but  gives,  with  bases,  nitrolamines  soluble  in 
alkali.    With   ammonia   it   thus  gives   terpinene-nitrolamine  C10H16 


494  ORGANIC  CHEMISTRY 

(N.OH).NH2,  m.p.  118°  (A.  241,  320).  With  zinc  dust  the  terpinene 
nitrosite  and  the  nitrolamines  are  reduced  to  carvenone,  while  sodium 
and  alcohol  reduce  them  to  tetrahydro-carvone  and  tetrahydro-carvyl- 
amine  (B.  40,  579). 

On  oxidation  with  potassium  permanganate,  a-terpinene  yields 
a,  ai-dioxy-a-methyl-aj-iso-propyl-adipinic  acid,  m.p.  189°,  which 
can  be  further  broken  down  to  co-dimethyl-  acetonyl-acetone  (A.  362, 
293): 

CH2—  C(CH3)=CH  _          CH2—  C(CH3)OH—  C02H  CH2—  CO.CH3 

CH2—  C(C3H7)  =CH          "*"  CH2—  C(C3H7)OH—  C02H  CH2—  CO.CH(CH3)a 


The  isomeric  y-terpinene,  similarly  oxidised,  yields  an  erythrite 
C10H16(OH)4,  m.p.  237°,  which,  under  the  action  of  dilute  sulphuric 
acid,  gives  a  mixture  of  thymol  and  carvacrol  (C.  1909,  II.  2159). 

Terpinene  Dihydro-halogenides.  —  These,  like  the  corresponding 
dipentene  compounds,  occur  in  two  stereo-isomeric  forms,  of  which 
only  the  trans-form  is  solid  at  ordinary  temperatures.  They  are 
formed  from  the  terpinenes,  but  with  greater  ease,  by  the  action  of 
halogen  hydride  upon  the  bicyclic  sabinene  and  thujene.  Also 
from  terpinene-terpin,  and  the  terpineols,  with  glacial  acetic  halogen 
hydride.  trans-Terpinene  diehloro-hydrate,  dibromo-hydrate,  and 
di-iodo-hydrate  melt  at  52°,  59°,  and  76°.  A  terpinene  monochloro- 
hydrate  C10H16HC1,  bp.12  87°-92°,  results  from  terpinene  and  sabinene 
with  dry  HC1  in  carbon  bisulphide  solution.  It  corresponds  to  ter- 
pineol-4,  since  sodium  and  alcohol  reduce  it  to  carvo-methene  (B.  40, 


Phellandrene  Group.  —  By  a-  and  j8-phellandrene  we  denote  two 
isomeric  dihydro-cymols,  both  marked  by  the  ease  with  which  they 
combine  with  nitrous  acid  to  form  well-marked  pseudo-nitrosites. 
The  phellandrenes  belong  to  the  most  unstable  terpenes,  converted 
by  acids  into  other  terpenes,  like  dipentene  and  terpinene.  With 
halogen  hydride  and  bromine  they  only  form  liquid  addition  pro- 
ducts, and,  since  they  cannot  be  regenerated  from  the  crystallised 
nitrites,  they  have  not  been  hitherto  obtained  pure. 

j3-Phellandrene  c10H16=CH3.c^-^^CH.CH<(^3>  bp.  i730_i750. 

is  optically  active  and  is  pretty  frequently  found  in  ethereal  oils,  both 
with  right-hand  and  left-hand  rotation.  d-a-Phellandrene  has  been 
found  in  water  of  fennel  oil,  elemi  oil  (A.  246,  233),  ginger-grass  oil, 
while  1-a-phellandrene  has  been  found  in  Australian  eucalyptus  oil  of 
Eucalyptus  amygdalina  and  in  aniseed  oil  (?).  1-a-Phellandrene  has 
been  synthesised  from  the  product  of  A2-iso-propyl-cyclo-hexenone 
and  CH3MgI  by  rejection  of  water  (A.  359,  285),  and  also  from  chloro- 
phellandrene,  the  product  of  the  action  of  PC15  upon  carvotane-acetone, 
by  reduction  with  sodium  and  alcohol  (B.  38,  1832). 

On  oxidation  with  potassium  permanganate,  a-phellandrene 
produces  a-oxy-/Mso-propyl-glutaric  acid  and  iso-propyl-succinic  acid. 
Sodium  and  alcohol  reduce  it  to  carvo-menthene  (B.  36,  1749). 

The  bimolecular  a-phellandrene  nitrite,  obtained  with  nitrous  acid, 
occurs  in  two  stereo-isomeric  (?)  forms,  m.p.  105°  and  113°,  and  on 
reducing  with  zinc  and  glacial  acetic  acid  it  yields  a-phellandrene- 
diamine  C10H16(NH2)2,  b.p.  133°  (17  mm.),  which  shows  that  both 


MONOCYCLIC  TEREENE  OR  MENTHANE  GROUP  495 

nitrogen  atoms  are  linked  with  carbon.  With  bases,  it  does  not  yield 
nitrolamines  like  the  formal  nitrosites.  With  sodium  alcoholate  it 
splits  off  hypo-nitrous  acid  and  forms  nitro-a-phellandrene,  b.p. 
I25°-I29°  (9  mm.),  which  can  be  reduced,  with  zinc  and  glacial  acetic 
acid,  to  active  carvotane-acetone,  and,  with  sodium  and  alcohol,  to 
tetrahydro-carvone  (A.  336,  9). 

C.CH3  C.CH3  C.CH3  CH.CH3 

//\  ./\  /\  x\ 

HC      CHNO2  HC      CNO2 HC      CO  H2C      CO 

H2C    CHNO  "      ^  H2C    CH          "*  H2C    CH2        "*  H2C    CH2 

v  \y  \/  \/ 

CH.CgH7  CH.CgH,  CH.CaH7  CH.QH, 

a-Phellandrene  Nitro-a-phellan-      Carvotane-acetone         Tetrahydro- 

nitrite  drene  carvone. 


>p>u  occurs 

in  a  dextro-rotatory  form  in  the  oil  of  Phellandrium  aquaticum.  In 
the  air  it  oxidises  very  readily,  splits  off  the  hemi-cyclic  CH2  group, 
and  passes  into  A2-iso-propyl-cyclo-hexenone  (A.  343,  29).  By 
oxidation  with  a  very  dilute  permanganate  solution,  we  obtain  a 
glycol  C10H16(OH)2,  b.p.  150°  (10  mm.),  which,  on  treatment  with 
dilute  sulphuric  acid,  yields  tetrahydro-cumin-aldehyde  besides 
dihydro-cumin-alcohol.  Stronger  action  by  potassium  permanganate 
produces  a-oxy-/?-iso-propyl-adipinic  acid : 

CH2— CH2 CO2H CH2— CH2— C  :  CH2  CH2— CH2— CO 

QH7.CH— CH(OH).CO2HTc3ll7CH — CH=CH  "^CgH7.CH — CH — CH 

a-Oxy-/Mso-propyl-               /9-Phellandrene  A2-Iso-propyl-cyclo- 

adipinic  acid             |  hexenone 

CH2— CH2— C(OH)CH2OH  CH2— CH2— CH.CHO 

CgH7CH-^cH — CH  ">c3H7.CH — CH=CH 

jS-Phellandrene-glycol         Tetrahydro-cumin-aldeliyde. 

The  j3-phellandrene  nitrite  C9H14(NC).CH2.NO2,  m.p.  98°  and  102°, 
produced  by  nitrous  acid,  is  reduced  by  zinc  and  glacial  acetic  acid  to 
jS-phellandrene-diamine,  b.p.  134°  (n  mm.),  while  sodium  and  alcohol 
reduce  it  to  cumin-aldehyde.  Sodium  alcoholate  converts  it  into 
nitro-jS-phellandrene  C10H15NO2,  which,  on  reduction  with  zinc  and 
acetic  acid,  passes  into  dihydro-cumin-aldehyde  (A.  340,  i). 

A2>4-Menthadiene  CH3.CH<^=£^CH.CH(CH3)2,  b.p.  174°,  usually 

obtained  synthetically  by  V.  Baeyer  from  succinylo-succinic  ester  by 
conversion  into  i-methyl-4-iso-propyl-cyclo-hexandione-2,5,  reduction, 
and  rejection  of  2H2O.  It  yields  no  crystalline  bromide  or  nitrosite, 
and  does  not  seem  to  be  identical  with  any  of  the  known  terpenes 
(B.  26,  232  ;  27,  453). 

A3«8(9)-p-Menthadiene  C10H16,  b.p.  184°,  tetrahydro-p-toluylic  acid 
ester  with  MgICH3  (C.  1910,  II.  80  ;  see  B.  39,  2585). 

Sylvestrene    C10H16=CH3-C=CH— CH.C(CH3) :  CH2>  bp    ^^  has 

been  found  in  the  Indian,  Swedish,  and  Russian  turpentine  oil,  and  oil 
of  pine-needles.  It  is  dextro-rotatory,  [a]D= +66-32°  (A.  252,  149), 
and  possesses  a  pleasant  odour  resembling  lemons.  Synthetically,  it 
has  been  prepared  from  d-A2-tetrahydro-m-toluic  ester  by  trans- 


496  ORGANIC  CHEMISTRY 

position  with  CH3MgI  and  elimination  of  water  (Perkin) .  Its  solution 
in  acetic  anhydride  is  coloured  a  deep  blue  by  the  addition  of  con- 
centrated sulphuric  acid.  Similar  behaviour  is  shown  by  carvestrene 
and  dihydro-benzol,  while  other  terpenes,  under  the  same  conditions, 
show  a  red  or  reddish-yellow  colour.  It  is  one  of  the  most  stable  of 
terpenes,  and  cannot  be  transformed  into  isomeric  terpenes  by  means 
of  either  heat  or  acids  (A.  239,  28).  On  bromination  of  its  dihydro- 
bromide  and  subsequent  reduction  with  zinc  dust  and  HC1,  m-cymol  is 
obtained,  while  limonene,  treated  similarly,  gives  p-cymol.  Sylves- 
trene  is  probably,  therefore,  the  limonene  of  the  m-cymol  series  (B.  31, 
2067) .  Like  limonene,  it  forms,  by  addition  of  two  molecules  halogen 
hydride,  dihalogenides,  which,  however,  in  contrast  with  the  corre- 
sponding limonene  compounds,  are  optically  active,  and  from  which,  by 
boiling  with  aniline  and  sodium  acetate,  optically  active  sylvestrene  is 
regenerated.  By  treatment  with  dilute  potash  the  dihydro-halogenides 
are  converted  into  the  alcohols  corresponding  to  terpin  and  terpineol, 
viz.  sylveterpineC10H18(OH)2,  m.p.  136°,  and  sylveterpineole  C10H17OH, 
b.p.  210°  (A.  357,  72) ;  dihydro-chloride  C10H18C12,  m.p.  72° ;  dihydro- 
bromide,  m.p.  72° ;  dihydro-iodide,  m.p.  67° ;  tetrabromide  C10H16Br4, 
m.p.  135°;  nitroso-chloride  C10H16(NO)C1,  m.p.  107°  (A.  252,  150). 

Carvestrene  C10H16,  boiling  at  178°,  results  from  the  distillation  of 
carylamine  chlorohydrate.  It  is  probably  the  optically  inactive 
isomeride  corresponding  to  sylvestrene  (B.  27,  3485).  Since,  like  the 
latter,  it  passes  into  m-cymol,  it  is  probably  the  dipentene  of  the  m-cymol 
series  (B.  31,  1405).  Blue  coloration,  see  Sylvestrene.  By  nuclear 
synthesis  it  has  been  obtained  from  the  racemic  A2-tetrahydro-m- 
toluic  ester  (C.  1907,  I.  1408). 

The  dihydro-chloride  melts  at  52°,  and  the  dihydro-bromide  at  48°-5o°. 
On  the  synthesis  of  a  terpene  linkage  isomeric  with  carvestrene,  viz. 
A6»8(9)-m-menthadiene,  b.p.  177°,  see  C.  1909,  I.  171. 

Hydro-terpenes.  —  Hydrocarbons  derived  from  menthol  and 
tetrahydro-carveol  as  foundation  substances,  and  containing  two  to 
four  atoms  more  of  hydrogen  than  the  preceding  bodies,  bear  close 
kinship  to  the  latter.  The  two  alcohols  just  mentioned  are  derived  in 
such  a  manner  from  hexahydro-p-cymol  that  in  both  of  them  there 
are  present  secondary  ring-alcohols  of  this  hydrocarbon.  When  they 
lose  water,  menthene  and  carvo-menthene  are  produced.  The  produc- 
tion of  the  latter  compounds  from  limonene  and  terpinene  monochloro- 
hydrate,  as  well  as  from  a-phellandrene,  by  reduction  with  sodium  and 
alcohol,  has  been  mentioned  above. 

Carvo-menthene  C10H18,  b.p.  175°  (cp.  /.  pr.  Ch.  2,  66, 274  ;  B.  40, 
2959).  Its  nitroso-chloride  melts  at  87°,  and  its  nitrol-benzyl-amine  at 
1007°. 

Menthene,  mentho-menthene  C10H18,  b.p.  167°,  with  specific  gravity 
0-806  or  0-814  (20°).  It  is  best  made  by  acting  with  potassium 
phenolate  upon  menthyl  chloride  (B.  29,  1843)  ;  or  by  the  dry  distilla- 
tion of  menthyl- xanthogenic  methyl  ester  Ci0H10OCSSCH3  (B.  32,  3332)  ; 
it  is  obtained  direct  from  menthol  by  heating  with  dilute  sulphuric  acid 
or  oxalic  acid  (C.  1900,  I.  noi ;  1901,  II.  1158;  B.  37,  1374).  i-Men- 
thene  has  been  obtained  from  the  condensation  product  of  I,  4-methyl- 
cyclo-hexanone  with  iso-propyl-magnesium  iodide  by  splitting  off  water 
(C.  1906,  I.  341).  Nitroso-chlorides,  see  B.  29,  4. 


MONOCYCLIC  TERPENE  OR  MENTHANE  GROUP     497 

The  constitution  of  the  two  hydrocarbons  follows  from  their  re- 
lation to  carvacrol  and  menthol.  Carvacrol  readily  results  from  a 
rearrangement  of  carvone,  which,  upon  reduction,  yields  tetrahydro- 
carveol,  with  which  menthol  is  isomeric.  The  constitution  of  menthol, 
on  the  other  hand,  is  proved  by  conversion  of  the  corresponding  ketone, 
menthone,  into  3-chloro-cymol  and  thymol.  By  removing  water  from 
these  alcohols,  or  hydrogen  chloride  from  their  chlorides,  two  different 
tetrahydro-cymols  are  formed  : 


2—  ^    rH3  2— 

[  [ 


CH2-CH2—  CH3 

Menthol  Menthene 


/CH(OH)—  CH2\         rH/CH3  rH   r^CH—  CH2\         rH 

[\CH2  --  CH2/(  [\CH3  ~         'H3-C\CH2-CH2/(  [\CH 

Tetrahydro-carveol  Carvo-menthene. 

When  oxidised  with  potassium  permanganate,  menthene  yields  (i) 
menthene  glycol,  (2)  a  keto-alcohol  boiling  at  105°  (13-5  mm.),  and 
(3)  the  fatty  acids  arising  from  menthone  (B.  27,  1636)  ;  while  carvo- 
menthene  yields  (i)  a  ketone  aldehyde  C10H18O2,  b.p.  about  120°,  (2)  a 
ketonic  acid  C10H18O3,  b.p.9  about  175°,  and  (3)  j3-iso-propyl-glutaric 
acid  (B.  40,  2959). 

A  A4(8)-menthene,  dihydro-terpinolene  CH3CH/™2~^22^>C  :  c<^23> 

\CH2  —  Cri2/  XClri/j 

b.p.  173°,  D  0-831,  has  been  obtained  from  the  condensation  product 
of  i,  4-methyl-cyclo-hexanone  with  bromiso-butyric  ester  and  zinc 
by  rejection  of  water,  and  distillation  of  the  resulting  unsaturated  acid. 
Nitroso-chloride,  m.p.  102°.  On  boiling  with  dilute  H2SO4  it  trans- 
poses into  i-mentho-menthene  (A.  360,  70).  In  the  same  manner  the 
corresponding  menthenes  of  the  o-  and  m-series  have  been  obtained 
(A.  360,  75). 

A80»-Menthene  CH3CH<^^^CH.C<^,  b.p.14  54°,  is  formed 

by  reduction  of  iso-pulegol  chloride  with  sodium  and  alcohol.  On 
oxidation,  it  yields  hexahydro-p-acetyl-toluol  and  hexahydro-p- 
toluic  acid  (B.  39,  2582). 

By  reducing  menthol  with  HI,  or  menthyl  chloride  with  sodium 
and  alcohol  (B.  29,  317  ;  /.  pr.  Ch.  2,  60,  158)  a  hydrocarbon  has  been 
obtained  which  is  probably  hexahydro-cymol. 

Hexahydro-eymol,  menthane,  mentho-naphthene 


b.p.  169°,  D0  0-8066.  The  same  hydrocarbon  is  probably  represented 
by  the  hexahydro-cymol  obtained  by  the  reduction  of  terpin  hydrate 
(B.  23,  R.  433),  terpineol  (C.  1905,  II  135),  and  d-limonene  (C.  1910,  1. 
349),  as  well  as  resin  oil. 

2.  ALCOHOLS  OF  THE  MONOCYCLIC  TERPENE  OR  MENTHANE  GROUP. 

Monacid     Menthane     Alcohols.  —  Hexahydro-p-cymol     yields    the 
isomeric  menthols. 

Secondary    Menthols.  —  1-Menthol,    mentha-camphor,  5-methyl-2- 

VOL.  II.  2  K 


4g8  ORGANIC  CHEMISTRY 


iso-propyl-hexahydro-phenol  CH3.CH<2<>CH.CH(CH3)2    (see 

\UJH.2.L/.tl2  -  * 

above),  m.p.  44°  and  b.p.  212°.  It  is  the  chief  constituent  of 
peppermint  oil  (from  Mentha  piperita  and  Mentha  arvensis,  var.  piper- 
ascens).  It  is  formed  in  the  reduction  of  menthone  (/.  pr.  Ch.  2,  55, 
14),  and  is  oxidised  by  chromic  acid  to  1-menthone.  By  the  exit  of 
water  it  yields  menthene  (see  above),  and  by  reduction  hexahydro- 
cymol  results  (above).  Potassium  permanganate  converts  it  into  oxo- 

menthylic  acidCH3.CH<^^2'^2l5co.CH.(CH3)2,  boiling  at  174°  (15  mm.) 


(A.    289,   362),   and    j3-methyl-adipic  acid 

melting  at  89°  (B.  27,  1818). 

A  mixture  of  two  racemic  menthols,  m.p.  25°  and  49°,  is  obtained 
by  the  reduction  of  thymol  with  hydrogen  and  nickel.  From  the 
first  of  these,  by  splitting  up  the  corresponding  phthalic  ester  acid 
with  cinchonin  or  brucin,  we  obtain  the  natural  1-menthol  (C.  1909, 
I.  1872). 

Menthyl  chloride  C10H19C1  boils  at  204°.  The  ethyl  ether  boils  at 
212°,  and  the  benzoyl  ester  melts  at  54°.  Menthyl-xanthogenie  methyl 
ester,  m.p.  39°,  gives  menthene  on  dry  distillation  (B.  35,  2473).  Iso- 
valerianic  ester,  b.p.10  126°,  is  recommended  under  the  name  of 
"  validol  "  as  a  remedy  for  sea-sickness.  The  chloro-methyl-men- 
thyl  ether,  formed  by  the  action  of  HC1  upon  a  mixture  of  menthol  and 
formaldehyde,  is  used  under  the  name  "formane"  as  an  antiseptic. 
Its  composition  is  C10H19OCH2C1,  b.p.16  161°. 


CJtl  2  -  (_/Jbl2/ 

isomeric  with  menthol,  is  a  thick  oil,  volatile  without  decomposition. 
It  is  formed  when  tetrahydro-carvone  and  carvenone  are  reduced  in 
moist  ethereal  solution  with  metallic  sodium.  A  mixture  of  racemic 
carvo-menthols  is  obtained  by  the  reduction  of  carvacrol  with  Ni  and 
H  (C.  1908,  I.  733). 

Its  genetic  connection  with  carvacrol  (see  above)  would  indicate  its 
constitution. 

Tertiary  menthols  are  produced  when  their  hydro-iodic  acid  esters, 
addition  products  of  HI  and  menthene  by  means  of  carvo-menthene, 
are  treated  with  moist  silver  oxide  (see  also  B.  29,  1844  ;  /.  pr,  Ch.  2, 
60,  259).  It  is  noteworthy  that  the  addition  of  the  halogen  hydrides 
to  the  menthenes  produces  the  same  tertiary  menthyl  halogenides  as 
are  obtained  from  menthol  and  tetrahydro-carveol,  with  the  phos- 
phorous halogenides  and  halogen  hydrides. 

Tertiary  menthol-4  CH3.CH/CH2~  CH2\c(OH).CH(CH3)2,   b.p.  100° 

\CH2  —  CHij/ 

(20  mm.),  has  a  faint  peppermint-like  odour.  It  is  formed  by  the 
action  of  iso-propyl  -  magnesium  iodide  upon  I,  4  -  methyl  -  cyclo  - 
hexanone  (C.  1906,  II.  342).  On  heating  with  KHSO  it  yields  A4^- 
menthene. 

Tertiary  carvo-menthol  CH3C(OH)/CH2—  CH2\  CH  CH(CH3)2  boils  at 

\CH2  —  CH2/ 

96°-ioo°  (17  mm.). 

Tertiary  menthanol-8  CH3CH/^2~  :^2V^H.C(OH)(CH3)2,  m.p.  36°, 

\CxH2  —  CH2/ 


MONOCYCLIC  TERPENE  OR  MENTHANE  GROUP  499 

b.p.  207°,  from  hexahydro-p-toluic  ester  and  methyl-magnesium  iodide 
(C.  1905,  II.  239). 

Diacid  Alcohols. — In  this  group  are  the  two  terpins,  cis-terpin 
and  trans-terpin,  corresponding  to  the  cis-  and  trans  -  dipentene  - 
dihydro-halogenides,  with  which  they  are  intimately  related.  At 
present  the  following  formulas  are  assigned  them  (see  B.  29,  5  ; 
C.  1897,  II.  420)  : 

CH3\     /CH2— CH2\     /H  H0\     XCH2-€H2\     /H 

HO/    \CH2— CH2/^\C(CH3)2OH  CHs/   \CH2— CH2/  \C(CH3)2OH 

cis-Terpin  trans-Terpin. 

These  are  in  harmony  with  the  oxidation  of  terpin  hydrate  to  terebic 
acid,  as  well  as  with  its  formation  from  linalool.  Cineol  is  to  be 
regarded  as  the  oxide  corresponding  to  the  cis-terpin. 

Terpin,  cis-terpin  C10H18(OH)2,  melting  at  104°  and  boiling  at 
258°,  readily  attracts  water  and  passes  into  a  body  distinguished  by 
its  great  power  of  crystallisation,  viz.  : 

Terpin  hydrate  C10H18(OH)2+H2O,  m.p.  117°,  from  which  it  is 
prepared  by  protracted  heating  to  100°.  Terpin  corresponds  to  cis- 
dipentene-dihydro-bromide,  from  which  it  can  be  obtained  by  treat- 
ment with  silver  acetate  in  glacial  acetic  acid,  and  saponifying  the  re- 
sulting diacetyl  derivative  with  alcoholic  potash.  Terpin  hydrate  is  also 
produced  if  turpentine  oil  is  allowed  to  stand  with  dilute  nitric  acid  and 
alcohol  (A.  227,  284),  as  well  as  from  pinene,  dipentene,  and  d-limonene 
with  dilute  acids.  It  forms,  furthermore,  on  bringing  dipentene  and 
d-limonene  dihydro-chloride  into  contact  with  water,  and  when  ter- 
pineol  and  cineol  are  acted  upon  by  dilute  acids.  Synthetically,  it  has 
been  obtained  by  the  action  of  methyl-magnesium  iodide  upon  I,  4- 
cyclo-hexanone-carboxylic  ester  (C.  1907,  I.  1412). 

The  haloid  acids  convert  terpin  hydrate  into  the  cis-  and  trans- 
dihydro-halides  of  dipentene.  When  boiled  with  dilute  acids  it  passes 
into  terpineols  (B.  27,  443,  815),  cineol,  dipentene,  terpins,  and  ter- 
pinolenes. 

trans-Terpin  C10H;8(OH)2,  m.p.  i56°-i58°  and  b.p.  26^-26^° ,  is 
formed  from  trans-dipentene-dihydro-bromide  (see  cis-Terpin),  into 
which  it  finally  reverts  upon  treatment  with  hydrogen  bromide.  It  does 
not  combine  with  water  of  crystallisation. 

Cineol,  eucalyptol  C1()H18O,  b.p.  176°,  with  specific  gravity  0-923 
(16°),  nD=i-4559,  is  a  liquid  with  a  camphor-like  odour,  and  repre- 
sents the  glycol  anhydride  corresponding  to  cis-terpin. 

It  occurs  in  many  ethereal  oils,  in  oleum  cince,  the  worm-seed  oil 
of  Artemisia  cina,  cajeput  oil,  eucalyptus  oil,  rosemary  oil,  sage  oil,  etc. 
Hydrochloric  acid  gas  conducted  into  a  petroleum  ether  solution  of 
cineol  precipitates  an  unstable  addition  product  C10H18O.HC1  (?), 
which  water  resolves  into  its  components,  and  which  serves  for  the 
separation  of  cineol.  With  phosphoric  acid,  resorcin,  hydrogen  ferro- 
and  ferri-cyanide,  etc.,  cineol  forms  compounds  resembling  salts 
(B.  34,  2689  ;  C.  1907,  II.  240). 

In  glacial  acetic  acid  solution  the  haloid  acids  change  cineol  into 
dipentene  dihydro-halides.  At  low  temperatures  hydrogen  bromide 
produces  cis-dipentene-dihydro-bromide.  P2S5  converts  cineol  into 
cymol.  Potassium  permanganate  oxidises  cineol  (i)  into  cineolic 


500  ORGANIC  CHEMISTRY 

(2),  the  anhydride  (3)  of  which  yields,  upon  distillation,  methyl-hexylene 
ketone  or  methyl-heptenone  (4),  while  the  latter  may  be  arranged  to 
m-dihydro-isoxylene  (5).  This  series  of  reactions  is  shown  in  the 
following  diagram  : 

CH2— CH- CH2       CH2— CHCO2H  CHa— CH2  CH2— CH 


C(CH3)2 

6 


C(CH3) 

6 


C(CH3)2  C(CH3)2 

6 


CH2— C(CH3)— CH2       CH2— C(CH3)CO2H       CH2— C(CH3)CO2H     CH2— COCH3. 

Cineolic  acid  melts  at  ig6°-igy°  with  decomposition ;  its  anhydride 
melts  at  78°  and  boils  at  157°  (13  mm.).  On  heating  with  concentrated 
H2SO4  it  yields  i,  3-dimethyl-benzoic  acid  (B.  39,  4083).  Cinenic 
acid  C9H16O3,  m.p.  84°,  is  formed  synthetically  from  the  hydrate  of 
methyl-heptenone  by  addition  of  prussic  acid  and  saponification.  By 
the  action  of  concentrated  H2SO4  it  passes  into  S-acetyl-aa-dimethyl- 
valerianic  acid  with  migration  of  a  methyl  group  (B.  33,  1129  ;  34, 
2191  ;  41,  1278). 

As  terpin  corresponds  to  the  dipentene-dihalogenides,  so  we 
have,  corresponding  to  the  terpinene  dihalogenides,  terpinene-terpin 
CH3(OH)C/™2—  ;H2\C(OH) .CH(CH3)2,  m.p.  138°,  b.p.  250°,  which 

\Url2 — Url2/ 

sublimes  on  heating.  It  is  formed  by  the  action  of  dilute  potash 
upon  terpinene  dichlorohydrate,  to  which  it  reverts  on  treating  with 
glacial  acetic-hydrochloric  acid.  It  is  also  obtained  from  sabinene, 
thujene,  and  terpinenols  with  dilute  sulphuric  acid  (A.  356,  200). 
On  heating  with  oxalic  acid  it  splits  off  water  and  passes  into  ter- 

/CH2— CH2\ 

pinenol-4  and  1,  4-cineol,  terpinene-cineol  CH3Cr O- -^C.CH(CH3)2, 

\CH  2 — CH  2  / 

b.p.  173°.  This,  with  HBr,  yields  terpinene  dibromo-hydrate  (A.  356, 
204). 

On  the  meta-series  compound  corresponding  to  terpin,  sylveterpin, 
see  above,  and  C.  1907,  I.  1408. 

Menthene-glyeol  C10H18(OH)2,  melting  at  77°  and  boiling  at  130° 
(13  mm.),  results  when  menthene  is  oxidised  with  potassium  perman- 
ganate (B.  27,  1636).  An  isomeric  3,  8-menthene-glycol  C1qH18(OH)2, 
m.p.  81°,  b.p.10  145°,  is  obtained  besides  iso-pulegol  by  treating  citron- 
ellal  with  dilute  H2SO4 ;  on  withdrawing  water  it  passes  into  iso- 
pulegol  (C.  1897,  II.  304). 

2,  8-Dioxy-hexahydro-cymol  C10H18[2,  8](OH)2,  a-form  m.p.  113°, 
j8-form  m.p.  103°,  is  formed  by  reduction  of  oxy-dihydro-carvone,  or 
by  shaking  up  dihydro-carveol  with  dilute  H^SO^.  On  boiling  with 
25  per  cent.  H2SO4,  it  yields  an  oxide  isomeric  with  cineol,  dihydro- 
pinol  C10H18O,  b.p. 9  58°,  which  unites  with  potassium  ferricyanide  to 
a  crystalline  compound  (B.  38,  1719). 

(c)  Triacid  menthane  alcohols  have  been  obtained  by  oxidising 
menthene  alcohols  with  potassium  permanganate. 

i.  2,  8,  9-Trioxy-hexahydro-cymol  C10H17[2,  8,  9](OH)3  (i),  from 
dihydro-carveol  (see  below),  is  a  syrup,  and  with  dilute  sulphuric  acid 
yields  an  indifferent  oxide  C10H16O,  boiling  at  I96°-I99°  (A.  277,  152) ; 
while  upon  oxidation  with  chromic  acid  it  forms  a  ketone-alcohol, 
5-aeetyl-hexahydro-o-cresol,  melting  at  58°  (2),  which,  upon  further 


MONOCYCLIC  TERPENE  OR  MENTHANE  GROUP  501 

oxidation,  changes  to  hexahydro-m-oxy-p-toluic  acid,  melting  at  153° 
(3).  The  constitution  of  this  last  acid  is  evident  from  its  conversion 
by  bromine  into  m-oxy-p-toluie  acid,  melting  at  203°  (4).  These 
experiments  give  rise  to  the  constitution  formulae  (B.  28,  2141)  : 


CH3  CH2 

CH3  CH2 

CH3  CH2 

CH3  CH2OH 

CH3 

v 

C 

Y 

v 

C 

\/ 

COH 

CO 

*CH 

4« 

*CH 

*CH 

*CH 

/\^ 

/\ 

y\ 

x\ 

/\ 

H2C     CH2 

H2C     CH2 

H2C     CH2 

H2C     CH2 

H2C     CH2 

1       1      > 

1       1     — 

—  >     |       |            — 

->      1       1    '       — 

->      1       1 

H2C     CH 

HC     CO 

H2C     CHOH 

H2C     CHOH 

H2C     CHOH 

v 

C 

Y 

"cH 

Y« 

Yc 

CH3 

U 

CH3 

CH3 

CH3 

Limonene 

Carvone 

Dihydro-carveol 

(i) 

(2) 

C02H 

CO2H 

/\  /\ 

H2C       CH2  HC       CH 

H2C       CHOH 


:HS 

(3)  (4)- 

2.  1,  2,  8-Trioxy-hexahydro-cymol,     dioxy-terpineol     C10H17(OH)3, 
melting  at  122°,  formed  from  the  terpineol  melting  at  35°,  passes  into 
carvenone  when  it  is  acted  upon  with  dilute  sulphuric  acid  (A.  277, 122). 

3.  1,  8,  9-Trioxy-hexahydro-eymol  C10H17[i,  8,  9](OH)3,  m.p.  118°, 
from  /3-terpineol. 

4.  1, 4,  8  -  Trioxy  -  hexahydro  -  cymol    C10H17[i,  4,  8] (OH)3+3H2O, 
melts  in  the  anhydrous  state  at  iio°-ii2°  and  boils  at  200°  (20  mm.). 
It  is  formed  from  A4>8-terpineol  (B.  28,  2296). 

5.  1,  2, 4-Trioxy-hexahydro-cymol    (i)    C10H17[i,  2,  4](OH)3+H2O, 
m.p.  117°,  anhydrous,  m.p.  129°,  and 

6.  1,  3, 4-Trioxy-hexahydro-eymol    (2)    C10H17[i,  3,  4](OH)3,    m.p. 
121°,  are  formed  by  the  oxidation  of  terpinenol-4  and  terpinenol-i.     On 
heating  with  HC1  the  former  passes  into  carvenone  (3)  and  the  latter 
into    A1-menthenone    (4).       KMnO4    oxidises    both    to    aaj-dioxy-a- 
methyl-ai-iso-propyl-adipinic   acid   (5).      These  transformations,   im- 
portant for  the  constitution  of  terpinenols  and  terpinene-terpin,  are 
shown  in  the  following  scheme  (A.  356,  207  ;   362,  261)  : 

(3)  CH3  (i)CH3OH  (5)CH3OH  (2)  CH3  OH  (4)  CH3 

CH  C  C  V  C 


H2C      CO 

H2C      CHOH 

H2C      COOH 

H2C      CH2 

H2C      CH 

1       1       «- 

-II            > 

1       1            <- 

—      II'     — 

->      1       1 

HC      CH2 

H2C      CH2 

H2C      COOH 

H2C      CHOH 

H2C     CO 

Y 

Y 

v 

C 

Y 

""CH 

^H 

L^rt, 

S\ 

HO          CgH, 

s\ 

HO      CsH, 

H7Cg          OH 

CsH, 

502  ORGANIC   CHEMISTRY 

Tetra-acid-methane  alcohols  are  formed  by  the  oxidation  of 
some  terpenes  with  potassium  permanganate  :  (i)  Limonetrite  C10H16 
(OH)4,  m.p.  192°,  from  d-limonene  (B.  23, 2315  ;  28, 2149) ;  (2)  erythrite 
of  terpinolene,  m.p.  150°  (anhydrous)  (A.  368,  10)  ;  (3)  erythrite  from 
y-terpinene,  m.p.  237°,  gives  a  mixture  of  carvacrol  and  thymol  on 
heating  with  dilute  H2SO4  (A.  362,  298  ;  C.  1909,  II.  2159). 

II.  Menthene  Alcohols  C10H17. — On  oxidation  with  potassium  per- 
manganate these  give  three-acid  alcohols  (see  above). 

Terpineols. — The  "  liquid  terpineol  "  used  in  perfumery,  obtained 
from  terpin  hydrate  by  elimination  of  2H2O  with  dilute  H2SO4,  consists 
chiefly  of  the  two  isomeric  a-  and  /?-terpineols,  m.p.  35°  and  32°. 

a-Terpineol,  fr-menthenol-S  CH3.C^CH"  ~CH2^>CH.C(OH)(CH3)2,  m.p. 

(optically  inactive  form)  35°,  (active  forms)  37°-38°,  b.p.  219°,  D15 
0-939,  can  also  be  obtained  from  linalool  and  geraniol.  By  nuclear 
synthesis  it  is  obtained  through  the  action  of  methyl-magnesium  iodide 
upon  A1-tetrahydro-p-toluic  ester  (C.  1909,  I.  170).  Terpineols,  of 
various  origins,  may  be  either  active  or  inactive  optically  (B.  28,  2180). 
A  specially  strongly  laevo-rotatory  a-terpineol,  aD=  — 106°,  is  obtained 
by  the  action  of  dilute  H2SO4  upon  methyl-nopinol  (A.  360,  88).  On 
a  laevo-rotatory  terpineol  from  oil  of  turpentine,  see  C.  1889,  I.  1241. 
Terpineol  combines  very  readily  with  nitrosyl  chloride.  When 
hydrogen  chloride  is  withdrawn  from  this  body,  an  oxy-oxime,  melting 
at  134°,  is  produced.  Boiling  dilute  acids  change  it  to  carvacrol  and 
carvone  (B.  29,  R.  587).  Hence  it  follows  that  in  terpineol  and  carvone 
the  carbon  atoms  are  similarly  grouped.  Terpineol  nitroso-chloride 
and  limonene  nitroso-chloride  are  correspondingly  constituted  (B.  29, 
9).  Potassium  permanganate  oxidises  terpineol  (i)  into  trioxy-hexa- 
hydro-cymene,  melting  at  121°  (2),  while  with  chromic  acid  it  yields  a 
ketone-lactone,  homo-terpenylic  acid  methyl-ketone  C10H16O3  (3), 
which,  under  the  influence  of  potassium  permanganate,  breaks  down 
into  acetic  acid  and  terpenylic  acid  (4).  Therefore,  in  terpineol  melting 
at  35°,  the  OH  group  probably  is  in  union  with  carbon  atom  8  (B.  28, 
1773,  1779)  : 

(CH3)2  (CH3)2 

(i)    C(OH)  (2)    C(OH) 
CH  CH 

/\  /\ 

H2C      CH2  H2C      CH2 

H2C      CH    "          *  H2C      CH(OH) 


C  COH 

CH3  CH3 

When  terpineol  is  heated  with  potassium  bisulphate  it  changes  to 
dipentene,  and  when  boiled  with  oxalic  acid  to  terpinolene  (A.  275, 
104;  368,io). 

j3-Terpineol,    &sW-menthenol-i    CH3C(OH)<(^CH2     'H2\CH.c^/CH"2( 

\CH2 — CH2/  \CH3' 

m.p.  32°,  b.p.  210°,  D15  0-923;  nitroso-chloride,  m.p.  103°  (A.  345, 
127),  yields  with  permanganate  i,  8,  g-trioxy-hexahydro-cymol,  which 
on  further  oxidation  with  chromic  acid  yields  4-acetyl-i,  i-methyl- 
cyclo-hexanol ;  the  latter  may  be  converted  into  tetrahydro-p-acetyl- 


MONOCYCLIC  TERPENE   OR  MENTHANE   GROUP     503 

toluol,  p-acetyl-toluol,  and  p-toluic  acid  (B.  35,  2147  ;  A.  324,  79). 
For  synthesis  of  /?-terpineol,  see  C.  1904,  II.  330. 

y-Terpineol,    AW-menthenol-i    CH3.C(OH)/CH2~  ;H2\c=c/CH3, 

\CH2  —  CH2/  \CH3' 

melts  at  69°.  Its  acetate  results  on  treating  tribromo-terpane  or  tetra- 
hydro-dipentene  tribromide  with  glacial  acetic  acid  and  zinc  dust. 
Glacial  acetic  acid  and  HC1  convert  it  into  a  mixture  of  dipentene  and 
terpinene  dichlorohydrate  (A.  350,  160).  With  NOC1  it  forms  a  blue 
nitroso-chloride,  just  as  tetramethyl-ethylene  does.  Consequently  it 
probably  also  contains  a  tertiary-tertiary  double  union.  In  addition, 
its  OH  group  must  be  in  such  a  position  that  dipentene  dihydro- 
bromide  can  be  produced  with  hydrogen  bromide. 

Terpinenols.  —  As  from  terpin,  so  also  from  terpinene-terpin,  un- 
saturated  alcohols  may  be  obtained,  by  splitting  off  one  molecule  of 
water.  These  are  termed  terpinenols  (A.  356,  206  ;  362,  261). 

Terpinenol-4,  AJ-menthenol-4  CHSC/C          ;H2\C(OH).CH/CH3,  b.p. 

\CH2  —  CH2/  \CH3 

212°,  found  in  dextro-form  in  cardamomene  and  majoran  oil 
(A.  356,  168).  d-Terpineol-4  is  formed  by  shaking  up  sabinene  and 
thujene  in  dilute  H2SO4,  sabinene  hydrate  being  formed  intermediately, 
and  easily  passing  into  terpinenol-4.  i-Terpinenol-4  is  produced  by 
the  action  of  dilute  potash  upon  terpinene  dihydro-chloride,  and  from 
terpinene-terpin  with  aqueous  oxalic  acid.  With  glacial  acetic  hydro- 
gen haloids  it  yields  terpinene  dihaloids,  with  dilute  H2SO4  terpinene- 
terpin.  By  oxidation  with  MnO4K  we  obtain  the  I,  2,  4-trioxy-hexa- 
hydro-cymol. 


Terpinenol-1,  &>-menthenol-i  CH3.C(OH)2—         c.CHa,  b.p. 

\CH 


209°,  is  found  in  the  first  samples  of  industrial  terpineol.  It  is 
synthesised  from  A3-iso-propyl-cyclo-hexanone  with  methyl-mag- 
nesium iodide.  On  oxidation  it  yields  I,  3,  4-  trioxy-hexahydro- 
cymol. 

Dihydro-carveol,  ^-menthenol-2 

b.p.  224°,  D15  0-937,  nD=  1-482,  optically  active,  with  a  pleasant  odour 
recalling  terpineols,  was  found  in  carraway  oil  (C.  1905,  I.  1470)  ;  it  is 
formed  by  the  reduction  of  carvone  ;  dihydro-carveol-xanthogenic 
methyl  ester  on  dry  distillation  yields  d-limonene  (C.  1908,  I.  1180). 

Iso  -  pulegol,    W>-menthenol  -  3 


b.p.13  91°,  from  the  isomerisation  of  citronellal  with  acids.     On  oxida- 
tion it  passes  into  the  ketone,  iso-pulegone. 

A3-Menthenol-8  CH3CH/^2-      V  qoH)/^  m  p>  ^}  b.p 

Nv^rl2  —  L/xl2/  \Uxl3 

97°,  by  the  action  of  CH3MgI  upon  A3-tetrahydro-p-toluic  ester  or 
A3-tetrahydro-p-acetyl-toluol  (C.  1910,  II.  80). 

A2-Menthenol-l  CH3(OH)C/^  =CH  \CH.cH/™3j  b>p.io  ^^  by 

\Uxl2  —  L/xl2/  X^*13 

transposition  of  A2-iso-propyl-cyclo-hexenone-4  with  CH3MgI.     Easily 
loses  water  and  forms  a-phellandrene  (A.  359,  283). 

Menthadiene  Alcohols.  —  Carveol-methyl  ether  C10H15OCH3,  boiling 
at  2o8°-2i2°,  with  sp.  gr.  0-9065,  nD=  1-47586  (18°),  represents  the 
methyl  ether  of  such  an  alcohol.  It  is  formed  in  the  action  of 


504  ORGANIC  CHEMISTRY 

sodium  upon  the  alcoholic  solution  of  limonene  tetrabromide.     Chromic 
acid  oxidises  it  to  inactive  carvone  (A.  281,  140). 

3.    BASES  OF  THE  MONOCYCLIC  TERPENE  OR  MENTHANE  GROUP. 

Menthane  bases  have  been  obtained  by  the  reduction  of  the  oximes 
of  the  methane-ketones  with  sodium  and  alcohol,  or  upon  heating  the 
ketones  with  ammonium  formate. 


d-Menthylamine  and  1-menthylamine  CH3.CH/CH2~C     \CH.CH(CH3)2, 

\CH2—  CH2/ 

boiling  at  205°,  have  an  unpleasant  odour,  and  attract  CO2  from 
the  air.  The  bases  have  opposite,  but  unequal,  rotatory  power  ; 
the  same  is  true  of  their  derivatives  (A.  276,  299).  They  can  be 
separated  by  means  of  their  formyl  compounds,  both  of  which  are 
formed  on  heating  menthene  with  ammonium  formate.  d-Formyl- 
menthylamine,  melting  at  117°,  dissolves  with  more  difficulty. 
1-Formyl-menthylamine  melts  at  102°.  1-Menthylamine  can  also  be 
obtained  from  1-menthoxime.  With  HNO2,  1-menthylamine  passes 
straight  into  1-menthol,  while  d-menthylamine  mostly  forms  menthene 
(conclusions  as  to  configuration,  see  A.  300,  278  ;  353,  323).  On 
treating  the  bromyl  compounds  of  menthylamines  with  Ag2O, 
1-menthylamine  yields  1-menthyl-hydrazin  C10H19NHNH2,  b.p.  241°, 
while  d-menthylamine  forms  menthazin  C10H18  :  N.N  :  C10H18,  m.p.  51° 
(C.  1900,  I.  654).  l-Menthyl-hydrazin  is  useful  for  splitting  up  racemic 
aldehydes  and  ketones  (B.  36,  1192).  1-Menthyl-carbimide  C10H19.N  : 
CO,  b.p.12  110°,  from  1-menthylamine,  chloro-carbonic  ester,  and 
distillation  of  the  resulting  menthyl-carbaminic  ester  with  P2O5.  May 
be  used  for  splitting  up  racemic  alcohols  (C.  1904,  II.  332). 
Tetrahydro-carvylamine,  carvo-menthylamine 


CH2  --  CH2 
boils  at  212°  (A.  277,  137  ;   C.  1908,  I.  733). 

Tert.   menthylamine  CH3.CH/^—  ^2\C(NH2)CH(CH3)2  and  tert. 

\CH2  —  CH2/ 

carvo-menthylamine    CH3(NH2)C/™2—  ™2\CH.CH(CH3)2    have    been 

\CM2  —  CJrl2/ 

obtained  by  the  interaction  of  menthene  hydrobromide,  carvo-rrtenthene 
hydrobromide,  and  silver  cyanate,  with  subsequent  saponification 
(B.  26,  2270,  2562). 

2,  4-Diamido-menthane  C10H18(NH2)2,  b.p.12  121°,  from  carvenone- 
oxamine  oxime  (B.  41,  2528). 

Menthene  bases  have  been  prepared  by  the  reduction  of  the  oximes 
of  menthene-ketones.  Carvenylamine  C10H17NH2,  b.p.10  86°-89°,  from 
carvenone  oxime  with  Al  amalgam.  Its  chlorohydrate  yields  a-ter- 
pinene  on  distillation  (B.  41,  2524). 

Dihydro-earvylamine  C10H17NH2,  b.p.  219°,  with  sp.  gr.  0-889  (20°), 
nD  =1-48294,  is  optically  active,  and  is  obtained  from  carvonoxime 
C10H14  :  NOH.  Its  chlorohydrate  breaks  down  completely  at  200°  into 
cymol  and  terpinene,  with  migration  of  linkage  (A.  368,  13). 

Pulegonamine  (A.  262,  13  ;   B.  29,  R.  173). 

Nitrolamines  have  been  obtained  from  nitroso-chlorides  —  e.g. 
limonene  —  by  transposition  with  primary  and  secondary  bases. 


MONOCYCLIC  TERPENE   OR  MENTHANE  GROUP     505 

4.     THE   RlNG-KETONES   OF  THE   MONOCYCLIC   TERPENE 

OR  MENTHANE  GROUP. 

Ketones  like  these  are  found  in  the  vegetable  kingdom.  They  are 
produced  by  the  oxidation  of  the  corresponding  secondary  alcohols, 
and  by  continued  oxidation  they  change  to  cyclic  and  aliphatic  car- 
boxylic  acids — decomposition  products, — the  constitution  of  which 
furnishes  insight  into  the  constitution  of  the  ring-ketones  and  their 
derivatives.  The  ring-ketones  of  the  terpane  group,  like  other  ketones, 
are  characterised  by  their  oximes  and  the  sparing  solubility  of  their 
semi-carbazones. 

(a)  Keto-menthanes,  keto-hexahydro-p-cymols  C10H18O. 

Menthone  CHg.CH/™*  •  CO\CH.CH(CH3)2,   boiling    at    208°,    sus- 

XCH^.Crij/ 

tains  the  same  relation  to  menthol  that  camphor  bears  to  borneol. 
It  occurs  in  Japanese,  American,  and  Russian  peppermint  oils,  together 
with  menthol,  esters  of  menthol,  menthene,  and  limonene.  Menthone 
is  known  in  two  optically  active  modifications.  1-Menthone  is  obtained 
upon  oxidising  menthol  with  potassium  bichromate  and  sulphuric  acid 
at  a  temperature  not  exceeding  50°  (A.  250,  322).  Its  specific  gravity 
equals  0-896  (20°),  [a]D=  —  28°.  Concentrated  sulphuric  acid,  in  the 
cold,  rearranges  1-menthone  to  d-menthone,  [a]D=+93-2°  (B.  42,  846). 

A  d-menthone,  [a]D=+43°  66',  is  found  in  the  American  polei  oil 
from  Hedeoma  pulegioides  (C.  1907,  II.  242).  Synthetically,  i-menthone 
has  been  formed  from  jS-methyl-pimelinic  ester  by  cyclic  aceto-acetic 
ester  condensation,  introduction  of  the  iso-propyl  group,  and  saponi- 
fication  (B.  34,  3793). 

An  optically  active  men th one  is  formed  from  the  active  I,  3-methyl- 
cyclo-hexanone  obtained  by  breaking  up  pulegone,  by  treating  with 
sodium  amide  and  iso-propyl  iodide  (C.  1905,  I.  605)  ;  for  other  syn- 
theses of  menthone,  see  A.  342,  306  ;  357,  209  ;  also  Rhodinal. 

The  constitution  of  menthone  is  demonstrated  (i)  by  its  conversion 
into  3-chloro-cymol ;  PC15  changes  menthone  to  dichloro-hexahydro- 
cymol,  which  splits  off  hydrogen  chloride  and  becomes  tetrahydro-chloro- 
cymol ;  this  in  turn,  by  the  action  of  bromine  and  quinolin,  loses 
hydrogen,  and  3-chloro-cymol  results  (B.  29,  314).  (2)  By  the  formation 
of  thymol  through  the  elimination  of  2HBr  from  dibromo-menthone 
C10H16Br2O,  melting  at  80°,  which  is  produced  in  the  bromination  of 
menthone  in  chloroform  solution  (B.  29,  418). 

When  1-menthone  is  reduced  by  sodium  it  forms  I -menthol, 
while  with  ammonium  formate  the  product  is  L  -  menthylamine. 
Potassium  permanganate  oxidises  it  to  oxo-menthylic  acid 

CH3.CH/™2-^2H/co-CH(CH3)2>  and  &-methyl-adipic  acid  (B.  27,  1820). 

>vx-H.2.CxAjL2.    * 

Caro's    acid    produces    the    e-lactone    of    dimethyl-octanolic    acid 

CH'CH<CH;=§H~?H.CH(CH3)2  <B-  27>  I82°;  32'  3621;  33,  860); 
dilute  nitric  acid  produces  nitro-menthone,  which  can  be  reduced  to 
amido-menthone  (C.  1898,  II.  301). 

Amyl  nitrite  and  hydrochloric  acid  convert  menthone  into  nitroso- 
menthone  and  menthoximie  acid,  melting  at  98°.  This  is  the  oxime 
of  oxo-menthylic  acid  (B.  29,  27). 

Illumination  of  an  aqueous  alcoholic  solution  of  menthone  leads 


506  ORGANIC   CHEMISTRY 

to  the  splitting  of  the  ring  and  produces  decylic  acid  (CH3)2CH.(CH2)3 
CH(CH3)CH2COOH,  and  an  aldehyde  C10H18O,  possibly  identical  with 
a  mentho-citronellal  obtained  by  a  transformation  of  menthone-oxime 
(B.  40,  2419) 

Sodium  and  amyl  formate  change  menthone  to  oxy-methylene- 
menthone,  boiling  at  121°  (12  mm.). 

Benzylidene-menthone,  m.p.  51°,  b.p.12  189°,  gives,  on  reduction 
benzyl-menthone,  b.p.10  i75°-i78°  (B.  37,  232)  .  With  sodium  and  CO2, 
in  ether  solution,  menthone  gives  menthone-mono-  and  dicarboxylie 
acids  (C.  1897,  11.759). 

1-Menthone-oxime,  m.p.  61°,  b.p.  250°,  [a]D=—  42°,  is  transposed 
into  1-menthone-isoxime  by  PC15  in  chloroform,  or  by  acetic  anhydride, 
or  by  concentrated  H2SO4.  The  substance  formed  is  the  e-lactame  of 
an  e-amido-methyl-iso-propyl-capronic  acid,  m.p.  119°,  b.p.  295°,  [a]D 
===_52-250.  With.P2O5  both  bodies  yield  mentho-nitrile  C9H17CN, 
b.p.  225°,  which,  on  saponification,  passes  into  the  liquid  menthonenic 
acid  C9H17COOH  ;  the  latter  is  constituted  somewhat  like  citronellic 
acid,  but  is  not  identical.  The  menthonylamine  produced  by  the 
reduction  of  mentKb-nitrile  yields  with  HNO2  a  mentho-citronellol 
closely  related  to  citronellol  (A.  296,  120). 

Tetrahydro-carvone   CH3.CH./^-^2\CH.CH(CH3)2,   with   sp.    gr. 

NL/.H.2.  1^X1-2' 

0-904  (20°),  nD=i-45539,  is  produced  in  the  oxidation  of  tetra- 
hydro-carveol  and  by  reduction  of  carone  with  Na  in  moist  ether. 
Benzylidene  compound,  m.p.  175°  (A.  305,  266).  The  oxime  melts  at 
104°,  the  a-isoxime  at  51°.  f$-Isoxime  melts  at  104°.  The  semi-car- 
bazone  melts  at  174°  (A.  277,  133  ;  286,  107  ;  B.  26,  822).  When  oxid- 
ised with  potassium  permanganate  or  treated  with  amyl  nitrite  and 
hydrochloric  acid,  tetrahydro-carvone  is  decomposed  like  menthone 

with  the  production  of  an  acid,  CHg.CO^^   "^^CH.CgH^     j8-tso- 

propyl-^-acetyl-valeric  acid,  isomeric  with  oxo-menthylic  acid.  Ener- 
getic oxidation  produces  iso-propyl-succinic  acid  (B.  29,  27). 

With  Caro's  acid  we  obtain  the  e-lactone  of  iso-propyl-heptanolic 


(b)  Keto-menthenes  C10H16O  occur  to  a  certain  extent  in  nature, 
others  are  produced  by  the  oxidation  of  the  corresponding  alcohols. 
They  contain  one  double  union. 

A3-Methene-5-ketone  CH3CH<^*—  ^Vc,*^  b.p.  213°,  D20  0-918, 

nD=*i-472O  ;  its  oxime,  nitroso-menthene,  is  obtained  from  menthene 
nitroso-chloride  by  splitting  off  HC1  (A.  305,  272  ;  362,  275). 

A^Menthene-S-ketone  CHgC^^^j^CHC^H,,  b.p.  236°,  semi- 

carbazone,  m.p.  225°,  has  been  found  in  Japanese  peppermint  oil  ;  it 
is  formed  besides  cymol  on  heating  1,3,  4-trioxy-hexahydro-cymol 
with  HC1  (A.  362,271). 


Dihydro-carvone,  b?W-menthene-2-on  CH3CH/CH2—  CH2\  CH 

\CO  —  CH2/ 

b.p.  221°,  D19  0-928,  nD=i-47i74,  was  found  in  carraway  oil  (C.  1905, 
I.  1470)  ;  the  d-  and  1-forms  are  produced  from  the  corresponding  di- 
hydro-carveols  by  oxidation,  or  direct  by  the  reduction  of  the  carvones 


MONOCYCLIC  TERPENE  OR  MENTHANE  GROUP     507 

with  zinc  dust  and  alcoholic  potash  (A.  279,  377).     Benzylidene  com- 
pound, b.p.10  i87°-i90°  (A.  305,  268). 

The  oximes  melt  at  88°,  and  unite  to  the  inactive  [d-\-l\-oxime,  melt- 
ing at  115°.  Boiling  ferric  chloride  converts  dihydro-carvone  into 
carvacrol  ;  cp.  carvenone  and  carone.  Oxidation  with  potassium 
permanganate  and  afterwards  with  chromic  acid  changes  it  to  2,  5- 
methyl-acetyl-cyclo-hexanone  (B.  28,  2147,  2704).  On  the  decom- 
position of  dihydro-carvone  by  light,  see  B.  41,  1928. 

Carvenone,  carveol,  &?-menthene-2-on  CH3 


b.p.  232°,  D  0-927,  ^'=1-4822,  results  from  I,  2,  8-  and  I,  2,  4-trioxy- 
hexahydro-cymol  on  heating  with  dilute  sulphuric  acid  besides  cymol  ; 
by  isomerising  dihydro-carvone  and  carone  with  mineral  or  formic  acids  ; 
by  treating  camphor,  or  rather  dichloro-camphane,  with  HgSO^;  and 
by  reduction  of  a-terpinene  nitrosite  with  zinc  and  glacial  acetic  acid 
(/.  pr.  Ch.  2,  60,  261  ;  A.  314,  369).  Oxime,  m.p.  91°.  Hydroxyl- 
amino-oxime,  m.p.  163°  (B.  31,  2896).  Semi-carbazone,  m.p.  202°.  It 
is  closely  related  to  carvo  tan-acetone.  Boiling  ferric  chloride  oxidises 
carvenone  to  carvacrol,  while  heating  with  P  anhydride  produces 
cymol,  and  permanganate  a-methyl-glutaric  acid  (A.  314,  380). 
With  PC15  it  produces  monochloro  -  carvenene  C10H15C1,  b.p.10 
95°-98°,  which  on  reduction  with  Na  and  alcohol  yields  a-terpinene 
(B.  41,  4477). 

Carvotan-acetone,    ^-menthene-6-on 


b.p.  228°,  D21  0-938,  nD  =1-47926,  results  in  an  inactive  form  from  the 
heating  of  thujone  (tanacetone)  to  280°.  Its  oxime  melts  at  92°,  and 
its  semi-carbazone  at  177°  (B.  28,  1959).  Optically  active  dextro- 
and  laevo-rotatory  carvotan-acetone,  [a]D+i9-2°,  is  obtained  by 
careful  reduction  of  a-phellandrene  nitrite  (A.  336,  39).  Its  oxime 
melts  at  72°,  its  semi-carbazone  at  173°.  A  dextro-rotatory  carvotan- 
acetone  has  also  been  obtained  from  carvone  hydrobromide  by  reduc- 
tion with  zinc  dust  and  methyl  alcohol  (B.  34,  1924).  With  H2S  it 
combines  like  carvone  to  form  the  compound  (C10H16O)2H2S,  m.p.  220°. 
On  oxidation  with  MnO4K  it  yields  pyro-racemic  acid  and  iso-propyl- 
succinic  acid  (B.  33,  2457).  With  PC15  it  gives  monochloro-phellan- 
drene  C10Hi6Cl,  b.p.15  108°,  which,  with  zinc  dust  and  methyl  alcohol, 
is  reduced  to  a-phellandrene  (B.  38,  1832). 

Pulegon,  b^^-menthene-^-ketone  CH3.CH<^;22~~?    NX=C(CH3)2,  b.p. 

\Crl  2  —  L/ri  2  / 

221°,  D  0-936,  nD  =1-4846,  is  contained  in  the  ethereal  oil  of  Meniha 
pulegium  and  Hedeoma  pulegioides,  which  are  sold  under  the  name 
polei  oil.  By  the  addition  of  hydrogen,  pulegone  is  converted  into 
menthone  ;  by  oxidation,  into  jS-methyl-adipinic  acid  and  acetone  ;  and 
by  heating  with  formic  acid  or  with  water  under  pressure,  into  acetone 
and  3-methyl-cyclo-hexanone,  which  on  oxidation  also  yields  jS-methyl- 
adipinic  acid  : 


If,  on  the  other  hand,  methyl-cyclo-hexanone  and  acetone  are 


508  ORGANIC  CHEMISTRY 

condensed,  by  means  of  alkalies,  we  obtain  a  geometrically  isomeric 
pulegone  boiling  at  215°  (A.  300,  267). 

If  pulegone  dibromide  (i)  is  boiled  with  sodium  methylate  solution, 
we  get  pulegenic  acid  (2)  C10H16O2,  in  which  case  the  six-membered 
ring  system  is  probably  converted  into  a  five-membered  system.  Oxi- 
dation with  potassium  permanganate  converts  the  pulegenic  acid  into 
an  oxy-lactone  (3),  which  on  heating  with  half-saturated  sulphuric  acid 
is  converted  into  pulenone  (4)  or  3,  6,  6-trimethyl-cyclo-hexanone, 
with  elimination  of  CO2  and  ring  expansion,  and  an  atomic  dis- 
placement quite  analogous  to  the  pinacolin  transposition  (A.  329,  82  ; 
cp.  also  A.  376,  154)  : 

CH3CH3 
CH3CH3 


,V  (2)    C  (3)    C  --  O  (4)    CH3CH3 

(i)    CBr 


CBr  C 

/\ 

H2C     CO    _       H2C     CHCOOH  _    _       H2C     CH.CO  H2C     CO 

H2C     CH2  >  H2C—  CHCH3  >  H2C—  CHCH3  >  H2C     CH2 

v  \/ 

CH  CH 

CH3 


From  pulegenic  acid  the  hydrocarbon  pulegen  C9H16,  b.p.  139°, 
D  0-791,  is  formed  by  rejection  of  CO2.  Its  nitroso-chloride  can  be 
converted  into  pulegenone  C9H14O,  b.p.  190°,  a  ketone  closely  related 
to  camphor-phorone  (A.  327,  125). 

Pulegone  combines,  like  other  a/?-unsaturated  ketones,  with  sodium- 
malonic  ester  (A.  345,  158,  188)  and  potassium  cyanide  (C.  1907,  1.  721). 

Benzylidene-pulegone,  b.p.  203°  (A.  305,  267)  :  by  the  action  of 
hydroxylamine  upon  pulegone  in  the  presence  of  alkali,  we  obtain  iso- 
pulegone-oxime  with  displacement  of  linkage.  Under  other  conditions 
we  obtain  the  hydroxylamine  addition  product,  pulegone-hydroxyl- 
amine  C10H17O(NHOH),  m.p.  157°,  which  yields  on  oxidation  nitroso- 
menthone,  m.p.  35°,  and  by  reduction  amido-menthone  (B.  31,  1809  J 
32,  3365),  as  well  as  pulegone-hydroxylamine-oxime  C10H17(NHOH) 
(  :  NOH),  m.p.  118°,  which  is  reduced  with  sodium  and  alcohol  to 
3,  8-diamido-menthane  (B.  38,  146). 

Iso-pulegone,   ^(^-menthene-^-ketone  CH3CH<^2~^  NcHC^^2, 

\CH2  —  CH2/  \CH2 

b.p.  14  103°,  is  obtained  from  its  oxime,  m.p.  120°,  on  heating  with 
oxalic  acid  (A.  365,  24),  from  pulegone  hydrobromide  with  basic  lead 
nitrate,  or  by  oxidising  its  alcohol,  iso-pulegol,  the  isomeric  product 
of  citronellal.  It  contains  two  unsym.  C  atoms,  and  therefore  occurs 
in  several  geometrically  isomeric  optically  active  modifications.  By 
treatment  with  baryta  water  it  is  converted  back  into  pulegone  (B.  32, 
3357)- 

2-Oxy-A1-menthene-3-ketone  CH^^-^VH.CH/^  m.p. 

\CH2  -  CH2/  \CH3 

84°,  b.p.10  110°,  is  probably  represented  by  the  bucco-camphor  or  dios- 
phenol  obtained  from  bucco  leaves  (Barosma).  In  its  behaviour  it 
shows  both  ketone  and  phenol  character.  With  ferric  chloride  it  gives 
a  green  coloration,  it  has  an  acetate  and  a  benzoate,  forms  with 
phenyl-iso-cyanate  a  phenyl-urethane,  m.p.  41°,  and  with  hydro  xyl- 


MONOCYCLIC  TERPENE  OR  MENTHANE  GROUP  509 

amine  a  monoxime,  m.p.  125°.  On  heating  with  concentrated  HC1  it 
is  converted  into  thymol,  and  a  little  carvacrol.'  On  oxidation  with 
ozone  we  obtain  a-iso-propyl-y-acetyl-butyric  acid  ;  and  on  reduction 
with  sodium  and  alcohol,  2,  3-dioxy-hexahydro-cymol,  which  is  oxidised 
by  permanganate  to  a-methyl-a-iso-propyl-adipinic  acid.  Syntheti- 
cally, bucco-camphor  is  formed  by  oxidation  of  oxy-methylene- 
menthone  with  ozone  (B.  39,  1158). 

(c)  Menthadiene-ketones,  keto-dihydro-p-cymols  C10H14O.  —  The  most 
important  member  of  this  group  is  carvone,  formerly  called  carvol. 
Its  importance  is  due  to  its  intimate  relationship  to  carvacrol  and 
limonene,  which  are  isomeric  with  it.  Carvone  is  known  in  three 
modifications,  the  d-,  1-,  and  [d+1]-. 

d-Carvone  CH3.c^°;£^C.CH(CH3)2    (3.  28,  31),    or 


(B.  28,  2145),  [a]D=-f-620,  boiling  at  225°,  occurs  in  carraway  oil  and 
in  dill  oil.  When  heated  with  potassium  hydroxide  or  phosphoric 
acid  it  changes  to  isomeric  carvacrol  or  2-methyl-5-iso-propyl-oxy- 
benzol  ;  hence  it  is  assumed  that  in  carvone  the  CO  group,  like  the 
OH  group  in  carvacrol,  is  in  the  ortho-position  with  reference  to  the 
methyl  group.  With  PC15  carvone  forms  a  dichloride  C10H14C12,  which 
on  distillation  with  quinolin  yields  2-chloro-cymol  (B.  32,  2555). 
Reduction  changes  it  to  dihydro-carveol,  while  ammonium  formate 
converts  it  into  dihydro-carvylamine.  Potassium  permanganate 
oxidises  carvone  to  oxy-terpenylic  acid  C8H12O5,  which  easily  changes 
to  a  dilactone  C8Hi0O4,  melting  at  129°  (B.  27,  3333  ;  28,  2148). 
The  carvones  combine  with  hydrogen  sulphide,  hydrogen  chloride, 
hydrogen  bromide,  and  bromine  (B.  28,  R.  548  ;  A.  305,  235  ; 
C.  1907,  I.  568).  *t)n  the  splitting  up  of  carvone  tribromide  to  car- 
venolidene  C10H14O2,  see  A.  305,  245.  With  sodium  bisulphite  we 
obtain  the  sodium  salt  of  carvone  dihydro-sulphonic  acid  (C.  1900,  I. 
1155)  .  On  shaking  up  with  dilute  H2SO4,  carvone  takes  up  one  molecule 
H2O  and  forms  oxy-dihydro-carvone  (carvone  hydrate,  B.  38,  1719  ; 
39,  677). 

With  aceto-acetic  ester  carvone  combines  in  the  presence  of  sodium 
alcoholate  to  a  dicyclic  condensation  product  (B.  36,  225). 

1-Carvone,  [a]D=—  60°,  boiling  at  230°,  occurs  in  mint  oil  and  curo- 
moji  oil  (B.  24,  81).  It  is  obtained  pure  by  distilling  its  hydrogen 
sulphide  compound,  melting  at  187°,  with  caustic  potash  (A.  305,  224). 

[d+1]  -Carvone,  boiling  at  230°,  is  formed  on  mixing  d-  and  1-carvone, 
as  well  as  by  oxidising  carveol-methyl  ether.  Formation  from  terpineol, 
B.  29,  R.  587. 

The  three  carvones  are  linked  through  the  three  carvoximes  to  the 
three  corresponding  limonenes.  The  carvoximes  are  prepared  not  only 
by  the  action  of  hydroxylamine  upon  the  carvones,  but  also  upon  boil- 
ing the  limonene  nitroso-chlorides  with  alcoholic  potash.  d-Carvone 
and  1-limonene  correspond  on  the  one  side  to  each  other,  while  on  the 
other  1-carvone  and  d-limonene  correspond,  inasmuch  as  1-limonene 
nitroso-chloride  yields  d-carvoxime,  and  d-limonene  nitroso-chloride 
1-carvoxime. 


510  ORGANIC  CHEMISTRY 

d-Carvoxime,  [a]D= +39-71°,  and  1-carvoxime,  [a]D=— 39-34°, 
melt  at  72°.  [d+l]-Carvoxime  melts  at  33°,  and  is  obtained  from 
dipentene  nitroso-chloride.  Concentrated  sulphuric  acid  rearranges 
carvoxime  to  p-amido-thymol  (compare  rearrangement  of  j8-phenyl- 
hydroxylamine  to  p-amido-phenol,  A.  279,  366).  Hydroxylamino- 
carvoxime  C10H15(NOH).NHOH,  a  syrup,  oxidises  to  form  the  di- 
oxime  of  a  diketone  C10H14O2,  m.p.  i85°-i87°,  which  is  also  formed  direct 
from  carvone  by  atmospheric  oxidation  in  the  presence  of  baryta,  and 
is  probably  I,  ^-methyl-iso-propenyl-dihydro-resorcin  (B.  34,  2105). 

C.  DICYCLIC  TERPENE  GROUP. 

The  terpenes  of  this  group  are  distinguished  from  the  monocyclic 
terpenes  by  the  fact  that  they  can  only  add  two  univalent  atoms  or 
atomic  groups.  They  therefore  contain  two  carbon  rings.  These  di- 
cyclic  terpenes,  and  their  derivatives  containing  oxygen,  are  joined 
up  with  the  monocyclic  terpene  compounds  by  numerous  transitions. 
Like  the  latter,  they  are  closely  related  to  p-cymol,  and  can  usually  be 
converted  into  this  with  facility. 

Their  dihydro-compounds  are  derived  from  hexahydro-cymol  either 
by  joining  two  carbon  atoms  in  the  m-position  towards  one  another, 
by  a  diagonal  link,  thus  forming  a  compound  of  the  trimethylene  and 
pentamethylene  group.  This  gives  the  sabinane  or  tanacetane  group. 
Or,  the  tertiary  carbon  atom  of  the  iso-propyl  group  is  joined  with  a 
second  carbon  atom  of  the  hexamethylene  ring.  According  as  to 
whether  this  link  occurs  in  the  o-,  m-,  or  p-position,  we  get  the  funda- 
mental hydrocarbons  of  the  carane,  pinane,  and  camphane  groups  : 

CH3                              CH3  CH3 

CH — CH— CH2          CH2 — CH— CH2          CH2 CH— CH 


(CH3)2C 


(CH3)2C- 


CH2 — CH— CH2 
Sabinane  Carane  Pinane  Camphane. 

While  these  nuclear  and  bridge-linkages  are  stable  as  regards  the 
usual  addition-reactions,  and  are  thus  clearly  distinguished  from 
double  linking,  they  are  broken  up  with  extraordinary  facility  by  the 
action  of  higher  temperatures,  but  especially  by  hydrating  agents, 
giving  rise  to  derivatives  of  the  monocyclic  terpenes. 

I.  SABINANE  OR  TANACETANE  GROUP. 

The  closely  related  compounds  of  this  group,  the  most  important 
representative  of  which  is  thujone  or  tanacetone,  contain  a  compound 
trimethylene  and  pentamethylene  ring,  and  can  be  broken  down  by 
oxidation  into  trimethylene-carboxylic  acids. 

i.  Hydrocarbons. — Sabinene  and  the  two  thujenes  belong  to  these. 
All  three  contain  the  same  carbon  skeleton,  and  only  differ  by  the 
position  of  the  double  linkage,  since  by  gentle  reaction  they  can  be 
transformed  into  the  equally  saturated  dicyclic  hydrocarbon  C10H18, 
i.e.  sabinane  or  thujane  (C.  1911,  I.  313). 

Sabinene  (i)  C10H16,  b.p.  i63°-i65°,  D20  0-842,  nD  1-468,  has  been 


SABINANE   OR  TANACETANE   GROUP  511 

found  in  its  dextro-rotatory  form  in  Ceylon  cardamom  oil,  majoran 
oil,  and  pilea  oil  (A.  357,  77  ;  B.  40,  2963).  With  quite  dry  HC1  in 
CS2  solution  it  yields  terpinene  monochlorohydrate,  with  glacial 
acetic  halogen  hydride  the  corresponding  terpinene-dihydro-haloids. 
By  dilute  H2SO4  it  is  converted,  in  the  cold,  into  optically  active 
terpinenol-4  and  terpinene-terpin,  and  with  heat  into  a-terpinene.  On 
oxidation  with  KMnO4,  sabinene  behaves  like  most  other  terpenes 
with  semi-cyclically  linked  methylene  group  (cp.  j8-pinene  and  cam- 
phene).  Sabinene-glycol  (2)  is  first  formed,  m.p.  54°,  which  is  then 
oxidised  to  an  a-oxy-acid  marked  by  its  sparingly  soluble  sodium  salt, 
viz.  sabineric  acid  (3),  m.p.  57°,  and  further  to  sabina-ketone  (4),  b.p. 
212°,  containing  one  C  atom  less.  The  latter,  on  heating  with  aqueous 
or  alcoholic  H2SO4,  easily  splits  the  trimethylene  ring,  and  forms 
A2-iso-propyl-cyclo-hexenone  (6),  and  on  further  disintegration 
a-tanacetone-dicarboxylic  acid  (5)  (A.  359,  266  ;  B.  35,  2045)  : 

CH2  CH2OH  COOH  __  > 

(i)     C  (2)     COH         (3)     COH        (4)     CO  (5)     COOH       (6)*CH 

/\  /\  /\  /\  /  /\ 

HC      CH2        HC      CH2        HC      CH2        HC     CH2        HC     COOH    HC     CH2 

H2C      CHo^HaCl    CH2  "*  H2C\    CH2^H2C\     CH2^H2C\    CH2        HC     CH2 

^/  \/  N\/  \X 

C  C  C  CH 

£3^7 


As  already  mentioned,  sabina-ketone  may  be  used  for  building  up 
jS-terpinene. 

x/->TT  _  PfT    \ 

a-Thujene  CH.C-CC.H,,  b.p.  152°,  D20  0-8275,  nD  1-4504, 


and    jS-thujene    CHSCH<^  _  ~.       -^C.GjH,  (?),   solid,    b.p.    150°,    D20 

\CH  —  CH2/ 

0-8248,  nD  1-4484,  have  been  obtained  by  distillation  from  the  methyl- 
xanthogenate  of  thujyl  alcohol,  and  from  thujylamine  by  thorough 
methylation  and  by  heating  the  resulting  quaternary  ammonium  base 
(B.  34,  2276  ;  37,  1481).  On  oxidation  with  KMnO4  a-thujene  yields 
a-thuja-keto-acid  (see  below),  and  combines,  with  two  molecules 
halogen  hydride,  to  form  the  corresponding  terpinene-dihalogen 
hydrates.  On  shaking  up  with  dilute  sulphuric  acid  it  becomes,  like 
sabinene,  active  terpinenol-4  and  terpinene-terpin  (A.  350,  166  ;  356, 
201).  Isomeric  with  these  two  hydrocarbons  is  iso-thujene,  b.p.  172°- 
175°,  D  0-840,  nD  1-476,  formed  by  the  dry  distillation  of  thujylamine- 
chlorohydrate  (A.  286,  99). 

Sabinane,  thujane,  C10H18,  b.p.  157°,  is  formed  by  the  reduction  of 
sabinene,  a-  and  jS-thujene,  with  hydrogen  in  the  presence  of  platinum 
black  (C.  1911,  I.  313). 

2.  Alcohols.  —  Sabinene    hydrate,     methyl-sabina-ketol 

CH3\      /CH2—  CH.\ 

m-P-  39°>  b.p.  i95°-20i°,  is  formed  besides 


, 

a-terpinene  by  the  action  of  methyl-magnesium  iodide  upon  sabina- 
ketone.  With  glacial  acetic  hydrogen  bromide  it  forms  terpinene- 
dibromo-hydrate,  and,  on  shaking  up  with  dilute  sulphuric  acid,  an 
optically  active  terpinenol-4  and  terpinene-terpin  (A.  357,  64). 

"  ~ 

Thujyl-alcohol,  tanacetyl-alcohol  CH3CH 


512  ORGANIC  CHEMISTRY 

92-5°,  D  0-9249,  nD  1-4635,  is  formed  by  reduction  of  thujone  or  tan- 
acetone,  into  which  it  reverts  on  oxidation.  It  is  found,  partly  free 
and  partly  in  the  form  of  aliphatic  esters,  in  wormwood  oil  (A.  272, 109). 

Sabinol   CH2=c/C  ^^C.CjH,,  b.p.  211°,    D20  0-9432,  an 

\CH CH2  / 

unsaturated  secondary  alcohol,  found  in  the  form  of  its  ester  in  oleum 
sabince.  It  is  converted  into  cymol  by  dehydrating  agents,  into 
tanacetone  by  short  heating  with  zinc  dust,  and  into  tanacetyl-alcohol 
by  reduction  with  sodium  and  alcohol.  Careful  oxidation  with 
KMnO4  converts  it  into  sabinyl-glycerin  C10H15(OH)3,  m.p.  153°,  which 
easily  passes  into  cumin-alcohol  by  splitting  off  water  ;  strong  oxida- 
tion produces  a-tanacetone-dicarboxylic  acid  (B.  33, 1191, 1459  ;  cp.  also 
A.  360,  98). 

3.  Amines. — Thujylamine  C10H17NH2,  b.p.   195°,  by  reduction  of 
thujone  oxime.     On  heating  its  chlorohydrate  it  yields  iso-thujene. 

4.  Ketones. — Thujone,  tanacetone  (i)  C1?H16O,  b.p.  200°,  D  0-917, 
nD=  1*4511,  is  found  in  two  physically  isomeric  forms — the  laevo-rotatory 
a-thujone,  [a]D=— 10-23°,  semi-carbazone,  m.p.    186°,   oxime  liquid, 
chiefly  in  thuja  oil;    the  dextro-rotatory  j3-thujone,  [a]D= +76-16°, 
semi-carbazone,  m.p.  171°  and  175°,  oxime,  m.p.  55° — chiefly  in  the 
oil  of  Tanacetum  vulgar  e.     Mixtures  of  both  forms  have  been  traced  in 
wormwood  oil,  sage  oil,  absinth  oil,  and  the  oil  of  Artemisia  Barrelieri 
(A.  336,  247).     On  oxidation  with  KMnO4  both  forms  give  the  chemi- 
cally isomeric   a-   and   jS-thuja   or   tanaeeto-ketone-carboxylic   acids 
CH3CO.C7H12.COOH,  m.p.  75°  and  78°,  the  a-acid  being  saturated  and 
the  j8-acid  unsaturated.     On  heating,  the  a-acid  turns  into  the  jS-acid, 
the  latter  (2)  being  oxidised  into  a  diketone  (3),  and  then  converted 
into  S-dimethyl-laevulinic  acid  (4).     The  a-tanaceto-ketonic  acid  (5) 
is  broken  down,  by  bromine  and  alkali,  to  a-tanacetone-dicarboxylie 
acid  (6)  C9H14O4,  m.p.  142°,  a  saturated  dibasic  acid,  which  easily 
turns  into  anhydride,  and  is  also  formed  by  the  oxidation  of  sabinol, 
sabinene,  and  a-thujene  : 

CH3  CH3  CH3  CH3 

(4)     C02H    (3)     CO         (2)     CO  (i)     C  (5)     CO  (6)     C02H 


H2C  H2C  H2C     CO2H        HC     CO         HC,    CO2H       HC     CO2H 

H2C  *~H2C  *~H2C     CH       ^H-jCl  CHa^HsjCy  CH2    ~^H2C\CH2 

\  \  \S  \/  \/    '  \1/ 

CO  CO  C  C  C  C 

C3H7 


Condensation  with  benzaldehyde  converts  thujone  into  benzylidene- 
thujone,  b.p.9  178°,  which  is  split  up  by  potassium  permanganate  into 
benzoic  acid  and  homo-tanacetone-diearboxylic  acid  C10H16O4,  m.p. 
148°.  This  acid,  like  a-tanacetone-dicarboxylic  acid,  and  tanacetone 
itself,  probably  contains  the  trimethylene  ring  (B.  36,  4367  ;  but  see 
B.  33,  1192). 

Thujone,  treated  with  alcoholic  sulphuric  acid,  turns  into  iso- 
thujone.  On  heating  to  280°,  it  turns  into  carvo-tanacetone.  These 
two  ketones  are  unsaturated,  in  contrast  with  thujone  (B.  28,  1959). 
Thujone-oxime,  m.p.  54°,  with  alcoholic  sulphuric  acid,  turns  into 
carvacryl-amine  (B.  30,  325)  ;  treatment  with  PC15  converts  it  into 
the  lactame-like  thujone-isoxime,  m.p.  90°  (A.  336,  270). 


SABINANE  OR  TANACETANE  GROUP  513 

Iso-thujonecH,c<c—  ^CH(CH)i  (?),  b.p.  231°,  D  0-927,  nD= 


1-4822,  m.p.  119°.  a-  and  j8-Semi-carbazone,  m.p.  208°  and  148°. 
Oxime,  m.p.  120°.  Benzylidene-isothujone  (C10H14O)  :  CHC6H5,  m.p. 
83°.  When  oxidised,  iso-thujone  yields  a  keto-lactone  C10H16O3,  and, 
further,  /S-iso-propyl-laevulinic  acid  CH3COCH(C3H7).CH2COOH  ;  by 
reduction  a  saturated  alcohol  is  obtained,  thuja-menthol,  dihydro-iso- 
thujol  C10H19OH,  b.p.  212°,  D  0-9015,  nD=  1-4636,  which,  on  oxidation 
with  chromic  acid,  forms  thuja-menthone  C10H18O,  b.p.  208°,  D  0-891, 
nD  1*447.  Oxime,  m.p.  95°  ;  isoxime,  m.p.  117°.  All  these  compounds 
are  probably  derivatives  of  cyclo-pentane  (A.  323,  348  ;  336,  276  ; 
B.  28,  1958). 

^CH  -  CO\ 

Umbellulone  CH3.c^  VfrH,,  b.p.10  93°,  [a]D-37°.  which 

xCrl  —  CJbij/ 

occurs  in  profusion  in  the  leaves  of  Californian  laurel,  Umbellularia 
calif  ornica.  Semi-carbazone,  m.p.  242°.  On  heating  to  280°,  it  trans- 
poses into  thymol.  Bromination  and  subsequent  distillation  produce 
p-cymol  and  other  brominated  bodies.  Sodium  and  alcohol  reduce  it 
to  the  saturated  alcohol  C10H17.OH,  b.p.10  90°,  which,  on  oxidation 
with  chromic  acid,  turns  into  dihydro-umbellulone  C10H16O,  b.p.10  85°. 
The  benzylidene  compound  of  the  latter,  on  oxidation  with  KMnO4, 
yields,  like  benzylidene-  thuj  one  (see  above),  1-homo-tanacetone-dicar- 
boxylic  acid  (B.  40,  5017  ;  41,  3988). 

CARANE,  PINANE,  AND  CAMPHANE  GROUP. 

The  derivatives  of  this  group  contain,  as  already  stated,  a  hexa- 
methylene  ring,  in  which  two  carbon  atoms  in  the  o-,  m-,  or  p-position 
are  joined  together  by  means  of  a  carbon  bridge.  In  nature  such 
compounds  have  only  been  found  with  an  m-  or  p-bridge.  Among 
the  former  we  have  pinene,  extremely  frequent  in  natural  substances  ; 
and  among  the  latter  we  have  camphor,  the  most  important  derivative 
in  this  group,  and  the  closely  related  fenchone,  as  well  as  the  derived 
terpenes,  camphene  and  fenchene.  Characteristic  of  the  compounds 
of  this  group  is  the  remarkable  facility  with  which  they  undergo  intra- 
molecular transpositions  under  the  influence  of  acid  reagents.  These 
transpositions  are  sometimes  accompanied  by  a  complete  change  in  the 
ring  system,  which  makes  a  recognition  of  the  connection  between  the 
products  and  the  elucidation  of  their  constitution  extremely  difficult. 

Nomenclature.  —  The  names  are  mostly  derived  from  botany,  and 
associated  with  the  extraction  of  some  of  the  more  important  sub- 
stances. Only  in  a  few  cases  does  a  systematic  nomenclature  appear 
possible.  Thus,  the  hitherto  unknown  demethylated  hydrocarbon 
corresponds  to  the  three  chief  types  of  these  groups,  and  designated  by 
nor-camphane,  nor-pinane,  and  nor-carane,  which  are  used  as  bases, 
and  their  carbon  atoms  are  given  numbers  as  follows  : 

345  345  345 

CH2—  CH—  CH2  CH2—  CH2—  CH  CH2—  CH2—  CH2 


7  CH2 


H2—  C 


7  CH/ 


H—  CH2  CH2—  CH  —  CH2  CH2—  CH  —  CH 

216  216  216 
Norcamphane                         Norpinane  Norcarane. 

VOL.  II.  2  L 


5i4  ORGANIC  CHEMISTRY 

II.  CARANE  GROUP. 

The  compounds  of  this  group  are  ranged  with  the  sabinane  group, 
since  they  also  contain  a  trimethylene  ring,  which,  however,  is  com- 
bined with  a  hexamethylene  ring.  Hydrocarbons  of  this  group,  which 
has  only  been  investigated  by  synthesis,  are  unknown. 

Garone  (formula  below),  b.p.15  100°,  is  formed  from  dihydro-carvone 
hydrobromide  with  alcoholic  potash.  It  is  comparatively  stable 
towards  potassium  permanganate,  which  only  attacks  it  at  water- 
bath  temperature,  and  oxidises  it  to  caronic  acid,  or  i,  i-dimethyl-2,  3- 
trimethylene-dicarboxylic  acid  (i).  On  the  other  hand,  the  trimethy- 
lene ring  of  carone  can  be  split  up  in  three  different  places  :  (i) 
Splitting  between  C6  and  C7 ;  on  heating  to  about  210°  carone  trans- 
poses into  carvenone  (2)  (B.  32,  1222)  ;  HBr  turns  it  into  dihydro- 
carvone  hydro-bromide,  and  sulphuric  acid  into  oxy-tetrahydro-carvone. 
(2)  Splitting  between  Cx  and  C7  ;  the  carylamine  C10H17NH2,  stable  in 
the  presence  of  KMnO4,  obtained  from  carone-oxime,  m.p.  78°,  by 
reduction  transposes,  in  the  presence  of  HC1,  into  the  isomeric  un- 
saturated  vestrylamine  (3),  whose  chlorohydrate,  on  heating,  yields 
carvestrene  (B.  27,  3486).  (3)  Splitting  between  Ct  and  C6 ;  the 
cyano-carone  C10H15(CN)O,  m.p.  55°,  obtained  from  cyano-dihydro- 
carvone  hydro-bromide  with  alcoholic  potash,  which  can  also  be 
disintegrated  to  caronic  acid,  yields,  on  heating  with  alcoholic  potash, 
eucarvone  (C.  1910,  I.  924). 

An  oxy-earone  C10H1?O2,  b.p.19  135°,  has  been  obtained  by  starting 
from  dihydro-carvone  dibromide  ;  the  latter,  with  soda,  yields  oxy- 
bromo-tetrahydro-carvone,  which,  on  treatment  with  methyl-alco- 
holic potash,  turns  into  oxy-carone  ;  on  digesting  the  latter  with 
dilute  sulphuric  acid  it  is  turned  into  a  ketone  derivative  of  terpin 
(B.  31,  3208). 

A  constitution  and  transformations  similar  to  those  of  carone  are 
shown  by  pseudo-phenyl-acetic  acid,  or  nor-caradiene-carboxylic  acid, 
obtained  from  benzol  and  diazo-acetic  ester. 

Eucarvone  (formula  4  above),  b.p.12  86°,  D20=o*952,  110=1-5048 
(A.  339,  94),  probably  belongs  to  the  heptacarbocyclic  compounds,  but 
is  treated  here  on  account  of  its  relation  to  carone.  It  is  formed  from 
carvone  hydro-bromide  with  alcoholic  potash,  evidently  with  inter- 
mediate formation  of  the  unstable  a/S-unsaturated  carone  (cp.  the 
transition  of  cyano-carone  into  eucarvone).  It  is  optically  inactive. 
On  boiling  down  with  methyl-alcoholic  potash,  it  gives  a  deep-blue 
unstable  coloration.  Semi-carbazone,  m.p.  184° ;  oxime,  m.p.  106°  ; 
oxamino-oxime,  m.p.  142°  (A.  330,  275).  It  unites  with  benzaldehyde 
to  form  benzylidene-eucarvone,  m.p.  113°.  On  oxidation  it  yields 
acetic  acid  and  unsym.  dimethyl-succinic  acid.  On  reduction  with 
Na  and  alcohol  we  get,  simultaneously,  dihydro-eucarveol  C10H17OH, 
b.p.21  109°,  and  tetrahydro-eucarveol  C10H19OH,  b.p.  220°,  which,  on 
oxidation,  turn  into  the  corresponding  ketones. 

Dihydro-eucarvone  C10H16O,  b.p.14  87°  (B.  28,  646),  and  tetra- 
hydro-eucarvone  C1(?H18O,  b.p.13  9i°-93°  (B.  31,  2071).  The  latter, 
with  chromic  acid,  gives  a  ketonic  acid  C10H18O3,  from  which  potassium 
hypobromite  forms  a  j3/3-dimethyl-pimelinic  acid,  indicating  the  exist- 
ence of  a  chain  of  seven  members. 


PINANE  GROUP  515 

On  prolonged  heating  eucarvone  turns  into  carvacrol ;  PC15  pro- 
duces 2-chloro-cymol.  The  unsaturated  diamine,  obtained  from  the 
oxamino-oxime  of  eucarvone  by  reduction,  yields  p-cymol  by  the 
distillation  of  its  phosphate.  In  this  case,  we  must  assume  the  inter- 
mediate formation  of  a  cyclo-heptatriene  derivative,  which  transposes 
into  the  more  stable  benzene  derivative. 

Dihydro-eucarvylamine  C10H17NH2,  b.p.4p  117°,  from  eucarvoxime  ; 
its  chlorohydrate  yields  euterpene  on  heating  (A.  305,  239).  Tetra- 
hydro-eucarvylamine  C10H19NH2,  b.p.  210°  (A.  339,  115). 


III.  PINANE  GROUP. 

Hydrocarbons.  —  Pinene.  —  Pinene  is  extremely  frequent  among  the 
ethereal  oils  and  is  the  chief  ingredient  of  the  turpentine  oils  obtained 
from  the  different  varieties  of  pine.  It  also  occurs  in  many  other 
ethereal  oils  —  eucalyptus,  juniper-berry,  sage,  etc. 

Turpentine  Oil.  —  Turpentine,  the  resinous  juice  exuding  from 
various  Coniferae,  consists  of  a  solution  of  resins  in  turpentine  oil 
which  distils  with  steam,  while  the  resin  (colophony)  remains  behind. 
Turpentine  oil  is  a  colourless  liquid,  boiling  at  i58°-i6o°,  with  specific 
gravity  of  o*856-o-87.  Its  peculiar  odour  is  due  to  the  aldehyde- 
like  oxidation  products  (B.  29,  R.  871)  produced  by  the  action  of 
sunlight. 

It  is  almost  insoluble  in  water,  but  is  miscible  with  absolute  alcohol 
and  ether.  It  dissolves  phosphorus  and  rubber,  and  serves  for  the 
preparation  of  varnishes  and  oil-colours. 

The  turpentine  oils,  according  to  their  origin,  are  distinguished  by 
different  rotatory  powers. 

The  American,  Algerian,  and  Greek  turpentine  oils  contain  chiefly 
d-pinene,  the  French  and  Spanish  oils  1-pinene.  Besides  these,  dextro- 
and  laevo-rotatory  pinenes  are  found  in  various  ethereal  oils,  such  as 
eucalyptus  oil,  hawthorn  (?)  oil,  sage  oil,  etc. 

In  most  cases  pinene  is  accompanied  by  small  quantities  of  a  closely 
related  terpene  of  higher  boiling-point,  which,  with  HC1,  gives  the  same 
chlorohydrate,  but  is  distinctly  different  from  it  in  its  oxidation  pro- 
ducts. This  is  especially  the  case  in  the  oils  of  turpentine,  and  the 
related  body  is  distinguished  as  j3-pinene  from  the  ordinary  or 
a-pinene. 

CH=C(CH3)—  CH 


[d+1]-  a-  Pinene       (CHg^c  ,    b.p.    155°,    Doo  0-858,   nD= 

CH2  --  CH—  CH, 
1.46553  (21°). 

d-a-Pinene  is  obtained  by  fractional  distillation  of  American  tur- 
pentine oil,  while  1-a-pinene  is  obtained  from  French  turpentine  oil, 
but  not  chemically  pure.  For  obtaining  pure  a-pinene  it  is  converted 
into  the  easily  purified  nitroso-chloride  (/J-pinene  gives  no  addition 
product  with  nitroso-chloride),  and  is  thus  liberated  with  the  help  of 
aniline,  or  by  boiling  with  sodium  acetate  and  glacial  acetic  acid.  It 
is  thus  obtained  pure,  but  always  inactive.  Artificially,  1-a-pinene  has 
been  obtained  by  heating  nopinol-acetic  acid,  and  d-a-pinene  by  the 


516  ORGANIC  CHEMISTRY 

dry  distillation  of  methyl-xanthogenate  from  pino-campheol  (A.  368, 
i  ;  C.  1908,  I.  1179). 

Pinene  has  one  double  link.  It  combines  with  2C1  or  2Br  to  form 
compounds  which  on  heating  disintegrate  into  hydrogen  haloid  and 
p-cymol.  By  the  action  of  moist  hydrogen  haloids,  pinene  is  con- 
verted into  dipentene  dihydro-haloids,  while  with  perfectly  dry 
hydrogen  haloids  in  the  cold,  monohalogen  hydrates  are  obtained. 
These,  however,  like  the  halogen  addition  products,  no  longer  contain 
the  pinene  ring,  the  hydrogen  haloid  having  produced  a  complete 
change  in  the  ring  system,  giving  rise  to  borneol  derivatives.  Thus 
the  pinenic  hydro-haloids  are  identical  with  the  bornyl  haloids.  In  the 
same  way  the  treatment  of  pinene  with  organic  acids,  such  as  oxalic 
acid,  salicylic  acid,  trichloracetic  acid,  etc.,  produces  esters  of  borneol, 
or  of  the  stereo-isomeric  iso-borneol.  This  easy  transition  of  pinene 
into  borneol,  and  iso-borneol,  has  been  industrially  utilised  for  the 
artificial  production  of  camphor  from  oil  of  turpentine.  The  action 
of  dilute  nitric  or  sulphuric  acid  upon  pinene  produces  terpine 
hydrate,  while,  with  sulphuric  acid  and  glacial  acetic  acid,  or  benzol- 
sulphonic  acid  (C.  1909,  II.  25),  the  primary  hydration  product 
a-terpineol  can  be  isolated.  On  heating  to  25O°-270°  pinene  is  con- 
verted into  dipentene. 

The  oxidation  products  of  pinene  have  been  examined  in  some 
detail.  In  air,  oil  of  turpentine  gradually  absorbs  oxygen  with  the 
formation  of  peroxides  (B.  31,  3046),  and  resinifies  with  formation  of 
certain  quantities  of  formic  acid,  acetic  acid,  and  cymol.  On  the 
formation  of  pinol  hydrate  from  pinene  in  air  and  sunlight,  see  below. 
Strong  oxidising  agents,  such  as  nitric  acid,  produce  terebinic  acid, 
p-toluic  acid,  terephthalic  acid,  etc.  Chromic  acid  mixture  produces 
terpenylic  acid  as  a  main  product. 

Oxidation  with  mercuric  acetate  produces  a  racemic  sobrerol,  which 
is  further  oxidised  to  oxy-dih}/dro-carvone  or  carvone  hydrate.  From 
the  latter,  on  heating  with  oxalic  acid,  water  is  eliminated,  with  forma- 
tion of  carvone  and  carvacrol,  and,  on  further  oxidation  with  potassium 
permanganate,  terpenylic  acid  (C.  1909,  I.  1561). 

By  careful  oxidation  of  pinene  with  potassium  permanganate,  we 
first  obtain  a-pinene-glycol  C10H16(OH)21,  b.p.14  146°  (B.  27,  2270),  and 
then  a  keto-monocarboxylic  acid  called  pinonic  acid  C10H16O3,  m.p. 
70°  (active)  and  m.p.  104°  (inactive),  b.p.15  187°  (C.  1909,  II.  2158). 
There  are  also  small  quantities  of  a  ketone-dicarboxylic  acid,  pinoyl- 
formic  acid  C10H14O5,  m.p.  79°.  The  pinene  ozonide,  obtained  by  the 
action  of  ozone  upon  pinene,  also  yields  pinonic  acid  in  the  decom- 
position with  water  (B.  40,  138). 

On  oxidising  the  very  unstable  pinonic  acid  with  bromine,  or 
alkali,  or  with  dilute  nitrous  acid,  we  obtain  the  stable  pinic  acid 
C9H14O4,  m.p.  102°,  and  from  this,  through  a-bromo-  and  a-oxy-pinic 
acid,  and  oxidation  of  the  latter,  we  obtain  nor-pinic  acid  C8H12O4, 
m.p.  174°.  The  two  latter  very  stable  acids  probably  contain  a  tetra- 
methylene  ring. 

Baeyer,  therefore,  in  agreement  with  Wagner,  assumes  for  pinonic 
acid  and  pinene  the  presence  of  a  4-member  so-called  piceane  ring 
(B.  29,  2776) .  The  course  of  the  oxidation  is  illustrated  in  the  following 
scheme  : 


PINANE  GROUP  517 

CO2H  CH3  CH3 

OC                        C                       OC                     HOaC  H02C 

\           S'\                \                \  \ 

H02C  H,C  /CH     HC  H.C/CH  HO2C  Hjg    CH    HO2C  HsC    CH  H,c     CH 

-                      •'                          /  / 


c-    '  c 

[CH;  ICH,  —"      ICH, 

H2C  CH2  H2C  CH2      H2C 

\         /  \         /  \ 


c     I    __ 


|CH 


CH2     H2C  CH2  HO8C 


CH, 


CH2 


CH  CH  CH  CH  CH 

Pinoyl-formic  acid     a-Pinene          Pinonic  acid          Pinic  acid         Nor-pinic  acid. 

The  decomposition  of  pinonic  acid  and  pinoyl-formic  acid  has  also 
been  accomplished  in  other  ways. 

(i)  By  means  of  chromic  acid,  keto-iso-eamphoric  acid  has  been 
obtained  from  pinonic  acid,  and  also  by  oxidation  of  campholinic  acid. 
The  keto-iso-camphoric  acid  can  be  disintegrated  into  iso-camphoronic 
acid  CO2HC(CH3)2CH(CH2CO2H)2  (synthesis,  C.  1901,  I.  221),  and 
further  to  dimethyl-triearballylie  acid  CpOHC(CH3)2CH(COOH)CH2 
COOH.  The  constitution  of  the  latter  acid  is  proved  by  the  splitting 
up  of  the  corresponding  oxy-acid  (B.  30, 1959)  on  fusing  with  potash  in 
dimethyl-succinic  acid  and  oxalic  acid.  The  peculiar  formation  of 
keto-iso-camphoric  acid  from  pinonic  acid  can,  according  to  modern 
ideas  (cp.  B.  32,  2080),  be  interpreted  in  a  sense  that  the  4-member 
piceane  ring  of  pinonic  acid  takes  up  water  and  is  converted  into  the 
5-member  camphoceane  ring  : 


;HCH,CO,H rnH 

CH.COCH.CtCH.),  '\C(CH,)(OH).C(CH,)2  C°*H\CH,CO.C(CH,), 

Pinonic  acid  a-Dioxy-dihydro-campholenic  acid  Keto-iso-camphoric  acid. 

(2)  On  heating  with  acids,  pinonic  acid  undergoes  an  intermediate 
hydrolytic  splitting,  and  then  a  transposition  into  homo-terpenylic- 

f 


methyl-ketone  [metho-ethyl-heptanonolide]       *z'';         ,  which 

CH2.u/H2.CO.Cri3 

we  have  learnt  to  regard  as  a  disintegration  product  of  terpineol. 
Similarly,  pinoyl-formic  acid  is  transposed  into  homc-terpinoyl-formie 

acid  (CH3)aC  CH  ^^CC^COOH'    These  transP°sition  products  on  further 
oxidation  yield  : 


Terebinicacid  (Cl«/caCH,.COO 

COUri 

Terebinic  acid  C7H10O4,  melting  at  175°,  was  first  obtained  by 
oxidising  turpentine  oil  with  nitric  acid  ;  it  is  also  produced  in  the 
oxidation  of  terpenylic  acid  with  potassium  permanganate,  or  of  iso- 
propyl-succinic  acid  with  chromic  acid.  Synthetically,  it  is  prepared  by 
the  condensation  of  acetone  and  bromo-succinic  ester  with  zinc-copper, 
or  by  the  action  of  CH3MgI  upon  aceto-succinic  ester  (C.  1907,  1.  1202). 
See  also  Teraconic  acid  (B.  29,  933  ;  C.  1898,  I.  558  ;  1899,  I.  1158) 
It  behaves  analogously  to  the  paraconic  acids.  When  heated  it  loses 


5i8  ORGANIC  CHEMISTRY 

carbon  dioxide  and  becomes  pyro-terebinic  acid  (CH3)2C  :  CHCH2COOH, 
together  with  iso-capro-lactone  and  teraconic  acid  (CH3)2C  :  C(COOH) 
CH2.COOH,  from  which  it  can  be  re-formed  by  digestion  with  mineral 
acids.  Baryta  water  converts  terebinic  acid  into  the  crystallising 
barium  salt  of  diaterebinic  acid  or  oxy-iso-propyl-succinic  acid. 

By  oxidation  with  HNO3,  terebinic  acid  is  turned  into  diearboxy- 

valero-lactonic  acid  COOH.C(CH3)CH(COOH)CH2Co6  (B.  32,  3662). 
See  the  formation  of  terebinic  acid  from  caronic  acid. 

Terpenylic  acid  C8H12O4  melts  at  90°  when  anhydrous.  It  is 
obtained  by  oxidising  turpentine  oil  with  a  chromic  acid  mixture,  and 
homo-terpenylic  acid  with  nitric  acid  (B.  29,  2789). 

Synthetically  it  has  been  obtained  by  the  action  of  CH3MgI  upon 
jS-acetyl-glutaric  ester  (C.  1907,  I.  1202). 

Upon  distillation  it  yields  teraerylic  acid  (CH3)2C  :  CH(CH3)CH2. 
COOH.  Terpenylic  acid,  by  reduction,  becomes  fi-iso-propyl-glutaric 
acid  (see  B.  29,  920,  2621). 

Homo-terpenylic  acid  C9H14O4,  melting  at  102°,  results  when  homo- 
terpenyl-formic  acid  is  oxidised  with  nitric  acid  or  with  lead  oxide 
(B.  29,  1916).  It  is  synthesised  by  means  of  CH3MgI  and  j9-acetyl- 
adipinic  ester  (C.  1907,  I.  1202). 

The  oxidation  of  pinene  to  pinonic  acid  and  the  hydrolytic  re- 
arrangement of  the  latter  to  homo-terpenylic  methyl-ketone  is  certainly 
to  be  regarded  as  the  reverse  of  the  processes  which  take  place  in  the 
hydrolytic  rearrangement  of  pinene  into  terpin  hydrate,  terpineol,  and 
the  oxidising  decomposition  of  the  latter  into  homo-terpenylic  methyl- 
ketone  (above). 

d-Pinene  hydrochloride,  smelling  of  camphor,  and  therefore  formerly 
called  artificial  camphor,  C10H17C1,  melting  at  125°  and  boiling  at  208°, 
is  formed  on  conducting  dry  hydrochloric  acid  gas  into  well-cooled 
pinene.  It  is  a  white  crystalline  mass,  with  an  odour  like  that  of 
camphor.  The  hydrochloride  from  d-pinene  is  optically  inactive,  while 
the  1-pinene  hydrochloride  is  laevo-rotatory,  [a]0=  — 30°.  Pinene 
hydrobromide  melts  at  40°  (A.  227,  282). 

Pinene  hydro-iodide  C10H17I,  b.p.15  119°.  The  pinene  hydro- 
haloids  are  identical  with  the  bornyl  haloids.  This  follows  from  the 
fact  that  the  Mg  compound  C10H17MgCl,  obtained  by  the  action  of 
Mg  upon  pinene  chlorohydrate  in  ether  solution,  turns  into  camphane 
by  decomposition  with  water,  and  into  borneol  by  the  action  of 
oxygen  (B.  39, 1127).  During  the  action  of  the  halogen  hydrides  upon 
pinene  there  is,  therefore,  a  "  sliding  "  of  the  dimethyl-methylene 
bridge,  from  the  m-position  into  the  p-position.  By  a  quite  analogous 
displacement  of  the  methylene  group  of  the  piceane  ring,  we  obtain 
the  derivatives  of  fenchyl  alcohol.  This  explains  the  secondary 
formation  of  fenchyl  chloride  in  the  action  of  HC1  upon  pinene.  The 
elimination  of  HC1  from  pinene  chlorohydrate,  which  is  attended  by 
much  difficulty,  produces  camphene.  This  transition  also  is  the  result 
of  a  far-reaching  transposition.  Hypochlorous  acid  attaches  itself  to 
pinene  with  dissolution  of  the  double  linking,  and  of  the  four-membered 
piceane  ring.  The  action  of  alkalies  upon  the  resulting  dichloro- 
hydrins  C10H18O2C12  has  been  made  to  produce  pinol  oxide,  sobrery- 
thrite,  pinol-chlorohydrin,  and  other  bodies  (B.  32,  2064). 


PINANE  GROUP  519 

Pinene  dibromide  C10H16Br2,  m.p.  170°,  by  the  action  of  bromine 
upon  pinene,  in  carbon  tetrachloride  (A.  264,  i).  Like  pinene  chloro- 
hydrate,  it  probably  also  belongs  to  the  camphor  type,  being  reduced 
to  camphane  by  Na  and  alcohol  (B.  33,  3423).  On  treatment  with 
zinc  dust  it  yields  a  terpene,  isomeric  with  pinene  and  camphene, 
m.p.  67°,  b.p.  153°,  containing  apparently  no  double  link,  a  so-called 
tricyclene. 

Pinene  nitroso-chloride,  melting  at  115°,  is  obtained  by  means  of 
nitrosyl  chloride,  or  amyl  nitrite,  glacial  acetic  acid,  and  hydrochloric 
acid.  Hydrogen  chloride  in  ether,  when  allowed  to  stand  in  contact 
with  it,  produces,  just  like  limonene  nitroso-chloride,  hydrochloro- 
carvoxime  (B.  29,  12).  With  KCN  it  turns  into  nitroso-cyanide,  m.p. 
171°  (C.  1902,  II.  363).  Pinene  nitroso-bromide,  m.p.  92°.  While 
aromatic  bases,  like  aniline  and  methyl-aniline,  reject  NOC1,  and  re- 
generate pinene,  it  turns  into  nitrolamines  with  aliphatic  bases  : 
pinene-nitrolamine,  m.p.  137°  (C.  1907,  I.  1040)  ;  pinene-nitrol- 
piperidide,  m.p.  119°.  By  the  action  of  sodium  alcoholate,  it  splits 
off  HC1  and  forms  nitroso-pinene  C10H14  :  NOH,  m.p.  131°,  which  is 
regarded  as  the  oxime  of  an  unsaturated  ketone,  carvo-pinone,  into 
which  it  turns,  on  heating  with  aqueous  oxalic  acid.  By  reduction 
with  zinc  dust  and  glacial  acetic  acid,  it  forms  pinylamine  C]0H15NH2 ; 
a  ketone  isomeric  with  camphor,  pino-camphone,  is  also  formed. 

j8-Pinene,  nopinene  (formula  below),  b.p.  i62°-i63°,  D22  0-866, 
nD =1-4724,  is  found  in  small  quantities  beside  a-pinene  in  turpentine 
oils,  especially  American,  in  a  laevo-rotatory  form.  It  has  also  been 
traced  in  lemon  oil,  coriander  oil,  hyssop  oil,  and  the  oil  of  Siberian 
pine  needles  (C.  1909,  II.  2158).  It  has  been  synthesised  from  nopinol- 
acetic  acid  by  heating  with  acetic  anhydride  (A.  363,  9).  It  unites 
with  HC1  to  form  a  mixture  of  bornyl  chloride  and  dipentene  dichloro- 
hydrate  ;  with  nitrosyl  chloride  it  does  not,  like  a-pinene,  form  an 
addition  product.  But  it  unites  with  nitrous  acid  to  a  very  unstable 
pseudo-nitrosite,  which,  on  treatment  with  ammonia,  or  by  distilla- 
tion with  steam  (A.  346,  243),  turns  into  nitro-terebentene,  nitro-j3- 
pinene  C10H15NO2,  with  rejection  of  hyponitrous  acid.  The  latter,  on 
reduction  with  Sn  and  HC1,  yields  amido-terebentene  C1?H15NH2,  b.p.12 
95°,  from  which,  with  nitrous  acid,  an  alcohol  is  obtained,  which,  on 
oxidation  with  chromic  acid,  turns  into  tetrahydro-cumin-aldehyde,  or 
cuminic  acid  (A.  346,  246;  cp.  Phellandrene) . 

On  oxidation  with  KMnO4,  we  obtain  from  the  j3-pinene-glyeol 
C10H16(OH)2,  m.p.  76°,  which  is  first  formed,  nopinic  acid  CjoH^Og, 
m.p.  126°,  an  a-oxy-acid  characterised  by  its  sparingly  soluble  sodium 
salt,  and  a  ketone,  nopinone  C9H14O  (A.  356,  227  ;  368,  9). 

CH2  CH2OH  COOH 

COH  CO 

H2CHsC/CH 

H2C  CH2  H2C  CH, 

CH  CH 

/?-Pinene-glycol  Nopinic  acid  Nopinone. 


520  ORGANIC  CHEMISTRY 

Alcohols.  —  Univalent  Alcohols.  —  Pino  -  carveol  C10H15OH,  b.p. 
2i5°-2i8°>  probably  contained  in  the  oil  of  Eucalyptus  globulus 
(A.  346,  277).  It  is  made  artificially  by  the  action  of  nitrous  acid  upon 
pinylamine  (A.  346,  221).  On  oxidation  with  chromic  acid  it  yields 
pino-carvone,  and  on  heating  with  potassium  bisulphate,  or  dilute 
sulphuric  acid,  p-cymol. 

CH=C(CH2OH).CH 


Myrtenol 


(CH3)2C 


,  b.p.  223°,  D20  0-9763,  [a]D+45°  45', 


CH? CH— CH2 

in  the  form  of  its  acetate,  the  chief  constituent  of  myrtle  oil.  The 
myrtenyl  chloride  C10H15C1,  formed  by  the  action  of  PC15,  yields,  on 
reduction  with  Na  and  alcohol,  d-a-pinene.  On  oxidation  with 
chromic  acid  the  corresponding  aldehyde  is  obtained,  myrtenal 
C10H14O,  b.p.1()  87°-90°.  By  means  of  KMnO4  myrtenol  can  be  re- 
duced to  d-pinic  acid  (B.  40,  1363). 

Methyl-nopinol,  pinene  hydrate  C9H14/°*? ,   m.p.   59°,   b.p.    205°, 

XL/WS 

smells  of  camphor,  and  is  obtained  from  nopinone  and  CH3MgI.  By 
the  action  of  dilute  sulphuric  acid,  it  passes  into  optically  active 
a-terpineol  (A.  360,  88)  and  terpin  hydrate.  With  glacial  acetic  acid 
and  HC1,  it  turns  into  dipentene-dihalogenide.  With  PC15  it  gives  a 
chloride,  b.p.12  97°-io5°,  which  must  be  regarded  as  the  true  chloro- 
hydrate  of  pinene  (A.  356,  239).  Ethyl-  and  propyl-nopinol,  see  A. 
360,  91. 

Pino-campheol  C10H17OH,  b.p.  218°,  by  reduction  of  pino-camphone. 
Its  methyl-xanthogenate,  m.p.  61°,  yields,  on  heating,  a-pinene  (C. 
1908,  I.  1179). 

Polyvalent  Alcohols. — These  no  longer  contain  the  carbon  skeleton 
of  pinene. 

Pinol  hydrate,  sobrerol  C10H16(OH)2,  is  known  in  three  modifications. 
d-Pinol  hydrate,  melting  at  150°,  [a]D=  +  150°,  and  1-pinol  hydrate, 
melting  at  150°,  [a]D  =  —  150°,  are  produced  when  dextro-  and  laevo- 
turpentine  oil  are  oxidised  in  the  air  on  exposure  to  sunlight,  [d-fl]- 
Pinol  hydrate  results  on  treating  pinol  with  hydrobromic  acid  and 
alkali,  as  well  as  upon  mixing  equimolecular  quantities  of  d-  and  1-pinol 
hydrates.  Pinol  hydrate  is  an  unsaturated  compound.  Bromine 
converts  it  into  a  dibromide,  melting  at  131°.  Potassium  perman- 
ganate changes  it  to  a  tetra-acid  alcohol,  sobrerythrite  C10H16(OH)4, 
melting  at  156°  (B.  29,  1195,  R.  587). 

An  isomeric  sobrerythrite,  m.p.  194°,  is  obtained  from  the  result 
of  the  action  of  C1OH  upon  pinene  (B.  32,  2069). 

Pinol,  [d+l]-sobrerone  C10H16O,  boiling  at  183°,  with  sp.  gr.  0-953 
(20°),  nD=i'46949,  is  optically  inactive.  It  is  formed  when  the  three 
pinol  hydrates  are  treated  with  dilute  sulphuric  acid,  and  from  the 
dibromide  of  terpineol  by  the  splitting  off  of  2HBr.  It  is  as  indifferent 
as  cineol  towards  hydroxylamine,  phenyl-hydrazin,  and  acid  chlorides. 
This,  as  well  as  its  formation  from  terpineol  dibromide,  is  represented 
in  the  following  formula  : 

CH3.CBr^HBr.CH,\CH  C(OH)(CH3)2 >  CU3C(^^pcil 

Terpineol  dibromide  Pinol. 


PINANE  GROUP  521 

Pinol  hydrate  is  a  hydrate  corresponding  to  this  oxide,  an  oxy- 
terpineol,  which  results  from  pinene  by  the  rupture  of  the  pinene 
ring. 

Pinol  dibromide  C10H16Br2O,  melting  at  94°  and  boiling  at  143° 
(u  mm.),  is  converted  by  sodium  or  alcoholic  potash  into  pinol. 

With  HBr  it  gives  pinol  tribromide  C10H17Br3O.  The  latter  splits 
oft  HBr,  and  forms  an  isomeric  iso-pinol  dibromide  which,  with 
potash,  easily  forms  i-carvone  and,  on  reduction,  a  new  ketone, 
pinolone  C10H16O  (A.  306,  267). 

Formic  acid  reduces  it  to  cymene  (A.  268,  225).  Pinol  nitroso- 
chloride  C10H16O.NOC1,  melting  at  103°,  forms  nitrolamines  with  bases. 
Pinol-glyeol  C10H16O(OH)2,  melting  at  125°,  is  obtained  from  pinol 
dibromide  with  silver  oxide  or  lead  hydroxide,  or  from  its  diacetate, 
melting  at  97°  (A.  268,  223).  It  is  also  formed  from  pinol  oxide 
C10H1?O2,  b.p.  207°,  with  dilute  acids.  The  latter  is  obtained  from 
the  pinene-dichloro-hydrins  with  alkalies,  and  should  be  regarded  as 
the  dianhydride  of  sobrerythrite.  A  stereo-isomeric  pinol-glycol  is 
formed  by  the  oxidation  of  pinol  with  KMnO4  (B.  28,  2710  ;  C.  1898, 

II-  543)- 

Pinol-chloro-hydrins  C10H16OC1  (OH),  m.p.  131°,  are  also  obtained 
from  the  pinene-dichloro-hydrins,  the  dextro-form  resulting  from 
1-pinene  and  the  laevo-form  from  d-pinene  (B.  32,  2070). 

Bases. — Pinylamine  C10H15NH2,  b.p.  207°,  D  0-943,  by  reduction 
of  nitroso-pinene  (A.  268,  197).  By  the  action  of  nitrous  acid  it 
turns  into  pino-carveol.  Amido-terebentene  (see  above). 

Dihydrp-pinylamine,  pino-camphylamine  C10H17NH2,  b.p.  199°, 
by  reduction  of  nitroso-pinene  with  Na  and  amyl  alcohol  (C.  1907, 
I.  252). 

CO— C(CH3)=C 

Ketones. —  Carvo-pinone        (CH3)8cx        (?),  b.p.12  95°  (A.  346, 

CH2 CH— CH2 

231),  is  formed  by  heating  nitroso-pinene,  which  may  be  regarded 
as  carvo-pinone-oxime,  with  aqueous  oxalic  acid.  Hydroxylamine 
regenerates  nitroso-pinenes.  Acids  easily  isomerise  it  to  carvone.  It 
is  isomeric  with — 

Pino-carvone  C10H160,  b.p.12  95°,  the  oxidation  product  of  pino- 
carveol.     KMn04  decomposes  it  to  form  pinic  acid  (A.  346,  222). 
CO— CH(CH3)-CH 

Pino-camphone         (CH^c/        ,  b.p.12  87°,  D  0-959,  is  formed 

CHa CH-CH2 

beside  pinylamine  in  the  reduction  of  nitroso-pinene  with  zinc  and 
glacial  acetic  acid.  1-Pino-camphone  has  been  found  in  the  oil  of 
Hyssopus  officinalis  (C.  1909,  II.  2158).  By  oxidation  with  KMnO4 
it  forms  pinonic  acid  and  a  dicarboxylic  acid  isomeric  with  camphoric 
acid,  C^A,  m.p.  186°  (A.  346,  235). 

Nopinone  (constitution,  see  above),  b.p.  209°,  D20  0-981,  an  oxidation 
product  of  ^-pinene.  On  heating  with  dilute  H2SO4,  it  is  isomerised 
into  A2-iso-propyl-cyclo-hexenone  (A.  356,  227).  The  nopinol-acetic 
acid  C9H14(OH)CH2COOH,  m.p.  84°,  obtained  by  condensation  with 
bromo-acetic  ester  and  zinc  (A.  363,  7),  forms  the  fundamental 


522  ORGANIC  CHEMISTRY 

material   for  the  partial  synthesis   of   a-  and   j8-pinene   as   well   as 
fenchene  (q.v.). 

IV.  CAMPHANE  GROUP. 

'CHa 


CH2— CH— < 


i.  Hydrocarbons. — Camphene 


CH, 


13 


,  m.p. 


o V^.H.2 v-'  —  v^-JT.2 

b.p.  i59°-i6i°,  D54  0-842,  nD= 1-45514  (54°),  is  the  only  known  natural 
solid  terpene.  It  is  known  in  a  d-,  1-,  and  an  optically  inactive  modi- 
fication ;  these  are  similar  in  chemical  deportment.  Camphene  has 
been  found,  by  a  rearrangement,  in  iso-borneol,  in  the  oil  from  Andro- 
pogon  nardus,  and  in  camphor  oil  (B.  27,  R.  163).  It  is  obtained  (i) 
from  borneol  by  the  action  of  potassium  bisulphate  at  200°  ;  (2)  by  the 
action  of  ZnCl2  or  dilute  sulphuric  acid  upon  iso-borneol  ;  (3)  when 
sodium  acetate  and  glacial  acetic  acid  at  200°  act  upon  pinene  hydro- 
chloride  ;  and  (4)  on  digesting  bornyl  chloride  with  aniline,  pyridin, 
alkaline  phenolates,  etc.  The  so-called  camphene  hydrate,  and 
synthetic  methyl-camphenilol,  turn  into  camphene  with  special  ease, 
eliminating  water. 

Camphene  only  contains  one  double  linking.  Camphene  and  bromine 
in  ether  produce  : 

Camphene  dibromide  C10H16Br2,  melting  at  89°,  together  with 
liquid  bromo-camphene  C10H15Br  (B.  29,  544,  697,  900). 

Camphene  hydrochloride  C10H17C1,  melting  at  i49°-i5i°,  is  produced 
when  HC1  is  conducted  into  an  alcoholic  camphene  solution.  It  is 
identical  with  the  iso-bornyl  chloride  obtained  from  iso-borneol,  and 
probably  stereo-isomeric  with  pinene  chlorohydrate,  since  both 
chlorides  turn  into  the  same  camphene,  on  reduction  with  Na  and 
alcohol,  or  by  decomposition  of  their  Mg  compound  with  water.  From 
pinene  chlorohydrate,  camphene  chlorohydrate  is  specially  dis- 
tinguished by  the  greater  ease  with  which  it  passes  into  camphene, 
under  the  influence  of  dehydrating  agents.  Camphene,  treated  with 
glacial  acetic  acid  and  concentrated  sulphuric  acid,  yields  iso-borneol 
acetate.  The  action  of  fuming  nitric  acid  upon  a  chloroform  solution 
of  camphene  leads  to  an  additive  product  C10H16(HNO3),  b.p.10 
110°,  which  regenerates  camphene  with  alcoholic  potash  (C.  1900, 
II.  261). 

Camphenile  nitrite,  nitro-camphene  C8H14>  C  :  CHNO2,  m.p.  66°, 
b.p.12  147°,  is  found  among  the  oxidation  products  of  camphene 
volatilising  in  steam  under  the  action  of  dilute  nitric  acid.  It  is  also 
produced  by  the  action  of  nitrous  acid  upon  camphene  (B.  32,  1498), 
probably  by  splitting  off  hypo-nitrous  acid  from  the  very  unstable 
pseudo-nitrosite  formed  at  first.  This,  on  reduction,  yields  cam- 
phenilane-aldehyde,  and,  by  oxidation  with  KMnO4  or  the  action 
of  alcoholic  potash,  camphenilone  ;  while,  with  concentrated  H2SO4, 
it  yields  the  completely  saturated  tricyelene-carboxylic  acid  C10H14O2, 
m.p.  148°,  which  is  indifferent  to  KMnO4  (B.  41,  2747;  Ch.  Ztg. 
34,  65). 

On  oxidising  camphene  with  KMnO4  (A.  340,  17),  camphene-glycol 
C10H16(OH)2,  m.p.  200°,  is  first  formed,  m.p.  200°  ;  and  this,  treated 


CAMPHANE  GROUP  523 

with  dilute  H2SO4,  splits  off  water  and  turns  into  camphenilane-alde- 
hyde  C10H16O,  melting  at  70°  and  boiling  at  96°  (14  mm.).  The 
oxidation  of  this  aldehyde  gives  rise  to  two  isomeric  camphenilanic 
acids  C10H16O2,  melting  at  65°  and  118°,  which  can  be  changed 
through  the  corresponding  a-bromo-acid  into  oxy-camphenilanic  acid, 
camphenilol  acid,  C10H16O3,  melting  at  171°.  This  latter  acid  is 
also  formed  when  camphene  is  oxidised  with  potassium  perman- 
ganate. Its  further  oxidation  causes  the  elimination  of  carbon  dioxide 
and  the  formation  of  a  ketone,  camphenilone  C10H14O,  melting  at 
43°  and  boiling  at  81°  (12  mm.).  This  is  the  lower  ring-homologue 
of  camphor  ;  it  resembles  the  latter  in  odour  and  in  chemical 
behaviour.  By  the  oxidation  of  sodium  amide,  camphenilone  is 
broken  up  to  the  amide  of  2-iso-propyl-cyclo-pentane-carboxylic 
acid  (B.  39,  2580),  which  has  been  disintegrated  into  2-iso-propyl- 
cyclo-pentanone  (C.  1908,  I.  1271),  and  has,  on  the  other  hand, 
been  obtained  synthetically  from  j8-iso-propyl-adipinic  acid  (C.  1909, 

I.  443). 

The  ozonide  produced  on  treating  camphene  with  ozone,  on  de- 
composition with  water,  or  glacial  acetic  acid,  yields  camphenilone  and 
the  lactone  of  S-oxy-camphenilonic  acid  (B.  43,  1432)  with  splitting  of 
the  camphene  ring.  This  has  also  been  obtained  synthetically  by 
the  action  of  methyl-magnesium  iodide  upon  the  anhydride  of  cyclo- 
pentane-i,  3-dicarboxylic  acid  (B.  42,  898).  These  various  trans- 
formations are  easily  understood  on  the  basis  of  G.  Wagner's  camphene 
formula  : 

CH  CH  CH  CH 


H^fX™3 

_^   I    rw  i   xc±13 


|    CH2    N  'na  ->   |    CH2!  ->          CH2|    '-"»-*        I    CH2 

H2C     |     C=CH2  H2C     i     C(OH)CH2OH   H,C    I     C(OH)CO2H  H2C         CO 


*|     CH3     ^CH' 


CH  CH  CH  CH 

Camphene  Camphene-glycol     a-Oxy-camphenilanic  acid  Camphenilone. 

CH  i  |  i 

v      //-»TT  CH  CH  Cri 

H,C         C<£5 

i    \v_/rl' 

"   n2v-,  \_/\  ^TT  Jn»^  I      v^\  ^TT  n.tf^     \ 

I  p-tr    i    ^^A^-3  i  ptr  i    ^«*^  i      r*ij 

I  »^n2 1  |  *^nti  '^ri_ 

CO2H 
CO 

CH  CH  CH 

:H 

^-Oxy-camphenilone  Camphenilane-  Camphenilanic  acid     Iso-propyl-cyclo- 

acid  lactone  aldehyde  pentane-carboxylic 

acid. 

On  oxidising  the  artificial  and  natural  camphenes  with  KMnO4 
(but  not  with  ozone)  we  obtain,  besides  the  compound  already  men- 
tioned, considerable  quantities  of  a  dicarboxylic  acid,  isomeric  with 
camphene-camphoric  acid  C10H16O4,  m.p.  136°  (inactive),  144°  (active) 
(A.  375,  336).  Its  genesis  from  the  above  camphene  formula  can 
hardly  be  imagined  to  take  place  without  the  supposition  of  considerable 
atomic  displacement.  It  yields  no  anhydride,  and  no  cyclic-ketone, 
in  the  distillation  of  its  calcium  salt.  Its  constitution,  and  its  connec- 


524  ORGANIC  CHEMISTRY 

tion  with  the  oxidation  products  of  camphene,  are  not  yet  clear  (A.  375, 
336).  It  is  possible  that  it  owes  its  origin  to  a  hydrocarbon  isomeric 
with  the  above  camphene,  which  would  indicate  that  camphene  is  a 
mixture  of  two  isomeric  terpenes  (see  also  Tricyclene,  below).  But 
this  can  hardly  be  made  to  agree  with  the  almost  quantitative 
conversion  of  camphene  into  iso-borneol  (see  also  A.  382,  265 ; 
383,  i). 

A  primary  transposition  is,  no  doubt,  the  cause  of  the  production 
of  the  tribasic  carboxyl-apo-camphoric  acid,  camphoric  acid  C7Hn 
(COOH)3,  m.p.  196°,  in  the  oxidation  of  camphene  with  dilute 
nitric  acid.  With  chromyl  chloride  in  CS2  solution,  camphene  yields 
an  additive  compound,  C10H16.2CrO2Cl2,  which  is  decomposed  by 
water  with  formation  of  a  camphenilane-aldehyde.  In  the  animal 
body  camphene  is  oxidised  to  camphenilane-aldehyde  (C.  1903, 
I.  594).  Oxidation  with  chromic  acid  converts  camphene  into 
camphor. 

The  above  camphene  formula  therefore  indicates  that  the  pre- 
paration of  camphene  from  the  chlorohydrate  of  pinene  or  camphene, 
or  from  borneol  and  iso-borneol,  is  accompanied  by  a  peculiar  atomic 
displacement,  which  is  reversed  by  the  attachment  of  halogen  hydride 
and  other  acids.  This  transposition  involves  the  conversion  of  a 
five-membered  ring  into  a  six-membered  ring,  as  shown  in  the  following 
diagram  : 

CH2— CH— CH2 

!       8I        I 

|  CH3CCH3 1  I  CH3.C.CH3|          or 

I 

CH2— C CHC1  CH2 CH  CH2— CH— C=CH2 

2  I  |  6  2  iQ          """  6  2  6l7 

7CH3 

7CH2 

It  is  closely  related  to  the  atomic  displacement  occurring  in  the  con- 
version of  pinacolin  alcohol  or  its  chloride  into  tetramethyl-ethylene 
(Vol.  I.). 

Under  special  conditions  it  is  possible  to  avoid  the  atomic  dis- 
placement occurring  during  the  elimination  of  water  from  borneol, 
or  the  elimination  of  halogen  hydride  from  bornyl  haloids,  and 
thus  to  attain  the  hydrocarbon  forming  the  foundation  of  these 
compounds  : 

CH2— CH— CH 


Bornylene 


CH3CCH3 


,  m.p.  113°,  b.p.  146°,  [a]D  —21-69°.     It  is 


CH2— C CH 

CH3 

remarkable  on  account  of  its  great  volatility.  It  is  formed  from 
bornyl  iodide  with  concentrated  alcoholic  potash  (C.  1910,  I.  2089),  or 
by  the  dry  distillation  of  bornyl-xanthogenic  methyl  ester  (C.  1905,  I. 
94),  besides  camphene,  which  can  be  separated  by  conversion  into 
iso-bornyl  acetate.  It  is  obtained  in  a  pure  state  from  bornylene- 
carboxylic  acid,  by  elimination  of  CO2.  Bornylene  is  oxidised  by 
KMnO4  to  camphoric  acid. 


CAMPHANE  GROUP  525 

Camphane,  i,  7,  7  -  trimethyl  -  nor  -  camphane,  dihydro  -  bornylene 
CH2— CH— CH2 

/->TT     ppTJ' 

,  m.p.  153°,  b.p.  159°,  sublimes  easily.     It  is  formed  by 
CH2 — C CH2 

CH3 

the  reduction  of  camphene  and  pinene  hydrochloride  or  hydro-iodide 
with  sodium  and  alcohol,  or  by  the  decomposition  of  their  magnesium 
compounds  with  water,  besides  small  quantities  of  hydro-dicamphene 
(C10H17)2,  m.p.  85°.  As  indicated  by  its  symmetrical  structure,  it  is 
always  inactive,  whether  we  start  with  active  or  inactive  material 
(B.  39,  1127).  On  heating  with  dilute  nitric  acid,  it  gives  nitro- 
camphane,  m.p.  i25°-i29°. 

Iso  -  camphane,  5,  5,  6-trimethyl- nor -camphane,  dihydro  -  camphene 
C10H18,  m.p.  63°,  is  formed  by  the  reduction  of  camphene  with 
molecular  hydrogen  in  the  presence  of  platinum  black  (A.  382, 
265),  and  by  heating  iso-borneol  with  zinc  dust  to  220°  (B.  33, 
774),  in  the  latter  case,  no  doubt,  with  intermediate  formation  of 
camphene. 

Tricyclene  C10H16,  m.p.  68°,  b.p.  153°,  is  completely  saturated.  It 
is  contained  in  small  quantities  (about  0*4  per  cent.)  in  crude  camphene, 
and  remains  unchanged  during  its  oxidation  with  KMnO4  (A.  340,  17). 
It  is  probably  identical  with  the  tricyclic  hydrocarbon  obtained  by 
reduction  with  zinc  dust  and  alcohol. 

Fenchene  C10H16  has  not  hitherto  been  traced  with  certainty  in 
nature.  It  is  formed  from  the  fenchyl  chlorides  by  heating  with 
aniline,  quinolin,  or  alcoholic  potash,  from  iso-fenchyl  alcohol  by 
heating  with  zinc  chloride,  or  by  the  action  of  nitrous  acid  upon 
fenchylamine.  According  to  the  nature  of  the  foundation  material, 
we  can  obtain  dextro-  or  laevo-rotatory  or  inactive  fenchenes,  with 
boiling-points  ranging  from  154°  to  158°,  D  about  0-87,  and  nD=  1-4724. 
Synthetically,  a  fenchene,  either  dextro-  or  laevo-rotatory  according  to 
the  conditions,  has  been  obtained  from  nopinol-acetic  ester  by  splitting 
off  water,  and  by  the  distillation  of  the  resulting  unsaturated  acid 
(A.  363,  i).  Fenchene  combines  with  bromine  to  form  a  crystalline 
dibromide,  m.p.  62°  (inactive),  88°  (active).  With  halogen  hydride  it 
forms  liquid  monohalogen  hydrates,  apparently  identical  with  fenchyl 
haloids.  In  the  oxidation  with  permanganate,  fenchene  behaves  very 
much  like  camphene.  An  a-oxy-acid,  oxy-fenchene  acid  C10H16O3,  is 
produced  first,  and  D-l-  and  L-d-fenchene  *  yield  the  two  optical 
antipodes  of  this  acid,  m.p.  153°,  [a]D=±63°,  while  the  less  stable 
D-d-fenchene  yields  a  feebly  dextro-rotatory  oxy-fenchenic  acid,  m.p. 
138°.  By  oxidation  of  these  acids  we  obtain  ketones  C9H14O,  fencho- 
camphorones,  m.p.  110°  and  63°,  lower  homologues  of  camphor  closely 
resembling  it  and  yielding  on  further  oxidation  apo-camphoric  acid, 
which  is  also  easily  obtained  from  fenchene  with  nitric  acid  (A.  302, 
371;  315,  273  ;  C.  1898,  I.  575  ;  1899,  II.  1052). 

The  gradual  disintegration  of  fenchene  is  represented  by  the 
following  series  of  formulae  : 

*  The  capital  letters  D-  and  L-  indicate  the  optical  rotation  of  the  d-  or  1- 
fenchones  used  in  the  preparation. 


526  ORGANIC  CHEMISTRY 

C  :  CH2  /C(OH)COOH  /CO  /COOH 

CH2  C7Hl2\CH2  C'Hl2\CH2  C7Hl2\COOH 

D-1-Fenchene  Oxy-fenchenic  acid      Fencho-camphorone      Ape-camphoric 

acid. 

Since  the  formula  of  fenchone  may  be  taken  as  clearly  established, 
we  must  assume  an  atomic  displacement  in  its  conversion  into  fenchene 
corresponding  to  what  happens  in  the  conversion  of  camphor  into 
camphene. 

Tetrahydro  -  fenchene  C10H20,  b.p.  i6o°-i65°,  D22  =  07945, 
nD=  1-4370,  from  fenchone  and  fenchyl  alcohol  by  heating  with  HI. 

Dihydro-fencholene  C9H18,  see  Fencholenic  acid. 

In  connection  with  camphene  and  fenchene,  we  may  mention  a 
hydrocarbon  which,  from  its  composition,  C9H14,  may  be  regarded  as  a 
lower  homologue  of  terpene.  It  is  found  in  Indian  sandal-wood,  in 
Siberian  pine-needle  oil,  and  other  pine-needle  oils  (B.  40,  4918),  and 

CH2— CH— C.CH3 


b.p.  140°,  D20  0-863, 


has  been  termed  santene  C9H14=          CHj 

CH2— CH— C.CH3 

nu = i  -46658.  It  is  optically  inactive.  The  nitroso-chloride  crystallises 
in  blue  needles  to  m.p.  109°,  which,  after  a  short  time,  become  colourless. 
Nitrosite,  m.p.  125°.  Monochlorohydrate,  m.p.  80°.  Tribromide 
C9H13Br3,  m.p.  63°.  During  the  oxidation  with  KMnO4  we  obtain, 
with  intermediate  formation  of  santene-glycol  C9H14(OH)2,  m.p.  197°, 
a  diketone  C5H8(COCH3)2,  b.p.9  I24°-I27°,  which,  on  treating  with 
alkaline  bromine  solution,  turns  into  trans-cyclo-pentane-i,  3-di- 
carboxylic  acid  (B.  41,  385). 

A  hydrocarbon,  probably  identical  with  santene,  is  formed  by  boil- 
ing the  teresantaric  acid  C1pH14O2,  m.p.  157°,  also  occurring  in  sandal- 
wood,  with  dilute  sulphuric  acid.  By  heating  with  formic  acid,  the 
teresantaric  acid  turns  into  an  alcohol,  the  so-called  7r-nor-borneol, 
santenol,  m.p.  98°,  b.p.9  88°,  which  is  also  obtained  from  santene  by 
hydration  with  formic  acid  or  glacial  acetic  acid  and  sulphuric  acid, 
and  whose  chloride,  m.p.  60°,  b.p.10  73°,  on  treatment  with  alcoholic 
potash,  reverts  into  santene  (B.  40,  4465  ;  41,  125). 

2.  Alcohols. — A.     Monacid   Alcohols. — Borneo    camphor,    borneol, 

CH2— CH— CH2 

icT~T  C  CTT 
8  i'  ,  melting  at  203°  and  boiling  at  212°,  occurs 

H2— C CHOH 

CH3 

in  three  modifications  in  nature.  d-Borneol  is  found  in  Dryobalanops 
camphor  a,  a  tree  growing  in  Borneo  and  Sumatra,  also  in  rosemary  oil. 
I- Borneol  and  inactive  borneol  are  present  in  the  so-called  baldrianic 
camphor.  Many  wood-spines  contain  it  in  the  form  of  a  fatty  acid 
ester,  more  especially  the  acetic  ester. 

Borneol  is  very  similar  to  Japan  camphor,  but  has  an  odour 
at  the  same  time  resembling  that  of  pepper.  It  sublimes  very 
readily. 

Artificially,  it  is  formed,  besides  iso-borneol,  by  the  reduction  of 
camphor  with  sodium  and  alcohol  (A.  230,  225),  and  by  the  action  of 
oxygen  upon  the  magnesium  compound  of  pinene  chlorohydrate,  which 


CAMPHANE  GROUP  527 

must  therefore  be  regarded  as  bornyl  chloride  (B.  39,  1127).  In  the 
form  of  its  ester,  borneol  is  obtained  by  heating  pinene  with  organic  acids 
such  as  oxalic,  benzoic,  salicylic,  chloro-  and  nitro-benzoic  acids,  etc. 
(C.  1906,  II.  1589  ;  1909, 1.  1025).  On  oxidation,  it  turns  into  camphor 
without  change  in  the  direction  of  optical  rotation.  On  heating  with 
potassium  bisulphate  or  zinc  chloride  it  splits  up,  though  with  some 
difficulty,  into  water  and  camphene. 

Methyl  ether,  b.p.  194°.  Ethyl  ether,  b.p.  204°  (B.  24,  3713).  Acetyl 
ester,  m.p.  29°,  rhombic  hemihedral,  b.p.10  98°,  nD= 1*46635,  [a]D= 
+38°  20',  also  found  in  oil  from  Siberian  fir  (C.  1903,  I.  515). 

The  bornyl  haloids  are  identical  with  the  so-called  pinene  hydro- 
haloids.  Bornyl  iodide,  on  treating  with  alcoholic  potash,  yields  borny- 
lene.  Bornyl-iso-valerianate,  b.p.  255°-26o°,  occurs  in  baldrian  oil,  and 
is  used  in  pharmacy  under  the  name  "  bornyval."  Bornyl  salicylate 
("  salite  ")  is  used  as  an  anti-neuralgic. 

d-  and  1-Bornyl-xanthogenie  methyl  esters  C10H16OCS.SCH3  yield 
d-  and  1-bornylene  on  distillation  at  ordinary  pressures. 

Iso-borneol  C10H17OH,  m.p.  212°,  is  probably  the  stereo-isomeric 
alcohol  corresponding  to  borneol.  It  is  more  volatile  than  borneol, 
and  is  formed  together  with  the  latter  in  the  reduction  of  camphor, 
into  which  it  passes  by  oxidation  with  KMnO4,  ozone,  etc.,  with  reversal 
of  its  optical  rotation  (B.  39, 1131).  By  the  action  of  sodium  in  xylol 
or  benzine  solution,  iso-borneol  is  transformed  into  borneol  (C.  1909,  II. 
25).  Iso-bornyl  acetate,  b.p.13  107°,  is  formed  by  heating  camphene 
with  glacial  acetic  acid  and  50  per  cent.  H2SO4  to  5o°-6o°  (German 
patent  67,255  ;  B.  27,  R.  102),  or  by  transformation  of  pinene  chloro- 
hydrate  with  Zn  acetate  and  glacial  acetic  acid,  in  which  case  the  zinc 
chloride  acts  catalytically  (C.  1907,  II.  434).  Both  reactions  are  of 
industrial  importance  as  regards  the  artificial  production  of  camphor 
from  pinene.  Both  borneol  and  iso-borneol  are  formed  by  the  action 
of  oxygen  upon  magnesium-camphene  chlorohydrate  (B.  39,  1135). 
With  dehydrating  agents  it  passes  into  camphene  much  more  easily 
than  borneol. 

Camphene  hydrate  C10HnOs,  m.p.  150°,  b.p.  205°,  is  formed  on 
digesting  camphene  chlorohydrate  with  milk  of  lime.  It  smells  both 
of  fungus  and  menthol,  and  passes  easily  into  camphene,  on  shaking 
up  with  dilute  mineral  acids,  and  sometimes  on  mere  distillation 
(B.  41,  1092  ;  A.  383,  i). 

Methyl-camphenilol  C10H17OH,  m.p.  118°,  b.p.  205°,  has  been  ob- 
tained by  the  action  of  CH3MgI  upon  camphenilone.  On  heating  with 
glacial  acetic  acid  and  H2SO4  it  splits  off  water  and  easily  passes  into 
camphene  (A.  340,  58). 

Camphol  alcohol  C10H18OH,  m.p.  60°,  b.p.  213°,  is  formed  by  the 
reduction  of  campholic  ester  with  sodium  and  alcohol  (C.  1904,  II.  303). 
It  differs  from  the  tertiary  alcohol  of  the  same  name,  b.p.  203°,  pro- 
duced by  the  action  of  silver  nitrite  upon  campholamine  chlorohydrate 
(B.  27,  R.  126).  This  indicates  that,  in  this  case,  a  change  in  the  ring 
system  has  taken  place  (cp.  A.  379,  202). 

Camphel  alcohol  C9H17OH,  melting  at  25°  and  boiling  at  179°,  re- 
sults from  the  interaction  of  camphelamine  hydrochloride  and  silver 
nitrite.  It  is  a  tertiary  alcohol.  It  readily  decomposes  into  water  and 
the  hydrocarbon  C9H16  (B.  27,  R.  126). 


528  ORGANIC  CHEMISTRY 

Gamphenilol  C9H15OH,  m.p.  84°,  by  reduction  of  camphenilone 
with  sodium  and  alcohol  (A.  366,  72). 

Fenchyl  alcohol  C10H17.OH,  melting  at  45°  and  boiling  at  201°,  with 
specific  gravity  0-933,  is  produced  in  two  modifications  :  by  the  re- 
duction of  d-  and  1-fenchone.  It  has  a  penetrating  and  very  disagree- 
able odour.  L-d-fenchyl  alcohol,  [a]D=-j-io°  36',  is  obtained  from 
1-fenchone  and  1-fenchyl  alcohol,  [a]D=— 10°  35',  from  d-fenchone 
(A.  284,  331). 

i-Fenchyl  alcohol  has  been  found  in  the  yellow  pine  oil  of  Pinus 
palustris.  It  is  also  formed,  besides  other  alcohols,  in  the  hydration  of 
/3-pinene  (C.  1909,  II.  25).  On  oxidation  it  yields  fenchone  besides 
oxy-dihydro-fencholenic  acid  (B.  42,  2698),  and,  on  splitting  off  water, 
fenchene. 

Fenchyl  chlorides  C10H17C1,  b.p.14  84°-86°,  are  formed  from  fenchyl 
alcohol  with  PC15  or  HC1,  and  from  fenchene  with  chlorine  hydride. 
Fenchyl  chlorides,  of  various  origins,  show  different  optical  rotatory 
powers,  and  are  probably  mixtures  of  isomeric  (secondary  and  tertiary  ?) 
chlorides.  1-Fenchyl  bromide  C10H17Br,  b.p.14  9o°-ioo°  (/.  pr.  Ch.  2, 
62,  i).  D-1-Fenchyl  acetate,  b.p.10  88°. 

Iso-fenchyl  alcohol,  m.p.  62°,  b.p.13  98°.  Like  iso-borneol,  its 
acetate  is  formed  from  fenchene  with  acetic-sulphuric  acid.  While 
fenchyl  alcohol  yields  fenchone  upon  oxidation,  iso-fenchyl  alcohol  pro- 
duces an  isomeric  ketone,  iso-fenchone. 

Iso-fencholene  alcohol  C10H17OH,  b.p.  218°,  with  specific  gravity 
0-927  (20°),  nD= 1*476,  is  produced  when  alcohol  and  sodium  act  upon 
fencholene  amide  (A.  284,  337).  It  is  readily  attacked  by  potassium 
permanganate.  When  heated  with  dilute  sulphuric  acid  it  changes 
to  fenchenol  C10H18O,  b.p.  183°,  with  specific  gravity  0-925  (20°), 
nD= 1-46108.  This  compound,  with  the  exception  of  the  boiling- 
point,  cannot  be  distinguished  from  cineol. 

Thio-borneol  C10H17SH,  m.p.  63°,  b.p.12  95°,  by  the  action  of  sulphur 
upon  bornyl-magnesium  chloride,  and  through  transposition  of  hydro- 
pinene-sulphinic  acid,  camphane-sulphinic  acid  C10H17SO2H,  m.p.  64°, 
obtained  from  bornyl-magnesium  chloride  and  SO2.  Chromic  acid 
oxidises  thio-borneol  into  bornyl  disulphide  (C10H17)2S2,  m.p.  178°, 
which,  on  distillation  at  ordinary  pressure,  decomposes  into  thio-borneol 
and  thio-camphor  (B.  39,  3503). 

3.  Amines  have  been  obtained  by  the  reduction  of  nitroso-pinenes, 
oximes,  and  nitriles,  as  well  as  ketones  with  ammonium  formate. 

Bornylamine  C10H17.NH2  melts  at  159°  and  boils  at  199°.  The 
formyl  compound  is  produced  when  camphor  is  heated  with  ammonium 
formate,  and  the  base  itself  by  the  reduction  of  camphor-oxime  with 
alcohol  and  sodium. 

In  the  latter  reaction  two  geometrically  isomeric  optically  active 
bases  are  obtained  :  bornyiamine,  m.p.  173°,  [a]D=+45'5°;  and  neo- 
bornylamine,  m.p.  180°,  [a]D=— 31-3°  (C.  1898,  II.  300). 

Bornylamine  possesses  an  odour  like  that  of  camphor  and  piperidin 
(A.  269,  347).  Heated  with  acetic  anhydride,  it  splits  up  at  2oo°-2io°, 
forming  camphene  (A.  269,  347). 

Gamphylamine  C9H15.CH2.NH2,  boiling  at  i94°-i96°,  is  produced 
when  the  nitrile  of  campholenic  acid  is  reduced.  The  benzoyl  com- 
pound melts  at  77°  (B.  20,  485  ;  21,  1128). 


CAMPHANE  GROUP  52$ 

Campholamine  C10H19.NH2,  and  camphelamine  C9H17NH2,  see 
Campholic  acid. 

Camphenamine  C8H14<(^H2,  b.p.200  161°,  D20  0-9399,  formed  from 

chloro  -  camphenamine  with  soda,  which  is  obtained  from  amido- 
borneol  C10H16(OH)(NH2),  the  reduction  product  of  amido-camphor 
(B.  33,  481).  With  HNO2,  camphenamine  gives  a  tertiary  unsaturated 
alcohol  C10H15(OH),  m.p.  102°,  the  so-called  jS-iso-camphor,  isomeric 
with  camphor  and  closely  resembling  it  (A.  313,  59). 

Campnenylamine  C?H15.NH2,  m.p.  91°,  b.p.  185°,  by  reduction  of 
camphenilone-oxime  with  Na  and  alcohol  (A.  366,  75). 

Camphane  -  diamine  C10H16(NH2)2,  a  wax-like  mass,  b.p.  246°, 
formed  by  reduction  of  camphor-dioxime  or  amido-camphor-oxime 
(C.  1905,  II.  178). 

Fenchylamine  and  fencholenamine  sustain  the  same  relation  to  each 
other  that  we  observed  in  bornylamine  and  camphylamine. 

Fenchylamine  C10H;7NH2,  boiling  at  195°,  with  specific  gravity 
0-9095  (22°),  is  known  in  three  modifications,  produced  from  the  cor- 
responding fenchones  on  heating  them  with  ammonium  carbonate,  or 
by  reducing  the  fenchone-oximes.  D-1-Fenchylamine,  [a]D=—  24-89°, 
obtained  from  d-fenchone,  yields  D-1-fenchene  and  d-limonene  on 
the  action  of  HN02.  The  optical  rotatory  power  of  a  series  of  deriva- 
tives has  been  studied  : 

Formyl-,  acetyl-,  propionyl-,  butyryl-fenchylamines,  [a]D=— 36-56°, 
-46-62°, -53-16°,  53-11°  (A.  276,  317)- 

Fencholenamine  CgHjs.CHg.NHjj,  boiling  at  iio°-ii5°  (21-24  mm.), 
results  from  the  reduction  of  the  nitrile  of  fencholenic  acid  nitrile 
(A.  263,  138). 

Fenchelylamine  CgH17NH2,  b.p.  173°,  is  formed  from  fenchelyl  iso- 
cyanate  C9H17N  :  CO,  the  result  of  the  action  of  potassium  hypo- 
bromite  upon  fencholic  acid  amide.  On  dry  distillation  its  chloro- 
hydrate  yields  apo-fenchene  CgH16,  b.p.  143°,  D21  07945  (A.  369,  79 ; 
C.  1910,  II.  875). 

4.  Ketones. — Various  transformation  products  of  the  ketones 
C10H16O,  camphor  and  fenchene,  have  been  treated  in  the  preceding 
sections.  By  reduction  they  yield  borneol  and  fenchyl  alcohol,  from 
which  they  are  conversely  again  obtained  by  oxidation. 

Camphor  is  known  in  two  optically  active  modifications  and  one 
optically  inactive  modification,  while  fenchone  is  known  in  two  opti- 
cally active  forms. 

d-Camphor,  common  camphor,  Japan  camphor  C10H16O2,  melting 
at  175°  and  boiling  at  204°,  with  [a]D= +44-22°  in  alcohol  (A.  250,  352), 
is  found  in  the  camphor  tree  (Cinnamomum  camphor  a}.  It  is  obtained 
by  distillation  with  steam  and  sublimation.  Artificially,  it  is  made 
on  an  industrial  scale  by  changing  oil  of  turpentine  (pinene)  into  borneol 
or  iso-borneol,  and  oxidising  with  KMnO4,  ozone,  nitric  acid,  etc.,  but 
the  result  is  mostly  inactive.  Camphor  is  also  formed  by  oxidation 
of  camphene  with  chromic  acid.  It  is  a  colourless,  transparent  mass, 
crystallises  from  alcohol,  and  sublimes  in  shining  prisms  of  specific 
gravity  0-985.  It  is  very  volatile,  and  is  applied  therapeutically  as 
well  as  in  the  manufacture  of  celluloid  and  smokeless  powder.  Its 
alcoholic  solution  is  dextro-rotatory.  Camphor  yields  pure  cymol  if 

VOL.  II.  2  M 


530  ORGANIC  CHEMISTRY 

distilled  with  P2O5,  and  on  boiling  with  iodine  forms  carvacrol  C10H14O. 
When  boiled  with  nitric  acid  it  yields  different  acids,  chiefly  camphonic 
and  camphoronic  acids.  Upon  reduction  it  passes  into  borneol  and 
iso-borneol. 

1- Camphor,  matricaria  camphor,  is  contained  in  the  oil  of  Matri- 
caria  Parthenium.  It  resembles  d-camphor  even  to  the  rotatory 
power  [a]D= — 44*22°.  It  yields  1-camphoric  acid  upon  oxidation. 

(d-f-1)- Camphor,  melting  at  178-6°,  is  produced  on  mixing  d-  and 
1-camphors,  and  by  the  oxidation  of  i-borneol  and  i-camphene  with 
chromic  acid  (B.  12,  1756).  Also  by  racemising  ordinary  camphor  with 
A1C13  (C.  1899,  I.  1243). 

Constitution  of  Camphor. — The  camphor  formula  (i)  proposed  by 
Kekule  (1873)  satisfactorily  accounted  for  the  change  of  camphor  into 
p-cymol  and  carvacrol.  However,  the  ready  anhydride  formation  of 
camphoric  acid,  which  had  led  to  a  seven-membered  ring,  could  not 
be  brought  by  it  into  accord  with  the  known  experiences  relating  to 
the  anhydride  formation  of  aliphatic  dicarboxylic  acids.  The  lack  of 
additive  power  also  remained  unexplained.  The  formulae  of  Kanonni- 
koff  and  Bredt  explained  these  relations  much  better.  In  them  the 
p-carbon  atoms  of  the  hexagon  of  camphor  were  brought  in  direct 
union.  The  anhydride  formation  of  camphoric  acid,  thus  made 
parallel  with  ethylene-succinic  acid,  could  be  understood  on  the  basis 
of  this  formula.  Baeyer  (1893)  showed  that,  as  camphoric  anhydride 
melted  higher  than  its  hydrate,  it  probably  contained  an  n-glutaric 
acid  anhydride  ring  (A.  276,  265). 

Camphoric  acid  is  not  the  only  oxidation  product  of  camphor,  for 
when  it  is  further  oxidised  camphanic  acid  and  camphoronic  acid  are 
produced.  In  the  latter  acid  J.  Bredt  recognised  a,  a,  /Mrimethyl- 
tricarballylic  acid,  inasmuch  as  it  decomposed,  upon  the  application 
of  heat,  into  trimethyl-succinic  anhydride,  iso-butyric  acid,  carbonic 
acid,  water,  and  carbon  ;  whereas,  when  camphoronic  acid,  the  lactone 
of  oxy-camphoronic  acid,  obtained  from  it,  is  fused  with  caustic  potash, 
trimethyl-succinic  acid  and  oxalic  acid  are  produced  very  readily. 
Bredt  concludes  from  this  behaviour  that  the  carbon  grouping  of  cam- 
phoronic acid,  as  well  as  that  of  trimethyl-succinic  acid,  must  be  present 
in  camphanic  acid,  camphoric  acid,  and  camphor.  The  formula  of 
Bredt  (1893)  may  be  imagined  (B.  26,  3047)  to  have  been  evolved  from 
that  of  Kekule  by  rotating  the  iso-propyl  group  about  180°,  until  it  lies 
within  the  hexagon,  and  then  its  middle  carbon  atom  is  allowed  to 
unite  the  two  p-carbon  atoms  of  the  hexagon  by  the  migration  of  an 
H  atom  and  the  dissolution  of  the  double  union  : 

CH,.CHCH3  CH3CHCH3  CH3CHCH3 

CH  C  C  CH 


H2C      C 
Hci      I 
Y 


O  H2C 


H,C 


H2C  NCH2 

!CH3.C.CH3| 
CO  H2C         I         CO 


Ho  H2C 

MX  \/ 

_ r  C  C  'C' 

CH3  CH3  CH3  CH3 

(Kekul6,  1873)        (Kanonnikoff,  1883)  (Bredt,  1884)          (Bredt,  1893). 


The  position  of  the  CO  group  is  proved  by  the  conversion  of 
camphor  into  carvacrol  (see  above). 


CAMPHANE  GROUP  531 

The  oxidation  of  camphor  (i)  to  camphoric  acid  (2),  camphanic 
acid  (3),  and  camphoronic  acid  (4),  as  well  as  the  decomposition  of  the 
latter  into  trimethyl-succinic  acid  (5),  also  found  among  the  oxidation 
products  of  camphor  (B.  26,  2337),  is  represented  in  the  following 
diagram  : — 

CH2 CH — CH2 

(CH3)2C 
CH2 C CO 

(i)  CH3  (2)  CH3 

C02H     C02H  C02H 

(CH3)2C  -  _>  (CH3)2C 

CH2 C— CO2H  CH— CO2H 

(4)          CH3  (5)        CH3 

This  interpretation  is  corroborated  by  the  synthesis  of  camphor, 
which  can  be  carried  out  as  follows  (Komppa,  A.  370,  209). 

Oxalic  ester  and  j3-dimethyl-glutaric  acid  ester  are  condensed  by 
sodium  ethylate  to  diketo-apo-camphoric  acid  ester  (i)  ;  by  means  of 
methylation  with  methyl  iodide  and  sodium,  in  alcoholic  solution, 
this  is  turned  into  diketo-camphoric  acid  ester  (2).  By  means  of  the 
intermediate  products — dioxy-,  dehydro-,  and  bromo-camphoric  acid — 
the  diketo-camphoric  acid  may  be  reduced  to  a  mixture  of  cis-  and 
trans-  [d+1]  -camphoric  acid  (3),  which  are  separated  by  utilising  their 
different  behaviour  in  forming  anhydrides.  cis-Camphoric  anhydride 
is  reduced  to  the  lactone  campholide  (4)  by  means  of  Na  amalgam, 
and  this  combines  with  potassium  cyanide  to  the  nitrile  of  homo- 
camphoric  acid  (5).  The  latter,  which  can  also  be  prepared  from 
cyano-camphor  by  saponifkation  and  splitting,  3/ields  camphor  (6)  on 
distillation  of  its  calcium  salt  : 


:OOR   CHZ  —  co2R 

+     C(CH3)2           --> 

:OOR   CH2  co2R 
:O.CH  co2H 

C(CH3)2                    —  > 
:O.C(CH3).C02H 

(I)  ( 

C 

(3)  ( 

C 

:O.CH  C02R               (2) 
C(CH3)2                    —  > 

;O.CH  —  co2R 
:HZ.CH  —  co2H         (4) 

C(CH3)2                 -* 
:H2.C(CH3).C02H 

CO2CH  CO2R 
|     C(CH3)2 
CO.C(CH3).CO2R 
CH2.CH  CH2 

|    C(CH3)2     ;>o 

CH2.C(CH3)—  CO 

:H2.CH.CH2CN 
|       C(CH3)2               > 
:H2.C(CH3).COOH 

(5)  CH2.CH.CH2C02                 (6) 
|       C(CH3)2       \Ca__> 
CH2.C(CH3).CO/ 

CH2.CH  CH2 
C(CH3)2  i 
CH2.C(CH3).CO. 

Since  racemic  camphoric  acid  can  be  split  up  into  d-  and  1-camphoric 
acids  by  means  of  its  cinchonidin  salt,  the  above  process  is  also  useful 
for  the  preparation  of  optically  active  camphor. 

On  a  second  method  of  synthesising  camphor,  see  Perkin  and 
Thorpe,  C.  1906,  II.  241. 

On  the  stereo-isomerism  of  the  camphor  molecule,  see  A.  316,  196 
(also  J.  Bredt,  Uber  die  racemliche  Configuration  des  Camphers, 
Leipzig,  1905). 


532  ORGANIC  CHEMISTRY 

The  camphor  formula  leads  to  the  formulae  for  borneol,  camphene, 
and  numerous  other  compounds  in  genetic  connection  with  camphor. 
The  recognition  of  the  connection  between  camphor  and  its  transforma- 
tion products  is  frequently  impeded  by  far-reaching  molecular  re- 
arrangements undergone  by  these  bodies,  especially  with  acid  reagents 
(cp.  j3-campholenic  acid,  j3-campholytic  acid,  etc.). 

Transformation  Products  of  Camphor.  —  Chlorine  and  bromine 
convert  camphor  into  mono-  and  di-substitution  products,  a-  and  j3,  d- 
.  chloro-camphor  melt  at  92°  and  100°.  a-  and  j3-Dichloro-camphor 
melt  at  93°  and  77°,  while  a-  and  jS-bromo-eamphor  melt  at  76°  and  61°. 
On  the  action  of  sodium  upon  bromo-camphor,  dicamphor  (C10H15O)2, 
and  dicamphene-dione  (C10H14O)2,  see  C.  1898,  1.  295,  and  B.  37,  1569. 
With  magnesium  in  ether  the  a-bromo-camphor  yields  bromo- 
magnesium-camphor,  which  is  found  to  be  very  suitable  for  syntheses 
(B.  36,  2608  ;  37,  749).  a-  and  j3-Dibromo-camphor,  m.p.  61°  and 
115°  (cp.  C.  1897,  II.  76)  ;  on  the  decomposition  of  a-dibromo-camphor, 
see  C.  1900,  I.  198.  a-Iodo-eamphor,  m.p.  43°,  is  formed  by  the 
saponification  of  iodo-formyl-camphor,  or  by  the  action  of  iodine  upon 
sodium-camphor.  a-Di-iodo-eamphor,  m.p.  109°,  is  formed  by  the 
action  of  iodine  upon  alkaline  alcoholic  solution  of  formyl-camphor 
(B.  37,  2156). 

With  PCL  camphor  gives  several  camphor  dichlorides,  dichloro- 

fCH2 
camphanes    C8H14|  |        which,    on    shaking    up    with    concentrated 

[CClg 
sulphuric  acid,  split  the  bridge  linkage,  and  pass  easily  into  carvenone, 

By  heating  camphor  with  alcoholic  ammonium  sulphide,  a  mixture 
of  sulphides  is  obtained  which,  on  distillation,  yields  thio-eamphor 
C10H16S,  red  crystals,  m.p.  119°,  b.p.]5  104°,  and  thio-borneol  (B. 
36,  863). 

By  heating  chloro-camphor  and  bromo-camphor  with  nitric  acid, 
or  by  chlorinating  or  brominating  nitro-camphor,  we  obtain  chloro- 
and  bromo-nitro-camphor,  which,  on  reduction  with  copper  zinc,  or 
on  treatment  with  sodium  methylate,  give  nitro-camphor  (B.  22, 
R.  266  ;  23,  R.  115  ;  29,  R.  270  ;  37,  2077  ;  C.  1899,  I.  1078).  By 
reduction,  nitro-camphor  yields  amido-camphor.  An  isomeric  nitro- 

camphor  C8Hi4\£/Q|Jv  (?),  m.p.  70°,  is  formed  from  iso-nitroso-camphor 

by  oxidation  with  nitric  acid  (C.  1902,  II.  897). 

Camphor-sulphonic  acids  and  their  transformation  products,  see 
B.  28,  R.  643  ;  29,  R.  512  ;  C.  1898,  I.  619  ;  1902,  II.  1464  ;  1903, 
I.  923.  The  d-camphor-sulphonic  acid,  and  especially  the  d-bromo- 
sulpho-camphoric  acid,  are  often  useful  for  splitting  up  racemic  bases. 

Camphor-oxime  C10H16  :  NOH,  m.p.  118°,  b.p.  249°  (A.  259,  331), 
gives,  on  reduction,  bornylamine.  Potassium  hypobromite  converts 

it  into  bromo-nitro-eamphane  c8Hi4\CBr(NO)  »  m-P-  220°>  wmcn>  on 
reduction,  gives  nitro-eamphane  C10H17N02,  m.p.  148°  (C.  1900,  1.  544). 
By  the  action  of  nitrous  acid  upon  camphor-oxime  we  obtain  the 


nitrate  of  a-camphorimine  C8H14       .  ^H(?),  m.p.  about  95 

with  j3-camphorimine  and  camphenamine,  besides  a  substance  C16H16 
N2O2,  m.p.   43°,  which   is  termed  pernitroso-camphor  or  camphenile 


CAMPHANE   GROUP  533 

nitramine,  isomeric  with  camphor  dioximes,  and  converted  by  sulphuric 
acid  into  a  ketone  isomeric  with  camphor  (B.  29,  2807  ;  C.  1905,  II. 
623).  Camphor-oxime  and  camphor-phenyl-hydrazone,  b.p.  210°, 
can  also  be  easily  prepared  from  thio-camphor  (B.  36,  868). 

j3-Camphor,  bornylone  C8H14<^°  ,  m.p.  185°,  b.p.  214°,  structurally 
isomeric  with  camphor,  is  formed  by  the  action  of  acids  upon  j3-cam- 
phorimine  C8H14<^^NH,  obtained  from  the  azide  of  bornylene-car- 

boxylic  acid  by  Curtius'  transposition.  In  small  quantities  it  is  also 
obtained  from  ct-oxy-camphane-5-carboxylic  acid  by  oxidation  with 
Cr03  (Ch.  Ztg.  35,  765). 

Camphor-quinone  C8H14<^,  m.p.  198°,  is  formed  from  iso-nitroso- 

camphor  by  boiling  with  dilute  sulphuric  acid,  upon  the  action  of 
nitrous  acid  or  sodium  bisulphite,  or  by  the  action  of  campho-carboxylic 
acid  (B.  27,  1447).  It  resembles  the  quinone  of  the  a-diketones,  has 
a  peculiar  sweet  odour,  is  volatile  with  steam,  and  sublimes  at  50°-6o° 
in  golden-yellow  needles  (A.  274,  71).  Camphor-quinone  easily  passes 
into  camphoric  acid  derivatives,  under  the  influence  of  various  reagents 
(cp.  B.  30,  657,  659).  Concentrated  sulphuric  acid  converts  it  into  a 
ketonic  acid  C^HjgOg ;  fuming  sulphuric  acid  produces  a  transposition 
of  camphor-quinone  even  at  0°,  with  splitting  up  of  the  CH3.C.CH3 
bridge,  and  enolisation  of  a  keto-group  (B.  35,  3829). 

Iso-nitroso-camphor  C8HX^ !  Q  {  H  exists  in  two  forms,  melting  at 

153°  and  114°  respectively  (C.  1908,  I.  1270)  ;  it  is  formed  by  the 
action  of  amyl  nitrite  and  sodium  ethylate  upon  camphor.  Concen- 
trated sulphuric  acid  converts  it  into  camphoric  acid  imide  (B.  26, 
241).  Acetyl  chloride,  PC13,  or  soda  and  acetic  anhydride  produce 
camphoric  acid  mononitrile  (B.  29,  R.  651).  Zinc  and  dilute  acids 
produce  amido-camphor  (A.  274,  71).  Camphor  -  quinone  -  phenyl- 
hydrazone  C,HM^^N  IC6H5j  m  p  I^°>  -1S  produced,  besides  its  desmo- 

tropicform  C8H14<^Q '  NC«HS,  m.p.  180°,  by  the  action  of  diazo-benzol 

chloride  upon  campho-carboxylic  acid  (B.  32,  1995  ;  cp.  C.  1902, 
II.  210). 

bis-Camphanonazine,  azo-camphenone  C8H14<^^N'N^T>C8H14,  m.p. 

222°,  is  obtained  from  camphor-quinone  with  hydrazin,  and  from  azo- 
camphor  by  heating,  together  with  camphenone  (B.  27,  R.  892  ;  C. 
1897,  II.  761). 

Camphor-dioxime,  a-dioxime,  m.p.  201°,  j3-dioxime,  m.p.  248°,  are 
formed  from  iso-nitroso-camphor  with  acetic  hydroxylamine.  y-Di- 
oxime,  m.p.  135°,  from  iso-nitroso-camphor  with  free  hydroxylamine, 
on  melting,  passes  into  S-dioxime,  m.p.  199°.  The  dioximes  are  dis- 
tinguished by  their  optical  rotatory  power  (C.  1903,  I.  1352).  By 
reduction  they  yield  the  peroxide  C10H16N2O2,  m.p.  144°.  They  are 
also  produced  from  bromo-pernitroso-camphor,  a  bromination  product 
of  pernitroso-camphor  with  hydroxylamine  (C.  1900,  II.  574)- 

a-Oxy-camphor  C8H14<^HOH,  m.p.  203°-205°,  is  formed  from 
camphor-quinone  by  reduction  with  glacial  acetic  acid  and  zinc  dust. 


534  ORGANIC  CHEMISTRY 

It  is  easily  alkylated  and  acylated.  Sodium  amalgam  reduces  it  to 
camphor.  Sodium  and  alcohol,  to  eamphor-glycol  C8HU<(£^Q^>  ™-P- 
231°.  This  eamphor-glycol  is  isomeric  with  the  camphene-glycol 
obtained  from  camphene  with  KMn04,  and  must  be  regarded  as 
the  glycol  of  bornylene.  By  oxidation  of  oxy-camphor,  camphor- 
quinone  is  regenerated  (B.  35,  3811). 

Campherol  C10H16O2,  m.p.  I97°-I98°,  is  apparently  isomeric  with 
a-oxy-camphor.  It  occurs  in  the  form  of  a  glucuronic  acid  compound 
in  the  urine  of  dogs  fed  with  camphor  (B.  30,  660). 

/CH.NH2 

Amido-eamphor  C8H14<  |  ,  b.p.  244°,  from  mtro-camphor,  or, 

XCO 

better,  from  iso-nitroso-camphor,  by  reduction.  It  is  a  mass  resembling 
paraffin,  and  smelling  of  fish.  It  condenses  on  standing  to  dihydro- 
camphene-pyrazin  C8H14<§^=^H>C8H14,  m.p.  116°,  and,  as  an 

a-amido-ketone,  it  is  suitable  for  hetero-ring  formations  (cp.  A.  313,  25). 
Amido-camphor-chlorohydrate,  m.p.  224°,  acts  like  curare,  but  much 
more  feebly.  Acetyl  compound,  m.p.  122°.  Camphoryl-glycoeoll  ester 
C10H15O.NHCH2CO2C2H5  is  poisonous  (A.  307,  207  ;  B.  31,  3260  ;  32, 

1538  ;  35,  3657)  .    Camphoryl-earbamide  C6H4<^'NHCONH2,  m.p.  169°, 

from  amido-camphor  and  potassium  cyanate,  yields,  with  nitrous  acid, 
camphoryl-iso-cyanate  C10H15O.N  :  C  :  O,  m.p.  77°,  a  substance  very 
prone  to  reaction,  from  which  numerous  counter-derivatives  have  been 
obtained. 

Camphoryl-mustard   oil   C10H15O.N  :  C  :  S,  m.p.  106-5°  (C.  1908, 

I-  257)- 


Azo-camphor,  monoketazo-camphor-qmnonec^/^^,    m.p.    74°, 

yellow  crystals,  is  obtained  by  the  action  of  nitrous  acid  upon  amido- 
camphor-chlorohydrate  (B.  26,  1718)  ;  with  potassium  sulphite  it 
gives  hydrazin  sulphonate,  which  is  split  up  by  concentrated  HC1  into 
hydrazin  and  camphor-quinone  (B.  29,  R.  1115). 

Camphenone  c8H13^?*r(?),  m.p.  i68°-i70°,  is  formed  besides  azo- 

camphenone  by  heating  azo-camphor.  It  smells  of  camphor.  Oxime, 
m.p.  132°  (B.  27,  R.  590).  For  the  action  of  bromine  and  HBr  upon 
camphenone,  see  B.  29,  R.  1108. 

If  we  wish  to  attach  carbon  groups  to  the  camphor  amalgam, 
sodium  camphor  (C10H15O)Na,  obtained  from  camphor  with  sodium 
and  sodium  amide,  is  particularly  suitable,  and  so  is  camphor-magnesium 
bromide  (C10H15O)MgBr,  obtained  from  a-bromo-camphor  with  mag- 
nesium in  ether,  in  benzene,  toluol,  etc.  By  the  action  of  halogen 
alkyl  CO  2,  cyanogen,  car  boxy  lie  esters,  chlorides  or  anhydrides,  of 
aldehydes  and  ketones  upon  these  bodies,  the  radicles  -CH3,  -CO2H, 
-CN,  -COR,  -CH(OH)R',  -C(OH)RR',  =CHR  are  introduced  instead 
of  the  hydrogens  of  the  -CH2  -CO  group  in  camphor.  The  resulting 
products  are  capable  of  many  transformations. 

d-Campho-carboxylic  acid  C8H14<^C°2H,  m.p.  128°,  with  evolution 
of  CO2.  It  is  formed  from  camphor  with  .sodium,  or,  better,  from 


CAMPHANE   GROUP  535 

sodium  amide  and  CO2  in  benzene,  or  from  bromo-camphor  Mg  and 
CO2  in  ether  (B.  36,  668,  1305).  The  acid  and  its  esters  :  methyl 
ester,  b.p.15  i55°-i6o° ;  ethyl  ester,  b.p.21  167°,  give  green  and  blue 
colorations  respectively,  with  ferric  chloride.  With  sodium  and 
alkyline  iodide  the  esters  yield  alkyl-campho-carboxylic  ester  :  methyl- 

campho-earboxylic  methyl  ester  C8H14</£^H3)C°2CH3,  m.p.  87°  (acid  : 

m.p.  104°),  ethyl-campho-carboxylic  ethyl  ester,  b.p.15  165°.  Some  of 
these  esters  are  difficult  to  saponify.  With  carboxylic  haloids  the 
sodium  campho-carboxylic  esters  change  into  O-acylated  products 

XCO2R 
C8H14<(  II          ;    but    with   benzol-sulpho-chloride    besides    benzol-sul- 

xCOAc 
phinic  acid,  a-chloro-campho-carboxylic  ester  is  formed.     a-Bromo- 

and  a-iodo-eampho-carboxylic  esters  C8H14<^^C°2R  are  easily  obtained 

(B.   36,   1732).     With  phenyl-hydrazin  and  campho-carboxylic  ester, 
two  isomeric  campho-phenyl-pyrazalones  are  obtained  (B.  32,  1987). 
By  electrolytic  reduction  of  campho-carboxylic  acid  in  alkaline 

/fTTPOOTT 

solution  we  obtain  cis-  and  trans-borneol-carboxylic  acid  C8H14<  XwXSa 

'    XCxiOrl 

m.p.  101°  and  171°  respectively.  KMnO4  oxidises  only  the  cis-acid 
of  camphoric  acid,  whereas  nitric  acid  oxidises  both.  With  acetyl 
chloride  both  give  rise  to  the  aceto-compounds  of  the  trans-acid,  m.p. 
123°.  By  elimination  of  water  both  acids,  but  the  cis-acid  more 

readily,  turn  into  bornylene-earboxylie  acid  C8H14<(^;OOH,  m-P-  IZ3°» 

b.p.13  158°.  The  latter  unites  with  HC1  or  HBr  in  glacial  acetic  acid 
to  form  j3-chloro-  and  jS-bromo-hydro-bornylene-carboxylic  acid,  m.p. 
85°  and  91°,  the  alkaline  salts  of  which,  on  boiling  in  aqueous  solution, 
yield  bornylene  besides  other  products,  and  yield  it  in  a  particularly 
pure  form.  By  reduction  of  j3-bromo-hydro-bornylene-carboxylic  acid 
with  potassium  amalgam,  or  of  bornylene-earboxylie  acid  with  hydrogen 
and  palladium,  we  obtain  : 

Camphane-5-carboxylic  acid  C8H14<^P*C°2H,  m.p.   91°,   which  is 

XCHg 

geometrically  isomeric  with  the  acid  obtained  by  the  action  of  CO2 
upon  bornyl-magnesium  chloride. 

Camphane  -  6  -  carboxylic     acid,      hydro  -  pinene  -  carboxylic      acid 

//^TT 

C°H»\CHCOOH'  m'P-  73°  (A-  366,  i  ;  B.  38,  3799)- 

/CHCN 

The  nitrile  of  campho-carboxylic  acid,  cyano-camphor  C8H14^Q     , 

m.p.  127°,  is  formed  from  sodium  camphor  with  gaseous  cyanogen, 
and  also  from  oxy-methylene  camphor,  by  heating  with  hydroxyl- 
amine  chlorohydrate,  which  also  produces  its  oxime  (A.  281,  349). 
From  sodium  cyano-camphor,  with  alkylene  iodide,  we  simultaneously 

obtain  0-  and  C-alkyl-cyano-camphor  C8H14<(^k  and  c8H14<^lk)CN 
(C.  1903,  I.  1085)  ;  from  the  latter,  by  saponification  and  elimination 
of  CO 2,  we  obtain  the  alkyl  camphor  methyl-camphor  C8H14<^^'CHs, 

m.p.  38°,  [a]D-f-27°,  which,  with  bromine,  produces  methyl-bromo- 
camphor,  which,  in  turn,  on  treatment  with  alcoholic  potash,  yields 
methylene-camphor  C10HUO  :  CH2,  m.p.  30°-35°,  b.p.  218°,  [a 


536  ORGANIC   CHEMISTRY 

(C.  1903,  I.  971).  Ethyl-camphor,  b.p.  226°-229°,  [a]D+40°,  yields 
after  the  same  treatment  ethylidene-camphor  (C10H14O)  :  CHCH3>  b.p.10 
IIO°-II5°,  [a]D  +  H3°  (C.  1904,  I-  948). 

Dimethyl-camphor    CSHU<(^H^*,   b.p.n    106°,    a    mobile   liquid 

smelling  at  the  same  time  of  camphor  and  menthone.  It  is  formed  by 
the  action  of  sodium  amide  and  methyl  iodide  upon  camphor  in  ether 
or  benzene  solution  ;  by  heating  with  NaNH2  it  is  split  up  to  form 
the  amide  of  dimethyl-campholic  acid,  m.p.  74°  (C.  1909,  II.  442  ; 
cp.  Fenchone). 

/P  .  ftTOT-T 

Oxy-methylene-eamphor,  formyl-camphor  C8H14<^ .  '  ,  m.p.  80°, 

b.p.  28  138°,  is  formed  from  sodium-camphor  or  camphor-magnesium 
bromide  and  formic  ester,  as  well  as  by  the  action  of  sodium 
methylate  free  from  alcohol  upon  a-monohalogen  and  dihalogen 
camphor  (B.  37,  2069)  ;  the  oxy-methylene-camphor  is  a  strong 
acid:  methyl  ether  (C10H14O)  :  CHOCH3,  m.p.  40°,  b.p.  262°;  acetate 
(C10H]4O)  :  CHOCOCH3,  m.p.  63°,  b.p.  29O°-293° ;  with  PC13,  chloro- 
methylene-camphor  (C10H14O)  :  CHC1,  b.p.16  119°  is  generated  ;  with 
bromine  and  iodine  in  neutral  solution  we  obtain  bromo-  and  iodo- 
formyl-camphor,  m.p.  41°  and  68°  respectively.  With  nascent  prussic 

X^vTT 

acid  we   obtain  the  cyano-hydrin  (C10H15O)CH<_    ,  m.p.  122°,  which, 

on  boiling  with  acetic  anhydride,  yields  cyano-methylene-camphor 
(C10H14O)  :  CHCN,  m.p.  46°,  b.p.  280°,  the  nitrile  of  camphor- 
methylene-carboxylic  acid  (C10H34O)  :  CHCO?H,  m.p.  101°  (A.  281, 306). 
By  reduction  of  the  formyl-camphors  with  sodium  and  alcohol  we 
obtain  two  stereo-isomeric  camphyl-glycols  C8H14/£H-CH2°H,  cis-glycol, 

\CHOH 

m.p.  87°,  trans-glyeol,  m.p.  118°.  KMnO4  oxidises  the  trans-glycol 
into  trans-borneol-carboxylic  acid,  while  the  cis-glycol — probably  with 
intermediate  formation  of  the  cis-borneol-carboxylic  acid,  which  is 
attacked  by  KMnO4,  yields  camphoric  acid  (A.  366,  62). 

The    homologous    acyl-camphors    C8H14</9iC(OH)R    (desmotropic 

^\s\J 

forms  :  C8H14^H.C(  R  and  ^^OCOR^  ig  obtained  from  camphor- 
magnesium  bromide  with  fatty-acid  esters,  chlorides,  and  anhydrides, 
in  which  case  dicamphonyl-alkyl-carbinols  (C10H15O)2C(OH)Alk  occur 
as  intermediate  products  (B.  36,  2663  ;  37,  762)  ;  or  by  the  action  of 
alkyl-magnesium  compounds  upon  cyano-camphor  (C.  1906,  I.  1468). 
Acetyl-,  propionyl-,  butyryl-,  i-valeryl-camphor,  b.p.n  118°,  129°,  132°, 
I4i°-i48°.  Benzoyl-camphor,  two  forms,  m.p.  87°-88°,  m.p.  89° 
respectively,  is  also  formed  from  sodium  camphor  with  benzoyl  chloride 
in  toluol  (C.  1903,  I.  233,  458). 

By  the  condensation  of  camphor-magnesium  bromide,  with  alde- 
hydes and  ketones  in  ether,  we  obtain  secondary  and  tertiary  alcohols, 
some  of  which  split  off  water  :  camphoryl-methyl-carbinol  (C10H15O)CH 
(OH)CH3,  b.p.  223°-226°,  is  formed  from  camphor-magnesium  bromide 
with  acetaldehyde  in  small  quantities,  together  with  acetyl-camphor. 
From  benzaldehyde  and  camphor-magnesium  bromide  we  only  obtain 
benzoyl-camphor.  From  sodium-camphor  and  benzaldehyde  we  obtain 
benzylidene-camphor  (C10H14O)CHC6H5,  m.p.  96°,  which  is  also  formed 


CAMPHANE   GROUP  537 

by  reduction  of  benzoyl-camphor,  and  which,  on  further  reduction, 
yields  benzyl-camphor  (C10H15O)CH2C6H5,  m.p.  128°,  and  is  split  up 
by  heating  with  HBr  to  benzylidene-campholic  acid  c'H"<(cooHHC'H5' 
their  aromatic  aldehydes  condense,  like  benzaldehydes,  with  sodium- 
camphor  (C.  1901,  II.  418).  From  (C10H15O)MgBr  with  acetone  we 
obtain  camphoryl-dimethyl-carbinol  (C10Hi6O)C(OH)(CH8)2,  m.p.  88°, 
b.p.  2io°-2i5°,  which,  on  boiling  with  dilute  sulphuric  acid,  yields 
iso-propylidene-camphor  (C10H14O)  :  C(CH3)2,  b.p.  200°-204° ;  cam- 
phoryl-diphenyl-carbinol  (C10H15O).C(OH)(C6H5)2,  m.p.  122°,  from 
(C10H15O)MgBr  with  benzo-phenone  (B.  36,  2627). 

With   oxalic   ester   and  sodium   ethylate,   camphor  condenses  to 

camphor-oxalic  acid  C8H14<(™-COC  )OH,  m.p.  88°,  from  which  a  number 

of  derivatives  have  been  prepared  (C.  1900,  I.  905  ;  1901,  II.  544  ; 
1908,  I.  1182). 

Broken  Ring-products  of  Camphor. — The  splitting  up  of  the  camphor- 
ring  system  can  take  place  in  two  ways  in  its  first  phase.  In  one  way 
the  bridge  group  CH3CCH3  of  camphor,  which  is  always  in  a  strong 
state  of  strain,  "  rises  up."  On  the  other  hand,  the  splitting  may  take 
place  at  the  keto-group  of  camphor,  in  which  case  derivatives  of  the 
5-membered  camphoceane-ring  contained  in  camphor  are  formed 
(A.  299,  162).  Examples  of  the  former  kind  are  shown  by  the 
transformations  of  camphor  into  cymol,  carvacrol,  and  carvenone  : 

CH2-CH  —  CH2  CH3CHCH3 

Camphor     CH3CCH3     | >   CHa— C=        =&*  Qaxveaxme. 

CH2— C(CH3).CO  CH2— CH(CH3).CO 

An  analogous  reaction  is  the  transformation  of  camphor-quinone 
by  fuming  sulphuric  acid  (cp.  the  splitting  up  of  carone  and  pinene, 
above.) 

The  second  group  of  disintegrations  comprises  the  transformations 
of  camphor  into  campholic  acid,  campholenic  acid,  and  camphoric 
acid. 

f*T-T 

(a)  Campholic  acid  C8H14  JJJ*    ,  m.p.  107°  (active),  m.p.  109°  (in- 

L/OOrl 

active),  is  formed  by  heating  camphor-borneol  or  iso-borneol  with  caustic 
potash  to  250°-28o°  (B.  28,  R.  376  ;  C.  1909,  I.  1562).  By  boiling 
with  nitric  acid  it  is  oxidised  to  camphor-camphoric  acid  and  cam- 
phoronic  acid  (B.  27,  R.  752)  ;  on  the  other  hand,  campholic  acid  can 
be  recovered  from  camphoric  acid  by  reducing  camphoric  anhydride 
to  a-campholide,  converting  the  latter  with  HBr  into  bromo-campholic 
acid  and  heating  this  with  zinc  dust  to  50°-6o°  (C.  1900,  I.  603). 
Anhydride,  m.p.  58°  (inactive),  m.p.  66°  (inactive).  Chloride,  b.p.  222°, 
decomposes  on  heating  with  P2O5  into  HC1,  CO,  and  campholene. 
The  amide  melts  at  79°  (active)  and  90°  (inactive). 

The  nitrile  melts  at  72°  and  boils  at  218°.  It  yields  campholamine, 
C10Hi9NH2,  melting  at  210°,  upon  reduction.  Bromine  and  caustic 
alkali  change  the  amide  to  camphelyl-iso-cyanate,  boiling  at  201°,  from 
which  camphelamine  CgN^NHa,  melting  at  43°  and  boiling  at  175°,  is 
obtained  (B.  26,  R.  21  ;  27,  R.  126).  Iso-campholic  acid,  B.  29,  R. 
356.  The  camphor-ring  in  camphor-oxime  can  be  very  easily  ruptured 


538  ORGANIC   CHEMISTRY 

by  mineral  acids,  the  products  being  a-  and  j8-campholene-nitrile, 
iso-amino-camphor,  and  dihydro-campholene-lactone. 

CH2 — CH CH2 

a-Campholenie     acid     |        >C(CH3)2|  boils    at    256°.      Its 

CH^C— CH3     COOH 

specific  gravity  equals  0-992  (19°).  It  is  optically  active,  nD= 1-47125. 
The  nitrite,  b.p.  226°,  of  this  acid  is  produced  with  water  exit  when 
dilute  sulphuric  acid  or  acetyl  chloride  acts  upon  camphor-oxime. 
The  reduction  of  the  nitrile  produces  a-camphylamine  C10H17NH2, 
boiling  at  195°.  Alcoholic  potash  saponifies  it  to  a-campholamide, 
melting  at  130°,  which  with  alkali  hypobromite  gives  the  lower  homo- 
logue  of  camphylamine,  a-amido-campholene  C9H15NH2,  b.p.  185° 
(C.  1899,  II.  385),  and  on  further  saponification  campholenic  acid. 
The  latter  is  oxidised  by  potassium  permanganate  to  : 

a-Dioxy-hydro-eampholenic  acid  C9H15(OH)2CO2H,  melting  at 
144°,  and  a  ketonic  acid,  1-pinonic  acid,  which  affords  decomposition 
products  similar  to  those  of  the  like-named  oxidation  product  of 
pinene.  Chromic  acid  oxidises  a-campholene-  or  dihydro-dioxy- 
campholenic  acid  to  iso-keto-camphoric  acid  C10H16O5=CH3.CO. 
C(CH3)2CH(CH2COOH)o,  and,  eventually,  to  iso-eamphoronic  acid 
C02H.C(CH3)2CH(CH2COOH)2  (A.  289,  19;  C.  1899,  II.  833),  m.p. 
167°.  Concentrated  sulphuric  acid,  when  warmed  with  the  latter 
body,  sets  free  CO,  and  terpenylic  acid  results  (B.  29,  3006). 

Campholenic  acid  is  stable  in  the  presence  of  alkalies,  but  acids 
transpose  it  in  a  peculiar  manner  (Ch.  Ztg.  1900,  858)  into 


CHo 

>CH3  I  . 

H2—C.(CH3)2COOH 


^ 

I 


j8-eampholenie  acid,  melting  at  52°  and  boiling  at  245°,  which  is 
optically  inactive.  Its  nitrile,  boiling  at  22O°-23O°,  is  produced  in  the 
action  of  stronger  acids  (concentrated  HI)  upon  camphor-oxime.  It  is 
reduced  to  j3-eamphylamine,  melting  at  197°,  which  may  be  saponified 
to  an  amide,  melting  at  86°.  Potassium  permanganate  oxidises 
jS-campholenic  acid  to  a  dihydroxy-acid,  melting  at  146°,  and  with  it 
an  oily  acid  which  readily  changes  to  iso-camphorone  C9H14O,  boiling 
at  217°.  Chromic  acid  oxidises  the  j3-acid  to  y-acetyl-iso-eapronic  acid 
CH3.CO.C(CH3)2CH2CH2COOH,  melting  at  48°.  Further  oxidation 
leads  to  a  decomposition  into  a-dimethyl-glutaric  acid  and  a-dimethyl- 
succinic  acid.  The  same  decomposition  products  are  obtained  from 
iso-camphorone  (B.  30,  242).  The  conversion  of  j3-campholenic  acid, 
when  heated  with  bromine,  into  I,  3,  4-xylyl- acetic  acid  (B.  29,  R. 
643)  is  peculiar. 

j8-Dihydro-eampholene-lactone,  melting  at  30°  and  boiling  at 
256°,  appears  as  the  principal  or  the  by-product  in  the  decomposi- 
tions of  camphor-oxime  by  strong  acids,  and  may  be  obtained  by 
acids  from  the  two  campholenic  acids,  as  well  as  from  iso-amino- 
camphor. 

Synthetically,  it  is  prepared  by  the  action  of  CH3MgI  upon  3,  3- 

CH2.CH— CH2.CO2R 

dimethyl-cyclo-pentanone-acetic ester         >CO  (C.  1908, 1.  1056). 

CH2.C(CH3)2 


CAMPHANE   GROUP  539 

Chromic  acid  oxidises  it  to  oxy-dihydro-campholene-lactone,  melting 
at  144°  (B.  30,  404). 

Iso-amino-camphor  C10H17ON,  boiling  at  254°,  is  formed  along  with 
the  preceding  bodies  when  stronger  acids  act  upon  camphor-oxime, 
campholene-amides,  and  nitriles.  It  apparently  contains  a  primary 
amine  group,  and  is  very  similar  to  the  isomeric  amido-camphor.  It 
changes  quite  readily  to  dihydro-campholeno-lactone  (B.  30,  324). 

a-Dihydro-campholenic  acid  C10H18O2,  b.p.22 160°  ;  the  nitrile,  b.p. 
225°-228°,  of  this  acid  is  obtained  by  heating  the  isomeric  camphor- 
imine  with  access  of  air  (B.  33,  1929).  By  bromination,  and  elimina- 
tion of  HBr,  we  obtain  the  isomeric  acid  (C8HU)  :  CHCOOH,  m.p.  70°, 
isomeric  with  campholenic  acid,  and  this  becomes  2,  3,  3-trimethyl- 

cyclo-pentanone,  m.p.  165°,  on  oxidation  with  KMnO4  (C.  1902, 1.  585). 
ftr rvpTT  ^ 

Campholene    I  ^CCH3  (?),  boiling  at  134°,  is  produced 

tH2— C(CH3)/ 

when  a-  or,  better,  j3-campholenic  acid  has  been  heated.  Carbon 
dioxide  is  eliminated.  It  is,  further,  formed  from  campholic  acid  or 
campholic  acid  chloride,  when  acted  upon  with  P2O5.  Synthetically, 
it  has  been  obtained  by  the  action  of  CH3MgI  upon  i,  i,  4-trimethyl- 
cyclo-pentanone-5,  and  elimination  of  water  from  the  resulting  tetra- 
methyl-cyclo-pentanol  (C.  1907,  II.  2050).  It  is  optically  inactive, 
and  yields  on  oxidation  jS/J-dimethyl-lsevulinie  acid  CH3COC(CH3)2 
CH2COOH,  and  unsym.  dimethyl-succinic  acid. 

Campholene  dibromide  melts  at  97°.  Campholene,  heated  with 
HI  acid  to  280°,  becomes  hexahydro-pseudo-cumol,  just  as  jS-campho- 
lenic  acid  changes  to  xylyl-acetic  acid  (B.  30,  594),  and  camphoric  acid 
to  tetrahydro-iso-xylol  (B.  26,  3053). 

An  apparently  isomeric  Campholene  C9H16,  boiling  at  137°,  has  been 
obtained  together  with  carvacrol  from  chloro-camphor  by  the  action  of 
zinc  chloride  (B.  26,  R.  492). 

Camphoric  Acid. — There  are  four  optically  active,  and  two  optically 
inactive,  camphoric  acids. 

CH,— CH— COOH 

d-Camphoric   acid,   ordinary   camphoric  acid  C(CH3)8 

CH2— C(CH3)— COOH 

m.p.  187°,  [a]D=  +497  in  alcohol,  is  obtained  by  heating  d-camphor, 
or  campholic  acid,  with  nitric  acid  (A.  163,  323),  and,  because  it  can  be 
made  without  great  trouble,  has  been  exhaustively  studied.  When  it 
is  heated  above  the  melting-point,  or  when  it  is  treated  with  acetyl 
chloride  (A.  226,  i),  it  changes  to  its  anhydride,  melting  at  221°  and 
boiling  at  270°.  Synthesis  of  camphor,  see  above. 

By  fusion  with  caustic  potash,  camphoric  acid  changes  to  iso-propyl- 
succinic  acid  and  1-iso-camphoric  acid ;  by  oxidation  with  nitric 

(CH3)2C.C02H 
acid,   camphoronic   acid  and  dinitro-capronic   acid  are 

CH3.(!:(N02)2 

produced,  while  with  chromic  acid  the  products  are  camphoronic 
and  trimethyl-succinic  acids.  Water  and  bromine  change  it  to  cam- 
phanic  acid  (B.  28,  2151).  On  oxidising  camphoric  acid  with  perman- 
ganate, we  obtain,  besides  oxalic  acid  as  a  characteristic  product,  a 
dibasic  acid  C8H12O5,  m.p.  121°,  which  can  be  divided  into  optical 
antipodes.  On  reduction  with  HI,  it  yields  ajSjS-trimethyl-glutaric 


540  ORGANIC  CHEMISTRY 

acid,  and  the  anhydride  of  aj8j8-trimethyl-glutaric  acid,  resembling 
ethylene  oxide.  Its  formula  and  formation  may  be  represented  as 
follows  : — 

CH2— CH— COOH  CH— COOH 

C(CH3)2         -->  gg  *+0<C(CH3)2 

CH2— C(CH3)— COOH  XC(CH3)— COOH. 

The    distillation     of    calcium     camphorate    yields     camphorone 

CHlII^CH(CH3])^C0'  b'P'10  83°  (R  26'  3°53)'  In  this  reaction  there 
is  not  only  a  cyclic  ketone  formation,  but  an  "  erection  "  of  the 
camphor  bridge  CH3.C.CH3.  The  constitution  of  camphorone,  first 
deduced  from  the  oxidation  products,  is  confirmed  by  its  synthesis 
from  2-methyl-cyclo-pentanone  and  acetone,  with  sodium  ethylate 
(C.  1900,  I.  604),  and  its  breaking  up  into  these  components,  on  heating 
with  caustic  potash  (A.  331,  322),  as  well  as  its  behaviour  towards 
hydroxylamine,  with  which  it  gives  an  addition  product,  camphorone- 
hydroxylamine  C9H15O(NHOH),  m.p.  120°  (B.  32,  1343).  By  reduc- 
tion with  sodium  and  alcohol  we  obtain  a  secondary  alcohol,  dihydro- 
camphorol  C9H17.OH,  and  from  this,  with  CrO3,  we  obtain  dihydro- 
eamphorone  C9H16O,  b.p.  i84°-i85°  (B.  37,  236),  identical  with 
dihydro-pulegenone,  and  obtained  synthetically  from  a-methyl-a!- 
iso-propyl-adipinic  acid  (C.  1908,  I.  1056). 

Tetrahydro-  and  hexahydro-isoxylol  are  produced  when  camphoric 
acid  is  heated  with  hydriodic  acid. 

The  d-camphoric  acid  forms  two  series  of  acid  esters  :  the  a-esters, 
produced  by  the  partial  saponification  of  the  neutral  esters,  and  the 
j8-esters,  resulting  from  the  partial  esterification  of  the  acids  (B.  26, 
289).  For  derivatives  of  ester  acids,  see  C.  1906,  I.  35. 

The  dichloride   C8H14/^l2\O  boils   at    140°    (15    mm.)    (B.   23, 

\V-*vJ  —  / 

R.  229). 

The  diamide  C8Hi4C2O2(NH2)2,  melting  at  197°,  is  converted  by- 
potassium  hypobromite  into  C10H16N2O2,  melting  at  235°.  This  is 
probably  the  ureide  of  an  oxy-acid  (B.  27,  R.  894),  corresponding  to 
campho-lactone.  Two  isomeric  camphor-amido-aeids,  a-,  m.p.  177°, 
and  j8-,  180°,  have  been  obtained  from  the  anhydride  with  ammonia, 
and  from  iso-nitroso-camphor  with  HC1  (B.  29,  R.  96).  The  j8-acid 
has  been  obtained  from  camphor-imide,  with  sodium  hydroxide  (B. 
29,  R.  96  ;  C.  1904,  II.  1222).  See  below  for  decomposition  products 
of  these  acids. 

The  imide  C8H14C2O2NH,  melting  at  248°  and  boiling  at  300°,  is 
also  formed  from  iso-nitroso-camphor  (B.  26,  58,  242  ;  A.  257,  308  ; 
328,  342),  and  from  camphoric  anhydride  by  distillation  in  a  current 
of  NH3.  In  sulphuric  acid  solution,  camphoric  acid  imide  is  reduced  at 

//"*T  T    \ 

lead  electrodes  to  two  isomeric  lactames,  camphidonene  C8H14<^~*2  \NH, 

\V>-V-/    w 

a-form,  m.p.  231°,  b.p.  295°,  j8-form,  m.p.  228°,  b.p.  308°,  and 
further  to  the  base  camphidin  C8H14(CH2)2NH,  m.p.  186°,  b.p.  209° 
(B.  34,  3274).  a-  and  j5-Camphidone  are  also  formed  by  heating  the 
chlorohydrates  of  a-  and  j8-amido-campholic  acids  (see  below),  the 
lactames  of  which  are  probably  the  camphidones  (B.  40,  4311). 
Nitroso-a-camphidone,  on  heating  with  alkali,  passes  into  a- 


CAMPHANE  GROUP  541 

campholide  (B.  38,  3806).    Thio-camphoric  acid  imide  C8H14(CS)2NH, 
m.p.  135°  (C.  1910,  I.  1253). 

The  methyl  imide   C8HU/^\NCH3  ,    m.p.   40°-42°,   is  obtained 

.  \UvJ/ 

from  silver  camphoron-imide  and  methyl  iodide,  as  well  as  by  heating 
•methyl  iso-imide  above  its  melting-point  (B.  29,  R.  96). 

Methyl  iso-imide  c8Hi«<'CH8,  melting  at  134°,  results  when 


camphor-methyl-amino-acid  is  treated  with  acetyl  chloride  or  PC13 
(B.  26,  R.  688). 

Camphoryl-hydroxylamine  C8H14<^>N.OH  melts  at  225°  (B.  27, 

R.  893).     It  seems  to  be  identical  with  so-called  camphor  nitro-phenol, 
obtained  by  boiling  nitro-camphor  in  HC1  (C.  1899,  I.  in). 

a-Camphor-nitrilic  acid,  cyano-lauronic  acid  C8H14(CN)COOH, 
melting  at  152°,  is  formed  when  camphor-amino-acid  is  treated  with 
acetyl  chloride  and  subsequently  with  ammonia,  or  by  the  interaction 
of  acetic  anhydride  or  PC15  and  iso-nitroso-camphor  (B.  29,  R.  651, 

779)- 

j8-Camphor-nitrilic  acid,  m.p.  iio°-ii3°,  from  p-camphor-amido- 
acid.  On  distillation  of  their  calcium  salts  both  isomeric  acids  break 
the  ring,  and  yield  the  nitrile  of  dimethyl-heptenic  acid  (CH3)2C  :  CH. 
CH2.CH2.CH(CH3)CN,  b.p.14  89°-90°,  which  is  also  produced  by 
the  distillation  of  camphoric  acid  imide,  and  camphor-amido-acids 
with  lime,  and  represents  the  lower  homologue  of  citronellic  acid 
nitrile  (A.  328,  338).  By  reduction  with  sodium  and  alcohol,  a-  and 
j3-camphor-nitrilic  acid  are  reduced  to  a-  and  j8-amido-campholic 
acid  C8H14(CH2NH2)COOH.  Their  chlorohydrates,  a-,  m.p.  248°, 
j8-,  m.p.  2i5°-222°,  on  heating  turn  into  a-  and  j8-camphidone 
(B.  40,  4311). 

1-  Camphoric  acid  results  from  the  oxidation  of  matricaria  camphor. 
It  resembles  the  d-variety  in  every  particular,  except  the  rotatory 
power. 

[d-f-1]-  Camphoric  acid,  paracamphoric  acid,  melting  at  204°,  is 
formed  upon  mixing  alcoholic  solutions  of  equimolecular  quantities 
of  d-  and  1-camphoric  acids  (B.  23,  R.  229). 

d-Iso-camphoric  acid,  d-cis-trans-camphoric  acid,  melting  at  171°, 
with  [a]D=+48°,  may  be  prepared  by  heating  1-camphoric  acid  with 
water,  or,  better,  with  a  mixture  of  glacial  acetic  acid  and  hydro- 
chloric acid,  which  produces  some  dextro  "  iso-camphoric  "  acid.  It 
does  not  form  a  real  anhydride,  hence  can  be  easily  separated  by  means 
of  acetyl  chloride  from  the  1-camphoric  acid. 

1-Iso-camphoric  acid,  [a]D=—  48°,  is  obtained  from  both  d- 
camphoric  acid  and  its  chloride. 

[d-f  1]  -Iso-camphoric  acid,  melting  at  191°,  results  from  the  union 
of  d-  and  1-iso-camphoric  acids.     When  they  are  heated  the  corre- 
sponding camphoric  anhydrides  are  produced  (B.  27,  2001).     Cp.  B.  29, 
1700,  for  the  crystal  forms  of  the  camphoric  acids. 
CH2—  C(CO2H).O 

Camphanic   acid    |  CH3CCH3       |    ,   melting   at   201°,  is   obtained 

CH2—  C(CH3)—  CO 

on    boiling    bromo-camphoric    anhydride    with    water.     Nitric    and 
chromic  acids  oxidise  it  to  camphororiic  acid.     By  distillation  cam- 


542  ORGANIC  CHEMISTRY 

phanic  acid  loses  carbon  dioxide,  and  becomes  campho-lactone  and 
lauronolic  acid  (A.  227,  i).  Cp.  B.  29,  R.  772,  861,  for  additional 
bromo-  and  oxy-camphoric  acids. 

On  the  breaking  up  of  camphanic  acid  nitrile  to  camphononic  acid, 
a  2, 2, 3-trimethyl-cyclo-pentanone-3-carboxylic  acid,  see  C.  1901, 

II.  1308. 

CH=C.C02H 

Dehydro-camphorie   acid    |  CH3CCH3  ,    m.p.    202°-203°,    is 

CH8— C(CH3)C02H 

obtained  by  heating  chloro-  and  bromo-camphoric  acid  ester  with 
quinolin  or  diethyl-aniline,  and  subsequent  saponification.  It  does 
not  itself  form  an  anhydride,  but,  on  distillation,  it  shifts  the 
double  link,  and  passes  into  the  anhydride  of  iso-dehydro- camphoric 
acid  (acid,  m.p.  I78°-I79° ;  anhydride,  m.p.  i82°-i83°).  Lauronolic 
acid  (see  below)  is  also  produced,  with  elimination  of  CO2  (B. 
35,  1286). 

On  treating  the  two  camphor-amido -acids  with  bromine  and  alkali, 
two  isomeric  amino-acids  are  produced  :  a  -  camphor  -  amido  -  acid 
yields  amino-dihydro-lauronolic  acid,  and  j3-camphor-amido-acid, 
amino-dihydro-a-campholytic  acid  : 

CHa—  CH.CONHj  CHa— CH.NH,  CHa— CH.COOH  CHa— CH.COOH 

>C(CH,)S  — >    |  >C(CH,)2  >C(CH4)a    >  |  >C(CH,)a. 

CHa.C(CH,).COOH  CH2.C(CHS)COOH  CH2.C(CH,).CONHa  CH2.C(CHa).NHa 

Amino-dihydro-lauronolic  acid  (also  called  amino-lauronic  acid), 
treated  with  acetic  anhydride,  gives  a  lactame  C8H14^  ,  the 

nitroso-compound  of  which,  on  boiling  with  potash,  forms  some  com- 
pounds which  include  the  corresponding  lactone,  dihydro-lauro- 

O 
lactone  C8H14<J    ,  m.p.  32°  (B.  35,  1291;  C.  1909,  I.  1095).    The 

amino-dihydro-a-campholytic  acid,  which  can  also  be  formed  from 
camphoric  acid  chlorimide,  with  sodium  alcoholate,  also  yields  a 

lactame  and,  in  the  same  way,  a  lactone  C8H14<\.  ,  dihydro- 
eampholyto-laetone,  m.p.  116°  (A.  314,  392). 

Lauronolic  acid  |  /^(CHg).,  (aiso  caneci  y-lauronolic  acid 

CH2— C(CH3)— COOH 

or  allo-campholytic  acid)  is  formed  from  amino-dihydro-lauronolic 
acid  with  nitrous  acid,  and  from  dehydro-camphoric  acid,  by  splitting 
off  CO2.  By  oxidation  in  KMnO4  or  nitric  acid,  and  splitting  at  the 
double  link,  it  yields  camphoronic  acid  (see  below). 

CH2— C.CH3 
Iso-lauronolic  acid  C.CH3  (?)     (Woringer's    lauronolic 

CH2— C(CH3)CO2H 

acid)  is  formed  from  camphanic  acid  by  distillation,  and  from  bromo- 
camphoric  anhydride  with  soda.  On  boiling  with  HC1,  lauronolic  acid 
and  iso-lauronolic  acid  give  the  same  y-lactone,  iso-dihydro-lauro- 

lactone    (formerly  called  campho-lactone)   C8H14/|    ,    m.p.    50°,    iso- 

Nbo 

meric  with  the  dihydro-lauro-lactone  (B.  35,  1290 ;  /.  pr.  Ch.  2,  83, 
400). 


CAMPHANE  GROUP  543 

CHa—  CH—  COOH 
a-Campholytic  acid  |          ^C(CH3)2  ,  liquid,  b.p.15  140°,  is  formed 

CH=C(CH3) 

in  the  action  of  nitrous  acid  upon  dihydro  -  amino  -  campholytic 
acid  (see  above)  (besides  oxy-dihydro-campholytic  acid  C8H14(OH) 
COOH,  m.p.  132°,  and  its  lactone,  m.p.  116°),  and  by  electrolysis  of 
the  potassium  salt  of  a-camphor-methyl-ester  acid.  By  oxidation 
with  nitric  acid,  a-campholytic  acid  is  oxidised  to  dimethyl-triearbal- 
lytic  acid  COOH.C(CH3)2.CH(COOH).CH2COOH  (B.  33,  2935).  By 
dilute  sulphuric  acid  it  is  transposed,  like  a-  into  j3-campholenic 

CH,—  C—  C02H 

acid  (see  above),  into  j8-eampholytic  acid   |         ^CCH3    ,   m.p.    134° 

CH,—  C  :  (CH3), 

(formerly  called  iso-lauronolic  acid).  It  is  formed  out  of  camphoric 
anhydride  by  the  action  of  A1C13  (cp.  C.  1900,  I.  545  ;  1901,  I.  78)  ;  it 
is  also  obtained  by  heating  sulpho-camphylic  acid  to  200°.  On  heating 
with  concentrated  sulphuric  acid,  sulpho-camphylic  acid  is  regenerated 
from  j3-campholytic  acid.  The  jS-campholytic  acid  contains  no  unsym. 
C  atom,  and  is  therefore  optically  inactive.  On  oxidation  with 
chromic  acid  it  yields,  like  j3-campholenic  acid,  dimethyl-hexanonic  or 
acetyl-capronic  acid  CH3COC(CH3)2CH2CH2COOH  and  a-dimethyl- 
glutaric  acid  (A.  Ch.  Phys.  7,  18,  181  ;  C.  1899,  n-  87J  '.  CP-  A-  314» 

392)- 

On  a  synthesis  of  a-  and  j8-campholytic  acid  from  I,  i-dimethyl- 

butane-i,  2,  4-tricarboxylic   acid,  see  C.  1903,  I.   923.      On   the  dis- 

integration  of   dihydro-a-  and  -j3-campholytic   acid   to   2,  2,  3-   and 

2,  3,  3-trimethyl-cyclo-pentanone,  see  C.  1902,  II.  265  ;    1903,  II.  287. 

CH2—  CH 

Iso-laurolene  |          ^CCH3  ,  b.p.  108°,  is  formed  on  heating  iso- 

CHa—  C:(CH3)2 

lauronolic  acid  to  300°.  Synthetically,  it  has  been  obtained  by  the 
action  of  CH3MgI  upon  2,  2-dimethyl-cyclo-pentanone,  and  elimina- 
tion of  water  from  the  resulting  alcohol.  With  KMnO4,  dimethyl- 
hexanonic  acid  is  formed,  as  in  the  case  of  j8-campholytic  acid.  With 
acetyl  chloride  and  A1C13,  it  yields,  like  the  aromatic  hydrocarbons,  a 
ketone  isomeric  with  camphor  :  j3-campholyto-methyl-ketone  C8H13 
(COCH3),  b.p.  202°,  also  obtained  from  the  chloride  of  j3-campholytic 
acid,  with  zinc  methyl  and  potassium  hypobromite  (C.  1909,  I.  751). 

Laurolene      '0™3  (?)'  b'p'  I2I°'  is  formed  b     heat> 


ing  camphanic  acid  with  water  to  180°,  and  from  the  nitroso-compound 
of  amino-laurolonic  acid  lactame,  by  boiling  with  soda  (C.  1909,  II. 
801). 


/ 

Sulpho-camphylic  acid,  sulpho-camphoric  acid  C8H12<(^;r  +3H2o, 


2 

\ 

melting  at  i6o°-i65°,  is  produced  in  the  action  of  sulphuric  acid  upon 
camphoric  acid.  Upon  heating  it  changes  to  j8-campholytic  acid  ;  on 
fusing  with  soda,  two  acids  are  formed,  C9H12O2,  a-  and  j3-camphylic 
acid,  m.p.  148°  and  106°  respectively.  The  former  is  reduced  by 
sodium  amalgam  to  inactive  a-campholytic  acid  (see  above,  and  C.  1902, 
II.  366  ;  1903,  II.  571).  On  oxidising  sulpho-camphylic  acid  with 
permanganate  at  o°,  it  changes  into  the  so-called  camphorylic  acid 


544  ORGANIC  CHEMISTRY 

C18H20O6,  a  diketocarboxylic  acid  (C.  1899,  1.  931),  and  upon  oxidation 
with  nitric  acid  it  yields  sulpho-iso-propyl-succinic  acid  and  dimethyl- 
malonic  acid  (B.  26,  2044). 

CH2—  CH  —  CH2, 
a-Campholide    |        C(CH3)2      /®>    melting  at  211°,  is  formed  in 

CH2—  C(CH3).CO 

the  reduction  of  camphoric  anhydride  with  alcohol  and  sodium,  just 
as  phthalide  is  obtained  from  phthalic  anhydride  (B.  29,  R.  221,  288). 
Also  by  heating  nitroso-a-camphidone  with  alkali,  and  by  oxidising 
camphor  with  Caro's  acid  (B.  32,  3630).  With  PC15  the  lactone  gives 
chloro-campholie  acid  chloride  C8H4(CH2C1)COC1,  m.p.  21°,  b.p.16  132°  ; 
by  treatment  with  HBr,  bromo-campholic  acid  C8H14(CH2Br)COOH, 
m.p.  177°  with  decomposition,  which,  by  reduction,  passes  into  cam- 
pholic  acid,  and,  with  PC15,  into  bromo-campholic  acid  chloride,  m.p. 

37°,  b-P-15  147°;    j3-campholide    c8Hu<(^°  />o,  m.p.  219°,  is  formed 

in  small  quantity  by  reduction  of  camphoric  acid  j3-methyl  ester  with 
Na  and  alcohol  (C.  1906,  1.  35  ;  cp.  B.  40,  4311).  Dialkyl-a-campholides, 
like  dimethyl-  and  diethyl-a-campholide,  b.p.10  146°  and  m.p.  38°,  are 
obtained  by  the  action  of  alkyl-magnesium  haloids  upon  camphoric 
acid  ester,  or  camphoric  anhydride.  In  the  latter  case  there  are  by- 
products in  the  shape  of  the  corresponding  campholides  :  dimethyl-jS- 

campholide,  m.p.  84°  (C.  1910,  II.  467). 

CH2—  CH^-COOH 

/C(CH3)2 

Carboxyl-apo-camphoricacid,c^w/)^o-ac^cH2—  C=-COOH  ,  melting 

COOH 

at  I96°-20O°,  is  produced  in  the  oxidation  of  camphene  with  dilute 
nitric  acid.  It  forms  an  anhydride  acid  when  it  is  heated.  This  melts  at 
205°.  It  subsequently  splits  off  C02  and  passes  into  the  anhydride  of  : 

CH2—  CH—  COOH 
Apo-camphoric  acid,  campho-pyro-acid  ^>C(CH3)2,  melting 

CH2—  CH—  COOH 

at^204°,  which  is  also  formed  by  oxidising  fenchene  with  nitric  acid. 
It  is  synthesised  by  a  series  of  suitable  reductions  from  diketo-apo- 
camphoric  acid  (cp.  synthesis  of  camphor)  and  obtained  in  a  cis-  and 
a  trans-  form  (m.p.  204°  and  190°  respectively).  The  anhydride  of 
the  former  melts  at  175°  (A.  368,  126).  In  accordance  with  its  sym- 
metrical formula,  apo-camphoric  acid  is  optically  inactive. 

C=C(C02C2H6)2 
d-Camphoryl-malonic  acid  ester  C8H14/  >o  ,  m.p.  82°, 

xco 

b.p.40  247°,  by  the  action  of  Na-malonic  ester  upon  camphoric  acid 
chloride  (A.  257,  298).  Similar  compounds  are  obtained  by  the 
transformation  of  chloro-  and  bromo-campholic  acid  chloride  with 
Na-malonic  methyl  ester,  which  gives,  besides  halogen  esters 


C8H14  CH  ,  ,  m.p.  56°  and  73°,  an  ester  free  from  halogens 


_ 

>C(C02CH3)2   (?),   m.p.   79°   (R.   Anschiitz).      Otherwise   it 

behaves  analogously  to  camphoric  acid  (B.  29,  R.  175,  773  ;   Ch.  Ztg., 
1896,  p.  840). 

d-Ho  mo-camphoric    acid,    hydro  xy-campho-carboxylic   acid 


CAMPHANE   GROUP  545 

2H°  IH,  melting  at  234°,  is  produced  when  cyano-camphor  is 

boiled  with  aqueous  caustic  potash.  Its  mononitrile  is  formed  on  heat- 
ing campholide  with  potassium  cyanide  (B.  29,  R.  288).  d-Camphor 
is  obtained  on  heating  calcium  homo-camphorate  in  a  current  of  carbon 
dioxide. 

d-Hydro-eamphoryl-acetic    acid     C8H14<^^^H»-CO2H,  melting  at 

142°,  is  produced  when  hydro-camphoryl-malonic  acid  is  heated  (A. 
257,  303). 

d-Hydro-camphoryl-malonie  acid  C*U"(™2£H  :o*U}\  melting  at 
178°,  is  obtained  by  the  reduction  of  camphoryl-malonic  ester.  (A.  257, 
301). 

Camphoronic       acid,      aa B  -  trimethyl  -  tricarballylic      acid 

(CH3)2C C(CH3)— CH2 

is  produced  in  the  oxidation  of  camphoric 
COOH     COOH    COOH 
acid,  lauronolic  acid,  and  campholic  acid  with  nitric  acid. 

It  has  been  synthesised  in  the  following  manner.  Aceto-acetic 
ester  and  a-bromiso-butyric  ester,  or  a-dimethyl-aceto-acetic  ester 
and  brom-acetic  ester,  are  condensed  by  zinc  to  j§-oxy-a,  j3-trimethyl- 
glutaric  ester  COOR.CH2C(OH)(CH3)C.(CH3)2COOR,  which  PC15  con- 
verts into  the  ester  of  the  j8-chloro-acid,  and  the  latter  is  then  changed 
by  potassium  cyanide  to  the  ester  of  j8-cyano-aa^-trimethyl-glutaric 
acid,  the  mononitrile  of  camphoronic  acid,  which  is  then  saponified  to 
camphoronic  acid.  The  synthetic  acid  is  racemic,  while  the  cam- 
phoronic acids  have  the  rotation  of  the  original  camphoric  acids 
(C.  1898, 1.  248  ;  A.  302,  53). 

The  importance  of  camphoronic  acid  in  the  determination  of  the 
constitution  of  camphor  has  been  explained.  Camphoronic  acid  melts 
at  135°,  changing  at  the  same  time  into  camphoro-anhydridic  acid,  melt- 
ing at  135°  and  boiling  at  205°  (12  mm.).  The  chloride  of  the  latter  is 
converted  by  bromine  into  two  isomeric  bromo-camphoro-anhydridic 
acid  chlorides  ;  one  of  these,  when  boiled  with  water,  forms  the  lactone 
of  unstable  oxy-camphoronic  acid,  camphoranic  acid,  while  the  other, 
under  similar  treatment,  yields  a  stable  oxy-camphoronic  acid,  melting 
at  248°.  Camphoronic  acid,  upon  distillation,  breaks  down  into  tri- 
methyl-succinic  anhydride,  iso-butyric  acid,  CO2,  H2O,  and  carbon. 

Camphoranie  acid  C9H12O4+H2O,  melting  at  209°,  is  a  lactonic  acid 
which  resists  decomposition  by  alkalies  very  strongly.  When  fused 
with  caustic  potash  it  is  readily  split  into  trimethyl-succinic  acid  and 
oxalic  acid  (privately  communicated  by  J.  Bredt)  : 

CO O  >  COOH 

(CH3)2C  C(CH3) (COOH)CHCOOH  (CH3)2C— CH(CH3)COOH 

Camphoranic  acid  Trimethyl-succinic  acid. 

CH2— CH        C(CH3)2 

Fenehone   |        CH2      |  (Ch.  Ztg.,  29,   1313),  m.p.  6°,  b.p. 

CH2— C(CH3).CO 

193°,  D19,  with  specific  gravity  0-9465  (19  mm.),  nD= 1-46306,  occurs 
naturally  in  two  isomeric  modifications.  Of  all  the  known  ketone 
derivatives  of  terpenes  this  ketone  is  most  like  camphor  in  its  behaviour. 

VOL.  II.  2  N 


546  ORGANIC   CHEMISTRY 

d-Fenehone  was  discovered  in  1890  by  Wallach  and  Hartmann  in 
fennel  oil,  while  1-fenehone  was  found  in  1892  by  Wallach,  together  with 
pinene  and  thujone  or  tanacetone,  in  the  oil  of  thuja.  Potassium  per- 
manganate oxidises  it  to  dimethyl-malonic  acid,  acetic  acid,  and  oxalic 
acid,  while  prolonged  heating  with  concentrated  acid  oxidises  it  to 
dimethyl-tricarballylic  acid,  dimethyl-malonic  acid,  and  iso-camphoro- 
nic  acid  (C.  1899,  I.  285).  On  reduction,  it  reverses  its  optical  rotation 
and  passes  into  d-  and  1-fenchyl  alcohol  respectively,  and  fenchone 
pinacone,  m.p.  97°.  On  heating  with  P2O5  fenchone  yields  m-cymol, 
probably  with  previous  transposition  ;  under  the  action  of  strong 
sulphuric  acid  it  is  transformed  into  acetyl-xylol  CH3CO.C6H3[3,  4] 
(CH3)2  (C.  1899,  II.  1120).  Fenchone  does  not  combine  with  sodium 
bisulphite  or  phenyl-hydrazin,  and  forms  no  oxy-methylene  compound. 
With  sodium  and  CO2  we  obtain  a-  and  jS-fencho-carboxylic  acid  C10H17O 
(COOH),  m.p.  142°  and  77°  respectively.  These  seem  to  be  a-oxy- 
acids  (A.  300,  294).  With  bromine,  fenchone,  at  100°,  gives  mono- 
bromo-fenchone  C10H15OBr,  b.p.18  I3i°-i34°  ;  while  with  phosphorus 
chloro-bromide,  it  yields  tribromo-fenchane  C10H15Br3  (B.  33,  2287). 
Fenchone  oxime  C10H16  :  NOH,  m.p.  165°  (active),  159°  (inactive),  b.p. 
240°.  Fenchone  semi-earbazone,  m.p.  183°  (active),  172°  (inactive). 
By  heating  with  caustic  potash  to  230°,  or  by  the  action  of  sodium 
amide,  fenchone,  like  camphor  and  camphenilone,  is  split  up  into 
fencholic  acid,  i-methyl-^-iso-propyl-cyclo-pentane-i-carboxylic  acid 
CH2— CH— CH  (CH3)  2 

CH2  ,  m.p.   19°,   b.p.17    152°,  which  has   also  been  ob- 

CH2— C(CH3)C02H 

tained  synthetically  (C.  1909,  II.  212).  Chloride,  b.p.15  100°  ;  amide, 
m.p.  94°  (A.  369,  71).  a-Feneholenie  acid  C9H15COOH,  liquid,  b.p. 
255°,  and  j3-fencholenie  acid  C9H15.COOH,  m.p.  73°,  b.p.  260°,  are 
formed  by  saponifying  their  nitriles,  a-nitrile,  b.p.  212°,  j8-nitrile,  b.p. 
218°,  which  are  obtained  together  on  boiling  fenchone  oxime  with  dilute 
sulphuric  acid  (C.  1899,  II.  115).  They  have  not  hitherto  been  changed 
one  into  the  other,  and  are  therefore  not  mutually  related  like  a-  and 
j3-campholenic  acid.  Both  acids  become  lactones  on  treating  with 
concentrated  sulphuric  acid  :  oxy  -  dihydro  -  a  -  f encholenic  lactone 
C10H18O2,  m.p.  78°,  and  oxy-dihydro-j3-f encholenic  lactone,  m.p.  69° 
(B.  39,  2853),  the  latter  being  found  also  in  the  oxidation  products 
of  fenchyl  alcohol.  A  third  isomeric  acid  C9H15COOH,  y-fencholenic 
acid,  b.p.10  146°,  easily  passing  into  the  a-form,  is  produced  on  heating 
bromo-fenchone  with  alcoholic  potash  (B.  40,  432). 

Iso-fenchone  C10H16O,  b.p.  201°,  is  formed  by  oxidation  of  iso- 
fenchyl  alcohol  with  chromic  acid.  Oxime,  m.p.  82°  (active),  133° 
(inactive),  easily  substituted  with  bromine,  forming  monobrom-iso- 
fenchone,  m.p.  57°.  By  heating  with  caustic  potash  it  is  split  up  into 
iso-fencholic  acid  C10H18O2,  m.p.  34° ;  amide,  m.p.  66°.  On  oxidation 
with  KMnO4,  a  dicarboxylic  acid  is  formed,  iso-feneho-eamphoric  acid 
Ci0H16O4,  m.p.  159°  (active),  175°  (inactive)  (A.  362,  194  ;  369,  97). 

D.  SESQUI-TERPENE  AND  POLY-TERPENE  GROUP. 

The  sesqui-terpenes  have  the  composition  C15H24.  They  are  re- 
lated to  the  terpenes  proper  in  a  manner  similar  to  the  hemi-terpene 


SESQUI-TERPENE  AND   POLY-TERPENE   GROUP      547 

isoprene.  The  sesqui-terpenes  are  widespread  among  the  ethereal  oils. 
Some  70  have  been  traced  hitherto,  but  many  of  these  may  be  identical. 
They  are  slightly  coloured,  rather  viscous  oils,  boiling  between  250°  and 
280°,  of  a  feeble  and  rather  unpleasant  odour,  and  many  of  them  re- 
sinify  easily,  like  the  terpenes.  On  the  basis  of  their  molecular  refrac- 
tion, and  other  physical  and  chemical  properties,  we  may  distinguish 
trebly  unsaturated  monocyclic,  doubly  unsaturated  bicyclic,  and  singly 
unsaturated  tricyclic  sesqui-terpenes.  A  probably  aliphatic  sesqui- 
terpene  has  been  found  in  Ceylon  citronella  oil  (C.  1899,  II.  880),  but 
completely  saturated  tetracyclic  sesqui-terpenes  are  unknown.  As 
from  the  terpenes  proper,  so  from  the  sesqui-terpenes,  oxygenated 
compounds  of  the  composition  C15H24O  and  C15H26O  are  derivable, 
called  sesqui-terpene  alcohols,  and  sesqui-terpene  camphors,  which 
are  distinguished  from  the  terpenes  themselves  by  generally  possessing 
a  great  power  of  crystallisation.  Practically  nothing  is  known  of  the 
constitution  of  the  sesqui-terpenes.  Many  of  them  contain,  perhaps, 
hydrated  naphthalin  rings  (B.  36,  1038).  With  halogen  hydrides 
NOC1,  N2O3,  and  N2O4  they  sometimes  form  easily  crystallising  deriva- 
tives, which  may  serve  for  their  separation  and  characterisation.  In 
the  following  we  enumerate  some  of  the  most  important  representa- 
tives of  this  group. 

Cadinene,  b.p.  270°,  D16  0-921  [O)D=  —98-56°,  is  found  in  many 
ethereal  oils,  such  as  Oleum  cadinum,  cubebene  oil,  sandal-wood  oil, 
angostura  bark  oil  (C.  1898,  II.  666  ;  1900, 1.  858). 

With  HC1  it  yields  a  dichlorohydrate,  m.p.  118°,  from  which,  by 
heating  with  aniline  or  sodium  acetate,  cadinene  can  be  regenerated 
(A.  238,  84  ;  C.  1908,  II.  1354). 

Caryo-phyllene,  b.p.20  137°,  D20  0-903,  found  in  carnation  and 
copaiva  oil.  It  probably  consists  of  two  isomeric  hydrocarbons,  the 
optically  inactive  caro-phyllene  found  in  hop  oil  (/.  pr.  Ch.  2,  83, 
483),  nitroso-chloride,  m.p.  177°,  and  the  active  jS-caryo-phyllene, 
nitroso-chloride,  m.p.  159° ;  nitrosite,  blue  needles,  m.p.  115°  ;  dichloro- 
hydrate, m.p.  70°  (C.  1899,  II.  1119).  By  hydration  with  glacial  acetic 
acid  and  sulphuric  acid  we  obtain  earyo-phyllene  hydrate  C^H^O, 
m.p.  95°,  from  which,  by  elimination  of  water,  a  probably  tricyclic 
hydrocarbon  isomeric  with  caryo-phyllene,  clovene,  is  obtained  (A.  271, 
294  ;  369,  41  ;  B.  42,  1062). 

a-Santalene,b.p.9  n8°-i2o°,  D20  0-8984,  nD= 1-491,  and  /?-santalene, 
b.p. 9  I25°-I27°,  D20  0-892,  nD=i.4932,  are  contained  in  the  first  dis- 
tillate of  sandal-wood  oil ;  the  former  is  probably  a  tricyclic,  and  the 
latter  a  bicyclic,  sesqui-terpene.  On  oxidation  with  ozone  the  a-santa- 
lene  yields  tricyclo-ek-santalic  acid  C11H16O2,  m.p.  68°,  and  the  j8- 
santalene  bicyclo-ek-santalic  acid  CUH16OH2,  m.p.  64°,  also  obtained 
by  disintegrating  santalol  (B.  40,  3321). 

Zingiberene,  b.p.22  160°,  D20  0-8731,  nD= 1-49399,  [a]D=— 73-38°, 
is  contained  in  ginger  oil.  Nitroso-chloride,  m.p.  97° ;  dichloro- 
hydrate, m.p.  169°  (C.  1901,  II.  1226). 

Galipene  is  the  name  of  a  dextro-rotatory  sesqui-terpene  obtained 
from  the  oil  of  angostura  bark,  Galipea  officinalis  (C.  1898,  II.  666). 

Santalol  C15H24O,  b.p.10  i6i°-i68°,  D20  0-973,  forms  the  chief  con- 
stituent of  the  Indian  sandal-wood  oil  from  Santalum  album.  It  prob- 
ably consists  of  a  mixture  of  two  unsaturated  primary  alcohols,  the 


548  ORGANIC  CHEMISTRY 

tricyclic  a-santalol  and  the  bicyclic  jS-santalol.  a-Santalol  yields 
on  oxidation  with  KMn04  or  ozone  tri-cyclo-ek-santalic  acid.  Acids 
convert  a-santalol  and  its  derivatives  into  isomeric,  and,  probably, 
bicyclic  compounds  (B.  40,  1120). 

Patchouli  alcohol  C15H26O,  m.p.  56°,  separates  out  from  patchouli 
oil  in  crystals  (A.  279,  394  ;  C.  1904,  1.  1265). 

Cedrol  C15H26O,  m.p.  87°,  [a]D=+9°  31',  from  cedar-wood  oil  of 
Juniper  us  virginiana. 

The  diterpenes  C20H32  and  polyterpenes  (C5H8)a.  are  yellow,  viscid 
oils,  boiling  above  300°,  volatilising  with  steam  with  some  difficulty, 
and  therefore  but  rarely  encountered  in  ethereal  oils.  They  are  found 
in  many  balsams  and  resins.  Their  characterisation  is  rendered  diffi- 
cult by  the  fact  that  they  only  yield  crystalline  addition  products  with 
difficulty.  . 

Addendum.  —  Closely  related  to  the  polyterpenes  is  the  cholesterin 
already  discussed  in  Vol.  I.,  which,  from  its  transformations,  must  be 
regarded  as  a  polycyclic  secondary  ring  alcohol,  with  a  vinyl  and  an 
iso-amyl  side  chain.  The  constitution  is  complex,  but  is  probably  as 
follows  (B.  42,  3770)  : 


| 
)—  CH2 


/CH2CH2CH(CH3)2 

\CH 


CH(OH)—  CH2          CH2 


RESINS. 

The  resins  are  closely  related  to  the  terpenes,  and  occur  with  them 
in  plants,  and  are  also  produced  by  their  oxidation  in  the  air.  Their 
natural,  thick  solutions  in  the  essential  oils  and  turpentines  are  called 
balsams  ;  whereas  the  true  gum  resins  are  amorphous,  mostly  vitreous 
bodies.  Their  solutions  in  alcohol,  ether,  or  turpentine  oils  constitute 
the  commercial  varnishes. 

Most  natural  resins  appear  to  consist  of  a  mixture  of  different, 
peculiar  acids,  the  resin  acids.  The  alkalies  dissolve  them,  forming 
resin  soaps,  from  which  acids  again  precipitate  the  resin  acids.  By  their 
fusion  with  alkalies  we  obtain  different  benzene  derivatives  (resorcinol, 
phloro-glucin,  proto-catechuic  acid)  ;  and  when  they  are  distilled  with 
zinc  dust  they  yield  benzenes,  naphthalenes,  etc. 

Colophony  is  found  in  turpentine  and,  in  the  distillation  of  the  latter, 
remains  as  a  fused  mass.  It  consists  principally  of  abietic  acid  Cigll28O2 
(sylvic  acid),  which  can  be  extracted  by  hot  alcohol,  crystallises  in 
leaflets,  and  melts  at  139°  (147°).  When  oxidised  it  yields  trimellitic, 
iso-phthalic,  and  terebic  acids. 

On  heating  with  sulphur  it  turns  into  retene.  It  is  therefore  prob- 
ably a  decahydro-retene-carboxylic  acid  (C.  1904,  II.  1308),  and  thus 
is  closely  connected  with  fichtelite,  a  fossil  resin,  which  has  been  recog- 
nised as  perhydro-retene. 

Gallipot  resin,  from  Pinus  maritima,  contains  pimarie  acid  C20H30O2, 
which  is  very  similar  to  sylvic  acid  and  passes  into  the  latter  when  dis- 
tilled in  vacuo.  It  melts  at  210°.  The  latest  investigations  show  that 
pimarie  acid  consists  of  three  isomerides  (B.  19,  2167). 

Gum  lac,  obtained  from  East  India  fig-trees,  constitutes  what  is 


RESINS  549 

known  as  shellac  when  fused.  This  is  employed  in  the  preparation  of 
sealing-wax  and  varnishes. 

Amber  is  a  fossil  resin,  found  in  peat-bogs.  It  consists  of 
succinic  acid,  two  resin  acids,  and  a  volatile  oil.  After  fusion  it 
dissolves  easily  in  alcohol  and  turpentine  oil,  and  serves  for  the 
preparation  of  varnishes. 

To  the  gum  resins,  occurring  mixed  with  vegetables  gums,  and  gum 
in  the  juice  of  plants,  belong  gamboge,  euphorbium,  asafcetida,  india- 
rubber,  and  gutta-percha. 

Caoutchouc,  india-rubber,  because  of  its  wide  applicability,  is  especi- 
ally important.  It  has  been  obtained  from  tropical  Euphorbiaceae, 
Apocinaceae,  etc.  In  Brazil  it  is  made  from  Siphonia  elastica,  in  India 
from  Ficus  elastica,  as  well  as  other  varieties  of  Ficus.  Purified 
caoutchouc  has  the  formula  (C5H8)X.  When  distilled  it  yields  isoprene 
C5Hg  (q.v.),  which  polymerises  spontaneously  to  caoutchouc  and  also 
to  dipentene. 

Caoutchouc  is  therefore  probably  a  polymeric  1,  5-dimethyl-cyclo- 


octadiene-1,  5  ~  -    In  accordance  with  its  unsatu- 

Jx 


rated  nature,  it  easily  absorbs  oxygen,  halogens,  and  nitrous-acid  gas. 
On  prolonged  treatment  of  a  benzene  solution  of  rubber  with  N2O3, 
we  obtain  yellow  crystalline  nitrosite  (C10H15N3O7)2,  decomposing  at 
i58°-i62°,  the  formation  of  which  can  be  used  for  the  quantitative 
determination  of  rubber  in  mixtures.  On  distillation,  india-rubber 
yields,  among  hydrocarbons  of  greater  molecular  weight,  isoprene 
C5H8,  which  under  various  conditions,  e.g.  on  simple  heating  in  closed 
vessels,  partly  polymerises  again  into  rubber  (B.  33,  779  ;  36,  1937  ; 
A.  383,  184). 


CH3C— CH2.CH2.CH         >    CH3.C— CH  :  CH2 

CH.CH2.CH2.CCH3     ^~  CH2         CH2 :  CH.C.CH3. 


+ 

.C.( 


This  last  reaction  promises  to  be  of  great  technical  importance  for 
the  artificial  production  of  rubber. 

India-rubber  takes  up  sulphur  when  it  is  thoroughly  kneaded  with 
it,  or  when  it  is  treated  with  a  mixture  of  S2C12  and  CS2  (B.  27,  R.  204, 
521,  601,  609,  701,  816  ;  29,  R.  136). 

The  product  is  a  vulcanised  rubber,  which  continues  elastic  within 
a  considerable  range  of  temperature. 


Aromatic  Hydrocarbons  containing  several  Nuclei. 

A.  PHENYL-BENZOLS  AND  POLYPHENYL-FATTY  HYDROCARBONS. 

Just  as  alkyl  groups  are  joined  to  one  another,  or  as  they  are  intro- 
duced into  benzene  and  its  homologues,  so  the  benzene  hydrogen 
atoms  can  be  replaced  by  phenyl-,  tolyl-,  benzyl-,  and  other  hydro- 
carbon residues.  The  products  are  :  (i)  the  phenyl-benzols,  in  which 
the  benzene  nuclei  are  in  immediate  union  : 

C6H5.C6H5  C6H5.C6H4CH3  C6H4(C6H5)2  C6H3(C«H5)3 

Diphenyl  Phenyl-tolyl  Diphenyl-benzol        Triphenyl-benzol. 


550  ORGANIC   CHEMISTRY 

(2)  The  polyphenyl  paraffins,  olefins  and  acetylenes,  in  which  the 
benzene  residues  are  held  together  by  fatty  hydrocarbons  : 

C6H6,  C6H3.CH2  C6H5.CH  C6H5.C 

\CH2  (C6H5)3.CH          (C6H5)4C                     I  ||                      III  etc. 

C6H/  C.H..CH,  C6H5.CH  C6H5.C 

Diphenyl-  Triphenyl-       Tetraphenyl-     Dibenzyl  Stilbene  Tolane. 

methane  methane            methane 

In  addition  to  these  groups  we  have  :  B.  The  aromatic  hydrocarbons 
with  condensed  nuclei. 

i.  PHENYL-BENZOL  GROUP. 

i.  A.  Diphenyl  Group. — The  first,  or  parent,  hydrocarbon  of  this 
group  is  diphenyl  or  phenyl-benzol. 

Diphenyl,  phenyl-benzol,  biphenyl  C6H5.C6H5,  melting  at  71°  and 
boiling  at  254°,  is  present  in  slight  amount  in  coal-tar.  It  is  formed 
(i)  upon  conducting  benzene  vapours  through  tubes  heated  to  redness 
(Berthelot,  Z./.  Ch.,  1866,  707  ;  B.  9,  547  ;  A.  230,  5)  ;  (2)  in  the  action 
of  sodium  upon  the  solution  of  bromo-benzol  in  ether  or  benzene — 
higher  condensed  hydrocarbons  being  produced  at  the  same  time 
(Fittig,  A.  121,  363  ;  B.  29,  115) — or,  better,  from  iodo-benzol  and 
copper  powder  by  heating  to  230°  (A.  332,  40)  ;  (3)  from  diazo-benzol 
chloride  (a)  by  action  of  benzene  and  aluminium  chloride,  (b)  with 
stannous  chloride,  (c)  when  alcohol  and  copper  powder  act  upon  diazo- 
benzol  sulphate,  (d)  from  the  latter  salt  and  warm  benzene  (B.  23, 1226  ; 
26,  1997). 

If  dissolved  in  glacial  acetic  acid,  and  oxidised  with  chromic 
anhydride,  it  yields  benzoic  acid.  Metallic  sodium  reduces  diphenyl, 
dissolved  in  amyl  alcohol,  to  tetrahydro-diphenyl  C12H14,  boiling  at 
245°.  The  latter  readily  forms  a  dibromide,  which  alcoholic  potash 
converts  into  dihydro-diphenyl  C12H12,  boiling  at  248°  (B.  21,  846). 
A  dihydro-diphenyl  of  m.p.  66°  has  been  obtained  from  phenyl-dihydro- 
resorcin  by  converting  this  diketone  into  the  corresponding  dihydric 
alcohol,  and  removing  two  molecules  of  water  from  the  latter,  by  means 
of  phosphorus  pentoxide  (A.  289,  168).  Hexahydro-diphenyl,  phenyl- 
cyclo-hexane  C6H5.C6Hn,  m.p.  7°,  b.p.  239°,  by  synthesis  from  benzene 
and  chloro-cyclo-hexane  or  cyclo-hexyl  chloride  with  A1C13  (C.  1907,  I. 
1745).  Perhydro-diphenyl,  dicyelo-hexyl  C6Hn.C6Hn,  b.p.  235°,  by 
reduction  of  diphenyl  with  hydrogen  and  nickel  under  pressure  (C.  1907, 
II.  2036),  or  of  cyclo-hexyl-cyclo-hexanol  (see  below)  with  HI,  and, 
synthetically,  from  iodo-cyclo-hexane  and  sodium  (B.  40,  70). 

Fluorene  (B.  19,  R.  672)  is  formed  when  methylene  chloride  and 
aluminium  chloride  act  upon  diphenyl. 

Alkylated  diphenyls  have  been  obtained  :  (i)  By  the  action  of 
nitrous  acid  upon  the  alcoholic  solution  of  their  amido-compounds 
(B.  17,  468  ;  21,  1096).  (2)  From  the  action  of  sodium  upon  the 
brominated  alkyl-benzols  (B.  4,  396)  ;  this  reaction  gives  by-products 
in  the  shape  of  substances  of  the  diphenyl-methane  and  dibenzyl  series 
(B.  4,  396  ;  32,  1056  ;  33,  334).  (3)  From  iodo-alkyl-benzolene  by 
heating  with  powdered  copper  (A.  332,  38  ;  C.  1910,  I.  1974).  (4) 
From  diphenyl,  chloro-alkyl  or  ethylene,  and  aluminium  chloride 
(B.  20,  R.  218).  (5)  From  aromatic  diazo-chlorides  containing  one 


PHENYL-BENZOL   GROUP  551 

nucleus.     The  position  of  the  alkyl  groups  is  determined  by  oxidation, 
if  it  has  not  been  made  evident  by  the  components  : 


m-Pheny\-to\yl,m-'methyl-diphenyl  .  b.p.  2 

p-Phenyl-tolyl    ....   m.p.  +3°  „     263°-267°  (B.  26,  1996) 

m-Ethyl-diphenyl        .....  ,,283° 

J02-Ditolyl   .....  m.p.  17-8°  „     258° 

m2-Ditolyl,  m,  m-dimethyl-diphenyl  .  286°  (B.  25,  1032) 

o,  m-Ditolyl    .......  „     286° 

p2-Ditolyl    .  .  m.p.  122°  „    -295°  (A.  332,  44). 

Hydrated  derivatives  of  the  diphenyl  series  are  obtained  syntheti- 
cally by  the  method  used  in  the  case  of  the  cyclo-hexenones  (q.v.),  e.g. 


phenyl-methyl-cyclo-hexenone  C8H5.CH<2^     R      CH,  m.p.  36°,  is 

formed  from  benzylidene-bis-aceto-acetic  ester,  and  yields,  on  reduction, 
phenyl-methyl-eyclo-hexanol  C6H5.C6H9(CH3)(OH),  b.p.20  177°,  which, 
on  splitting  off  water,  forms  phenyl-methyl-cyclo-hexene  C6H5.C6H8 
(CH3),  b.p.17  129°  (A.  303,  259).  See  also  Phenyl-dihydro-resorcin. 

Cyclo-hexyl-2-eyclo-hexanol  C6Hn.C6H10OH,  m.p.  31°,  b.p.  270°, 
by  reduction  of  cyclo-hexalidene-cyclo-hexanone  (B.  40,  70). 

Diphenyl  Substitution  Products.  —  Each  mono-substitution  product 
of  diphenyl  can  exist  theoretically  in  three  isomeric  forms.  Chlorine, 
bromine,  the  N02  group,  and  the  sulpho-group  prefer  the  p-position 
with  reference  to  the  point  of  union  of  the  two  benzene  residues,  o-  and 
o,  p-Derivatives  are  formed  together  with  the  p-  and  p2-derivatives. 
The  p2-derivatives,  having  two  different  substituents  —  e.g.  p-bromo- 
p-nitro-diphenyl  —  yield  both  p-bromo-  and  p-nitro-benzoic  acids  when 
they  are  oxidised  (see  Benzidin).  The  amido-diphenylenes,  particularly 
benzidin,  or  p2-diamido-diphenyl  and  the  diphenyl-sulphonic  acids, 
afford,  as  in  the  case  of  the  corresponding  benzene  derivatives,  numerous 
derivatives  of  diphenyl. 

It  is  interesting  to  note  that  o2-di-substitution  products  are  known 
in  which  a  bivalent  atom,  O  and  S,  or  a  bivalent  group,  NH,  CH2,  CO, 
replaces  two  hydrogen  atoms  in  the  ortho-position  with  reference  to 
the  point  of  union  of  the  two  benzene  nuclei. 

The  principal  representatives  of  such  diphenylene  compounds  are  : 

eH4,                   C6H4.  C6H4V  /C6H4V          \  /C6H4v         \ 

>0               |        >S  |        \NH  [I        \CH2)  (I        >CO 

.H/                 fc.H/  6.H/  \C.H/  \C.H/      / 

Diphenylene  Diphenylene  Carbazol  Fluorene  Fluorenone. 
oxide                sulphide 

The  first  three  will  be  treated  in  connection  with  the  heterocyclic 
derivatives  after  furfurane,  thiophene,  and  pyrrol,  from  which  they  can 
also  be  derived.  They  are  formed  by  pyro-reactions  from  phenyl  ether, 
phenyl  sulphide,  and  diphenyl-amine. 

Halogen  Diphenyls.  —  o-  and  p-Chloro-diphenyl  melt  at  34°  and  boil 
at  267°,  and  at  75°  and  282°,  respectively,  o-  and  p-Bromo-diphenyls, 
liquid,  b.p.  310°.  p-Iodo-diphenyl,  m.p.  m°.  p2-Difluoro-,  p2-dichloro-, 
p2-dibromo-,  and  p2-di-iodo-diphenyl,  m.p.  87°,  148°,  164°,  and  202° 
respectively  (A.  207,  333  ;  B.  30,  2800). 

o2-Di-iodo-diphenyl,   m.p.    108°,   with    chlorine    yields    diphenyl- 


552  ORGANIC  CHEMISTRY 

di-iodide  tetrachloride  C12IC6H4.C6H4IC12,  m.p.  I3o°-i35°,  from  which 
o2-di-iodoso  and  o2-di-iodo-phenyl  are  obtained.  The  latter,  by  the 
action  of  potassium  iodide,  passes  into  diphenylene-iodonium  iodide 

C*  H 

*v  >I.I,  m.p.   211°,  also  formed,  besides   o2-di-iodo-diphenyl,   from 


i   > 

C6H/ 


the  tetrazo-compound  of  o2-diamido-diphenyl,  and  is  transposed  on 
heating  into  the  isomeric  o2-di-iodo-diphenyl  (C.  1909,  I.  374).  On 
derivatives  of  p2-di-iodo-diphenyl  with  multivalent  iodine,  see  B. 
42,  3826. 

Perehloro-diphenyl  C12C110  does  not  melt  at  270°.  It  is  often  pro- 
duced in  exhaustive  chlorinations  (B.  16,  2881). 

Nitro-diphenyls. — The  nitration  of  diphenyl  gives  rise  to  o-  and  p- 
nitro-  as  well  as  to  p2-  and  o,  p-dinitro-diphenyls. 

Symmetrical  di-  and  poly-nitro-diphenyls  can  be  easily  prepared 
from  o-  and  p-halogen-nitro-benzols  and  from  m-iodo-nitro-benzols  by 
heating  with  copper  powder  (B.  34,  2174).  They  are  also  obtained  by 
the  decomposition  of  diazoriium  salts  of  nitranilines  by  means  of 
cuprous  chloride  or  ammoniacal  oxide  solutions  (B.  34,  3802  ;  38,  725  ; 
A.  320,  123). 

o2-  and  m2-Dinitro-diphenyls  are  obtained  from  benzidin  (B. 
20,  1028). 

o-,  m-,  and  p-Nitro-diphenyl,  m.p.  37°,  58°,  and  113°. 

02-,  m2-,  p2-,  and  o,  p-Dinitro-diphenyls  melt  at  124°,  197°,  233°, 
and  93°.  p2-  and  o,  p-Dinitro-diphenyl  have  also  been  obtained  from 
sodium  iso-diazo-nitro-benzene  and  nitro-benzene  (B.  29,  165). 

02>  P2->  and  m2>  P2-Tetranitro-diphenyl,  m.p.  163°  and  186°  respec- 
tively, from  i,  2,  4-chloro-dinitro-  and  i,  3,  4-iodo-dinitro-benzol 
respectively  with  Cu  dust. 

02,  02,  p2-Hexanitro-diphenyl,  m.p.  238°,  from  picryl  chloride  with 
Cu  dust. 

p-Bromo-p-nitro-diphenyl,  m.p.  173°  (A.  174,  218). 

p2-Dichloro-o2-dinitro-diphenyl,  m.p.  136°,  from  2,  5-dichloro-nitro- 
benzol  or  4,  2-chloro-nitraniline. 

The  o2-dinitro-diphenyls  are  reduced  by  Na  amalgam  in  alcohol,  by 
sodium  sulphide  and  stannous  chloride  in  HC1,  or  by  electrolysis,  in 
such  a  manner  that  cyclic  azoxy-compounds,  phenazone  oxides,  and 
further  cyclic  azo-compounds,  phenazones,  are  formed  (B.  37,  23). 
These  compounds  are  dealt  with  in  detail  in  connection  with  ortho- 
diazins  (see  Hetero-cyclic  Compounds,  Vol.  III.)  : 

C6H4— N02 C6H4— N\n C6H4— N 

C6H4— N02  ~  *  C6H4— tt/*  *  C6H4— N' 

Amido-diphenyls  and  amido-ditolyls  can  be  prepared  by  the  reduc- 
tion of  the  corresponding  nitro-compounds.  The  formation  of  p2- 
diamido-diphenyl  by  the  rearrangement  of  its  isomeride  hydrazo- 
benzol  is  of  great  technical  importance,  because  p2-diamido-diphenyl 
or  benzidin  is  a  basic  substance  for  the  preparation  of  substantive 
cotton  dyes — dyes  which  unite  directly  with  the  cotton  fibre  without 
the  aid  of  mordants. 

o-Amido-diphenyl,  melting  at  45°,  is  also  obtained  from  o-phenyl- 
benzamide  by  means  of  bromine  and  caustic  soda  (A.  279,  266  ;  B.  25, 


PHENYL-BENZOL  GROUP  553 

1974)  .  When  conducted  over  heated  lime  it  forms  carbazol  .  m-Amido- 
diphenyl,  m.p.  30°  (B.  37,  882).  p-Amido-diphenyl,  xenylamine,  melts 
at  51°  and  boils  at  322°  (A.  260,  233).  p2-Nitro-amido-diphenyl,  from 
p2-dinitro-diphenyl,  melts  at  98°. 

o2-Diamido-diphenyl,  m.p.  81°,  and  m2-diamido-diphenyl  have  been 
obtained  by  reducing  o2-  and  m2-dmitro-diphenyl.  When  o2-diamido- 
diphenyl  is  heated  with  concentrated  sulphuric  acid,  it  yields  carbazol. 
Its  tetrazo-chloride  is  changed  by  potassium  sulphydrate  to  carbazol, 
and  when  its  aqueous  solution  is  heated,  diphenylene  oxide  is  produced 
(B.  26,  1703).  The  reduction  of  the  tetrazo-compound  of  o2-diamido- 

C6H4[2]NHNH2 
diphenyl  gives  rise  to  diphenylene-o2-dihydrazin    I  ,  m.p. 

GjH^fi'JNHNHj 

110°  (B.  29,  2270).  When  heated  with  hydrochloric  acid  at  150°,  it 
breaks  down  easily  into  ammonium  chloride  and  an  o2-azo-diphenylene, 
the  so-called  phenazone. 

Benzidin,  p^diamido-diphenyl,  m.p.  122°  (Zinin,  1845),  is  obtained 
by  the  reduction  of  p2-dinitro-diphenyl  and  p2-nitro-amido-diphenyl. 
It  is  commercially  prepared  by  the  reduction  of  azo-benzol  in  acid 
solution  ;  the  hydrazo-benzol,  formed  at  first,  rearranges  itself  to 
benzidin  and  diphenyl,  or  o,  p-oliamido-diphenyl.  This  is  a  remarkable 
reaction,  to  which  attention  has  already  been  called  in  connection  with 
hydrazo-benzol  (A.  207,  330). 

The  great  insolubility  of  the  sulphate  in  water  affords  a  means  of 
separating  benzidin  from  diphenylin.  When  treated  with  concen- 
trated sulphuric  acid  and  nitric  acid,  one  or  two  NO2  groups  enter  in 
the  m-position  with  reference  to  the  amido-groups  of  benzidin.  The 
products  are  o-nitro-p2-diamido-diphenyl  and  o2-dinitro-p2-diamido- 
diphenyl  (B.  23,  794).  m2-Dinitro-p2-diacetamido-diphenyl  results  on 
nitrating  diaceto-benzidin.  By  chlorine  and  bromine  the  four  H  atoms 
are  replaced  in  the  o-position  towards  the  amido-groups  (A.  363,  332). 
By  oxidation  with  lead  peroxide  in  indifferent  solvents,  benzidin  first 
forms  the  unstable  pp'-dipheno-quinone  di-imines,  and  then  the  pp'- 
diamido-azo-diphenyls  (cp.  the  analogous  transformation  of  o-phenyl- 
ene-diamine  into  o2-diamido-azo-benzol)  (B.  39,  3474). 

Benzidin  is,  on  the  other  hand,  oxidised  in  acid  solution  by  perman- 
ganate, ferric  chloride,  potassium  ferricyanide,  or  chromic  acid,  etc.,  to 
a  blue  dye,  probably  belonging  to  the  quino-hydrones,  and  built  up  in 
a  manner  analogous  to  the  Wurster  salts  (A.  363,  324  ;  B.  41,  3248). 

Constitution.  —  The  p-position  of  the  two  amido-groups  of  benzidin 
(i)  is  evident  from  the  oxidation  of  p2-bromo-mtro-diphenyl  to  p-bromo- 
and  p-nitro-benzoic  acids  (5,  6),  because  benzidin  (i)  is  formed  from 
p2-dinitro-diphenyl  (2),  which  may  be  rearranged  to  p2-amido-nitro- 
diphenyl  (3)  and  p2-bromo-nitro-diphenyl  (4)  (Gustav  Schultz,  A. 
174,  227)  : 

(i)  (2)  (3)  (4)  C6H4[4]N02 

C6H4[4]NH2        CCH4[4]N02        C6H4[4]N02        C6H4[4]NO2        ^CC^H 


C6H4[4]NH,        CCH4[4]N02  ~*  C6H4[4]NH2  ~*  CGH4[4]Br    ~1      CO2H 


C6H4[4]Br 

The  constitution  of  benzidin  forms  the  basis  for  one  of  the  proofs 
of  the  constitution  of  diphenic  acid  ;  also  for  that  of  phenanthrene 
isomeric  with  anthracene. 


554  ORGANIC  CHEMISTRY 

Benzidin  sulphate  consists  of  small  scales  with  a  silvery  lustre  ; 
preparation,  B.  26,  R.  321.     Concentrated  sulphuric  acid  converts  it 


into  benzidin-sulphone    632>S°2  (B-  22»  2467).    Diaceto-benzidin, 

C6Jrl3(JNJrl2)/ 

m.p.  317°.  Thionyl-benzidin  (C6H4.N  :  S0)2  (B.  24,  753).  Di-(o-nitro- 
benzyl-)  benzidin,  m.p.  227°  with  decomposition  (B.  29,  1450). 

o2-o'2-Tetrachloro-  and  tetrabromo-benzidin,  m.p.  227°  and  288°. 

o-Nitro-p2-diamido-diphenyl,  m-nitro-benzidin,  melts  at  143°  (B.  23, 
796)  ;  see  Benzidin. 

NN-Dimethyl-benzidin  CH3NHC6H4.C6H4NHCH3,  m.p.  75°,  see 
B.  37,  3771.  On  its  behaviour  towards  oxidising  agents,  see  B.  41,  3250. 

Tetramethyl-benzidin  (CH3)2NC6H4.C6H4N(CH3)2,  m.p.  197°,  from 
dimethyl-aniline  by  oxidation  with  concentrated  sulphuric  acid  at 
i9o°-20o°  (B.  37,  29).  NNi-Diphenyl-benzidin  C6H5NHC6H4.C6H4 
NHC6H5,  m.p.  242°,  is  formed  by  the  action  of  fuming  sulphuric  acid 
upon  diphenyl-amine  (B.  38,  3575). 

o2-Dinitro-p2-diamido-diphenyl,  m-dinitro-benzidin,  melts  at  214° 
(B.  23,  795).  o2-Dinitro-tetramethyl-  and  tetra-ethyl-benzidin,  red 
needles,  m.p.  229°  and  132°  (B.  37,  29,  34). 

32-Dinitro-42-diaceto-diamido-diphenyl  melts  above  300°,  and  is 
converted  by  caustic  potash  into  32-dinitro-42-diamido-diphenyl, 
o-dinitro-benzidin,  m.p.  220°  (B.  5,  237  ;  20,  1024).  52-Dinitro-22- 
diamido-diphenyl  (B.  25,  128). 

o,  p'-Diamido-diphenyl,  diphenylin,  melts  at  45°  and  boils  at  362°. 
Preparation,  see  Benzidin  (A.  207,  348  ;  B.  22,  3011).  o,  p2-Triamido- 
diphenyl,  m-amido-benzidin  (B.  23,  797).  o2,  p2-Tetramido-diphenyl, 
m^-diamido-benzidin,  melting  at  165°,  is  obtained  from  o2-dinitro-p2- 
diamido-diphenyl  (see  Benzidin),  and  by  loss  of  ammonia  becomes 
p2-diamido-carbazol. 

Di-p-phenylene-diamine  (NH2)2[2,  5]C6H3.C6H3[2,  5](NH2)2,  melting 
at  168°,  is  converted  by  hydrochloric  acid  at  180°  into  52-diamido- 
carbazol  (B.  25,  131). 

Diamido-dixenylamine  NH(C6H4.C6H4.NH2)2,  m.p.  221°,  is  obtained 
by  heating  benzidin  with  benzidin  chloride  (/.  pr.  Ch.  2,  61,  103). 

Benzidin  Homologues.  —  p2-Diamido-phenyl-m-tolyl,  o-methyl-benzi- 
din  H2N.C6H4.C6H3(CH3).NH2,  is  formed  upon  reducing  a  mixture  of 
nitro-benzol  and  o-nitro-toluol.  It  melts  at  90°  (B.  23,  3222). 

o-Tolidin,  p2-diamido-m2-dimethyl-diphenyl,  from  o-hydrazo-toluol, 
melts  at  128°  (B.  20,  2017  ;  23,  3252  ;  A.  352,  in). 

m-Tolidin,  p2-diamido-o2-dimethyl-diphenyl,  from  m-hydrazo-toluol, 
melts  at  109°.  Isomeric  ditolylin  (B.  23,  3252)  is  produced  at  the 
same  time. 

o-  and  m-Hydrazo-toluols  suffer  under  the  influence  of  acids  the 
benzidin  rearrangement.  p-Hydrazo-toluol,  under  like  conditions, 
follows  the  semidin  rearrangement. 

p2-Diamido-m2-diethyl-diphenyl,  from  o-nitro-ethyl-benzol  (/.  pr. 
Ch.  2,  66,  153). 

Diazo-amido-  and  Azo-compounds  of  Diphenyl.  —  The  diphenyl- 
tetrazo-chloride,  formed  by  diazotation  of  benzidin  in  hydrochloric 
solution,  unites  with  two  molecules  aniline  to  form  : 

Diphenyl  -  bis  -  diazo  -  amido  -  benzol  C6H5NH.N  :  NC6H4.C6H4N  : 
NNC6H5,  reddish-yellow  crystals,  m.p.  180°,  also  obtained  from  benzidin 


PHENYL-BENZOL   GROUP  555 

and  diazo-benzol  chloride.  On  heating  with  aniline  and  its  chloro 
hydrate  it  transposes  into  the  isomeric  diphenyl-diazo-amido-benzol 
NH2C6H4N  :  NC6H4.C6H4N  :  NC6H4NH3,  m.p.  159°  (C.  1906,  I.  1254). 

pp'-Diamido-azo-biphenyl  NH2[4]C6H4.C6H4N  :  NC6H4.C6H4[4]NH2, 
m.p.  287°,  is  formed  by  oxidising  benzidin  with  PbO2,  and  from  pp'- 
amido-nitro-diphenyl  by  reduction  with  zinc  dust  and  NaOH,  and 
oxidation  of  the  resultant  hydrazo-compound  (B.  39,  3479). 

Benzidin  Dyes.  —  Benzidin  yields  azo-dyes,  transposition  products  of 
the  diazo-chloride  from  benzidin  and  amido-sulphonic  acids,  phenol- 
carboxylic  acids,  and  phenol-sulphonic  acids,  which  unite  directly  with 
cotton  fibre  (Griess,  B.  22,  2469).  These  dyes  are  obtained  as  sodium 
salts,  which  are  prepared  by  adding  the  aqueous  solution  of  the  tetrazo- 
chloride  to  the  aqueous  solution  of  two  molecules  of  the  sodium  salt 
of  the  other  component. 

Sodium  acetate,  sodium  carbonate,  or  ammonia  is  added  to  the 
solution  of  the  sodium  salt  to  neutralise  the  hydrochloric  acid  which 
is  liberated  : 


C.H.N.-Cl    C.H^OHJCOjNa  C.H4N  :  N.C.H,(OH).CO,Na 

+  I  +CO,Na.=  |  +  2NaCl+CO.+H.O. 

C.H4N,.C1    C.H4(OH)CO,Na  C«H4N  :  N.C«Hs(OH).CO,Na 

The  diphenyl-tetrazo-chloride,  which  can  also  be  readily  formed 
in  the  solid  state,  reacts  more  readily  with  one  of  its  diazo-groups  than 
it  does  with  the  other  (cp.  B.  30,  2800  ;  31,  482). 

The  sodium  salts  of  two  different  components  can  thus  be,  step  by 
step,  brought  into  reaction  with  the  tetrazo-chloride,  and  mixed  tetrazo- 
dyes  (B.  19,  1697,  1755  ;  20,  R.  273  ;  21,  R.  71)  result. 

Representatives  of  the  class  of  benzidin  dyes  are  : 

C6H4.N  :  N.C6H3(OH).C02Na 

Chrysamme,  flavo-phemn  ,  which  is  made 

C6H4.N  :  N.C.H3(OH).C02Na 

from  diphenyl-tetrazo-chloride  and  sodium  salicylate  (equation  above) 
(B.  22,  2459). 

C,H4.N  :  N.C6H3(NH2).S03Na 
Congo  yellow  I  is  obtained  from  diphenyl- 

C6H4.N  :  N.C8H4.OH 
tetrazo-chloride,  phenol,  and  sulphanilic  acid. 

The  preceding  dyes  colour  cotton  fibre  yellow. 

The  first  red  dye  brought  into  commerce  was  Congo  red,  which  is 
formed  from  the  interaction  of  diphenyl-tetrazo-chloride  and  sodium 
naphthionate.  It  will  be  brought  forward  again  under  the  naphthalene 
azo-dyes.  The  jS-naphthyl-amine-sulphonic  acids  are  particularly  valu- 
able in  the  preparation  of  substantive  dyes. 

Substantive  dyes,  similar  to  those  from  benzidin,  have  been  obtained 
from  p2-amido-methyl-diphenyl,  o-methyl-benzidin,  o-  and  m-tolidins, 
dianisidin,  thio-benzidin,  thio-tolidin  (B.  20,  R.  272),  p2-diamido-benzo- 
phenone,  p  2-diamido-stilbene  (B.  21,  R.  383). 

It  may  be  said  that,  as  a  rule,  those  substituted,  benzidins  (nitro-  and 
sulpho-benzidins,  tolidins,  etc.)  having  the  substituent  in  the  meta- 
position  (relative  to  the  amido-group)  yield  inactive  or  feeble  substantive 
azo-dyes.  Diamido-diphenylene  oxide,  benzidin  sulphone,  and  diamido- 
carbazol  constitute  exceptions.  They  contain  a  third  ring-shaped  chain 
(B.  23,  3252,  3268  ;  24,  1958). 

It  is  interesting  to  observe  that  benzidin  hydrochloride  itself  unites 


556  ORGANIC  CHEMISTRY 

with  cotton.  It  mordants  the  cotton.  Hence  it  is  possible  to  produce 
the  benzidin  upon  the  fibre  (B.  19,  2014). 

The  "  one-sided  diazotising  "  of  benzidin  is  attained  through  the 
action  of  a  p-tetrazo-diphenyl  salt  upon  the  aqueous  solution  of  a 
benzidin  salt  (B.  27,  2627)  ;  compare  migrations  of  the  diazo-group. 
When  the  bis-diazo-compound  of  benzidin  is  allowed  to  act  upon 
aceto-acetic  ester  there  result,  with  one  molecule  of  the  ester,  eyclo- 

.N.NH— C6H4 

formazyl-carboxylie    ester    COOC2H5c^  ,    a    reddish-brown 

\N :  N — C6H4 

powder,  fusing  with  difficulty  (see  Formazyl-carboxylie  acid)  ;  and, 
with  two  molecules  of  the  ester,  bis-aeetyl-glyoxylie  ester-phenyl- 
hydrazone  [CH3COC(CO2C2H5)  :  NNHC6H4— ]2,  yellow  needles,  melting 
at  198°  (A.  295,  332  ;  cp.  C.  1899,  I.  563).  Similar  compounds  with 
malonic  and  cyano-acetic  ester,  see  C.  1902,  I.  721,  1205. 

p-Hydrazino-diphenyl  C6H5.C6H4[4]NH.NH2  (B.  27,  3105).  p2-Di- 
hydrazino-diphenyl  (C6H4.NHNH2)2,  m.p.  167°  with  decomposition, 
yields,  with  formaldehyde,  a  characteristic  hydrazone  (B.  32,  1961)  ; 
see  also  Diphenylene-o2-dihydrazin. 

Biphenyl-sulphonic  Acids. — On  digesting  biphenyl  with  sulphuric 
acid  the  first  product  is  biphenyl-p-sulphonie  acid  (its  chloride  melting 
at  115°,  and  its  amide  at  229°),  and,  later,  biphenyl-p2-disulphonic  acid, 
melting  at  72°,  and  its  chloride  at  203°  (B.  13,  288).  When  potassium- 
biphenyl-p-sulphonate  is  heated  it  changes  to  biphenyl  and  potassium- 
biphenyl-p  2-disulphonate. 

Biphenyl-p2-disulphonic  acid  is  obtained  from  benzidin-o2-di- 
sulphonic  acid  (A.  261,  310). 

C6H4[2]NH 

Biphenylene  sultame  I  |     ,  m.p.  196°,  in  colourless  crystals  of 

C6H4[2]S02 

strongly  acid  character.  Formed  from  the  diazo-compound  of 
o-amido-benzol  sulphanilide  on  heating  in  acid  solution  (B.  43,  2694). 

Benzidin-sulphonic  A  cids. — 42-Diamido-biphenyl-22-disulphonic  acid 
is  formed  from  m-hydrazo-benzol-sulphonic  acid  (A.  261,  310  ;  268, 
X3°  i  /•  P*>  Ch.  2,  66,  558),  and,  when  fused  with  caustic  potash,  yields 
42-diamido-diphenylene  oxide. 

42-Diamido-biphenyl-32-disulphonic  acid  is  produced  on  heating 
benzidin  with  ordinary  sulphuric  acid  to  210°  (B.  22,  2466  ;  39,  3341). 

o-Tolidin-disulphonie  acid,  ^-diamido-^  ^-dimethyl-biphenyl-2  2-disul- 
phonic  acid  (A.  270,  359). 

42-Dihydrazino-biphenyl-22-disulphonic  acid  (c6H3<(?"!H3  \     see  A. 

V  ^^^3-n-/2 

261,  323. 

Oxy-biphenyls  are  obtained  from  the  biphenyl  derivatives  by 
methods  similar  to  those  by  which  the  phenols  themselves  are  prepared 
from  the  benzene  derivatives,  and  also  in  the  oxidation  of  phenols  con- 
taining a  single  nucleus,  when  they  are  fused  with  caustic  potash 
(B.  27,  2107). 

Monoxy-biphenyls. — p-Oxy-biphenyl  C6H5.C6H4[4]OH,  m.p.  165° 
and  b.p.  306°,  is  obtained  from  diazo-benzol  chloride  and  phenol 
(B.  23,3708). 

Dioxy-biphenyls. — o2-Dioxy-biphenyl,  o2-biphenol,  m.p.  109°,  b.p. 
326°,  from  biphenyl-o2-disulphonic  acid  (A.  261,  332)  and  from 


PHENYL-BENZOL   GROUP  557 

diphenylene  oxide  (coal-tar)  by  fusing  with  potash  (B.  34,  1662). 
By  fusing  with  zinc  chloride  it  reverts  clearly  into  diphenylene  oxide. 
Its  dimethyl  ether,  m.p.  155°,  b.p.  308°,  is  also  formed  from  o-iodanisol 
with  sodium  or  copper  dust.  Ethylene  bromide  gives  an  ethylene 
ether,  m.p.  98°  (B.  35,302). 

m-Biphenol,  m.p.  I23°-I25°,  is  obtained  from  o-dianisidin  and 
m2-diamido-triphenyl  (B.  27,  2107).  p2-Biphenol,  m.p.  272°,  is  pre- 
pared from  benzidin,  biphenyl-p2-disulphonic  acid,  and  from  phenol 
by  the  action  of  KMnO4  (B.  25,  R.  335) .  o,  p-Biphenol,  from  diphenylin, 
melts  at  160°.  2, 5-Dioxy-diphenyl,  phenyl-benzo-hydroquinone 
(HO)2[2,  5].C6H3C6H5,  m.p.  97°,  is  formed  by  reduction  of  phenyl- 
benzo-quinone  (see  below)  ;  and  mamVtetramethyl-p^dioxy-diphenol 
OH[4](CH3)2[3, 3']C6H2.C6H2[3, 3/](CH3)2[4]OH,  m.p.  221°,  from 
tetramethyl-dipheno-quinone  (see  below). 

Tetra-oxy-biphenyls. — Bipyro-eatechin  (HO)2C6H3.C6H3(OH)2,  m.p. 
84°,  biresorcin,  melting  at  310°,  and  bihydroquinone,  m.p.  237°,  result 
when  the  three  dioxy-benzols  are  fused  with  sodium  hydroxide  (B. 
11,  1336  ;  12,  503  ;  18,  R.  23). 

Hexa-oxy-biphenyls. — Hexa-oxy-biphenyl  (HO)3C6H2.C6H2(OH)3  is 
formed  from  pyrogallol  in  baryta  solution  by  oxidation  in  air  (B.  35, 
2954).  An  isomeric  hexa-oxy-biphenyl  has  been  obtained  from  its 
tetramethyl  ether,  hydro-ccerulignone  C16H18O6,  m.p.  190°,  by  heating 
with  concentrated  HC1  (B.  11,  797).  3,  4,  5,  3',  4',  5'-hexamethoxy- 
biphenyl,  m.p.  126°,  and  2,  3,  4,  2',  3',  4/-hexamethoxy-biphenyI,  m.p. 
123°,  is  obtained  from  5-  and  4-iodo-pyrogaUol-trimethyl  ether  with 
copper  dust  (A.  340,  230). 

Amido-oxy-biphenyls  are  obtained  from  oxy-biphenyls  (B.  22,  335) 
and  from  the  alkyl  ethers  of  oxy-azo-derivatives,  having  free  p-positions, 
by  the  benzidin  rearrangement  (B.  23,  3256).  In  the  coal-tar  industry 
o-dianisidin  or  42-diamido-32-dimethoxy-biphenyl  and  ethoxy-benzidin, 
from  o-nitro-anisol,  are  of  great  value.  They  yield  violet,  blue,  and 
black  substantive  cotton  dyes  with  amido-naphthalene-sulphonic 
acid,  naphthol-sulphonic  acid,  and  amido-naphthol-sulphonic  acids  : 
azo-violet,  benzazurin,  diamine  black,  etc.  (B.  22,  R.  372  ;  24,  R.  55, 
56,  etc.). 

2,  5-Amido-oxy-diphenyl  C6H5.C6H3[2,  5](OH)(NH2),  m.p.  199°,  is 
obtained  by  reduction  of  2, 5-nitroso-oxy-diphenyl  C6H5.C6H3[2, 5] 
(OH) (NO),  generated  by  the  action  of  diazo-benzol  chloride  upon 
p-nitroso-phenate  of  sodium.  The  latter,  on  oxidation,  passes  into 
2,  5-nitro-oxy-diphenyl,  m.p.  126°,  also  obtained  synthetically  from 
benzyl-methyl-ketone  C6H5CH2COCH3  and  nitro-malonic  aldehyde 
NO2CH(CHO)2  (C.  1905,  I.  505). 

Quinones  of  the  Diphenyl  Series. — Phenyl-benzo-quinone  CgHg. 
C6H3O2,  m.p.  114°,  has  been  obtained  by  the  oxidation  of  2,  5-amido- 
oxy-diphenyl,  or  of  o-amido-diphenyl  with  MnO2  and  sulphuric  acid. 
With  sulphurous  acid  it  gives  a  stable  quinhydrone,  also  formed  by 
oxidation  in  air  from  the  2,  5-dioxy-diphenyl  produced  with  stronger 
reducing  agents  (A.  312,  211  ;  B.  37,  878). 

Special  interest  attaches  to  a  number  of  quinone  compounds  of 
diphenyl,  in  which  the  two  quinone  oxygen  atoms  belong  to  different 
benzene  rings.  Regarding  the  quinones  as  carboxyl  compounds,  the 
following  three  fundamental  forms  of  these  so-called  bi-nuclear 


558  ORGANIC  CHEMISTRY 

quinones  are  possible,  and  may  be  distinguished  as  pp'-,  op'-,  and 
oo'-dipheno-quinones  : 

/CH=CH\     .     /CH=CH\  /CH-CO\     .  C</CH=CH\CO 

C\CH=CH/C  '  C\CH=CH/C  l\CH=CH/C  '  C\CH=CH/( 


/CH-CO\     .     /C- 
i\CH^CH/C  '  C\CH=CH 


Of  these,  only  the  pp'-dipheno-quinone  could  hitherto  be  prepared 
in  the  free  state,  but  nitrogenated  derivatives  (quinone  chlorimines)  of 
the  other  two  forms  are  known  (A.  368,  271). 

pp'-Dipheno-quinone  O  :  C6H3  :  C6H3  :  O,  decomposing  at  165°,  is 
formed  by  the  oxidation  of  p-diphenol  with  silver  oxide  or  lead  per- 
oxide in  benzene.  It  crystallises  in  two  modifications,  hard  spears 
resembling  chromic  acid,  and  fine,  soft  needles.  In  its  oxidising  action 
it  resembles  p-benzo-quinone,  but  in  contrast  with  this  it  is  odourless 
and  not  volatile.  It  can  be  reduced  to  p-diphenol,  with  which  it 
unites  in  molecular  ratio  to  form  dipheno-quin-hydrone,  dark-green 
needles  decomposing  at  180°  (B.  38,  1232). 

m2,  m'2-Tetramethyl-p,  p'-dipheno-quinone  O  :  C6H2(CH3)2  :  C6H2 
(CH3)2  :  O,  m.p.  about  210°,  red  needles,  formed  by  the  oxidation  of 
vic-m-xylenol  with  chromic  acid.  It  yields,  on  reduction,  tetramethyl- 
dioxy-biphenyl,  with  which  it  forms  a  quin-hydrone,  m.p.  201°,  steel- 
blue  flakes  (B.  38,226). 

Tetrachloro-  and  tetrabromo-pp'-dipheno-quinone  have  been  ob- 
tained by  the  oxidation  of  the  corresponding  p-diphenol  derivatives 
with  fuming  HNO3  in  glacial  acetic  acid.  They  form  infusible  deep- 
red  crystals  with  blue  surface  colour,  which  revert  to  the  original 
substances  under  the  action  of  sulphurous  acid  (B.  13,  224). 

Coerulignone  or  cedriret  must  be  regarded  as  a  tetramethoxy-pp'- 
dipheno-quinone. 

It  separates  as  a  violet  powder  when  crude  wood-spirit  is  purified 
on  a  large  scale  by  means  of  potassium  chromate.  It  is  further  formed 
on  oxidising  dimethyl-pyrogallol  from  beech-wood  tar  with  potassium 
chromate  or  ferric  chloride  : 

OCH3     H  —  2H  QCH3     H    .    H     OCH3 

1         OCH3     H  '    OCH3     H    '    H     OCH3    '     ' 

Coerulignone  is  insoluble  in  the  ordinary  solvents,  and  is  precipi- 
tated in  fine,  steel-blue  needles,  from  its  phenol  solution,  by  alcohol  or 
ether.  It  dissolves  in  concentrated  sulphuric  acid  with  a  beautiful 
blue  colour.  Large  quantities  of  water  colour  the  solution  red  at  first. 
Reducing  agents  (tin  and  hydrochloric  acid)  convert  ccerulignone  into 
colourless  hydro-ccerulignone,  which  changes  again  to  the  first  by 
oxidation.  Ccerulignone  is,  therefore,  a  quinone  body,  and  may  be 
called  a  binuclear  quinone. 

It  unites  with  primary  aromatic  amines,  forming  blue  dyes.  It  is 
very  probable  that  in  doing  this  two  methoxyl  groups  are  replaced  by 
amino-residues  (B.  30,  235). 

On  the  action  of  alcoholic  HC1  upon  ccerulignone,  see  B.  31,  615  ', 
cp.  also  A.  368,  276. 

A  derivative  of  pp'-dipheno-quinone  is  probably  also  the  so-called 
tribromo-reso-quinone,  m.p.  214°,  obtained  from  pentabromo-resorcin 


PHENYL-BENZOL   GROUP  559 

by  heating,  or  by  treatment  with  silver  nitrate  solution,  with  elimina- 
tion of  two  bromine  atoms  (B.  42,  2814). 

Aldehydes  and  Ketones  of  the  Diphenyl  Series. — o-Phenyl-benzalde- 
hyde  C6H5.C6H4[2]CHO,  b.p.21  184°,  is  formed  by  the  distillation  of 
calcium-o-phenyl-benzoate  with  calcium  formate.  p-Phenyl-benzalde- 
hyde,  m.p.  57°,  b.p.  184°,  has  been  obtained  from  diphenyl-glyoxylic 
acid  C6H5C6H4CO.COOH,  m.p.  170°,  whose  ester  is  obtained  by  the 
condensation  of  diphenyl  and  ethoxalyl  chloride  by  means  of  A1C13 
(C.  1897,  II.  799;  1899,  I.  424).  4,  4'-Diphenyl-dialdehyde  CHO[4] 
C6H4.C6H4[4]CHO,  m.p.  145°  ;  its  dianile  is  formed  by  heating  p-iodo- 
benzylidene-aniline  with  copper  dust  (A.  332,  76). 

m-Phenyl-acto-phenone  C6H5.C6H4[3]COCH3,  m.p.  121°,  from 
diphenyl,  acetyl  chloride,  and  A1C13  (/.  pr.  Ch.  2,  81,  394).  Nitro- 
phenyl-benzaldehyde  NO2G6H4.C6H4CHO  and  nitro-phenyl-aceto- 
phenone  NO2C6H4.C6H4COCH3  are  formed  from  sodium  iso-diazo- 
nitro-benzate,  with  benzaldehyde  and  aceto-phenone  respectively,  in 
the  presence  of  acetyl  chloride  (B.  28,  525).  oo'-Diaeetyl-diphenyl 
CH3CO[2]C6H4.C6H4[2]COCH3,  m.p.  84°,  see  A.  363,  305. 

Biphenyl-carboxylic  acids  are  obtained  from  diphenyl  derivatives 
by  reactions  similar  to  those  by  which  the  benzene-carboxylic  acids  are 
prepared  from  the  derivatives  of  benzene. 

Biphenyl-mo  no  carboxylic  Acids. — There  are  three  possible  acids  : 
o-Phenyl-benzoie  acid  C6H5.C6H4[2]CO2H,  melting  at  m°,  is  produced 
by  fusing  diphenylene-ketone  with  caustic  potash  (A.  166,  374)  ;  by 
the  distillation  of  sodium  salicylate  with  triphenyl-phosphate  (/.  pr. 
Ch.  2,  28,  305)  ;  and  from  o-amido-  and  o-methyl-diphenyl.  If  the 
acid  be  treated  with  PC15,  or  if  it  be  heated  with  sulphuric  acid  to 
100°,  or  with  lime  to  more  elevated  temperatures,  diphenylene-ketone 
will  be  formed  (A.  266,  142  ;  279,  259). 

o-Phenyl-hexamethylene  -  carboxylic  acid  C6H5[i]C6H10[2]COOH, 
m.p.  150°,  is  synthesised  from  phenyl-pentamethylene  dibromide  with 
sodium-malonic  ester,  etc.  (B.  35,  2122). 

m-Phenyl-benzoic  acid,  melting  at  160°,  results  from  the  oxidation 
of  m-methyl-biphenyl,  of  iso-diphenyl-benzol,  and  in  the  reduction  of 
bromo-m-phenyl-benzoic  acid  (B.  27,  3390). 

p-Phenyl-benzoic  acid,  melting  at  218°,  is  obtained  from  p-methyl- 
biphenyl,  from  p-diphenyl-benzol,  from  sodium  biphenyl-sulphonate 
(A.  282,  143),  from  p-amido-diphenyl,  and  by  fusing  benzoic  acid  with 
caustic  potash.  It  is  reduced  to  p-phenyl-hexahydro-benzoic  acid 
C6H5C6H10[4]CO2H,  in  two  modifications  melting  at  202°  and  113° 
respectively  (A.  282,  139).  p2-Nitro-phenyl-benzoic  acid,  melting  at 
222°-225°,  results  from  the  oxidation  of  p2-nitro-phenyl-tolyl.  It  yields 
the  corresponding  amido-acid  (B.  29,  166)  on  reduction. 

Biphenyl-m-acetic  acid  C6H5.C6H4[3]CH2COOH,  m.p.  153°,  from 
m-phenyl-aceto-phenone  (see  above),  by  heating  with  yellow  ammonium 
sulphide. 

Oxy-  bipheny  I -carboxylic  Acids. — The  following  acids  are  all 
derivatives  of  o-phenyl-benzoic-acid  : — 

6-Phenyl-salicylie  acid  C6H5[6]C6H3[2](OH)CO2H,  melting  at  159°, 
results  upon  fusing  3-oxy-diphenylene-ketone  and  potassium  hydroxide 
(B.  28,  112). 

2-Phenyl-m-oxy-benzoie  acid  C6H5[2]C6H3[3]OH.CO2H,  melting  at 


560  ORGANIC  CHEMISTRY 

154°,  is  obtained  as  the  principal  product  in  the  fusion  of  6-oxy- 
diphenylene-ketone  with  potassium  hydroxide  (A.  284,  307). 

o-Oxy-phenyl-o-benzoic  acid  is  only  known  in  the  form  of  its 

lactone,   biphenyl-methylolid     |  |    ,  melting  at   92-5°,   which   is 

C6H4[2]0 

formed  as  a  by-product  on  fusing  6-oxy-diphenylene-ketone  or  o-oxy- 
fluorenone  with  caustic  potash,  in  small  quantities  by  the  action  of 
POC13  upon  sodium  salicylate,  and  when  phenol  acts  upon  the  sulphate 
of  o-diazo-benzene  (A.  284,  316).  It  corresponds  in  composition  to 

CaH4[2]CO 
phenanthridone    \  \     ,  melting  at  203°  (see  this),  which  is  pro- 


duced  when  bromine  and  caustic  potash  act  upon  diphenamic  acid 
(A.  276,  245). 

p-Oxy-phenyl-o-benzoic  acid  HO[4]C6H4[i]C6H4[2]C02H,  melting 
at  206°,  is  produced,  together  with  biphenyl-methylolid  and  phenyl- 
ether-salicylic  acid,  by  the  action  of  phenol  upon  the  sulphate  of 
o-diazo-benzoic  acid  (A.  286,  323). 

Biphenyl-dicarboxylic  acids  contain  the  two  C02H  groups,  either 
linked  to  the  same  or  to  different  benzene  residues.  Diphenic  acid  is 
the  most  important  biphenyl-dicarboxylic  acid. 

Phenyl-iso-phthalic  acid  C6H5C6H3[3,  5](COOH)2  melts  above  310°, 
and  is  formed  on  boiling  benzaldehyde  and  pyro-racemic  acid  with 
baryta  water  (B.  24,  1750). 

Diphenic  acid,  o2-biphenyl-dicarboxylic  acid  CO2H[2]C6H4.C6H4[2] 
CO2H  melts  at  229°. 

It  is  formed  from  diazo-anthranilic  acid  by  the  action  of  ammoniacal 
cuprous  oxide  solution  (A.  320,  123).  Its  dimethyl  ester,  m.p.  74°, 
forms  on  heating  o-iodo-benzoic  ester  with  copper  (A.  332,  70). 

It  is  produced  in  the  oxidation  of  phenanthraquinone  with  a 
chromic  acid  mixture,  or  by  boiling  it  with  alcoholic  potash.  The 
constitution  of  phenanthrene  follows  from  it.  That  of  diphenic 
acid  (2)  is  evident  from  its  oxidation  to  o-phthalic  acid  (i)  (Anschiitz 
and  Japp,  B.  11,  211)  by  potassium  permanganate,  and  its  formation 
by  the  deamidation  of  p2-diamido-diphenyl-o2-dicar  boxy  lie  acid  (3), 
which  is  obtained  on  the  one  hand  from  p2-dinitro-diphenic  acid 

(4)  ,  and  on  the  other  by  the  rearrangement  of  m-hydrazo-benzoic  acid 

(5)  (G.  Schultz,  A.  204,  95)  : 


C,H,[ 


(*>JU]NO,  j'VjNH,  ^[3]C.H,CO,H 

C,H4[2]COaH  C6H4[2]COaH  ^  (  [2]COaH  C6H3  \  [2]CO2H 

COaH 


C8H4[2]CH 


[2]C02H  A(J  H    r  [2]C02H  CIH_/!X!CP,H  NH[3]C,H4CO2H 


(6) 


CACaKO ^  Y   3  ^  ^co  C6H4[4]NHa  Y 

C6H4[2]CH  ~C.H4[2]CO  "^^^   /[2]CO  C.H4[4]NHa  ^ 

In  this  circle  of  reactions  there  should  also  be  included  the  formation 
of  p2-dinitro-diphenic  acid  by  the  oxidation  of  p2-dinitro-phenanthra- 
quinone  (6)  and  the  transposition  of  diamido-diphenic  acid  to  benzidin 
(7),  the  constitution  of  which  was  previously  deduced,  and  to  p2- 
diamido-fluorene  (8). 


PHENYL-BENZOL  GROUP  561 

Concentrated  sulphuric  acid  changes  diphenic  acid  to  diphenylene- 
ketone-car  boxy  lie  acid.     When  it  is  digested  with  acetyl  chloride  or 

C6H4.C(X 
acetic  anhydride  it  yields  diphenic  anhydride  I  ^>O,  melting  at 

213°  (A.  226,  i).     This  is  a  remarkable  compound,  inasmuch  as  it  can 
be  viewed  as  adipinic  anhydride  and  contains  a  "  seven-membered  " 

C6H4.COC1 
ring.      Diphenic   chloride    I  ,  melting   at  93°,  is  reduced  in 


ethereal  solution  by  zinc  and  hydrochloric  acid  to  phenanthrene-hydro- 
C6H4.C(OH)  C6H4.CO.NH2 

quinone    I  (A.  247,  268).      Diphenamino  acid    I 

C6H4.C(OH)  C8H4.CO.OH 

melting  at  193  ,  is  converted  by  a  hypobromite  or  hypochlorite,  in 
alkaline  solution,  into  phenanthridone  (A.  276,  248).  Diphenimide 
CflH4.COx 

>NH,  melts  at  219°  (A.  247,  271). 
C6H4.C(X 

o-,  m-,  and  p-Nitro-diphenic  acid,  m.p.  248°-25o°  with  decomposition, 
268°,  and  2i4°-2i6°  respectively,  02-  and  p2-dinitro-diphenic  acid,  m.p. 
303°  with  decomposition,  and  253°  respectively,  are  formed  from  the 
nitro-  and  dinitro-phenanthrene-quinones  by  oxidation  with  chromic 
acid  mixture  ;  in  the  o2-  and  p2-dinitro-acid  the  anhydride  formation 
is  more  difficult  (B.  36,  3730,  3738).  The  ester  of  the  p2-acid  is  also 
obtained  from  two  molecules  of  2-bromo-5-nitro-benzoic  ester,  by 
heating  with  copper  dust.  In  the  same  manner,  o2-dinitro-biphenyl- 
p2-dicarboxylie  ester  is  obtained  from  4-bromo-3-nitro-benzoic  ester 
(B.  34,  2682).  By  reduction,  the  nitrated  diphenic  acids  yield  amido- 
and  diamido-diphenic  acids,  from  which  amido-oxy-  and  dioxy- 
diphenic  acids  are  obtained  (B.  38,  3769). 

Hexa-oxy-biphenyl-o  2-dicarboxylic  acid.     The  formula  of  a  dilactone 

of  this  acid  °§g]c3£:  SSSp  Probably  aPPUes  to  eUa«ic  acid 
(q.v.),  the  oxidation  product  of  gallic  acid  (B.  36,  212). 

Iso-diphenie  acid  (o,  m')  CO2H[3]C6H4.C6H4[2]CO2H,  melting  at 
216°,  is  produced  when  diphenylene-ketone-carboxylic  acid  is  fused 
with  caustic  potash. 

o,  p'-Biphenyl-dicarboxylie  acid  CO2H[4]C6H4.C6H4[2]CO2H,  melting 
at  251°,  is  obtained  from  diphenylin  (B.  22,  3019). 

m2-Biphenyl-dicarboxylic  acid,  m.p.  357°  ;  its  dimethyl  ester,  m.p. 
104°,  has  been  obtained  by  heating  m-iodo-benzoic  ester  with  copper 
dust  (A.  332,  71). 

p2-Biphenyl-dicarboxylic  acid  decomposes  at  a  higher  temperature. 
It  is  obtained  from  benzidin  and  by  oxidising  p2-ditolyl.  Its  dimethyl 
ester,  m.p.  212°,  is  obtained  from  p-iodo-benzoic  ester  and  copper 
(A.  332,  73). 

p2-Diamido-biphenyl-m2-dicarboxylic  acid  is  obtained  from  o-nitro- 
benzoic  acid,  just  as  p2-diamido-diphenic  acid  is  prepared  from  m-nitro- 
benzoic  acid  (B.  25,  2797  ;  31,  2574).  It  is  converted  through  its 
tetrazo-compounds  into  p2-dioxy-biphenyl-m2-diearboxylic  acid,  di- 
salicylic  acid,  m.p.  3O2°-305°. 

m2-Dimethyl-biphenyl-p2-dicarboxylic  acid  melts  above  300°,  is 
formed  from  o-tolidin,  and  is  oxidised  to  diphthalic  acid,  biphenyl-m2, 
p2-dicarboxylic  acid  (CO2H)2[3,  4]C6H3.C6H3[3,  4](CO2H)2  (B.  26,  2486). 

VOL.  II.  2O 


562  ORGANIC  CHEMISTRY 

1.  B.  Diphenyl-benzols,  diphenyl-phenylenes  C6H4(C6H5)  2. — Two  such 
bodies  are  known :  m-diphenyl-benzol,  iso-diphenyl-benzol,  melting  at 
85°  and  boiling  at  369°,  and  p-diphenyl-benzol,  melting  at  205°  and 
boiling   at   383°.     They   are   formed   simultaneously   on   conducting 
benzene  through  a  tube  heated  to  redness,  and  by  the  action  of  diazo- 
benzol  chloride  upon  diphenyl  and  A12C16  (B.  26,  1998).     The  p-body 
is  also  produced  in  the  action  of  sodium  upon  a  mixture  of  p-dibromo- 
benzol  and  bromo-benzol  (A.  164,  168).     Iso-diphenyl-benzol  is  also 
prepared  from  m-dichloro-benzol  and  chloro-benzol  by  the  action  of 
sodium  in  xylol  (B.  29,  R.  773). 

p-Diphenyl-phenol  C6H3(OH)[2,  4](C6H5)2,  formed  by  the  condensa- 
tion of  cinnamic  aldehyde  and  sodium  phenyl-succinate,  by  means  of 
acetic  anhydride,  the  intermediately  formed  diphenyl-butadiene-acetic 
acid  C6H5CH  :  CH.CH  :  C(C6H5)CH2COOH  undergoing  benzene  ring 
condensation  ;  the  phenol,  on  distillation  with  zinc  dust,  gives  p- 
diphenyl-benzol  (B.  36,  1407). 

2,  6-Diphenyl-l,  4-nitro-phenol  (C6H5)2[2,  6]C6H2[4]NO2[i]OH,  m.p. 
136°,  is  obtained  synthetically  from  dibenzyl-ketone  and  nitro-malonic 
aldehyde.     It  has  been  converted  into  the  corresponding  amido-phenol, 
quinone,  and  hydroquinone  (C.  1900,  II.  560).    The  latter  substance 
has  also  been  obtained  by  way  of  diphenyl-nitroso-phenol,  formed, 
besides  phenyl-nitroso-phenol,  from  nitroso-phenol  and  two  molecules 
diazo-benzol  chloride  (A.  312,  227). 

Di-biphenyl  C6H5.C6H.4C6H4.C6H5,  m.p.  320°,  from  p-iodo-biphenyl 
and  copper  (A.  332,  52). 

I.  C.  Triphenyl-benzols  C6H3(C6H5)3. — The  symmetrical  or  [i,  3,  5] 
modification  is  formed  from  aceto-phenone  when  heated  with  P2O6, 
or  by  conducting  hydrochloric  acid  gas  into  it,  just  as  mesitylene  is 
obtained  from  acetone.  It  melts  at  169°  (B.  23,  2533).  [i,  2,  3]  (?)- 
Triphenyl-benzol  melts  at  157°  (B.  26,  69).  Synthetically,  several 
hydrated  derivatives  of  [i,  2, 3]-triphenyl-benzol  (cp.  C.  1898,  II. 
979  ;  1904,  I.  806  ;  B.  32,  2009). 

I.  D.  1,  2,  4,  5-Tetraphenyl-benzol  C6H2(C?H5)4,  m.p.  278°,  from  the 
cyclic  pinacone  obtained  from  diphenyl-dibenzoyl-butadiene  (q.v.) 
(A.  302,  210). 

II.  BENZYL-BENZOL  GROUP. 

Benzyl-benzol  or  diphenyl-methane  is  the  simplest  hydrocarbon 
of  this  group.  The  alkyl  diphenyl-methanes  and  the  compounds 
substituted  in  the  benzene  residues  by  the  NO2,  NH2,  or  OH  groups 
are  derived  from  it.  If  we  suppose  a  hydrogen  atom  of  the  CH2  group 
to  be  replaced  by  OH,  we  obtain  the  formula  of  benzo-hydrol  or 
diphenyl-carbinol,  which  changes  by  oxidation  to  benzo-phenone 
or  diphenyl  -  ketone.  Diphenyl-methane  CH2(C6H5)2,  benzo-hydrol 
HOCH(C6H5)2,  and  benzo-phenone  CO(C6H5)2  are  the  simplest  repre- 
sentatives of  the  hydrocarbons,  the  secondary  alcohols  and  the  ketones 
of  this  group.  Attached  to  them  are  the  corresponding  carboxylic 
acids — e.g.  : 

H<CO>H  CH(OH)/C«H*CO*H  CO/C6H4C02H 

C6H5  \C6H5  \C6H6 

Benzo-benzoic  acid         Benzo-hydrol-benzoic  acid         Benzoyl-benzoic  acid. 


BENZYL-BENZOL  GROUP  563 

i.  HYDROCARBONS  (DIPHENYL-METHANES). 

Formation. — (i)  From  benzyl  chloride,  benzene  and  zinc  dust 
(Zincke,  A.  159,  374),  or  aluminium  chloride  (Friedel  and  Crafts).  (2) 
From  formaldehyde,  methylal,  or  methylene  diacetate  with  benzene 
and  sulphuric  acid  (Baeyer,  B.  6,  963).  Both  reactions  are  capable  of 
wide  generalisation.  Thus,  by  use  of  the  second  reaction,  substituting 
other  aldehydes  for  formaldehyde,  numerous  hydrocarbons  have  been 
obtained  in  which  two  benzene  residues  are  attached  to  the  same 
carbon  atom  (see  unsym.  diphenyl-methane,  below).  (20)  Benzyl 
alcohol  and  benzene,  by  treatment  with  concentrated  sulphuric  acid, 
yield  diphenyl-methane  (B.  6,  963).  (3)  By  the  reduction  of  ketones, 
into  which  the  benzyl  -  benzols  are  oxidised.  Diphenyl-methane 
derivatives  are  formed  as  by-products.  (4)  By  the  action  of  sodium 
upon  mixtures  of  bromo-benzols  and  alkyl-benzols  (B.  33,  334). 
(5)  By  the  oxidation  of  alkyl-benzols  with  manganese  dioxide 
and  sulphuric  acid,  from  which  we  obtain  tolyl-phenyl-methane 
(B.  33,  464). 

Diphenyl-methane  C6H5.CH2.C6H5,  benzyl-benzol,  is  obtained  (i) 
from  benzyl  chloride  and  benzene  with  zinc  dust  or  A1C13.  (2)  From 
CH2C12  with  benzene  and  A1C13.  (3)  From  methylal,  or  (4)  from  benzyl 
alcohol,  benzene,  and  sulphuric  acid.  (5)  By  the  reduction  of  benzo- 
phenone  with  zinc  dust  or  zinc  and  sulphuric  acid,  or  hydriodic  acid 
and  phosphorus  ;  and  (6)  upon  distilling  diphenyl-acetic  acid  with  soda- 
lime  (A.  155,  86). 

Diphenyl-methane  possesses  the  odour  of  oranges.  It  melts  at 
26-5°  and  boils  at  261°.  When  conducted  through  ignited  tubes  it 
yields  diphenylene-methane  or  fluorene ;  a  chromic  acid  mixture 
oxidises  it  to  benzo  -  phenone,  whereas  concentrated  nitric  acid 
changes  it  to  p2-,  o,  p-dinitro-,  and  tetra-nitro-diphenyl-methane 
(A.  283,  154)- 

Benzyl -toluenes,  phenyl  -  tolyl  -  methanes  C6H5.CH2.C6H4.CH3.— A 
liquid  mixture  of  o-  and  p-benzyl-toluol,  which  cannot  be  separated, 
is  obtained  by  the  action  of  zinc  dust  on  a  mixture  of  benzyl  chloride 
and  toluol.  Anthracene  is  formed  at  the  same  time.  The  pure  para- 
body  has  been  formed  by  heating  para-phenyl-tolyl-ketone  with  zinc 
dust,  and  is  a  liquid,  boiling  at  285°.  It  appears  also  to  be  produced 
in  the  action  of  sodium  upon  p-bromo-toluol  along  with  p-ditolyl. 
Bromo  -  mesitylene  and  sodium  yield,  together  with  dimesityl,  a 
pentamethyl-diphenyl-methane  (B.  29,  in). 

Benzyl-p-xylene  boils  at  294°.  Benzyl-mesitylene  melts  at  36°  and 
boils  at  301°.  The  benzyl-durols  melt  at  60°  and  boil  at  310° ;  and  at 
145°  and  326°.  Benzyl-penta-ethyl-benzol  melts  at  88°  (B.  26,  R.  58). 
p2-Ditolyl-methane  melts  at  22°  and  boils  at  286°.  Dimesityl-methane 
melts  at  139°.  The  unsym.  hydrocarbons  were  obtained  according  to 
methods  i  and  4,  and  the  sym.  according  to  method  i. 

Nitro-diphenyl-methanes  C6H3.CH2.C6H4.NO2  (A.  283,  157).— The 
o^Ao-compound,  prepared  from  o-nitro-benzyl  chloride  and  benzene 
with  A1C13,  is  liquid  (B.  18,  2402  ;  29,  1303).  The  meta-  and  para- 
bodies  are  derived  from  meta-  and  para-nitro-benzyl  alcohol  by  means 
of  benzene  and  sulphuric  acid.  The  first  is  an  oil ;  the  second  melts 
at  31°  (B.  16,  2716). 


564  ORGANIC   CHEMISTRY 

o2-Dinitro-diphenyl-methane,m.p.  159°,  from  p2-diamido-o2-dinitro- 
diphenyl-methane  by  de-amidation  (/.  pr.  Ch.  2,  65,  327). 

m2-Dinitro-diphenyl-methane,  melting  at  174°,  is  formed  from 
m-nitro-benzyl  alcohol  with  nitro-benzol,  or  from  formaldehyde,  nitro- 
benzol,  and  concentrated  sulphuric  acid  (B.  27,  2293,  2321).  m,  p-Di- 
nitro-diphenyl-methane,  p-nitro-benzyl-m-nitro-benzol  melts  at  103°. 
p2-Dinitro-diphenyl  -  methane  melts  at  183°.  It  is  obtained  from 
diphenyl-methane  along  with  o,  p-dinitro-diphenyl-methane,  melting 
at  118°  (B.  27,  2110  ;  A.  194,  363). 

Tetranitro  -  diphenyl  -  methane,  melting  at  172°,  forms  dark-blue 
coloured  salts  with  alcoholic  potash  (B.  21,  2475). 

Amido-diphenyl-methanes. — o-Amido-diphenyl-methane  is  a  liquid. 
When  its  vapours  are  conducted  over  ignited  lead  oxide,  acridin  (q.v.) 
results.  Nitrous  acid  converts  it  into  fluorene  (B.  27,  2786).  m-  and 
p-Amido-diphenyl-methane  melt  at  46°  and  34°  respectively  (B.  16, 2718). 

o2-Diamido-diphenyl-methane,  m.p.  160°  (see  /.  pr.  Ch.  2,  65,  331). 

p2-Diamido-diphenyl-methanes  are  formed  (i)  from  methylene 
dianilines  on  heating  with  aniline  chlorohydrates  ;  in  this  reaction 
amido-benzyl  anilines  may  be  formed  as  intermediate  products,  which 
are  further  transposed  into  diamido-diphenyl-methanes  : 

C6H5NH.CH2.NHC6H5  >  C6H5NH.CH2C6H4NH2 >  NH2C6H4CH2C6H4NH2 

This  reaction  is  confirmed  (2)  by  the  easy  formation  of  diamido-diphenyl- 
methanes  from  amido-benzyl-anilines  by  heating  with  aniline  chloro- 
hydrates (C.  1900,  I.  mo  ;  cp.  B.  33,  250). 

p2-Diamido-diphenyl-methane,  melting  at  85°,  changes  completely 
to  para-rosanilin  or  rosanilin  when  heated  with  aniline  or  o-toluidin 
in  the  presence  of  an  oxidising  agent  (B.  25,  303). 

Its  tetmmethyl  derivative  results  from  dimethyl-aniline  by  means  of 
C2H2I2,  CClgH  (or  CC14),  or  with  methylal,  or  by  the  action  of  CS2  and 
zinc  upon  dimethyl-aniline.  It  melts  at  90°. 

The  hydrogen  of  the  group  CH2  attached  to  basic  radicles  is  very 
readily  replaced  by  sulphur  ;  see  p2-tetramethyl-diamido-thio-benzo- 
phenone.  See  A.  283,  149,  for  isomeric  diamido-diphenyl-methanes. 

p2-Diamido-o2-dinitro-diphenyl-methane  and  its  reduction  products, 
see  C.  1910,  II.  569.  p2-Dihydrazino-diphenyl-methane  CH2(C6H4. 
NHNH2)2,  m.p.  140°  (/.  pr.  Ch.  2,  74,  155). 

Oxy-benzyl-benzols. — p-Benzyl-phenol,  melting  at  84°  and  boiling 
at  325°  (in  CO 2),  is  produced  (i)  from  benzyl  chloride,  phenol,  and  zinc  ; 
(2)  from  benzyl  alcohol,  phenol  with  concentrated  sulphuric  acid,  or 
zinc  chloride  ;  (3)  from  p-amido-diphenyl-methane. 

The  bromination  products  of  this  phenol,  like  the  brominated 
phenol-alcohol  bromides,  can  easily  be  converted  into  methylene- 
quinones,  e.g.  C6H5CH  :  C6H2Br2  :  O+H2O,  a  yellow  precipitate,  easily 
passing  into  dibromo-oxy-benzo-hydrol  (A.  334,  367)  : 

Amido-benzyl-phenols  are  easily  obtained  by  the  condensation  of 
amido-benzyl  alcohols  with  phenols  (C.  1903,  I.  288). 

p-Dialkyl- amido-benzyl -phenols,  e.g.  C6H2OHBr2.CH2.C6H4[4]N 
(CH3)2,  are  formed  by  the  action  of  o-  and  p-pseudo-phenol  bromides 
upon  tertiary  anilines  (A.  334,  264). 

o2-Dioxy-diphenyl-methane  is  only  known  in  the  form  of  its  an- 
hydride, xanthene  (q.v.). 


BENZYL-BENZOL   GROUP  565 

p2-Dioxy-diphenyl-me thane  is  produced  on  fusing  diphenyl-methane- 
disulphonic  acid  with  KOH  (A.  194,  318).  It  melts  at  158°.  Its 
dimethyl  ether  is  formed  from  anisol  and  methylal  by  the  action  of 
concentrated  sulphuric  acid  (B.  7,  1200),  and  melts  at  52°  (B.  7,  1200). 
By  exhaustive  bromination  it  is  converted  into  a  hepta-bromide,  which 
easily  splits  off  HBr  and  turns  into  a  methylene-quinone  O  :  C6Br3H  : 
CHC6BrH3(OH),  red  needles,  m.p.  245°  (/.  pr  Ch.  2,  58,  441  ;  A.  330, 
61).  Substituted  p2-dioxy-diphenyl-methanes  have  been  obtained,  in 
various  ways,  from  p-oxy-benzyl  alcohols,  and  the  derived  pseudo- 
phenol  haloids  (A.  356,  124). 

Multivalent  phenols  are  easily  concentrated  by  formaldehyde  into 
polyoxy-diphenyl-methanes  :  methylene-dipyro-eateehin,  m.p.  220°  with 
decomposition  (B.  26,  254).  Methylene-diresorcin,  methylene-diorein, 
methylene-diphloro-gluein  (A.  329,  269  ;  C.  1907,  I.  547). 

Methylene-bis-hydro-resorcinCH2(C6H7O2)2,  m.p.  132°,  from  hydro- 
resorcin  and  formaldehyde,  on  boiling  with  acetic  anhydride,  yields 
octohydro-xanthene-dione  CH2(C6H6O)2O,  and  with  ammonia  deka- 
hydro-acridin-dione  CH2(C6H6O)2NH  (A.  309,  356). 

2.  ALCOHOLS  (BENZO-HYDROLS). 

Diphenyl-carbinol,  benzo-hydrol  (CgH^CH.OH  melts  at  68°  and 
boils  at  298°  with  partial  decomposition  into  water  and  benzo-hydrol 
ether  [(C6H5)2.CH]2O,  melting  at  109°  (B.  34,  1965).  It  is  produced 
on  heating  diphenyl-bromo-methane  with  water  to  150°,  or,  more  readily, 
from  benzo-phenone  with  sodium  amalgam,  or  by  heating  with  alcoholic 
potassium  hydroxide  and  zinc  dust  (together  with  benzo-pinacone) 
(A.  184,  174).  Synthetically,  it  is  prepared  from  formic  ester  with 
phenyl-magnesium  bromide  (C.  1902,  II.  1209).  By  oxidation  it 
passes  into  benzo-phenone,  also  by  heating  in  the  presence  of  palladium 
black  (R.  36,  2816).  With  quinones  and  quinoid  substances  benzo- 
hydrol  condenses  with  entrance  of  one  or  two  CH(C6H5)2  groups  into 
the  quinoid  nucleus  (B.  32,  2146  ;  33,  799). 

Phenyl-p-tolyl-carbinol  melts  at  52°  (A.  194,  265). 

Diphenyl-carbinol  chloride,  diphenyl  -  chloro  -  methane,  melting  at 
14°,  is  obtained  from  benzo-hydrol  and  HC1.  When  heated  it  breaks 
down  into  HC1  and  tetraphenyl-ethylene  (B.  7,  1128).  Diphenyl- 
bromo-methane,  from  diphenyl -methane  and  bromine,  melts  at 

45°- 

Benzo-hydrylamine  NH2.CH(C6H5)2,  b.p.  288°,  is  obtained  from 
diphenyl-bromo-methane  and  from  benzo-phenon-oxime  (B.  19,  3233). 
The  latter  method  has  afforded  the  homologous  alkyl-benzo-hydroxyl- 
amines  (B.  24,  2797).  The  formyl  derivative,  from  benzo-phenone 
and  ammonium  formate  at  200°-25o°  (B.  19,  2129),  melts  at  132°. 
Formamidine-benzo-hydryl  CH(NH)NHCH(C6H5)2  is  formed  from 
prussic  sesqui-chlorohydrate  2CNH.3HC1,  benzene,  and  A1C13  (B. 
31,  1771). 

Dibenzo-hydrylamine  melts  at  136°. 

Phenyl-benzo-hydrylamine  C6H5NH.CH(C6H5)2,  b.p.20  233°,  is 
formed  when  C6H5MgBr  is  attached  to  benzyliden  e-aniline  and  the 
product  is  decomposed  with  acids  (B.  38,  1767). 

/3-Benzo-hydryl-hydroxylamine   [diphenyl-aminol -methane}  HO.NH 


566  ORGANIC  CHEMISTRY 

CH(C6H5)2,  m.p.  78°,  is  formed  on  boiling  a  solution  of  diphenyl- 
bromo-methane  and  acetoxime  with  glacial  acetic  acid  and  water 
(A.  278,  364)- 

Benzo-hydryl-hydrazin  (C6H5)2CH.NHNH2,  m.p.  59°,  b.p.12  188°, 
and  bis-benzo-hydryl-hydrazin  (C6H5)2CH.NHNH.CH(C6H5)2  m.p. 
133°,  from  benzo-phenone-hydrazone  and  bis-benzo-phenone-hydrazone 
by  reduction  with  sodium  amalgam  and  alcohol.  Benzo-hydryl- 
hydrazin,  on  boiling  with  HC1,  splits  into  diphenyl-chloro-methane  and 
hydrazin  (/.  pr.  Ch.  2,  67,  112). 

o-Amido-benzo-hydrol    C6H4/™(OH)C6H5,    m.p.    120°,    is    formed 

\rsrl2 

in  the  reduction  of  o-amido-benzo-phenone.  It  is  capable,  like 
o-amido-benzyl  alcohol,  of  producing  heterocyclic  compounds  (B.  29, 
1034).  The  isomeric  o-oxy-benzo-hydrylamine  c6H4/™(NH2)C6H5, 


m.p.  103°,  is  obtained  by  reduction  of  phenyl-indoxazene  (C.  1898, 
II.  284). 

p-Oxy-benzo-hydrol  HO[4]C6H4CH(OH)C6H5,  m.p.  161°,  from 
benzoyl-phenol  by  reduction  (A.  210,  253).  op-Dioxy-benzo-hydrol  is 
formed  by  condensation  of  benzaldehyde  and  resorcin  by  means  of 
alkali  (C.  1910,  I.  920).  o2p2-Tetramethoxy-l3enzo-hydrol,  m.p.  179°, 
from  vic-iodo-resorcino-dimethyl  ether,  Mg,  and  formic  ester  (A. 
372,  128). 

In  the  aldol  condensation  of  benzaldehyde,  or  p-nitro-benzaldehyde 
and  dimethyl-aniline,  with  hydrochloric  acid  (by  ZnCl2  or  oxalic  acid 
the  products  are  triphenyl-methane  derivatives)  there  arise  :  p-nitro- 
p-amido-benzo-hydrol  NO2C6H4CH(OH)C6H4NH2  (C.  1901,  I.  866), 
p-dimethyl-amido-benzo-hydrol  C6H5CH(OH).C6H4N(CH3)2,  m.p.  69°, 
and  p-dimethyl-amido-p-nitro-benzo-hydrol,  m.p.  96°  (B.  21,  3292). 
By  reduction  the  latter  compound  yields  p-dimethyl-amido-p-amido- 
diphenyl-methane,  m.p.  165°.  p2-Tetramethyl-diamido-benzo-hydrol, 
m.p.  96°,  has  been  obtained  by  the  reduction  of  p2-tetramethyl-diamido- 
benzo-phenone  (B.  22,  1879).  On  boiling  the  former  with  dilute 
mineral  acids  until  the  blue  colour  has  disappeared,  it  breaks  down  into 
dimethyl-aniline  and  dimethyl-amido-benzaldehyde  (B.  27,  3316).  In 
the  solid  condition  p2-tetramethyl-diamido-benzo-hydrol  is  white, 
while  its  solution  is  blue  in  colour  (B.  20,  1733,  footnote).  In  acid 
solution  the  tetramethyl-diamido-benzo-thio-hydrol  has,  like  auramin, 
perhaps  a  quinoid  structure  (B.  30,  2803  ;  33,  283).  It  is  a  very 
reactive  body.  On  standing,  or  on  boiling  with  alcohols,  ethers  are 
generated.  Methyl  ether  CH3OCH[C6H4N(CH3)2]2,  m.p.  72°  (C.  1902, 
I.  471)  ;  with  SH2  it  yields  in  alcoholic  solution  tetramethyl-diamido- 
benzo-thio-hydrol  HS.CH[C6H4N(CH3)2]2,  m.p.  82°.  With  aromatic 
amine  it  spontaneously  transposes  into  tetramethyl-diamido-benzo- 
hydryl-aryl-amines  ArNHCH[C6H4N(CH3)2]2,  the  so-called  aryl-leuc- 
auramines.  The  simplest  leucauramine  NH2CH[C6H4N(CH3)2]2,  m.p. 
135°,  is  formed  from  auramine  by  reduction  with  sodium  amalgam  in 
alcohol  ;  oxidation  regenerates  auramine.  With  Am  sulphide  the 
leucauramines  yield  tetramethyl  -  diamido  -  benzo  -  hydryl  sulphide 
S[CH[C6H4N(CH3)2]2]2,  m.p.  172°  (B.  35,  375,  913).  With  compounds 
having  a  reactive  CH2  group,  like  malonic  ester,  aceto-acetic  ester,  etc., 
the  hydrol  easily  unites  with  expulsion  of  water  (C.  1910,  1.  181).  With 


BENZYL-BENZOL   GROUP  567 

quinones  and  quinoid  substances  it  condenses  like  benzo-hydrol  itself 
(B.  34,  881,  etc.). 

3.  KETONES  (BENZO-PHENONES). 

The  ketones  of  the  benzyl-benzol  group  bear  the  same  relation  to 
the  benzoic  acids  that  the  acetones  bear  to  the  fatty  acids  : 


CH,COSH  CO3  C6H5.C02H  CO 

,H3  X^«il5 

Acetic  acid  Acetone  Benzoic  acid  Benzo-phenone. 

This  analogy  is  shown  in  the  various  methods  of  formation. 
Methods  of  Formation.  —  (i)  By  oxidising  (a)   the  benzyl-benzols 
and  (b)  the  benzo-hydrols  with  chromic  acid  : 


CH  /C«H5     2°->  co/c'H5 

'Ha\C6H5~  \C8H5 


If  the  CH2  group  contains  alkyls  or  carboxyl  these  groups  will  be 
split  off  by  the  oxidation,  with  the  production  of  ketones.  If  the 
benzene  residues  contain  alkyl  groups  these  are  converted  into  carboxyl 
groups. 

(2)  By  the  action  of  hot  water  upon  the  ketone  chlorides  (see 
Benzo-phenone  chloride,  below). 

Nuclear  Syntheses.  —  (3)  By  the  distillation  of  the  calcium  salts  of 
mononucleus,  aromatic  monocarboxylic  acids,  the  CO2H  groups  of 
which  are  in  direct  union  with  the  benzene  residue  : 

(C6H5.C02)2Ca  --  *  (C6H5)2CO+C03Ca. 

(4)  By  the  condensation  of  benzoic  acid  or  its  anhydride  on  heating 
with  benzene  and  P205. 

(5)  By  the  action  of  benzoyl  chloride  on  benzene,  in  the  presence 
of  aluminium  chloride. 

Phosgene  reacts  in  the  same  manner,  and  acid  chlorides  are  the 
first  products.  These  then  change  into  ketones  (B.  10,  1854)  : 

C6H6+COC12         £L>  C6H5.COC1+C6H6  -U  C6H5COC6H5. 


(6)  By  the  action  of  carbon  tetrachloride  upon  aromatic  hydro- 
carbons and  their  halogen  substitution  products,  in  the  presence  of 
A1C13,  benzo-phenone  chlorides  are  obtained,  which,  on  heating  with 
water,  turn  into  ketones  (C.  1904,  I.  283  ;   1905,  I.  1248). 

(7)  By  the  action  of  mercury  diphenyl  upon  the  acid  chlorides  — 
e.g.  benzoyl  chloride. 

Behaviour.  —  (i)  On  heating  with  zinc  dust  or  hydriodic  acid  and 
amorphous  phosphorus,  the  ketones  sustain  a  reduction  of  the  CO 
group  and  revert  to  the  hydrocarbons  ;  for  example,  benzo-phenone 
yields  diphenyl  -  methane.  (2)  Sodium  amalgam  changes  them  to 
secondary  alcohols  (benzo-hydrols)  and  pinacones.  (3)  Splitting  up  of 
alkylated  benzo-phenones  by  heating  with  phosphoric  acid,  HI  or 
HC1,  into  hydrocarbons  and  carboxylic  acids  (see  B.  32,  1565;  1908). 

Benzo-phenone,  diphenyl-ketone  CO(C6H5)2,  is  known  in  two  modifi- 
cations, the  unstable  (labile),  melting  at  26°,  and  produced  on  boiling 
the  stable  form,  melting  at  46°.  The  unstable  modification  slowly 
reverts  to  the  more  stable  variety.  This  takes  place  rapidly,  and  with 


568  ORGANIC   CHEMISTRY 

a  very  perceptible  evolution  of  heat,  upon  touching  it,  with  a  trace  of 
the  stable  variety  (B.  26,  R.  380  ;  C.  1898,  I.  1177  ;  1900,  I.  340).  It 
boils  at  307°  (760  mm.)  and  at  162°  (12  mm.).  It  is  produced  according 
to  the  general  methods  :  (i)  by  oxidising  diphenyl-methane,  unsym- 
metrical  diphenyl-ethane,  benzo-hydrol,  diphenyl-acetic  acid,  etc.  ; 
(2)  from  benzo-phenone  chloride  ;  (3)  by  the  distillation  of  calcium 
benzoate  (Peligot,  A.  12,  41) ;  (4)  by  the  action  of  P2O5  upon  benzoic 
acid  and  benzene  ;  (5)  from  phosgene  or  benzoyl  chloride,  benzene 
and  aluminium  chloride  ;  and  (6)  from  benzoyl  chloride  and  mercury 
diphenyl.  It  is  also  found  with  benzoic  acid  and  triphenyl-carbinol 
(7)  among  the  products  of  the  action  of  C02  upon  C6H5MgBr  (B.  36, 
3005).  On  fusing  with  potassium  hydrate  it  dissolves  into  benzoic 
acid  and  benzene,  and  on  heating  with  sodium  amide,  in  benzene 
solution,  into  benzamide  and  benzene  (C.  1909,  II.  22).  It  is  converted 
into  diphenyl-methane,  benzol-hydrol,  and  benzo-pinacone  by  reduc- 
tion. Hexahydro-benzo-phenone,  m.p.  54°,  from  hexahydro-benzoyl 
chloride,  benzene,  and  A1C13  (B.  30,  1940). 

Benzo-phenone  Homologues. — o-Phenyl-tplyl-ketone,  b.p.  315°,  when 
conducted  over  heated  lead  oxide,  passes  into  anthra-quinone  (q.v.), 
while  it  yields  anthracene  when  heated  with  zinc  dust  (B.  6,  754). 
m-Phenyl-tolyl  ketone  boils  at  314°. 

p-Tolyl-phenyl  ketone  is  known  in  two  modifications  :  the  unstable 
(labile)  form  melts  at  55°  ;  it  is  hexagonal.  The  stable  form,  m.p. 
59°,  is  monoclinic  (A.  189,  84  ;  B.  12,  2299). 

p-Ditolyl  ketone  melts  at  92°  and  boils  at  333°.  Benzoyl-xylol  melts 
at  36°  and  boils  at  317°  (B.  17,  2847).  Benzoyl-mesitylene  melts  at 
36°  and  boils  at  317°.  Mesitoyl-mesitylene,  m.p.  85°  (/.  pr.  Ch.  2, 
35,  486),  etc.  All  these  are  most  conveniently  prepared  by  method  5. 

Derivatives  of  Benzo-phenone  obtained  by  the  Replacement  of  Oxygen. — 
Benzo-phenone  chloride,  diphenyl-dichloro-methane  CC12(C6H5)2,  boiling 
at  193°  (30  mm.),  is  produced  when  PC15  acts  upon  benzo-phenone. 
Also  by  the  action  of  benzene  upon  carbon  tetrachloride  in  the  presence 
of  A1C13  (C.  1905,  I.  1248). 

When  heated  with  water  it  reverts  to  benzo-phenone,  while  with 
silver  it  yields  tetraphenyl-ethylene,  and  with  zinc  dust  tetraphenyl- 
ethylene,  a-  and  j8-benzo-pinacolin  (B.  29,  1790).  By  transposition 
with  two  molecules  sodium  azide,  nitrogen  is  split  off,  and  N,  a-diphenyl- 

tetrazol  C6H6c/      '   5 '  \\  is  formed  (B.  42,  3359). 

^N N 

Benzo-phenone  bromide  CBr2(C6H5)2  is  produced  on  dropping 
bromine  into  diphenyl-methane  heated  to  150°. 

Acetals  of  benzo-phenone  are  obtained  from  benzo-phenone  chloride 
with  sodium  alcoholates,  as  well  as  from  benzo-phenone  and  ortho- 
formic  ethers.  Benzo-phenone  dimethyl  and  diethyl  acetals  melt  at 
107°  and  52°,  and  boil  at  289°  and  295°  respectively  (B.  29,  2932  ; 
R-  774> 

Thio-benzo-phenone  CS(C6H5)2  is  derived  from  benzene  by  means  of 
thio-phosgene,  CS2C12,  and  aluminium  chloride.  In  this  reaction  the 
phenol  ethers  react  more  readily  than  the  hydrocarbons  (B.  28,  2869). 
Thio-benzo-phenone  is  further  produced  by  the  action  of  phosphorus 
sulphide  upon  benzo-phenone,  but  best  of  all  when  an  alcoholic  solution 


BENZYL-BENZOL   GROUP  569 

of  potassium  sulphide  reacts  with  benzo-phenone  chloride.  It  is  an 
intensely  blue-coloured  oil,  which  congeals  at  lower  temperatures  to 
blue  needles,  and  under  a  pressure  of  14  mm.  distils  at  174°.  The 
thio-benzo-phenones,  when  acted  upon  with  metallic  copper,  yield 
tetraphenyl-ethylene  (B.  29,  2944). 

Benzo-phenone-diethyl-anddibenzyl-mereaptol  (C6H5)  2C(SCH2C6H5)  2 
m.p.  144°,  on  careful  oxidation,  yield  the  corresponding  sulphonals, 
m.p.  137°  and  208°  (B.  35,  2343). 

Diphenyl-dinitro-methane  (C6H5)2C(N2O4),  melting  at  78°,  results 
upon  saturating  a  solution  of  benzo-phenone-oxime  in  ether  with  nitro- 
gen tetroxide.  It  is  changed  back  to  benzo-phenone-oxime  with  zinc 
dust  and  glacial  acetic  acid.  Benzo-hydrylamine  is  also  formed  (B.  23, 
3490). 

Imino-benzo-phenone  (C6H5)2C=NH  is  a  colourless  oil,  obtained 
in  the  action  of  dry  ammonia  upon  a  chloroform  solution  of  amido- 
benzo-phenone  chlorohydrate.  The  chlorohydrate  results  when  benzo- 
phenone  chloride  is  heated  with  ure thane  to  130°.  Phenyl-benzal- 
sultime  C6H4<^^CeH6^N,  melting  at  164°,  should  be  viewed  as  a  deriva- 

XSOg     ' 

tive  of  imino-benzo-phenone,  produced  in  the  condensation  of  pseudo- 
saccharin  chloride  with  benzene  and  aluminium  chloride  (B.  29,  2296). 

Phenyl-imino-benzo-phenone,  benzo  -  phenone  -  anile  (C6H5)  2C = N . 
C6H5,  melting  at  116°,  is  formed  from  benzo-phenone  chloride  and  ani- 
line (A.  187,  199),  or  benzo-phenone  and  aniline  at  240°-25O°,  as  well 
as  by  the  action  of  C6H5MgBr  upon  phenyl-imino-benzoic  ester  C6H5C 
(OCH3)  :  NC6H5  (C.  1906, 1.  1431).  It  forms  unstable  salts  with  acids, 
and  with  methyl  iodide  an  addition  product,  m.p.  202°  (B.  35,  2615). 
A  series  of  o-substituted  benzo-phenone-aniles,  all  coloured  more  or  less 
strongly  yellow  (cp.  auramin)  have  been  obtained  from  the  corre- 
sponding ketones  by  heating  with  aniline  in  the  presence  of  sulphuric 
acid  (B.  32,  1683). 

Benzo-phenonoxime  (C6H5)2C  :  N.OH,  melting  at  140°,  is  known  in 
only  one  modification  (for  the  possible  existence  of  an  unstable  form, 
consult  B.  28,  R.  1008),  while  unsymmetrical  benzo-phenones — e.g. 
bromo-benzo-phenone  and  phenyl-tolyl-ketone — each  form  two  oximes 
(B.  23,2776). 

Hexahydro-benzo-phenone  also  forms  two  oximes — a-,  m.p.  158° ; 
j3-,  m.p.  in0 — the  first  of  which,  on  transformation,  yields  benzoyl- 
amido-hexamethylene,  while  the  second  yields  hexahydro-benzanilide 
(B.  30,2862). 

Benzo-phenone-hydrazone  (C6H5)2C :  NNH2,  m.p.  98°,  and  bis- 
benzo-phenone-hydrazone,  diphenyl-ketazin  (C6H5)2C  :  N.N  :  C(C6H5)2, 
m.p.  162°  (/.  pr.  Ch.  2,  44,  194).  Benzo-phenone-semi-earbazone, 
m.p.  165°.  The  phenyl-hydrazone  (C6H5)2C  :  N2H.C6H5  melts  at  137° 
(B.  19,  R.  302). 

Benzo-phenone  Halogen  Derivatives  are  mostly  produced  by  method 
5  (p-  5^7)-  o-Bromo-benzo-phenone,  melting  at  42°,  is  noteworthy 
because  of  the  mobility  of  its  bromine  atom.  If  o-bromo-benzo- 
phenone-oxime,  melting  at  132°,  be  acted  upon  with  caustic  alkali  it 

splits  off  hydrogen  bromide  and  becomes  phenyl-indoxazene  C6H4< 


570  ORGANIC   CHEMISTRY 

(B.  27, 1452),  while  m-  and  p-bromo-benzo-phenone,  on  the  other  hand, 
yield  with  o-bromo-benzo-phenone  two  isomeric  oximes  (B.  25,  3292  ; 
A.  264,  152,  171). 

The  sym.  m-,  p-dibromo-benzo-phenones  (BrC6H4)2CO,  melting  at 
142°  and  171°,  yield  but  one  oxime  (A.  264, 160).  o-,  p-Dibromo-benzo- 
phenone,  melting  at  52°,  yields  one  oxime,  melting  at  141°  ;  this  can  be 
readily  rearranged  to  p-bromo-phenyl-indoxazene  (B.  27, 1453). 

o-Chloro-benzo-phenone-oxime  shows  less  readily,  and  o-iodo-benzo- 
phenone-oxime  more  readily,  than  o-bromo-benzo-phenone-oxime  the 
formation  of  phenyl-indoxazene  (B.  26,  1250). 

Benzo-phenone  hexachloride  C6H5COC6H5C16,  m.p.  215°,  from  benzo- 
phenone  and  chlorine  in  chloroform,  on  heating  gives  triehloro-benzo- 
phenone  C6H5COC6H2C13,  m.p.  131°  (C.  1898,  I.  1178). 

Nitro-benzo-phenones. — o-,  m-,  and  p-Nitro-benzo-phenone  melt  at 
195°,  94°,  and  138°  (B.  16,  2717  ;  18,  2401  ;  /.  pr.  Ch.  2,  65,  308). 
Phenyl-indoxazene  is  produced  when  the  oxime  of  the  o-body  is  boiled 
with  caustic  soda  (B.  26,  1250).  On  heating  at  ordinary  pressures  it 
forms  acridone,  probably  by  way  of  phenyl-anthranile  (B.  42,  591). 

02-,  m2-,  p2-Dinitro-benzo-phenone  melt  at  188°,  148°,  and  189°. 
o,  n-,  o,  p-,  and  m,  p-Dinitro-benzo-phenone  (NO2C6H4)2CO  melt  at 
126°,  196°,  and  172°.  02-  and  o,  n-Dinitro-benzo-phenones  are  formed 
in  the  nitration  of  benzo-phenone  (A.  283,  164  ;  B.  27,  2111).  02,  p2- 
Tetranitro-benzo-phenone  melts  at  225°  (B.  27,  2318).  Other  sub- 
stituted benzo-phenones  are  described  in  the  A.  286,  306,  etc. 

c-Phenyl-anthranile    C6H4{^.(C6H5^O,    feebly   yellow    crystals    of 

m.p.  53°,  may  be  regarded  as  an  inner  anhydride  of  o-hydroxylamino- 
benzo-phenone.  Following  anthranile  and  c-methyl-anthr anile,  it 
is  obtained  by  reduction  of  o-nitro-aceto-phenone  with  tin  and 
glacial  acetic  acid,  or  by  oxidation  of  o-amido-aceto-phenone  with 
Caro's  acid  (B.  42,  1723),  and,  in  small  quantities,  by  the  condensation 
of  o-nitro-benzaldehyde  and  benzene,  by  means  of  concentrated  H2SO4 
(B.  41, 1845).  On  heating  at  ordinary  pressure  it  transposes  into  the 
isomeric  acridone  (B.  42,  592).  The  same  transformation  is  also 
produced  by  the  simultaneous  action  of  sulphuric  and  nitrous  acids, 
probably  by  way  of  nitroso-o-hydroxylamino-benzo-phenone  (B.  42, 
1716).  Cp.  the  analogous  breaking  up  of  anthranile,  and  the  trans- 
position of  c-methyl-anthranile  into  indoxyl.  Derivatives  of  phenyl- 
anthranile  are  probably  represented  by  a  series  of  compounds  obtained 
by  the  condensation  of  o-nitro-benzaldehyde  with  tertiary  anilines  and 
phenols,  by  means  of  concentrated  HC1  (B.  42,  1714). 

Amido-benzo-phenones  are  obtained  from  nitro-benzo-phenones, 
from  benzoic  acid,  dimethyl-aniline  and  P2O5,  benzoyl  chloride, 
phthalanile  and  ZnCl2  (B.  14,  1838),  etc.  o-,  m-,  p-Amido-benzo- 
phenone  melt  at  106°,  87°,  and  124°.  o-Amido-benzo-phenone  is  made 
from  toluol-sulphon-anthranilic  acid  chloride,  with  benzene  and  A1C13, 
and  saponification  of  the  resulting  toluol-sulphon-amido-benzo-phenone 
(B.  35,  4273  ;  39,  4332).  Or  from  the  amide  of  o-benzoyl-benzoic  acid 
by  means  of  sodium  hypo-bromite  (B.  27,  3483  ;  A.  291,  8).  A  mixture 
of  o-  and  p-amino-benzo-phenone  in  the  form  of  their  benzoyl  deriva- 
tives C6H5CONHC6H4COC6H5  is  obtained  by  intramolecular  atomic 
migration  from  the  intermediate  dibenzoyl-aniline  (C6H5CO)2NC6H5  on 


BENZYL-BENZOL   GROUP  571 

heating  aniline  with  two  molecules  benzoyl  chloride  to  220°  (C.  1903,  1. 
924  ;  1904,  I.  1404). 

o-Amido-benzo-phenone-oxime,  m.p.  156°,  is  rearranged  at  high 
temperatures  by  hydrochloric  acid  into  o-phenylene-benzamidin  (B.  24, 
2385).  Acetyl-o-amido-benzo-phenone,  m.p.  89°.  p-Dimethyl-amido- 
benzo-phenone,  p-benzoyl-dimethyl-aniline,  m.p.  90°,  is  also  formed 
on  heating  malachite  green  with  concentrated  hydrochloric  acid  at  180° 
(A.  217,  257  ;  B.  21,  3293  ;  A.  307,  307),  and  by  heating  dimethyl- 
aniline-phthaloylic'  acid.  On  further  derivatives  of  p-amido-benzo- 
phenone,  see  A.  311,  147. 

Ring-formations  of  o-Amido-benzo-phenone.  —  (i)  Acridone  is  pro- 
duced when  o-amido-benzo-phenone  is  heated  with  lead  oxide  (B.  27, 
3484).  (2)  Nitrous  acid  converts  this  o-body  into  fluorenone  or 
diphenylene-ketone  (B.  27,  3484).  (3)  Phenyl-indoxazene  is  readily 
obtained  from  o-amido-benzo-phenone-oxime  and  nitrous  acid  (B.  26, 
1667).  (4)  When  acetyl-o-amido-benzo-phenone  is  heated  with  alco- 
holic ammonia  it  condenses  to  a-phenyl-jS-methyl-quinazolin  (B.  25, 
3082).  (5)  Acetyl-phenyl-isindazol  (B.  24,  2383  ;  29,  1255)  results 
when  acetyl-o-amido-benzo-phenone-oxime  is  acted  upon  by  acetic 
anhydride.  (6)  o-Amido-benzo-phenone  condenses  with  acetone  and 
sodium  hydroxide  to  a-methyl-y-phenyl-quinolin  (B.  18,  2405). 
(7)  When  the  chlorohydrate  of  o-amido-benzo-phenone  is  heated  water 
is  eliminated,  and  there  results  an  anhydro-bis-o-amido-benzo-phenone, 
which  probably  contains  an  "  8-membered  "  ring  (B.  29,  1272)  : 


Acridone 
CaH4. 

NH2[2]C6H4\  NO.OH      C6H4\.  Fluorenone  or  di- 

C6H5/         -N,-2H^  C.H.A  phenylene-ketone 


3.     C.H4N.OH  -->  C6H«5N  Phenyl-indoxazene 

' 


X-IJ.A2 

/CO.C6H5             NH3                 /C(C6H5)  :  N  a-Phenyl-0-methyl- 

*\NH.CO.CH3                       6    4\N              .CCH5  quinazolin 

C8H4CHNCO.CH3  '  CeH4<™H3) 

r  „  /CO.C6H5        CH.CO.CH.            /C(C6H5)  :  CH  a-Methyl-y-phenyl- 

4\NH2                                     6    4\N==C.CH3  quinolin 


^r  „  /COC6H5  -^HtO  /C(C6H5)  :  N\_      '  Anhydro-bis-o-amido- 

C(!H4\.NH2  C6H4\N  :  C(C6H5) /C6H4     benzo-phenone. 

Diamido-benzo-phenones. — 02-,  m2-,  p.2-Diamido-benzo-phenones 
melt  at  134°,  173°,  and  239°  respectively.  Nitrous  acid  converts 
the  o-body  into  xanthone  (q.v.)  and  o-oxy-fluorenone  (B.  28,  in). 
p.2-Diamido-benzo-phenone  yields  substantive  cotton  dyes  (B.  22,  988). 

Tetramethyl-p2-diamido-benzo-phenone,  Miehler's  ketone 

<C  TT    ^CYPTT  ^ 
r-6Tj4  ^  ^n3N  »  results  upon  heating  hexamethvl  violet  \vith  hydro- 
C6H4.JN(CH3)2 

chloric  acid  (B.  19,  109).  It  is  technically  prepared  by  the  action  of 
COC12  upon  dimethyl-aniline  in  the  presence  of  A1C13.  It  melts  at  173°. 
Nitrous  acid  converts  it  into  nitroso-trimethyl-diamido-benzo-phenone 


572  ORGANIC   CHEMISTRY 

(B.  24,  3198).  Dimethyl-aniline  and  PC13  convert  it  into  methyl  violet, 
while  it  yields  Victoria  blue  with  phenyl-naphthylamine.  Its  oxime 
melts  at  233°  (B.  19,  1852).  Its  hydrazone  melts  at  174°  (B.  35,  366). 
With  two  molecules  dimethyl  sulphate  the  ketone  combines  to  form  a 
bis-quaternary  ammonium  salt  (/.  pr.  Ch.  2,  66,  393). 

Tetramethyl  -  p2  -  diamido-thio-benzo-phenone  CS[C6H4.N  (CH3)  2]  2, 
results  from  the  action  of  hydrogen  sulphide  upon  an  alcoholic  auramin 
solution  heated  to  60°,  or  it  can  be  prepared  from  dimethyl-aniline  and 
CSC12.  It  consists  of  ruby-red  crystalline  flakes  with  a  blue  lustre  or 
a  cantharides-green  crystalline  powder,  melting  at  202°  (B.  20,  3266, 
3290 ;  C.  1898,  1. 1029) ;  on  heating  with  alcoholic  NH3  under  pressure 
it  forms  auramin  base  quantitatively. 

Tetramethyl-p2-diamido-benzo-phenone  imide,  auramin  base 
[(CH3)2NC6H4]2C  :  NH,  m.p.  136°,  combines  with  dimethy]  sulphate 
to  form  the  methyl  sulphate  of  methyl-auramin  (/.  pr.  Ch.  2,  66,  387). 
The  dyestuff  auramin  is  the  chlorohydrate  of  the  auramin  base 
[(CH3)2NC6H4)2C  :  NH2C1,  or  of  a  quinoid  pseudo-form  of  it 
NH^r^CeHj :  N(CH3)2C1  /»  oo-i  ~0.\ 
^\C6H4N(CH3)2  (A.  381,234). 

Auramin  results  when  tetramethyl-diamido-benzo-phenone  is  heated 
with  ammonium  chloride  and  zinc  chloride,  as  well  as  from  p-dimethyl- 
amido-benzamide  by  the  action  of  dimethyl-aniline  and  zinc  chloride 
(B.  28,  R.  86).  Perfectly  analogous  dyestuffs  are  obtained  from  the 
primary  anilines  and  diamines  (B.  20,  2844  ;  28,  R.  65).  Auramin, 
golden-yellow  flakes,  is  important  as  a  cotton  dye.  Cotton  mordanted 
with  tannin  is  coloured  a  beautiful  yellow  by  this  salt. 

Potassium  cyanide  changes  it  to  the  nitrile  of  the  corresponding 
tetramethyl-diamido-diphenyl-acetic  acid  (B.  27,  3294). 

o,  m-,  o,  p-,  m,  p-Diamido-benzo-phenones  melt  at  80°,  128°,  and 
126°  respectively  (A.  283, 149  ;  B.  28,  in). 

Benzo-phenone-o-sulphonic  acid  C6H5COC6H4[2]SO3H  from  sulpho- 
benzoic  anhydride  with  benzene  and  A1C13  (B.  33,  3486). 

Benzo-phenone-3,  3  (P)-disulphonic  acid  (SO3HC6H4)  2CO  ;  chloride, 
m.p.  138°  (C.  1898,  II.  347). 

Oxy-benzo-phenones  are  formed  :  (i)  From  amido-benzo-phenones  ; 
in  this  change  the  o-amido-benzo-phenones  pass  chiefly  into  fluorenones. 
(2)  By  decomposing  the  xanthones,  which  may  be  viewed  as  cyclic 
phenyl  ethers  of  o2-dioxy-benzo-phenones,  with  caustic  potash.  (3)  By 
the  condensation  of  benzoic  acids  or  oxy-benzoic  acids  and  phenols 
with  zinc  chloride  or  phosphorus  oxy-chlofide  (B.  26,  R.  587),  sulphuric 
acid,  or  tin  tetrachloride  (B.  23,  R.  43, 188  ;  24, 967) .  (4)  From  phenols 
by  means  of  benzoyl  chloride,  zinc  dust,  or  zinc  chloride,  or  aluminium 
chloride  (B.  12,  261).  (5)  By  the  action  of  benzo-trichloride  and  zinc 
oxide  (B.  10,  1969)  upon  phenols  or  their  benzoyl  esters.  (6)  By  the 
action  of  alkalies  upon  benzo-trichloride  and  phenols  (B.  24,  3677). 
(7)  From  the  phenol-carboxylic  chlorides  or  their  methyl-acetyl-  or 
carbo-methoxy  derivatives  by  condensation  with  benzene  and  A1C13 
(A.  346,  381  ;  B.  42, 1015). 

Oxy-benzo-phenones  containing  but  one  Hydroxyl  Group  in  the  Benzene 
Nucleus. — o-Oxy-benzo-phenone,  o-benzoyl-phenol,  melting  at  41°,  is 
produced,  together  with  the  phenyl  ester  of  benzoic  acid,  by  the  6th 
method  of  formation  ;  also  from  phenyl-indoxazene  upon  heating  it 


BENZYL-BENZOL   GROUP  573 

with  hydriodic  acid  and  phosphorus  (B.  29,  R.  350).  The  best  method, 
however,  consists  in  treating  methyl-salicylic  chloride  with  benzene 
and  aluminium  chloride  (B.  35,  2811).  o-Methoxy-benzo-phenone, 
m.p.  39°,  see  B.  41,  332.  o-Oxy-benzo-phenone  anile,  m.p.  138°. 

m-Oxy-benzo-phenone,  melting  at  116°,  is  produced  according  to 
methods  i,  4,  5,  and  7  (B.  25,  3533).  m-  and  p-Methoxy-benzo-phen- 
one,  m.p.  37°  and  61°  respectively,  b.p.  343°  and  355°,  from  m-  and  p- 
methoxy-benzoyl  chloride  with  benzene  and  A1C13  (B.  35,  2813). 

o2-,  m2-,  p2-Dioxy-benzo-phenones  melt  at  173°,  162°,  and  210°,  and 
o,  m-,  o,  p-Dioxy-benzo-phenones  melt  at  126°  and  142°.  They  are 
obtained  from  the  corresponding  diamido-benzo-phenones. 

o2-Dioxy-benzo-phenone  is  also  made  from  its  anhydride,  xanthone 
or  diphenylene  ketone  oxide,  by  careful  fusion  with  potassium  hydrate 
(B.  19,  2609).  o,  p-,  and  p2-Dioxy-benzo-phenones  are  also  produced  in 
the  condensation  of  salicylic  acid  and  phenol  with  tin  tetrachloride  (A. 
354,  177).  p2-Dioxy-benzo-phenone  appears  also  in  the  decomposi- 
tion of  aurin,  benzaurin,  phenol-phthalein,  and  rosanilin  upon  heat- 
ing them  with  water  or  caustic  potash  (B.  16,  1931).  m,  p-Dioxy- 
benzo-phenone,  m.p.  206°,  from  the  diamido-compound. 

Oxy-benzo-phenones  containing  more  than  one  Hydroxyl  attached  to 
the  Benzene  Nucleus.  —  These  are  prepared  mainly  by  method  3.  Men- 
tion must  be  made  of  the  ketones  obtained  from  pyrogallic  acid  and 
gallic  acid,  for  they,  like  alizarine,  are  dyes. 

The  dyestuff  prepared  from  benzoic  acid  and  pyrogallol  melts  at 
140°.  It  bears  the  name  alizarin  yellow  A  in  trade  (A.  269,  295  ;  B. 
32,  1686).  Isomeric  with  the  latter  is  the  3,  4,  5-trioxy-benzo-phenone, 
m.p.  176°,  obtained  from  tricarbo-methoxy-galloyl  chloride,  benzene, 
and  A1C13  (B.  42,  1015). 

2,  5-Dioxy-benzo-pheaone  C6H5COC6H3[2,  5](OH)2,  melting  at  125°, 
is  obtained  from  benzaldehyde  and  quinone,  exposed  to  sunlight  (B. 
24,  1340;  41,  143). 

02  p2-Tetraoxy-benzo-phenone  [(OH)2C6H3]2CO  is  obtained  on  melt- 
ing up  fluorescei'n  chloride  with  soda.  On  heating  it  passes  into  dioxy- 
xanthane  (B.  32,  2103).  2,  5,  2',  5'-Tetramethoxy-benzo-phenone, 
m.p.  109°,  from  iodo-hydroquinone-dimethyl  ether,  Mg,  and  CO2  (B. 


The  barks  of  coto  and  paracoto,  found  in  Bolivia,  and  possessing 
therapeutic  value,  contain  a  series  of  benzo-phenone  derivatives. 
They  are  : 

Cotoin  C6H5.CO.C6H2(OH)2(OCH3),  m.p.  130°. 

Hydroeotoin  C6H5.CO.C6H2(OH)(OCH3)2,  m.p.  98°. 

Methyl-hydrocotoin  C6H5.CO.C6H3(OCH3)3,  melting  at  113°  (B.  25, 
1119  ;  26,  2340  ;  27,  419),  which  are  methyl  ethers  of  benzoyl  phloro- 
glucin;  and  protocotoin  (CH3O)2(HO).C6H2.CO.C6H3(O2CH2),  m.p. 
141°,  as  well  as  methyl-protocotoin  (CH3O)3.C6H2.CO.C6H3(O2CH2),  m.p. 
134°,  derivatives  of  i,  3,  5-trioxy-benzo-proto-catechone.  During  the 
oxidation  of  protocotoin  with  permanganate,  we  obtain  aceto-piperone 
(B.  34,  1468  ;  see  alsoC.  1907,  I.  817).  Most  closely  related  with  these 
compounds  is,  according  to  recent  investigations  (B.  39,  4014),  the 
previously  mentioned  maelurin  (OH)2[3,  4]C6H3.CO.C6H2[2,  4,  6] 
(OH)3,  which,  on  heating  with  concentrated  KOH,  decomposes  into 
proto-catechuic  acid  and  phloro-glucin.  The  pentamethyl  ether, 


574  ORGANIC  CHEMISTRY 

formed  by  methylation  with  dimethyl  sulphate,  and  melting  at  157°, 
has  been  obtained  synthetically  from  veratroyl  chloride,  phloro-glucin- 
trimethyl  ether,  and  A1C13  (B.  39,  4022). 

4.  CARBOXYLIC  ACIDS  OF  THE  DIPHENYL-METHANE  GROUP. 

There  are  three  classes  of  these  acids  :  A.  Diphenyl-methane  Car- 
boxylic  Acids  ;  B.  Benzo-hydrol  Carboxylic  Acids  ;  C.  Benzo-phenone 
Carboxylic  Acids. 

A.  Diphenyl-methane  Carboxylic  Acids.  —  o-,  m-,  p-Benzyl-benzoie 
acids  CeH5.CH2.C6H4.CO2H  melt  at  117°,  107°,  and  154°.  When  the 
o-acid  is  digested  with  sulphuric  acid,  anthranol  (q.v.)  is  produced  (B. 
25,3022;  27,2789;  A.  291,  17;  B.  9,633). 

o-Cyano-diphenyl-methane,  m.p.  19°  and  b.p.  313°,  is  obtained  from 
o-cyano-benzyl  chloride  by  means  of  benzene  and  aluminium  chloride 
as  well  as  from  o-amido-diphenyl-methane. 

Benzyl-iso-  and  terephthalie  acid  C6H5.CH2.C6H3(C02H),  see  B.  9, 


Diphenyl-methane-o2-dicarboxylic  acid  CH2(C6H4[2]CO2H)2,  m.p. 
254°,  results  from  the  reduction  of  the  lactone  of  benzo-hydrol-o2-di- 
car  boxy  lie  acid,  and  that  of  the  dilactone  of  benzo-phenone-o2-dicar- 
boxylic  acid.  Concentrated  sulphuric  acid  changes  it  to  anthranol- 
carboxylic  acid  (A.  242,  253). 

Diphenyl-methane-m2-diearboxylie  acid  melts  at  220°-225°.  Di- 
phenyl-methane-p-dicarboxylic  acid  melts  at  290°  (B.  27,  2324).  Di- 
phenyl-methane-o,  p-diearboxylie  acid,  m.p.  220°  (A.  309,  115). 

B.  Benzo-hydrol-carboxylic    Acids.  —  o-Benzo-hydryl-benzoic    acid 

,  I-      -1/-»TT  _  /->     TT 

lactone,  phenyl  phthalide  caH4j       X.         5  ,    m.p.    115°,    is    formed 

I  [21090 

by  the  reduction  of  o-benzoyl-benzoic  acid,  and  by  the  breaking  down 
of  benzo-hydrol-o2-carboxylic  acid  on  the  application  of  heat.  The 
acid  corresponding  to  the  lactone  is  not  capable  of  existing  as  such  ; 
its  salts,  however,  are  known.  PC15  converts  the  lactone  into  anthra- 
quinone  (B.  21,  2005). 

o-Cyano-benzo-hydrol  C6H5(CHOH)C6H4[2]CN  has  been  prepared 
from  o-cyano-diphenyl-chloro-methane  C6H5CHC1.C6H4CN,  the  reaction 
product  from  chlorine  and  cyano-diphenyl-methane  (B.  29,  1315). 
m-  and  p-Benzo-hydryl-benzoic  acid  melt  at  121°  and  at  164°  (A.  220, 
242).  p-Tolyl-phthalide  melts  at  129°  ;  for  its  homologues,  see  A.  234, 

(CH.C6H4.OH 
237.     Oxy-phenyl-phthalide  C6H4^  \  ,  m.p.  180°,  is  obtained 

I  COO 
from  phthal-aldehydic  acid,  phenol,  and  sulphuric  acid  (73  per  cent.) 

(B.  27,2632  ;    31,  2790). 

(  CH—  C6H4C02H 

Benzo-hydrol-o2-lactone-carboxylic  acid  C6H4{  \  ,  m.p. 

I  coo 

202°,  is  produced  on  heating  benzo-hydrol-tricarboxylic  acid 
monolactone  (HOOCC6H4)2C(OH),  the  reaction  product  of  alkalies 
upon  diphthalic  acid  (A.  242,  233). 

C.  Benzo-phenone-carboxylic  acids  are  formed  (i)  in  the  oxidation 
of     the     alkyl-diphenyl-methanes,     alkyl-benzo-phenones,     diphenyl- 
methane-carboxylic  acids,  and  benzo-hydrol-carboxylic  acids  ;   (2)  from 


BENZYL-BENZOL  GROUP  575 

benzoyl  chloride  and  benzole  anhydride  with  zinc  chloride  (B.  14,  647)  ; 
(3)  from  phthalic  anhydride  and  benzene  with  aluminium  chloride. 

o-Benzoyl-benzoie  acid  C6H5.CO.C6H4[2]CO2H+H2O  melts,  when 
anhydrous,  at  127°.  It  is  produced  by  oxidising  o-tolyl-phenyl-methane, 
o-methyl-benzo-phenone,  o-benzyl-  and  o-benzo-hydryl-benzoic  acid. 
It  can  be  prepared  by  method  3.  Heated  with  phosphorus  pentoxide, 
water  is  eliminated  and  anthraquinone  is  produced.  Anthracene  is 
produced  when  it  is  heated  with  zinc  dust.  With  benzene  and  alu- 
minium chloride  ortho-benzoyl-benzoic  acid  yields  phthalo-phenone  ; 
with  phenol  and  stannic  chloride,  oxy-phthalo-phenone.  When  di- 
gested with  acetic  anhydride  (B.  14,  1865)  it  changes  to  : 


Aceto-benzoyl-benzoie  acid  C6H4{W£\^'cacH3,  melting  at  117° 

(compare  aceto-laevulinic  acid).  The  oxime  anhydride  melts  at  162°. 
It  is  formed  when  hydroxylamine  hydrochloride  acts  upon  benzoyl- 
benzoic  acid.  At  130°  it  yields  phthalanil  (B.  26,  1262,  1795).  Phenyl- 

(  [i]C(C6H5)  :  N 
lactazame  C6H4^  ,  melting  at  181°  (compare  laevulinic 

l[2]CO  -  N.C6H5 
acid)  (B.  18,  805). 

Chlorinated  benzoyl-benzoic  acids  have  been  prepared  from  chlorin- 
ated phthalic  anhydrides  by  the  action  of  benzene  and  aluminium 
chloride  (A.  238,  338),  and  homologous  methyl-benzoyl-benzoic  acids 
from  phthalic  anhydride  and  toluol  or  other  methyl  benzols  (B.  19, 
R.  686  ;  A.  311,  178).  Phthalic  anhydride  and  dimethyl-aniHne  give 
dimethyl-aniline-phthaloylic  acid  C6H4(COOH)COC6H4N(CH3)2,  m.p. 
205°  (A.  307,  305).  For  transformation  and  substitution  products  of 
this  acid,  see  C.  1901,  1.  631,  944,  etc. 

m-Benzoyl-benzoic  acid  C6H5.CO.C6H4[3]CO2H,  melting  at  161°, 
is  made  from  iso-phthalic  chloride,  benzene,  and  aluminium  chloride 
(A.  220,  236  ;  B.  13,  320).  p-Benzoyl-benzoie  acid,  melting  at  194°,  is 
prepared  according  to  method  I  (B.  9,  92). 

Benzo-phenone-o2-diearboxylic  acid  CO(C6H4[2]CO2H)2  melts  ir- 
regularly at  I5o°-200°  with  the  elimination  of  water  and  a  change  to 
the  dilactone.  It  is  produced  by  oxidising  benzo-hydrol-o2-lactone-car- 
boxylic  acid  with  potassium  permanganate.  Benzo-phenone-dicarboxylic 
COO.  ,OCO 


dilactone    \       ^c\    I      >  melting  at  212°,  is  produced  on  boiling  the 

C6H4          s    C6H4 

aqueous  solution  of  the  acid,  as  well  as  by  digesting  its  alcoholic  solution 
with  hydrochloric  acid  (A.  242,  246). 

0,  p-  and  p2-Benzo-phenone-diearboxylic  acid,  m.p.  235°  and  above 
360°   respectively    (A.   309,   98  ;     311,   96).     Phthaloyl-salicylic   acid 
COOHC6H4COC6H3(OH)COOH,  m.p.  244°,  from  salicylic  methyl  ester, 
phthalyl  chloride,  and  A1C13  (A.  303,  280). 

Benzoyl-phthalic  acid  C6H5CO.C6H3[2,  3](COOH)2,  from  hemi- 
mellitic  anhydride,  benzene,  and  A12C16,  melts  at  183°  with  the  formation 
of  an  anhydride  (A.  290,  217).  Concentrated  sulphuric  acid  converts 
it  into  anthraquinone-carboxylic  acid. 

1,  3,  4-Benzoyl-phthalie  acid,  m.p.  189°,  is  obtained  by  the  oxidation 
of  o-xyloyl-benzoic  acid  (A.  312,  99). 

Benzyl-diphenyls  C6H5.CH2.C6H4.C6H5  are  formed  from  diphenyl, 


576  ORGANIC  CHEMISTRY 

benzyl  chloride,  and  zinc  dust.  p-Benzyl-diphenyl  melts  at  85°  and 
boils  at  285°  (100  mm.).  Iso-benzyl-diphenyl  melts  at  54°  and  boils  at 
283°-287°  (no  mm.)  (B.  14,  2242). 

p-Phenyl-benzyl-o-benzoie  acid  C6H5[4]C6H4[i]CH2[2]C6H4[i]CO2H 
melts  at  184°,  and  p-phenyl-benzo-hydryl-o-benzoie  acid  C6H5[4]C6H4 
[i]CH(OH).C6H4[2]CO2H  melts  at  204°.  Both  are  produced  in  the 
reduction  of  p-phenyl-benzoyl-o-benzoic  acid  C6H5[4]C6H4[i]CO[2] 
C6H4[i]C02H,  melting  at  225°,  which  results  from  the  action  of 
aluminium  chloride  upon  a  ligroi'n  solution  of  diphenyl  and  phthalic 
anhydride  (A.  257,  96  ;  /.  pr.  Ch.  2,  41,  149). 

Dibenzyl-benzenes. — The  second  benzyl  nucleus  can  be  introduced 
into  benzene  and  its  homologues,  containing  replaceable  hydrogen  atoms 
attached  to  the  nucleus,  by  the  same  reactions  which  were  employed  in 
introducing  the  first  benzyl  nucleus — i.e.  by  the  action  of  zinc  dust 
(B.  9,  31)  or  aluminium  chloride  upon  a  solution  of  the  benzyl  chloride 
in  the  hydrocarbons,  and  by  the  action  of  sulphuric  acid  upon  benzene 
and  methylal  (B.  6, 221 ;  37,  1467).  a-  and  /MMbenzyl-benzol  melt  at 
86°  and  78°. 

Bis-amido-benzyl-resorein  (NH2C6H4.CH2)2C6H2(OH)2,  m.p.  213°, 
is  formed  as  a  by-product  of  the  condensation  of  p-amido-benzyl 
alcohol  with  resorcin  by  hot  dilute  sulphuric  acid  (C.  1903,  I.  288). 

p2-Dibenzo-hydryl-benzol  C6H4(CHOHC6H5)2,  m.p.  120°,  from 
o2-dibenzoyl-benzol  by  reduction  with  sodium  amalgam.  By  the 
action  of  mineral  acids  it  easily  passes  into  sym.  diphenyl-phtlialane 

(CH;-C6H5 

C6H4-^       ^>O     ,  m.p.  96°,  with  expulsion  of  H20.     This  is  also  obtained 

I  CH<— C6H5 

synthetically  from  the  result  of  the  action  of  C6H5MgBr  upon  phenol 
phthalide  by  rejection  of  water  and  reduction  (C.  1905,  II.  137). 

/CO  P  TT 

o2-,  m2-,  and  p2-Dibenzoyl-benzols  c6H/XVr55»  phthalo-phenones, 

xL/vJ.L^girlg 

phenylene-diphenyl  ketones,  m.p.  146°,  100°,  and  160°  respectively. 
The  ortho-  and  para-derivatives  are  produced  by  the  oxidation  of  the 
corresponding  dibenzyl-benzenes  (B.  9,  31). 

The  meta-  and  ^w0-compounds  may  be  obtained  from  meta-  and 
para-phthalyl  chlorides  with  benzene  and  A1C13  (B.  13,  320),  whereas 
the  so-called  ortho-phthalyl  chloride  yields  diphenyl-phthalide. 

l-Amido-2,  4-dibenzoyl-benzol  C6H3[i]NH2[2,  4](COC6H5)2,  m.p. 
138°,  is  obtained  in  the  form  of  its  benzoyl  compound,  m.p.  156°,  by 
heating  one  molecule  aniline  with  three  molecules  benzoyl  chloride  by 
intramolecular  atomic  displacement  by  way  of  dibenzoyl  amido- 
benzo-phenone  (C.  1905,  I.  444). 

Dibenzoyl-mesitylene  (CH3)3[i,  3,  5]C6H(COC6H5)2,  m.p.  117°,  from 
mesitylene,  two  molecules  benzoyl  chloride,  and  A1C13,  gives  on  oxida- 
tion sym.  and  unsym.  dibenzoyl-mesitylenic  acid  (C6H5CO)2C6H(CH3)2 
COOH,  m.p.  222°  and  174°,  sym.  and  unsym.  dibenzoyl-uvitinic  acid 
(C6H5CO)2C6H(CH3)(COOH)2,  m.p.  262°  and  211°,  and  finally  dibenzoyl- 
trimesinic  acid  (C6H5CO)2C6H(COOH)3,  m.p.  250°  (C.  1902,  II.  1181). 

III.  TRIPHENYL-METHANE  GROUP. 

Triphenyl-methane,  tolyl-diphenyl-methane,  and  ditolyl-phenyl- 
methane  are  the  parent  hydrocarbons  from  which  originate  the  ros- 


TRIPHENYL-METHANE  GROUP  577 

anilin  dyes,  the  malachite  greens,  the  aurins,  and  phthale'ins,  from 
which  they  can  be  obtained  by  various  transposition  and  decomposition 
reactions.  However,  in  no  one  of  these  instances  do  they  constitute 
the  foundation  material  for  the  technical  preparation  of  the  above- 
mentioned  dyes. 

i.  Hydrocarbons. — The  methods  of  forming  the  triphenyl-methane 
hydrocarbons  are  evident  if  one  simply  makes  more  general  those 
methods  which  are  employed  in  the  preparation  of  triphenyl-methane. 

Triphenyl-methane  CH(C6H5)3,  m.p.  92°  and  b.p.  358°.  It  is 
produced  : 

(1)  By  the  action  of  benzal  chloride  upon  mercury  diphenyl  (1872, 
Kekule  and  Franchimont,  B.  5,  907). 

(2)  From  benzal  chloride  or  benzo-trichloride  and  benzene  (a)  by 
the  action  of  zinc  dust,  (b)  with  aluminium  chloride  (B.  12,  976,  1468 ; 
14,  1526). 

(3)  From  chloroform  or  carbon  tetrachloride  and  benzene,  aided  by 
A1C13  (A.  194,  254  ;  227,  107  ;  B.  18,  R.  327). 

(4)  From  chloroform  or  benzal  chloride  and  phenyl-magnesium 
bromide  (C.  1906,  II.  1262). 

(5)  By  the  action  of  P2O5  at  140°  (B.  7, 1204)  upon  benzo-hydrol  and 
benzene. 

(6)  From  triphenyl-carbinol  or  its  bromide  by  reduction  (B.  37, 
616,  1249  ;  44,  441). 

(7)  By  the  action  of  nitrous  acid  and  alcohol  upon  di-  and  tri- 
amido-triphenyl-methane  sulphate  (A.  206,  152). 

The  latter  reaction  is  of  the  greatest  fundamental  importance  in 
demonstrating  the  connection  between  p-rosanilin  and  triphenyl- 
methane. 

Triphenyl-methane  crystallised  from  benzene  contains  benzene  of 
crystallisation  CH(C6H5)3+C6H6,  m.p.  75°;  and  from  thiophene, 
pyrrol,  and  aniline  it  separates  with  thiophene  (pyrrol,  or  aniline)  of 
crystallisation  CH(C6H5)3+C4H4S  (B.  26,  853).  It  is  oxidised  to 
triphenyl-carbinol,  and  is  reduced  with  hydrogen  and  finely  divided 
nickelat22O0totricyclo-hexyl-methane,b.p.20i4o°(C.i9O9,I.i73),andby 
hydriodic  acid,  and  some  red  phosphorus  at  280°,  to  benzene  and  toluol. 
When  heated  with  potassium,  it  yields  triphenyl-methane-potassium 
(C6H5)3CK,  which  combines  with  CO2  to  potassium-triphenyl  acetate. 

o-,  m-,  p  -  Methyl  -  triphenyl  -  methane,  diphenyl -o-,  m-,  p-tolyl- 
methane  (C6H5)3CH.C6H4.CH3,  melt  at  83°,  62°,  and  71°;  from  the 
carbinols  by  reduction.  The  m-compound  was  obtained  by  the  action 
of  nitrous  acid  and  alcohol  upon  leucaniline  sulphate  (A.  194,  282  ; 
cp.  B.  37,  1245).  The  p-tolyl-diphenyl-methane  is  easily  prepared 
from  benzo-hydrol  and  toluol,  with  tin  tetrachloride  (B.  37,  659). 

Diphenyl-o-,  m-,  p-xylyl-methanes  melt  at  68°,  61°,  and  92° ;  they 
have  been  obtained  from  benzo-hydrols  with  o-,  m-,  and  p-xylol  by 
means  of  P2O5  (B.  16,  2360). 

Nitro-substitution  Products.  —  m-  and  p-Nitro-diphenyl-methane 
NO2.C6H4.CH(C6H5)2,  m.p.  90°  and  93°,  are  obtained  from  m-  and  p- 
nitre-benzaldehyde,  benzene,  and  zinc  chloride  (B.  21,  188  ;  23,  1622). 

When  triphenyl-methane  is  dissolved  in  fuming  nitric  acid  (sp. 
gr.  1-5)  it  forms  p-trinitro-phenyl-methane  CH(CeH4[4]NO2)3,  which 
melts  at  206°.  Sodium  alcoholate  converts  the  nitro-compound  into 
VOL.  II,  2  P 


578  ORGANIC  CHEMISTRY 

a  deep  violet-coloured  sodium  salt.  It  dissolves  in  alcoholic  potassium 
hydroxide  with  a  violet  colour  (B.  21,  2476).  On  further  nitration 
with  nitro-sulphuric  acid  we  obtain  O3p3-hexanitro-triphenyl-methane 
CH[C6H4(NO2)2]3,  m.p.  260°  with  decomposition,  which,  on  reduction 
with  alcoholic  Am  sulphide,  yields  trinitro-triamido-triphenyl-methane 
(B.  36,  2779). 

p-Trinitro-diphenyl-m-tolyl-methane  (NO2[4]C6H4)  2CH.C6H3[4]NO2 
[3]CH3. 

Amido-derivatives  are  produced  (i)  by  the  reduction  of  the 
corresponding  nitro-bodies  ;  (2)  by  reduction  of  the  corresponding 
amido-carbinols,  the  colour-bases  of  the  malachite  green  and  rosanilin 
groups,  as  the  leuco-derivatives  of  which  they  are  frequently  designated  ; 

(3)  by  the  condensation  of  benzo-hydrol  or  benzaldehyde  and  aniline 
hydrochloride,  or  dimethyl-aniline  hydrochloride,  with  P2O5  or  ZnCl2. 

(4)  Mixed  diamido-triphenyl-methanes  are  also  obtained  as  follows  :  — 
Benzylidene-anilines  unite  with  anilines  to  form  amido-benzo-hydril- 
phenylamines  :  the  latter,  with  aromatic  amine  salts,  yield  diamido- 
triphenyl-methanes  (C.  1900,  II.  548)  : 


H  CH  •  NC  H        e»,  rH</C6H4NH2      C7H7NH,     C  H5CH/«** 

6H5Ci        *C8H6_         -_^  C6H6CH\NHC6H6    -     HCI  \C,H6NH2 


When  oxidised  with  chloranile,  or  PbO2  and  hydrochloric  acid,  etc., 
their  salts  change  to  those  of  the  colour-bases  to  which  malachite  green 
and  rosanilin  belong  ;  they  are  derived  from  triphenyl-carbinol. 

o-Amino-triphenyl  -  methane  (C?H5)2CHC6H4[2]HN2,  m.p.  129°, 
from  the  corresponding  amino-carbinol  by  reduction  with  zinc  dust 
and  glacial  acetic  acid  (B.  37,  3198). 

m-Amino-triphenyl-methane  (C6H5)2CHC6H4[3]NH2,  melting  at 
120°,  is  obtained  from  m-nitro-triphenyl-methane  (B.  21,  189). 

p-Amino-triphenyl-methane,  melting  at  84°,  is  formed  (i)  from 
p-nitro-triphenyl-methane  (B.  23,  1623)  ;  (2)  from  benzo-hydrol,  aniline 
hydrochloride,  and  zinc  chloride  (A.  206,  155)  ;  (3)  from  phenyl-benzo- 
hydrylamine  by  heating  with  aniline  chlorohydrate  (B.  38,  1768). 

p-Dimethyl-amido-triphenyl  -  methane  (C6H5)2CH.C6H4[4]N(CH3)2, 
melting  at  132°,  is  formed  from  benzo-phenone  chloride  and  dimethyl- 
aniline,  as  well  as  from  benzo-hydrol  and  dimethyl-aniline  with  P2O5 
(A.  206,  113),  as  well  as  from  benzo-phenone,  dimethyl-aniline,  and 
zinc  chloride  (A.  242,  341).  p-Aeetamido-triphenyl-methane  melts  at 
176°  (B.  24,  728). 

p2-Diamido-triphenyl-methane  C6H5.CH(C6H4[4]NH2)2,  melting  at 
139°,  -|-  C6H6  at  106°,  the  parent  substance  of  malachite  green,  is 
obtained  (i)  from  benzal  chloride  and  aniline  with  zinc  dust  ;  (2)  from 
benzaldehyde  with  aniline  hydrochloride  on  heating  with  zinc  chloride 
to  120°  (B.  15,  676),  or  by  boiling  benzaldehyde  with  aniline  and 
hydrochloric  acid  (B.  18,  R.  334)  ;  (3)  by  reducing  diamino-triphenyl- 
carbinol  chloride  with  zinc  dust.  The  diacetyl  derivative,  m.p.  234°, 
s  sparingly  soluble. 

P2  -  Tetramethyl  -  diamino  -  triphenyl  -  methane  C6H5.CH[C6H4[4]N 
(CH3)2]2,  leuco-malachite  green,  is  dimorphous,  and  crystallises  in 
flakes,  melting  at  93°-94°,  or  in  needles,  which  melt  at  102°.  The  first 
modification  is  obtained  pure  by  crystallisation  from  alcohol,  the  second 
from  benzene.  It  is  obtained  by  methylating  p2-diamido-triphenyl- 


TRIPHENYL-METHANE  GROUP  579 

methane,  as  well  as  by  the  action  of  benzaldehyde  upon  dimethyl- 
aniline.  Technically,  it  is  made  by  the  condensation  of  benzaldehyde 
and  dimethyl-aniline  with  hydrochloric  or  sulphuric  acid  (formerly  zinc 
chloride  or  oxalic  acid).  By  oxidation  it  becomes  p2-tetramethyl- 
diamido-triphenyl-carbinol,  the  basis  of  malachite  green. 

By  heating  with  BrCN,  leuco-malachite  green  yields  dimethyl- 
dicyano-diamido-triphenyl-methane  [CH3N(CN)C6H4]  2CHC6H5,  m.p. 
163°,  which,  on  saponification  with  HC1,  yields  p2-dimethyl-diamino- 
triphenyl-methane  (CH3NH.C6H4)2CHC6H5,  m.p.  104°  (B.  37,  637). 

o-  and  m-Nitro-p2-diamido-triphenyl-methane  are  produced  in  the 
condensation  of  o-  and  m-nitro-benzaldehyde  with  aniline  sulphate  by 
means  of  zinc  chloride.  The  m-body  melts  at  136°  (B.  13,  671  ;  16, 
1305)- 

p-Nitro-p2-diamino-triphenyl-methane  is  obtained  from  p-nitro- 
benzaldehyde,  just  as  the  o-  and  m-compounds  are  prepared.  See 
p-Leucaniline  (B.  25,  676). 

Benzaldehyde  and  the  nitro-benzaldehydes  condense  with  o-  and 
p-toluidin,  just  as  they  do  with  aniline  and  dimethyl-aniline  (B.  18, 
2094),  whereas  m-toluidin  and  m-derivatives  of  aniline  only  react 
readily  if  the  amido-group  is  methylated  (B.  20,  1563). 

Triamino-triphenyl-methanes  result  from  the  reduction  of  the  nitro- 
and  nitro-amido-triphenyl-methanes  and  of  the  triamido-triphenyl- 
carbinols.  The  latter  are  the  rosanilin  bases  if  the  three  amido- 
groups  occur  in  the  p-position  with  reference  to  the  C(OH)  group. 
Their  reduction  products  are  also  called  leucanilines.  These  are  white 
precipitates,  and  when  oxidised  yield  the  carbinols  : 

o,  p2-Triamido-triphenyl-methane,  or  o-leucaniline, 
and  m,  p2-Triamido-triphenyl-methane,  or  pseudo-leucaniline, 
and  p3-Triamido-triphenyl-methane,  or  para-leucaniline, 

which,  upon  oxidation,  yield  dyestuffs.  That  from  the  o-body  is 
brown  in  colour,  that  from  the  m-body  is  violet,  while  that  from  the 
p-compound  is  para-rosanilin.  p-Triamido-triphenyl-methane  is  also 
produced  in  the  condensation  of  p-amino-benzaldehyde  and  aniline 
with  zinc  chloride  ;  its  tris-diazo-chloride  CH(C6H4.N2C1)3,  when  boiled 
with  alcohol,  forms  triphenyl-amine. 

p3-Triamido-diphenyl-m-tolyl-methane,  leucaniline  (NH2[4]C6H4) 2 
CH.C6H3[4](CH3).NH2[3],  is  the  leuco-compound  corresponding  to  the 
chief  constituent  of  rosanilin  obtained  by  the  reduction  of  trinitro- 
diphenyl-meta-tolyl-methane,  and  is  also  made  by  digesting  the 
fuchsine  salts  with  ammonium  sulphide,  or  zinc  dust  and  hydrochloric 
acid.  By  diazotising,  and  replacing  the  diazo-groups  by  hydrogen 
(best  effected  by  dissolving  in  concentrated  sulphuric  acid,  conducting 
nitrous  acid  into  the  same,  and  boiling  with  alcohol),  leucaniline  is 
changed  into  diphenyl-m-tolyl-methane. 

2.  Carbinols  are  formed  (i)  by  oxidising  the  triphenyl-methane 
hydrocarbons,  and  their  nitro-  and  amido-compounds,  and  by  many 
synthetic  methods ;  (2)  from  aryl-magnesium  haloids,  (a)  with  aromatic 
carboxylic  esters  or  benzo-phenones  (B.  35,  3024  ;  36,  406  ;  37,  663, 
990)  : 

C6H5COOCH3+2C6H5MgBrv  . 

C6H5COC6H5+C6H5MgBr_/~       (C6H5)3<-( 


580  ORGANIC   CHEMISTRY 

(b)  with  other  products,  by  the  action  of  CO2,  COS,  COC12,  C1COOR 
(B.  36,  1010,  3005,  3087,  3236)  : 

3C6H5MgBr  -  ^->  (C6H5)3C(OH). 

(3)  from  triaryl-acetic  acids  by  rejection  of  CO  on  treating  with  con- 
centrated H2SO4  (B.  37,  655)  : 


(C6H5)2C(C6H4CH3)COOH  -      -->  (C6H5)2C(C6H4.CH3)OH. 

Triphenyl-carbinol  (C6H5)3C.OH,  m.p.  163°,  b.p.  above  360°. 
o-,  m-,  and  p-Tolyl-diphenyl-carbinol  (C6H5)2(C6H4.CH3)C.OH,  m.p. 
98°,  65°,  and  74°  (B.  37,  656,  992,  1245).  Tri-p-tolyl-earbinol  (CH3 
C6H4)3.C.OH,  m.p.  96°  (B.  37,  3153). 

Diphenyl-mono-biphenyl-carbinol  (C6H5)2C(OH).C6H4.C6H5,  m.p. 
136° ;  phenyl-di-biphenyl-carbinol  (C6H5.C6H4)2C(OH)C6H5,  m.p.  151° ; 
tri-biphenyl-carbinol  (C6H5.C6H4)3C.OH,  m.p.  208°,  see  A.  368,  298. 

The  OH  group  of  triphenyl-carbinol  and  its  homologues  is  very 
reactive.  Triphenyl-carbinol  is  easily  etherified  by  alcohols,  forming 
triphenyl-carbinol-methyl  ether  (C6H5)3COCH3,  m.p.  82°.  The  ethers 
are  easily  saponified  with  acids.  With  bisulphites  we  obtain  salts  of 
triphenyl-methyl-sulphonic  acids  (C6H5)3C.SO3Na ;  with  aniline  we 
obtain  triphenyl-carbinol-aniline,  while  aniline  chlorohydrate  yields 
p-amido-tetraphenyl-methane,  and  tetraphenyl-methane  derivatives 
are  similarly  formed  with  phenol  and  anisol.  With  sulphuric  acid  the 
carbinols  form  coloured  unstable  acid  sulphates,  whose  stability  is 
increased  with  the  introduction  of  halogen  or  methoxylene  into  the 
benzene  nuclei  of  the  carbinols  (B.  38, 1156).  Especially  characteristic 
are  the  easily  crystallised  perchlorates  of  the  triphenyl-carbinols,  which 
are  also  intensely  coloured  (B.  43,  183).  With  pyridin  and  quinolin 
also,  triphenyl-carbinol  produces  saline  compounds  (B.  35,  4007). 

Triphenyl-ehloro-methane,  triphenyl-carbinol  chloride  (C6H5)3CC1, 
m.p.  ni°,  is  formed  from  carbinol  by  treatment  with  hydrochloric 
acid  in  glacial  acetic  acid,  with  PC15  or  with  acetyl  chloride  (B.  36,  384, 
3924)  ;  also  on  heating  triphenyl-acetic  chloride  with  concentrated 
sulphuric  acid,  CO  being  eliminated.  It  is  formed  synthetically  from 
benzene  and  CC14  with  aluminium  chloride  (cp.  C.  1902,  I.  463). 
Triphenyl-bromo-methane,  from  triphenyl-methane  in  CS2  with 
bromine  in  sunlight  (A.  227,  no),  or  from  the  carbinol  with  glacial 
acetic  hydrobromic  acid  (B.  42,  3024).  Triphenyl-iodo-methane,  m.p. 
132°,  by  the  action  of  iodine  in  CS2  upon  a  solution  of  triphenyl- 
methyl.  Its  solutions,  when  exposed  to  the  oxygen  of  the  air,  eliminate 
iodine,  and  form  triphenyl-methyl  peroxide.  With  excess  of  halogen 
the  triphenyl-halogen-methanes  unite  to  form  well-crystallised  per- 
haloids  (C6H5)3CBr.Br5,  (C6H5)3CBr.I5,  (C6H5)3CI.I5,  etc.  (B.  35,  1831). 

The  halogen  is  bound  up  in  the  triphenyl-halogen-methanes  remark- 
ably loosely.  In  many  respects  they  behave  like  metallic  salts,  their 
solutions  in  sulphurous  acid,  pyridin,  and  acetone  conducting  the 
electric  current  (B.  43,  336).  In  the  electrolysis  of  triphenyl-bromo- 
methane  in  a  solution  of  SO2,  it  is  split  up,  just  like  a  metallic  salt,  into 
bromine,  and  the  radicle  triphenyl-methyl  (C6H5)3C,  which  is  partly 
transformed  into  the  dimeric  hexaphenyl-ethane  (A.  372,  n).  On 


TRIPHENYL-METHANE   GROUP  581 

boiling  with  water  the  triphenyl-halogen-methanes  are  transposed  into 
triphenyl-carbinol.  On  treatment  with  silver  acetate  we  obtain 
triphenyl-carbinol  acetate  (C6H5)3COCOCH3,  m.p.  88°  (B.  36,  3926)  ; 
with  potassium  cyanide  we  obtain  triphenyl-aceto-nitrile. 

Triphenyl-chloro-methane  is  colourless  in  the  solid  state,  and  dis- 
solves in  SO  2  with  a  yellow  colour,  being  probably  transposed  into  the 

quinoid   form   (C6H5)2C :  C6H4<^.     In  agreement  with  this  view,  the 

\(_xi 

p3  -  tribromo  -  triphenyl  -  chloro  -  methane  can  be  transformed,  by 
crystallisation,  from  sulphurous  acid  into  the  isomeric,  and  less 
soluble,  p3-monochloro-dibromo-triphenyl-bromo-methane  with  ex- 
change of  a  bromine  and  chlorine  atom,  the  following  bases  being 
passed  through  (B.  42,  406)  : 

BrC6H4\rn  ri  \C6H4%r 

(BrC6H4)2^  (BrC6H4)/ 

With  metallic  chlorides,  such  as  A1C13,  ZnQ3,  SnCl4,  etc.,  triphenyl- 
chloro-methane  yields  intensely  coloured  double  compounds,  which, 
like  the  carbinol  sulphates  and  perchlorates  mentioned  above,  probably 
belong  to  the  quinoid  type.  With  magnesium  and  ether,  it  forms  the 
very  unstable  triphenyl-methyl-magnesium  chloride  (C6H5)3CMgCl.  By 
the  action  of  zinc,  or  molecular  silver,  or  copper,  upon  the  benzene 
solution  of  triphenyl-chloro-methane  with  the  exclusion  of  air,  we 
obtain  triphenyl-methyl  and  hexaphenyl-ethane  respectively.  By 
heating  above  280°  triphenyl-chloro-  and  bromo-methane  are  con- 
densed to  diphenylene-phenyl-methane  (C6H4)  2CHC6H5. 

Triphenyl-methyl-amine,  triphenyl-carbinol-amine  (C6H5)3C.NH2, 
m.p.  103°,  is  prepared  by  conducting  dry  ammonia  gas  into  a  benzene 
solution  of  triphenyl-carbinol  bromide,  chloride,  or  iodide  (B.  17,  442, 
741  ;  35,  1827). 

Triphenyl-methyl-aniline  (C6H5)3C.NHC6H5,  m.p.  144°,  is  also  formed 
from  triphenyl-carbinol  by  heating  with  aniline  in  glacial  acetic  acid 
(B.  17,  703,  746  ;  35,  3016).  A  derivative  of  triphenyl-methyl-amine 

is   the   so-called  diphenyl-benzyl-sultame  C6H4/W^6H5)2\NH^  mp 

UL2jbo2 / 

210°,  formed  besides  phenyl-benzal-sultime  in  the  condensation  of 
pseudo-saccharin  chloride  with  benzene  and  A1C13  (B.  29,  2296). 

Triphenyl-methyl-hydrazin  (C6H5)3C.NHNH2,  chlorohydrate,  m.p. 
133°,  is  formed,  besides  hydrazo-triphenyl-methane,  in  the  action  of 
hydrazin  hydrate  upon  triphenyl-chloro-methane.  With  HNO2  it 

yields  triphenyl-methyl-azide   (C6H5)3CN<^J,  m.p.    64°,  a   remarkably 

stable  ester  of  hydrogen  nitride  (B.  42,  3024). 

Tripnenyl-methane-hydrazo-benzol  (C6H5)3CNHNHC6H5,  m.p.  137°, 
from  triphenyl-carbinol  chloride  or  bromide  with  phenyl-hydrazin.  It 
is  oxidised  by  HNO2  to  triphenyl-methane-azo-benzol  (C6H5)3CN  : 
NC6H5,  m.p.  114°  (B.  36,  1088). 

Hydrazo-triphenyl-methane  (C6H5)3C.NHNH.C(C6H5)3,  m.p.  209°, 
from  triphenyl-chloro-methane  and  hydrazin  hydrate.  By  oxidation 
with  sodium  hypo-bromite  it  decomposes  by  way  of  the  very  unstable 
azo-triphenyl-methane  into  nitrogen  and  triphenyl-methyl.  Bromine  or 


582  ORGANIC  CHEMISTRY 

iodine  converts  it  into  triphenyl-bromo-  and  iodo-methane  respectively, 
or  into  the  perhaloids  (B.  42,  3020). 

m-  and  p-Bromo-triphenyl-earbinol,  m.p.  67°  and  114°,  from  m-  and 
p-bromo-benzoic  ester  and  C6H5MgBr.  p-Trichloro-triphenyl-carbinol, 
m.p.  99°,  from  p-chloro-iodo-benzol,  p-chloro-benzoic  ester,  and 
magnesium.  p-Tri-iodo-triphenyl-carbinol,  m.p.  163°,  from  the  tri- 
diazonium  sulphate  of  p-rosanilin  with  iodo-potassium  iodide  (B. 
38,  585). 

m-  and  p-Nitro-triphenyl-earbinol  (C6H5)2C(OH)C6H4NO2,  m.p.  75° 
and  98°  ;  the  p-compound  is  obtained  pure  from  its  chloride,  the  con- 
densation product  of  p-nitro-benzo-phenone  chloride  with  benzene 
and  A1C13  (B.  21,  190  ;  37,  604). 

p3-Trinitro-phenyl-carbinol  (NO2[4]C6H4)3.C.OH,  m.p.  171°,  is  pre- 
pared from  p3-trinitro-phenyl-methane  by  the  action  of  chromic  acid 
in  glacial  acetic  acid.  It  yields  p-rosanilin  upon  reduction. 

Amido  -  triphenyl  -  carbinols. — p2-Diamido  -  triphenyl  -  carbinol  and 
pg-triamido-carbinols,  of  this  class,  deserve  special  consideration. 
p2-Tetramethyl-diamido-triphenyl-carbinol  is  the  basis  of  malachite 
green,  and  p3-triamido-triphenyl-carbinol  that  of  p-rosanilin.  The  free 
amido-carbinols  are  colourless.  In  contact  with  acids  water  is  elimi- 
nated and  colour  salts  result.  These  are  also  formed  by  the  direct 
oxidation  of  the  salts  of  the  leuco-compounds,  and  pass  into  the  latter 
upon  reduction.  Thus  p-leucaniline  hydrochloride  (i)  yields,  upon 
oxidation,  p-rosanilin  chloride,  from  which  colourless  p3-triamido- 
triphenyl-carbinol  is  separated  by  bases  ;  hydrochloric  acid  converts 
this  compound  again  into  p-rosanilin  chloride  : 

NHt[4]C8H4\    /C,H4[4]NH,HC1  ^_2JL_  NH1[4]C,H4\C/C.H4NH1C1  +_     Hcl  NH2C.H4\  c  /C,H4NH, 
NH1[4]C.Hi/*'\H ^NH.MC.H/^ '  l^T^  NH.C.H,/  \OH 

Only  these  mono-,  di-,  and  triphenyl-carbinols  are  capable  of  forming 
coloured  salts  with  expulsion  of  water,  which  contain  at  least  one 
amido-group  in  the  p-position.  Dyestuffs  are  only  formed  if  two 
p-amido-groups  are  present. 

With  a  careful  transposition  of  the  dye  salts  with  soda  solution, 
the  first  phase  is  the  production  of  more  or  less  unstable  methylene- 
quinone-imide  Ar2C  :  CqH4  :  NR,  or  Ar2C  :  C6H4  :  NR2OH  (cp.  Methy- 
lene  quinones),  and  in  a  second  phase  they  either  attach  or 
transpose  water  and  form  amino-carbinols. 

These  reactions,  occurring  even  in  the  simplest  p-amino-carbinols, 
are  similarly  repeated  in  the  p-oxy-triphenyl-carbinols.  According  to 
this  we  may  regard  diphenyl-quino-methane  as  the  foundation  sub- 
stance for  the  dyestuffs  of  the  triphenyl-methane  series,  which  there- 
fore can  be  termed  fuchsone  on  account  of  the  most  important  dye 
(B.  37,  2848)  : 

(C6H5)2C  :  C6H4  :  O    (C6H5)2C  :  C6H4  :  NH    (C6H5)2C  :  C6H4  :  NH2C1 
Fuchsone  [Fuchsone-imine]    Fuchsone-imonium  chloride. 

p-Amino-triphenyl-carbinol  HO.C(C6H5)2.C6H4NH2,  from  its  acetyl 
derivative  formed  by  oxidation  from  acetamido-triphenyl-methane 
with  PbO2.  With  HC1  it  first  forms  the  feebly  coloured  or  colour- 
less salts  HO.C(C6H5)2C6H4NH2.HClland  C1C(C6H5)2C6H4NH2.HC1, 


TRIPHENYL-METHANE  GROUP  583 

which,  on  heating,  expel  H2O  or  HC1,  and  form  the  strongly  coloured 
salts  of  the  bases  free  from  oxygen.  The  latter,  anhydro-p-amido- 
triphenyl-carbinol  (fuchsone-imine)  ,  is  dimolecular  and  colourless  in  the 
free  state  [(C6H5)2C.C6H4  :  NH]2.  Its  salts  are  also  obtained  from  the 
condensation  products  of  p-amido-benzo-phenone  with  phenyl-mag- 
nesium  bromide  (B.  37,  597). 

p-Anilino-triphenyl-carbinol,  colourless,  is  formed  from  the  anhydro- 
base,  diphenyl-methylene-quinone-phenyl-imine,  fuchsone-anile  (see 
above)  (C6H5)2C  :  C6H4  :  NC6H5,  red  prisms,  melting  at  I33°-I38°,  by 
addition  of  water.  For  forming  the  latter,  diphenyl-p-anisile-carbinol- 
anilide  (C6H5)2C(NHC6H5)C6H4OCH3,  with  organic  acids  like  benzoic 
acid  (B.  37,  608). 

p-Dimethyl-amino-triphenyl-earbinol  (CH3)  2N.C6H4C(OH)  (CQU5)  2, 
m-P-  93  °>  from  p-dimethyl-amino-phenyl-magnesium  bromide  with 
benzo-phenone,  or  benzo-phenone  chloride,  dimethyl-aniline,  and  ZnCl2 
(B.  36,  4296  ;  37,  2857). 

o-Amino-triphenyl-earbinol,  m.p.  121°,  from  anthranilic  ester  and 
C6H5MgBr.  On  prolonged  heating  it  expels  water  and  forms  phenyl- 
acridin.  The  chlorohydrate  of  carbinol  chloride,  on  treatment  with 
pyridin,  gives  an  anhydro-compound  (C19H15N)2  analogous  to  the 
p-compound,  m.p.  250°  with  decomposition  (B.  37,  3191). 

m-Amino-triphenyl-earbinol,  m.p.  155°  (B.  21,  190). 

p2-Diamino-triphenyl-carbinol  (NH2C6H4)2C(OH)C6H5,  colourless 
crystals,  best  obtained  by  oxidising  the  diaceto-diamino-triphenyl- 
methane  with  MnO4,  saponification  and  purification  over  methyl  ether, 
m.p.  i6i°-i63°.  On  heating  it  splits  off  water  and  passes  into  the 
unstable  methylene-quinone-imine  base  (amino-fuchsone-imine),  the 
salts  of  which  are  purple-  violet  dyestuffs,  resembling  fuchsine  (B. 
37,2859). 

p2-Dimethyl-diamino-triphenyl-carbinol  (CH3NH.C6H4)  2C(OH)C6H5, 
m.p.  95°,  is  formed  by  saponifying  the  cyanated  carbinol  [CH3N(CN) 
C6H4]2C(OH)C6H5,  generated  from  the  corresponding  triphenyl-methane 
derivative  by  oxidation  with  permanganate  in  acetone  solution  (B. 
37,  641). 

p2-Tetramethyl-diamido-triphenyl-carbinoI  C6H5.C(OH)[C6H4[4]N 
(CH3)2]2,  melting  at  132°,  crystallises  from  benzene  in  colourless  forms. 
It  is  obtained  from  its  salts  (malachite  green)  by  precipitation  with  the 
alkalies  and  by  oxidising  an  alcoholic  solution  of  p2-tetramethyl- 
diamido-  triphenyl-methane  with  chloranile  (A.  206,  130),  and  from 
p-dimethyl-amido-phenyl-magnesium  bromide  with  benzoic  acid  ester 
(B.  36,  4296). 

Methyl  ether  CtH,C(OCH8)[CiHtN(CHt)Jf,  m.p.  151°  (B.  33,  3356  ; 
37,  2867).  lodo-methylate  C6H5C(OCH8)[C6H4N(CH8)8I]a+2H2O  is 
obtained  by  heating  p2-diamido-triphenyl-carbinol  and  p2-tetramethyl- 
diamido-triphenyl-carbinol  with  methyl  iodide  and  methyl  alcohol. 

The  free  base  yields  almost  colourless  solutions  with  acids  in  the 
cold  ;  upon  standing,  and  more  rapidly  on  heating,  the  solution  acquires 
a  green  colour  and  then  contains  the  green  salts  —  malachite  greens  —  of 
the  anhydro-base  of  the  carbinol  (B.  12,  2348  ;  33,  298). 

Malachite  green,  bitter  almond  oil  green  C6H6  .  C<^«H4N(CH3)2      ^ 

(  \Lx<jJtl4JN(Url3J2^1 


hydrochloride  of  the  anhydro-base,  is  produced  when  zinc    chloride 


584  ORGANIC   CHEMISTRY 

acts  upon  a  mixture  of  benzo-trichloride  and  dimethyl-aniline,  or 
upon  a  mixture  of  benzoyl  chloride  and  dimethyl-aniline  (A.  206,  137). 

Technically,  leuco-malachite  green  is  first  prepared,  and  its  hydro- 
chloride  then  oxidised  with  lead  peroxide.  While  benzoic  acid  cannot 
be  condensed  with  dimethyl-aniline,  ortho-methylated  benzoic  acids 
with  tertiary  anilines  give  green  dyes  corresponding  to  malachite 
green  by  a  clean  reaction  (C.  1899,  I.  1089). 

Malachite  green,  characterised  by  its  strong  colouring  power,  is 
usually  supplied  commercially  in  the  form  of  its  zinc  chloride  double 
salt  (C23H25N2Cl)3.2ZnCl2+2H2O,  or  its  oxalate  (C23H25N2)23C2O4H2. 

History. — Malachite  green,  or  bitter  almond  oil  green,  was  obtained 
in  1877  by  O.  Fischer,  in  the  oxidation  of  p2-tetramethyl-diamido-tri- 
phenyl-methane.  He  obtained  the  latter  compound  by  condensing 
benzaldehyde  with  dimethyl-aniline.  Doebner  (1878)  showed  how 
malachite  green  could  be  prepared  from  benzo-trichloride  and  dimethyl- 
aniline. 

Brilliant  green,  solid  green,  new  Victoria  green,  is  the  tetra-ethyl 
derivative,  corresponding  to  malachite  green,  which  is  made  from 
diethyl-aniline  and  benzaldehyde  (B.  14,  2521).  The  colour  is  more 
yellow- tinted  than  that  of  malachite  green. 

Acid  green  is  a  dye  obtained  from  benzaldehyde  and  benzyl-ethyl 
aniline  by  condensation,  oxidation,  and  sulphonation.  The  sulpho- 
groups  are  in  the  benzyl  residue  (B.  22,  588). 

Nitro-malachite  greens  have  been  prepared  with  o-,  m-,  and  p-nitro- 
benzaldehydes  and  dimethyl-aniline  as  the  foundation  substances 
(B.  15,  682).  o-Amino-malaehite  green  is  a  blue  dye.  The  base  is 
formed  from  the  urethane  of  o-amino-lemo-malachite  green  COOC2H5. 
NH[2]C6H4CH[C6H4  :  NfCH^Jg  by  oxidation  and  saponification  (B.  36, 
2776).  Further  substituted  malachite  greens,  see  B.  39,  2041. 

o,  p'-,  m,  p'-,  o,  m'-  and  m,  m'-Tetramethyl-diamino-triphenyl-ear- 
binol,  m.p.  170°,  140°,  184°,  and  129°  respectively,  have  been  obtained 
from  the  corresponding  amido-benzo-phenones  by  transformation 
with  C6HsMgBr  or  (CH3)  2NC6H4Mg  (A.  354,  195). 

Triamido-triphenyl-earbinols.  —  p  2-  Triamido-triphenyl-carbinol,  p3- 
triamido-diphenyl-m-tolyl-carbinol,  and  their  methyl,  ethyl,  benzyl,  and 
phenyl  derivatives,  are  of  the  highest  importance  in  the  coal-tar  colour 
industry.  Their  salts,  with  one  equivalent  of  acid,  hydrochloric  or 
acetic,  constitute  the  group  of  rosanilin  dyes  in  the  more  restricted 
sense.  Like  malachite  green,  the  rosanilin  dye  substances  are  free 
from  carbinol  oxygen,  as  the  salt  formation  is  accompanied  by  an 
intramolecular  anhydride  formation.  The  carbinols  separated  from 
these  salts  by  alkalies  are  colourless,  but  turn  red  on  exposure  to  the 
air.  Careful  treatment  of  p-rosanilin  with  sodium  hydroxide  yields 
first  a  polymeride  of  the  methylene-quinone-imine  base  (of  pz-diamino- 
fuchsone-imine,  free  from  oxygen)  in  feebly  tinted  needles.  On  heating 
p3-triamino-triphenyl-carbinol  in  a  current  of  hydrogen  to  200°,  a  base, 
also  free  from  oxygen,  forms  as  a  red  amorphous  mass,  which,  with 
acids,  regenerates  para-rosanilin  quantitatively  (B.  37,  1183,  2867). 
This  process  may  be  represented  as  follows  : 

(NH1C.H4),C(OH)C.H4NH,  + — >  [(NH2C,H4),C  :  C.H4  :  NH]x   •< — >  (NH,C,H4)SC  :  C,H4  :  NH,C1. 

Fuchsine  is  the  dyestuff  produced  in  the  oxidation  of  a  mixture  of 


TRIPHENYL-METHANE   GROUP  585 

aniline,  o-toluidin,  and  p-toluidin.  It  is  the  so-called  red  oil.  Rosanilin 
is  the  chief  ingredient  of  fuchsine.  It  is  the  hydrochloride  or  acetate 
of  anhydro-p$-triamido-diphenyl-m-tolyl-carbinol  C 2oH19N3 . H Cl -f  4H  2O 
or  C20H19N3.C2H4O2.  The  mon-acid  salts  combine  with  two  addi- 
tional equivalents  of  acid,  forming  yellowish-brown  coloured  salts, 
which  water  decomposes  into  the  stable  mon-acid  salts  with  intense 
colours.  These  are  applied  as  dyes.  They  are  mostly  readily  soluble 
in  water  and  alcohol,  and  crystallise  in  metallic  greenish  crystals. 
Their  solutions  are  carmine-red  in  colour,  and  stain  animal  tissue 
directly  violet-red,  while  vegetable  fibre  (cotton)  must  first  be  mor- 
danted (tannin). 

The  mono-  and  tri-acid  salts  of  rosanilin,  on  taking  up  four  mole- 
cules HC1,  NH3,  or  H2O,  become  colourless  additive  compounds,  which 
easily  split  off  the  added  substances  and  reproduce  the  dyes  (A .  Chim. 
Phys.  8,  7,  195). 

Fuchsine  combines  with  sulphurous  acid,  forming  the  readily 
soluble,  colourless  fuchsine- sulphurous  acid. 

Aldehydes  impart  a  red  colour  to  this  solution,  which  serves  as  a 
reagent  for  them. 

Oxidants  used  with  red  oil  are  stannic  chloride  (Verguin,  1859), 
mercurous  and  mercuric  nitrates,  arsenic  acid  at  i8o°-2OO°  (Medloc, 
Nicholson,  Girard,  and  de  Laire,  1860)  ;  nitro-benzol  with  a  little 
ferrous  chloride  or  ammonium  vanadate  at  i8o°-i90°,  when  the  half 
of  the  red  oil  is  applied  as  hydrochloride  (Coupier,  1869  ;  cp.  B.  6, 
25,  423,  1072). 

In  the  arsenic  acid  method  the  fuchsine  is  obtained  in  the  form  of 
arsenites,  which  are  then  converted  into  the  chlorohydrate  or  acetate, 
and  obtained  free  from  arsenious  acid  by  recrystallisation. 

The  nitro-benzol  method  yields  immediately  a  fuchsine  which  is  not 
poisonous.  The  nitro-benzol  only  acts  as  an  oxidant,  without  entering 
into  the  fuchsine  formation  at  all. 

Fuchsine  is  not  formed  either  from  aniline  or  from  p-toluidin,  or 
from  o-toluidin  alone.  Even  a  mixture  of  aniline  with  o-toluidin  is 
not  oxidised  to  fuchsine.  However,  not  only  a  mixture  of  aniline 
with  o-  and  p-toluidin  yields  fuchsine,  but  in  the  oxidation  of  a  mixture 
of  aniline  and  p-toluidin  a  dye,  with  the  properties  of  fuchsine,  called 
para-rosanilin,  is  produced.  This  is  also  present  in  small  amount  in 
the  fuchsine  made  from  aniline  and  o-  and  p-toluidins  ;  whereas  the 
principal  constituent  of  ordinary  fuchsine  consists  of  the  next  higher 
homologue  of  para-rosanilin,  namely,  rosanilin  (B.  13,  2204). 

By-products  in  the  Formation  of  Fuchsine. — The  fuchsine  solution 
contains,  in  addition  to  34  per  cent,  of  fuchsine,  other  violet  and  brown 
dyes  :  mauvanilin,  violanilin,  substances  belonging  probably  to  the 
indulins,  and  other  less  thoroughly  investigated  substances,  as  well  as 
slight  amounts  of  a  yellow  acridin  dye,  known  as  phosphin  or  chrysanilin. 

History  of  the  Recognition  of  the  Constitution  of  Rosanilin  and  Para- 
rosanilin. — A.  W.  Hofmann  was  the  first  person  to  engage  in  a  scientific 
study  of  fuchsine.  He  began  his  investigations  in  the  sixties,  and  was 
led,  as  a  consequence,  to  present  a  formula  for  fuchsine  and  its  funda- 
mental dye-base.  He  became  acquainted  with  numerous  derivatives 
of  fuchsine,  especially  the  methyl  and  ethyl  violet  fuchsines.  He 
assumed  that  the  nitrogen  atoms  held  together  the  radicles  in  the 


586  ORGANIC  CHEMISTRY 

fuchsine  molecule.  However,  Kekule  (1867)  argued  for  the  possibility 
that  the  methyl  groups  of  the  toluidin  molecules,  necessary  for  the 
production  of  fuchsine,  afforded  the  connection.  K.  Zulkowsky  (1869) 
assumed  the  presence  of  three  amido-groups  in  fuchsine,  and  considered 
it  a  derivative  of  a  hydrocarbon  with  the  formula  C18H34.  Gradually, 
however,  the  conviction  grew  that  fuchsine  sprang  from  a  higher 
aromatic  hydrocarbon.  This  idea  had  its  basis  or  origin  in  the  experi- 
ments of  Wanklyn,  Caro,  Graebe,  Dale,  Schorlemmer,  and  others, 
which,  in  the  main,  established  the  relationship  of  fuchsine  to  rosolic 
acid.  The  "  keystone  to  that  extended  series  of  experimental  and 
speculative  investigations  "  was  the  conversion  (1878)  of  para-rosanilin, 
prepared  by  the  oxidation  of  aniline  and  p-toluidin,  into  triphenyl- 
methane.  This  was  the  work  of  Emil  and  Otto  Fischer.  The  hydro- 
carbon prepared  by  them  from  rosanilin,  the  chief  constituent  of 
fuchsine,  proved  to  be  diphenyl-m-tolyl-methane. 

Triphenyl-methane  (4)  is  formed  in  the  decomposition  of  the  tri- 
diazo-sulphate  of  para-leucaniline  with  alcohol.  In  the  diagram  the 
formula  of  the  tridiazo-chloride  (3)  of  para-leucaniline  (2)  is  used  for 
the  sake  of  simplicity.  Concentrated  nitric  acid  converts  triphenyl- 
methane  into  p3-trinitro-triphenyl-methane  (5),  which,  upon  reduction, 
yields  p3-triamido-triphenyl-methane  or  para-leucaniline  (2).  The 
latter,  by  oxidation,  is  converted  into  p3-trinitro-triphenyl-carbinol  (6). 
On  oxidising  para-leucaniline  with  arsenic  acid,  or  by  reducing  p3-tri- 
nitro-phenyl-carbinol  with  acetic  acid  and  zinc  dust,  para-rosanilin 
(i)  results.  The  following  diagram  illustrates  this  series  of  reactions, 
which  were  carried  out,  beginning  with  rosanilin  itself  (A.  194,  242)  : 

(I)'    /C8H4[4]NH2  (2)    /C6H4[4]NH2.HC1  (3)    /C6H4[4]N:N.C1 


^-C6H4[4]NH2       2H  CH(-C6H4[4]NH2.HC1- 


^C6H4[4]NH.C1 


2HC1 


(6)      /CaH4[4]NOt 
C(OH)  f-CaH4[4]N(V 


\C6H4[4]NH2.HC1 

(5)     /C6H4[4]N02 
CHf-C6H4[4]N02« 


CH^— C6H4[4]N:N.C1 

\C6H4[4]N:N.C1 

(4) 
CH-C6H 


C6H4[4]N02  \C6H4[4]N02  \C6H 


Para-rosanilin  is  produced  by  oxidising  a  mixture  of  aniline  and 
p-toluidin  according  to  the  arsenic  acid  or  nitro-benzol  method.  The 
reaction  may  be  imagined  to  proceed  in  that  a  molecule  of  p-toluidin 
is  oxidised  to  p-amido-benzaldehyde  ;  the  latter  then  condenses  with 
two  molecules  of  aniline  to  para-leucaniline  or  p3-triamido-triphenyl- 
methane,  from  which,  finally,  para-rosanilin  results  by  oxidation. 

When  working  with  small  quantities,  the  most  convenient  way  of 
oxidising  aniline  and  p-toluidin  to  para  rosanilin  consists  in  using 
mercuric  chloride  (B.  24,  3552).  An  interesting  formation  of  para- 
rosanilin  is  that  of  heating  aniline  with  carbon  tetrachloride  to  230°, 
when  the  latter  furnishes  the  linking  carbon  atom.  The  hydro-iodide 
of  para-rosanilin  results  by  using  iodoform  CHI3. 

Para-rosanilin  is  further  formed  by  the  reduction  of  p3-trinitro- 
triphenyl-carbinol  (see  above)  ;  by  heating  y3-nitro-diamido-triphenyl- 
methane  with  ferrous  chloride  (B.  15,  678)  ;  triamido-triphenyl-car- 
binol  is  also  formed  by  moderated  reduction  of  p-nitro-diamido- 
triphenyl  -  methane,  inasmuch  as  the  diamido  -  diphenyl  -  methane- 
phenyl-hydroxylamine  (C6H4NH2)2CH.C6H4.NHOH,  formed  at  first, 


TRIPHENYL-METHANE  GROUP  587 

rearranges  itself  (B.  29,  R.  32).  Cp.  also  the  action  of  NaOH  upon  nitro- 
diamido-triphenyl-methane  (C.  1897,  II.  416)  ;  it  is  also  obtained  from 
formaldehyde,  aniline,  and  phenyl-hydroxylamine  (C.  1897,  II.  1064)  ; 
and,  further,  by  heating  p-diamido-diphenyl-methane  with  aniline  and 
some  oxidising  agent  (B.  25,  302)  ;  by  heating  p-nitro-benzal  chloride 
with  aniline  (B.  18,  997)  ;  and  by  heating  aurin  to  120°  with  aqueous 
ammonia  (B.  10,  1016,  1123). 

Nitrous  acid  converts  it  into  auria  Triphenyl-carbinol  results 
when  para-rosanilin  diazo-chloride  is  decomposed  with  finely  divided 
copper  (B.  26,  2225).  At  i8o°-20O°  para-rosanilin  is  converted,  by 
concentrated  hydriodic  acid,  into  aniline  and  p-toluidin.  Evidence 
favouring  the  p-position  of  the  two  amido-groups  is  found  in  the  con- 
version of  p-rosanilin,  by  boiling  hydrochloric  acid,  into  p2-diamido- 
benzo-phenone,  which  is  also  obtained  from  p-diamido-triphenyl- 
methane,  the  condensation  product  of  benzaldehyde  with  aniline. 
Para-leucaniline,  the  reduction  product  from  para-rosanilin,  is  also 
formed  by  the  reduction  of  p3-nitro-diamido-triphenyl-methane.  The 
p-position  of  the  three  groups  in  the  latter  compound  follows  from  the 
fact  that  it  is  produced  by  the  same  condensation  reaction  from  p-nitro- 
benzaldehyde  and  aniline  by  which  p-diamido-triphenyl-methane  is 
made  from  benzaldehyde  and  aniline. 

The  rosanilin  salts  give  a  deeper  blue  shade  than  the  salts  of  para- 
rosanilin  (B.  15,  680). 

Homologous  rosanilins  have  been  prepared  by  the  oxidation  of  a 
mixture  of  aniline  and  unsym.  meta-xylidin  (B.  15,  1543),  by  condensa- 
tion of  p-nitro-benzaldehyde  with  o-toluidin,  reduction  and  oxidation 
of  the  resulting  condensation  product  (B.  15,  679),  and  by  the  condensa- 
tion of  p-nitro-dimethyl-amido-benzo-hydrol  with  m-toluidin,  etc. 
(B.  24,  553). 

Rosanilin-sulphonie  acid,  acid  fuchsine,  fuchsine  S,  is  produced  in 
the  action  of  fuming  sulphuric  acid  at  120°  upon  rosanilin.  Nucleus- 
substituted  fuchsines,  see  C.  1909,  II.  362. 

Alkylie  Para-rosanilins.  —  The  introduction  of  methyl  residues  into 
the  amido-groups  of  rosanilin  produces  violet  dyes  —  methyl  violet.  The 
violet  colour  assumes  a  deeper  blue  tint  with  the  increase  of  methyl 
groups.  These  dyes  are  made  by  methylating  para-rosanilin  and  by 
oxidising  dimethyl-aniline.  The  methyl  violets  are  reduced  to  leuco- 
compounds  when  they  are  heated  with  ammonium  sulphide  to  120°. 
Boiling  hydrochloric  acid  resolves  them  into  dimethyl-aniline  and 
methylated  p-diamido-benzo-phenones  (B.  19,  108). 

Hexamethyl-para-rosanilin,  crystal  violet  [(CH3)2N.C6H4]2.C=HC6 
=N(CH3)2C1,  is  distinguished  from  the  lower  methyl  derivatives  by 
great  power  of  crystallisation.  It  forms  one  of  the  principal  con- 
stituents of  methyl  violet,  and  is  produced  (i)  by  the  condensation 
of  p2-tetramethyl-diamido-benzo-phenone  and  dimethyl-  aniline  with 
dehydrating  agents  : 


(2)  By  heating  dimethyl-aniline  with  COC12  and  A1C13  or  ZnCl2 
(B.  18,  767  ;  R.  7).  Formic  acid,  formic  ester,  chloro-carbonic  ester, 
perchloro-methyl-mercaptan,  CSC12,  etc.,  act  the  same  as  phosgene 


588  ORGANIC   CHEMISTRY 

(B.  19,  109)  ;  (3)  by  oxidation  of  p2-tetramethyl-diamido-diphenyl- 
methane  with  dimethyl-aniline  ;  (4)  by  heating  its  methyl  chloride  or 
iodide  to  no°-i2O°  ;  (5)  by  oxidising  its  leuco-base. 

P3  -  Hexamethyl  -  triamido  -  triphenyl  -  carbinol,  crystal  -  violet  base 
C(OH) [C6H4[4]N(CH3)  Jg,  melts  at  195°.  It  is  also  formed  by  condensa- 
tion of  p-dimethyl-phenyl-magnesium  bromide  with  p2-tetramethyl- 
diamido-benzo-phenone  (B.  36,  4297).  Tribromo-hydrate,  see  B. 
33,  753- 

P3  -  Hexamethyl  -  triamido  -  triphenyl  -  methane,  leuco-crystal  violet 
CH[C6H4[4]N(CH3)2]3,  melting  at  173°,  results  by  the  reduction  of 
crystal  violet,  by  the  condensation  of  ortho-formic  ester  and  dimethyl- 
aniline  with  ZnCl2,  and  by  the  condensation  of  p2-tetramethyl-diamido- 
benzo-hydrol  with  dimethyl- aniline.  Also  by  condensation  of  prussic 
sesqui-chlorohydrate  with  dimethyl-aniline,  by  way  of  tetramethyl- 
diamido-benzo-hydrylamine  (C.  1900,  I.  239). 

Methyl  violet  is  a  mixture  of  hexamethyl-para-rosanilin  with  lower 
methylated  derivatives  (B.  19,  107).  It  is  produced  in  oxidising 
dimethyl-aniline,  alone  or  when  mixed  with  monomethyl-aniline,  with 
iodine  or  chloranile,  copper  sulphate  or  chloride.  When  copper  chloride 
is  used  it  is  advisable  to  add  acetic  acid  or  phenol. 

Pentamethyl  violet  C19H12N3(CH3)5HC1  is  formed  by  oxidising 
p3-pentamethyl-triamido-triphenyl-methane  [(CH3)  2NC6H4]  2CH.C6H4 
[4]NH.CH3,  melting  at  .116°.  The  latter  can  be  isolated  from  the 
reduction-product  of  commercial  methyl  violet,  a  mixture  of  penta- 
and  hexamethyl  violet,  by  means  of  the  acetyl  derivative.  This,  when 
oxidised  with  acetyl-pentamethyl-rosanilin,  yields  a  green  dyestuff 
(B.  16,  2906). 

Tetramethyl  violet  is  formed  by  oxidising  p3-amido-tetramethyl- 
diamido-triphenyl-methane,  melting  at  152°.  The  latter  is  a  tetra- 
methyl-para-leucaniline  NH2[4]C6H4CH[C6H4[4]N(CH3)  2]  2,  produced 
in  the  reduction  of  p-nitro-malachite  green.  Its  acetyl  derivative,  like 
that  of  pentamethyl-leucaniline,  yields  a  green  dye  upon  oxidation. 

Methyl  green,  methyl  chloride  of  hexamethyl-para-rosanilin  chloride 

H*^-jN^CH^ci,  is  produced  when  methyl  chloride 

acts  upon  an  alcoholic  solution  of  methyl  violet  heated  to  40°,  sodium 
hydrate  being  gradually  added. 

Alkylated  Rosanilins. — When  rosanilin  is  heated  with  methyl 
iodide,  methyl  chloride,  ethyl  iodide  or  chloride,  and  methyl  or 
ethyl  alcohol,  three  amide  hydrogen  atoms  are  replaced  by  methyl 
or  ethyl  radicles.  The  methyl  base  yields  reddish-violet-coloured  salts, 
and  the  ethyl  base  pure  violet  (Hofmann's  violet,  dahlia)  ;  these 
dissolve  with  difficulty  in  water,  but  dissolve  easily  in  alcohol. 

The  violet  dyes,  by  the  addition  of  more  methyl  or  ethyl  groups, 
yield  tetra  -  alkylic  rosanilin  iodides,  which  are  capable  of  adding 
another  molecule  of  methyl  or  ethyl  iodide  and  forming  iodine  greens 
— i.e.  iodo-methylate  of  tetramethyl-rosanilin  iodide  C20H16(CH3)4N3I. 
CH3I+H2O,  which  has  been  displaced  in  the  dye  industry  by  methyl 
green  (see  B.  28,  1008). 

Aldehyde  green  (Usebe,  /.  pr.  Ch.,  92,  337),  another  green  rosanilin 
dye,  has  been  prepared  by  heating  rosanilin  with  aldehyde  and  sul- 


TRIPHENYL-METHANE   GROUP  589 

phuric  acid,  and  by  further  action  of  sodium  hyposulphite.  The  most 
recent  opinion  is  that  in  this  reaction  an  aniline  group  has  been  changed 
to  quinaldin,  while  the  other  two  groups  have  occasioned  the  forma- 
tion of  aldol-aniline  residues,  which  latter  then  add  sulphur,  just  as  is 
done  by  aldol-aniline  itself  (cp.  B.  24,  1700  ;  29,  60). 

Phenylated  para-rosanilins. — Just  as  methyl  violet  is  prepared  from 
dimethyl-aniline  by  means  of  COC12,  etc.,  so 

Diphenylamine  blue  can  be  obtained  by  heating  diphenylamine  with 
carbon  hexachloride  C2C16  or  oxalic  acid  to  120°.  It  is  identical  with 
triphenyl-para-rosanilin  C(OH)(C6H4.NH.C6H5)3  (B.  23,  1964),  obtained 
by  the  action  of  aniline  upon  para-rosanilin.  By  heating  trianisyl- 
carbinol  with  aniline  and  benzoic  acid  we  obtain  the  benzoate  of  the  pure 
dye  base ;  the  latter  is  called  dianilino-fuchs one-anile  (C6H5NH.C6H4)  2C  : 
C6H4  :  NC6H5 ;  it  is  a  black  crystalline  powder,  m.p.  238°,  which  on 
taking  up  water  yields  the  colourless  p3-trianilino-triphenyl-earbinol, 
and,  by  reduction,  trianilino-triphenyl-methane  (B.  37,  2870). 

At  present  it  is  only  the  sodium  salts  of  its  mono-  and  disulpho- 
acids  which  are  applied  as  alkali  blue  and  water  blue  in  dyeing. 

Perchloro-formic  ester  CC1O2CC13,  in  a  similar  manner  converts 
diphenyl-methylamine  (C6H5)2N.CH3  into  trimethyl-triphenyl-para- 

rosanilin     C(OH)(c,H4.N<f^  )     (B.    19,    278).      Phosgene    converts 

\  \CxgJrl6/3 

triphenylamine  into  the  hydrochloride  of  hexaphenyl-para-rosanilin 
C(OH)[C6H4.N(C6H5)2]3  (B.  19,  758).  Tricarbazol-earbinol  C(OH) 
(C12H7NH)3  (B.  20,  1904),  is  produced  by  heating  together  carbazol 
or  diphenylimide  and  oxalic  acid.  It  is  analogous  to  the  triphenyl- 
amine derivative. 

Phenylated  rosanilins  are  obtained  by  heating  rosanilin  hydro- 
chloride  with  aniline  or  toluidins,  or  the  free  base  with  aniline  and  some 
benzoic  acid.  The  triphenyl-rosanilin  hydroehloride  C20H16(C6H5)3N3. 
HC1  appeared  in  commerce  as  aniline  blue,  a  bluish-brown  crystalline 
powder,  with  copper  lustre,  soluble  in  alcohol  but  not  in  water.  To 
dissolve  it  in  the  latter,  sulpho-salts  are  prepared,  which  exhibit  different 
shades  of  blue  (soluble  blue),  corresponding  to  the  number  of  sulpho- 
groups  in  them.  At  present  diphenylamine  blue,  and  other  dyes,  have 
taken  its  place.  Diphenylamine  results  on  distilling  triphenyl- 
rosanilin. 

By  converting  rosanilin,  by  means  of  the  tridiazo-compound,  into 
the  trihydrazin  derivative,  there  results  roshydrazin  C(OH)(C6H5.NH. 
NH2)3  ;  this,  by  condensation  with  aldehydes  and  ketones,  yields  red 
and  blue  dyestuffs  (B.  20,  1557). 

Other  hexamethyl-triamino-triphenyl-carbinols  have  been  obtained 
by  transposition  of  the  dimethyl-amido-benzoic  esters  with  dimethyl- 
aniline-magnesium  iodide  (CH3)2NC6H4MgI  (A.  354,  200). 

3.  Phenol  Derivatives  of  the  Triphenyl-methanes. — The  phenol  deriva- 
tives of  the  triphenyl-methanes  are  produced  (i)  from  the  correspond- 
ing amido-compounds  through  the  diazo-derivatives  ;  (2)  by  condensa- 
tions similar  to  those  of  the  amido-compounds  if  phenols  be  substituted 
for  the  anilines  ;  (3)  by  the  reduction  of  the  phenol-carbinols  into 
which  they  are  changed  by  oxidation. 

Monoocy-triphenyl-methanes. — o-Oxy-triphenyl-methane  (C6H5)  2CH. 
CGH4[2]OH,  m.p.  124°,  from  o-amido-triphenyl-methane  (A.  241,  367) 


590  ORGANIC  CHEMISTRY 

or  the  carbinol  by  reduction.  m-Oxy-triphenyl-methane,  m.p.  106°  (A. 
354, 171).  p-Oxy-triphenyl-methane,  m.p.  no0,  and  o-kresyl-diphenyl- 
methane  (C6H5)2CHC6H3[3]CH3[4]OH,  m.p.  100°,  from  the  carbinols 
or  from  benzo-hydrol  with  phenol  and  o-cresol  respectively  and 
SnCl4  (B.  35,  3137  ;  36,  356 1).  By  condensation  of  salicyl-aldehyde 
and  anisaldehyde,  with  aniline  sulphate,  or  dimethyl-aniline,  and  ZnCl2, 
oxy-diamido-triphenyl-methanes  have  been  obtained  (B.  14,  2522  ;  16, 

1307). 

The  di-  and  trioxy-triphenyl-methanes  yield,  on  oxidation,  di-  and 
triphenol-carbinols,  which,  as  a  rule,  possess  the  character  of  dye- 
substances.  Carbinols  in  which  two  benzene  nuclei  are  hydroxylated, 
and  which  correspond  to  the  malachite-green  compounds,  are  termed 
benze'ins,  and  the  corresponding  dioxy-triphenyl-methanes,  leuco- 
benzelns  ;  whereas  the  derivatives  with  three  hydroxylated  benzene 
nuclei  are  called  aurins  or  rosolic  acids,  while  corresponding  trioxy- 
triphenyl-methanes  are  designated  as  leucaurins  or  leuco-rosalic  acids. 
iPg-Dioxy-triphenyl-methane,  leuco-benze'in,  leuco-benzaurin  C6H5. 
CH(C6H4[4]OH)2,  m.p.  161°,  is  obtained  (i)  from  p2-diamido-triphenyl- 
methane  (A.  206,  153),  (2)  by  reducing  benzaurin  (A.  217,  230),  as 
well  as  (3)  by  the  condensation  of  benzaldehyde  and  phenol  with 
sulphuric  acid  (B.  22,  1944).  It  melts  at  161°. 
IfeDioxy-dimethyl-triphenyl-methane  C6H5CH[C6H3(OH)CH3]2  melts 
at*i7o°  (A.  257,  70).  Phenyl-dithymol-methane  melts  at  166°. 

See  B.  24,  R.  562,  for  the  condensation  of  m-nitro-benzaldehyde 
with  phenols. 

P3  -  Trioxy  -  triphenyl  -  methane,  leueaurin  [triphenylol  -  methane] 
CH(C6H4[4]OH)3,  is  obtained  in  the  reduction  of  aurin,  its  carbinol 
anhydride,  by  means  of  zinc  dust  and  sodium  hydrate  or  acetic  acid. 
It  crystallises  in  colourless  needles,  which  become  coloured  on  exposure 
to  the  air  (A.  166,  286  ;  194,  136  ;  202,  198).  The  triacetate  melts  at 
138°  (B.  11,  1117). 

p3-Trianisyl-methane  (CH3O[4]C6H4)3CH,  m.p.  45°-47°,  from  anis- 
aldehyde and  anisol  with  glacial  acetic-sulphuric  acid  (B.  35,  1197). 

Leueo-rosolie  acid  (HO[4]C6H4)2.CH.C6H3[4]OH[3]CH3,  results  from 
the  reduction  of  rosolic  acid.  Its  triacetate  melts  at  148°  (A.  179,  198). 

III.  A.  PHENOL  DERIVATIVES  OF  TRIPHENYL-CARBINOL. 

These  substances  are  formed  by  the  oxidation  of  the  oxy-triphenyl- 
methanes  or  their  ethers.  They  may  also  be  produced  by  the  direct 
synthetic  methods  applicable  to  all  triaryl-carbinols. 

The  p-hydroxylated  triaryl-carbinols  split  off  water  more  or  less 
easily,  turning  into  methylene-quinones  or  diaryl-quino-methanes. 
From  p-oxy-triphenyl-carbinol  we  obtain,  on  heating,  diphenyl-quino- 
methane,  which  may  be  regarded  as  the  root-substance  of  the  dye- 
stuffs  of  the  triphenyl-methane  series  : 

(C6H5)2C(OH)C6H4[4]OH  j=5.^  (C6H5)2C  :  C6H4  :  O 

p-Oxy-triphenyl-carbinol       Diphenyl-quino-methane,  fuchsone. 

A.  Triphenyl-carbinols  hydroxylated  in  a  Benzene  Nucleus. — o-Oxy- 
triphenyl-carbinol,  m.p.  140°,  from  salicylic  ester  and  phenyl-magnesium 
bromide.  It  turns  into  phenyl-xanthone  on  distillation  in  a  vacuum. 


PHENOL  DERIVATIVES   OF  TRIPHENYL-CARBINOL    591 

m-Oxy-triphenyl-earbinol,  m.p.  148°  (A.  354,  167).     p-Oxy-triphenyl- 

carbinol.  Two  modifications,  melting  at  139°  and  165°  respectively, 
from  p-oxy-triphenyl-acetic  acid  by  expulsion  of  CO  with  H2SO4  ; 
also  from  the  methyl  ether,  p-anisyl-diphenyl-carbinol,  m.p.  84°,  the 
condensation  product  of  anisic  acid  ester  with  phenyl-magnesium- 
bromide.  p-Oxy-triphenyl-carbinol,  and  p-methoxy-triphenyl-carbinol 
chloride,  on  heating  to  200°,  expel  H2O  and  CH3C1  respectively,  forming 
diphenyl-quino-methane,  fuchsone,  orange  crystals,  m.p.  168°,  which 
easily  takes  up  water  and  reverts  into  the  carbinol.  Oxy-dibromo- 
triphenyl-carbinol ;  diphenyl-dibromo-quino-methane,  from  diphenyl- 
o-cresol-carbinol ;  diphenyl-methyl-quino-methane  (B.  36,  3558). 
Diphenyl-quino-methanes  are  also  produced  by  the  condensation  of 
diphenyl-ketene  with  excess  of  quinones,  by  splitting  off  CO2  from 
the  /Mactones  first  formed. 

2,  5-Dioxy-triphenyl-carbinol,  m.p.  136°,  from  gentisinic  ester  and 
C6H5MgBr.  2, 4-Dioxy-triphenyl-carbinol,  m.p.  124°,  from  benzo- 
resorcin  and  C6H5MgBr.  3,  4-Dioxy-triphenyl-carbinol,  by  condensa- 
tion of  benzo-phenone  chloride  and  pyro-catechin  by  means  of  con- 
centrated H2SO4.  On  heating  it  expels  water,  and  forms  3-oxy- 
fuchsone,  m.p.  123°  (A.  372,  82). 

B.  Benzeins  (see  above)  are  produced  by  the  condensation  of 
benzo-trichloride  with  mono-  and  polyhydric  phenols,  in  which  the 
para-position  with  reference  to  a  hydroxyl  group  is  not  substituted 
— e.g.  o-  and  m-cresol,  resorcinol,  and  pyro-catechin  (but  not  p-cresol, 
hydroquinone,  etc.)  (B.  23,  R.  340).  They  are  also  formed  when 
their  leuco-compounds,  the  corresponding  oxy-triphenyl  -  methanes, 
are  oxidised. 

The  benzeins  are  generally  red-coloured  compounds  with  metallic 
lustre.  They  dissolve  on  boiling  with  sodium  bisulphite ;  acids 
precipitate  them.  Alkalies  dissolve  them  with  the  formation  of  red 
or  violet-coloured  salts.  The  carbon  dioxide  of  the  air  decomposes 
the  latter. 

p2-Dioxy-triphenyl-carbinol,    phenol-benzein,    benzaurin 

r  xi    /-'/CgH^.OH  /P  W    OTT 

c»li»-c\CTH  o   or  C6H5.C/    6    4-        is  produced  in  the  condensation  of 

|  I  ^VfH«  =  O 

benzo-trichloride  and  phenol  (similar  to  the  formation  of  malachite 
green)  (A.  217, 223),  and  by  the  oxidation  of  p-dioxy-triphenyl-methane, 
into  which  it  passes  upon  reduction.  It  is  a  brick-red,  crystalline 
powder.  It  breaks  down,  when  fused  with  alkalies,  into  benzene  and 
dioxy-benzo-phenone,  and  this  latter  decomposes  further  into  para-oxy- 
benzoic  acid  and  phenol.  Its  diacetate  melts  at  119°.  Dimethyl  ether, 
phenyl-p2-dianisyl-carbinol,  m.p.  77°,  from  phenyl-dianisyl-methane, 
the  condensation  product  of  benzaldehyde  and  anisol,  yields,  on  boiling 
with  dilute  sulphuric  acid,  benzaurin  (B.  36,  2791). 

p2-Dioxy-m2-dimethyl-triphenyl-earbinol,  o-cresol  benze'in  C6H5. 
C(OH).[C6H3[3]CH3[4]OH]2,  melts  at  22O°-225°  (A.  257,  69).  Further, 
dioxy-triphenyl-carbinols  have  been  obtained  from  the  corresponding 
dioxy-benzo-phenones  with  phenyl-magnesium  bromide  (A.  354,  177). 

The  oo '-dioxy-triphenyl-carbinols  are  only  known  in  the  form 
of  their  anhydrides,  the  phenyl-xanthydrols  C6H5.C(OH)^«^*^O. 
Special  interest  attaches  to  the  phenyl-xanthydrols,  hydroxylated  or 


592  ORGANIC  CHEMISTRY 

amidated  in  the  p-position,  with  regard  to  the  central  carbon  atom, 
which  split  off  water  spontaneously  and  pass  into  the  quinoid  .     Phenyl- 

/[i]C,H4[6]     \Q 
fluorones  C6H6.C^  f[6]/    and  phenyl-fluorimes  C6H5.C/^6jrL4  )O 


the  root-substances  of  the  fluorescei'n  and  rhodamin  dyes.  The  solu- 
tions of  these  compounds  in  alkalies  or  acids  show  a  strong  fluorescence. 

/C  H  \ 

Phenyl-fluorone    C6H5.C/  6   4>o   chrome-red    needles,   m.p.   207° 

^C6ri3—  O 

is  formed  from  the  4-amido-phenyl-fluorone  by  eliminating  the  amido- 
group,  and  by  condensation  of  4-methoxy-xanthone  with  C6H5MgBr 
and  saponification  of  the  methoxyl  group  with  A1C13.  It  is  insoluble  in 
alkalies,  but  soluble  in  acids.  By  alcoholic  potash  the  solution  is  made 
colourless,  and  the  carbinol  is  formed  (A.  372,  293).  3-  and  5-Oxy- 
phenyl-xanthydrol,  m.p.  170°  and  162°  respectively,  are  similarly 
formed  from  3-  and  5-methoxy-xanthone. 

Resorcin-benzein,   ^-oxy-phenyl-fluorone    CgH^.C/Sf^J°!J    No,  is 

\^C6H3(  :  O)  —  / 

formed  when  water  acts  upon  the  reaction  product  of  resorcinol  and 
benzo-trichloride  (A.  217,  234),  and  when  ZnCl2  acts  upon  benzoic  acid 
and  resorcin  (/.  pr.  Ch.  2,  48,  387).  Also  from  4-amido-phenyl- 
fluorone  by  way  of  the  diazo-compound  (A.  372,  294).  Dinitro- 
resorcin-benzein,  see  B.  26,  2064. 

vic-Resorein-benzein,  2,  z'-dio  xy-phenyl-xanthydrol 
C,u,.C(OH)<(^^^\o,  from  ^  2'_dioxy_xanthone  and  G6H5MgBr 

(A.  372,  132)." 

Hydroquinone-benzein,  3,  ^'-dioxy-phenyl-xanthydrol,  is  obtained 
from  3,  3'-dimethoxy-xanthone  and  phenyl-magnesium  bromide  with 
subsequent  saponification  (A.  372,  141),  or  by  the  condensation  of 
benzaldehyde  and  hydroquinone  by  means  of  concentrated  H2SO4  and 
oxidation  of  the  resulting  xanthene  derivative  with  FeCl3  (A.  372,  301). 

Oxy-hydroquinone-benzein,  phenyl-trio  xy  -fluorone 

C«H»C^C8H*(OH)'  -O^0'  by  condensation  of  benzaldehyde  and  oxy- 
hydroquinone  with  sulphuric  acid  (B.  37,  1171). 

C.  Amido  -  oxy  -  triphenyl  -  carbinols.  —  4  -  Amido  -  phenyl  -  fluorone 
C6H5.C/^H3(NH2)\0^  m  0)  d  red  needieS)  obtained  in  the  form 

M-'6Jrl3(  :  '-V     / 

of  its  acetyl  compound  by  condensation  of  N-acetyl-m-amido-phenol 
with  benzo-trichloride  besides  4,  4'-diacetamido-phenyl-xanthydrol,  m.p. 
248°  (A.  372,  322). 

Rosamines.  —  These  are  the  alkyl  compounds  of  4-amido-phenyl- 
fluorime.  They  are  formed  when  monoalkylic  and  dialkylic  o-amido- 
phenols  act  upon  benzo-trichloride.  While  the  benzei'ns  from  phenols 
are  very  feeble  dyes,  whose  alkali  salts  are  even  decomposed  by  carbon 
dioxide,  the  hydrochlorides  of  the  rosamines  are  red  and  violet  dyes, 
having  great  similarity  to  the  rhodamines,  possessing  a  blue  tint  and 
a  redder  fluorescence  (B.  22,  3001).  They  also  result  on  heating  re- 
sorcinol benzem  with  dimethyl-  and  diethyl-aniline. 

The    simplest,   rosamine,    4-amido-phenyl-fluorime 

is  obtained  in  the  form  of  its  chlorohydrate 


PHENOL  DERIVATIVES   OF  TRIPHENYL-CARBINOL     593 

in  red  needles,  from  the  4,  4'-  diacetamido  -  phenyl  -  xanthydrol  by 
boiling  with  HC1  (A.  372,  316). 

/QH  /[4]N(CH3)2 

Rosamine  chloride  C6Hftc/         ^No  may  be  obtained  from 


[4]=N(CH3)2C1 

benzo-trichloride  and  dimethyl-amido-phenol.  Red  and  blue  mordant 
dyes  are  obtained  by  the  condensation  of  proto-catechu-aldehyde  with 
dialkyl-m-amido-phenols  and  with  diakyl-anilines  :  proto-red  (leuco- 
compound)  (HO)2C6H3CH[C6H3(OH)N(CH3)2]2  and  proto-blue  (leuco- 
compound)  (HO2)C6H3CH[C6H4N(CH3)2]2)  (B.  36,  2913). 

D.  Aurins  and  Rosolic  Acids.  —  These  compounds  correspond 
perfectly  to  the  rosanilins.  The  free  p3-trioxy-triphenyl-carbinols  are 
not  known.  When  freed  from  their  salts  they  sustain  an  intramolecular 
anhydride  formation. 

These  carbinol  anhydrides  are  yellow  in  colour  ;  their  alkali  salts 
dissolve  in  water,  with  a  red  colour.  They  are  incompletely  fixed  by 
the  fibre  of  the  material,  and  are  only  applied  in  the  form  of  lakes  in 
the  paper  industry. 


Aurin,  para-rosolie  acid,  yellow  corallin  , 

±1UI  4JU6rl4/        \  -  / 

is  produced  (i)  on  boiling  the  diazo-hydrochloride  of  para-rosanilin 
with  water  (A.  194,  301)  ;  (2)  by  the  condensation  of  p-dioxy-benzo- 
phenone-chloride  with  phenol  (B.  11,  1350)  ;  (3)  by  the  condensation 
of  phenol  with  formic  acid  on  heating  with  zinc  chloride  (/.  pr.  Ch., 
2,  23,  549)  ;  and  (4)  by  heating  phenol  (i  part)  with  oxalic  acid  (f  part) 
and  sulphuric  acid  (J  part)  to  I3o°-i5o°  (A.  202,  185).  For  the 
by-products  arising  when  aurin  is  prepared  by  method  4,  and  for 
its  separation  from  the  same,  see  A.  194,  123  ;  196,  77  ;  B.  28, 

R.  743- 

Aurin  dissolves  in  glacial  acetic  acid  and  alcohol  with  a  yellowish- 
red  colour,  crystallises  in  dark-red  needles  or  prisms  with  metallic 
lustre,  and  decomposes  when  heated  above  220°.  It  dissolves  in 
alkalies  with  a  fuchsine-red  colour.  With  the  primary  alkaline 
sulphites  it  readily  yields  colourless,  crystalline  derivatives,  decom- 
posable by  acids  and  alkalies.  Aurin  forms  crystalline  compounds 
with  hydrochloric  acid.  Water  decomposes  them.  Digested  with 
zinc  dust  and  hydrochloric  acid  or  acetic  acid,  aurin  is  reduced  to 
leucaurin  or  p3-trioxy-triphenyl-methane.  Heated  to  250°  with  water, 
it  breaks  up  into  p2-dioxy-benzo-phenone  and  phenol. 

Aurin  is  changed  to  para-rosanilin  when  it  is  heated  with  aqueous 
ammonia  to  150°.  An  intermediate  product  (having  i  or  2  amide 
groups)  is  the  so-called  peonine  (red  corallin).  With  aniline  we  obtain 
triphenyl-para-rosanilin,  and  the  intermediate  product  is  azulin. 
Consult  B.  29,  R.  510,  for  isomeric  acetyl-aurins.  Dimethyl-aurin,  m.p. 
i83°-i86°,  is  easily  formed  by  methylation  of  aurin  with  diazo-methane 
in  ether  suspension  (M.  29,  653). 

p3-Trianisyl-earbinol  (CH3O[4]C6H4)3COH,  m.p.  84°,  colourless 
crystals,  from  p3-trianisyl-methane  with  PbO2  ;  its  OH  group  is  more 
capable  of  reaction  than  that  of  triphenyl-carbinol.  It  even  transposes 
to  trianisyl-aceto-nitrile  with  prussic  acid.  o3-,  m3-,  and  Ogp-Trianisyl 
carbinols,  m.p.  181°,  119°,  and  110°  respectively,  have  been  prepared 
VOL.  II.  2  Q 


594  ORGANIC  CHEMISTRY 

from  the  magnesium  compounds  of  o-  and  m-iodanisol  with  o-,  m-, 
and  p-methoxy-benzoic  ester  (B.  35,  3024). 

Rosolic  acid  C20H16O3  is  the  inner  anhydride  of  ps-trioxy-diphenyl- 
m-tolyl-carbinoL  Rosolic  acid,  like  aurin,  is  obtained  by  boiling  the 
diazo-chloride  of  rosanilin  with  water  (A.  179,  192)  and  by  oxidising 
a  mixture  of  phenol  and  cresol  C6H4(CH3)OH  with  arsenic  acid  and 
sulphuric  acid,  whereby  the  linking  menthane  carbon  is  furnished  by 
the  methyl  group.  When  rosolic  acid  is  digested  with  alcohol  and 
zinc  dust,  it  is  reduced  to  leuco-rosolic  acid,  from  which  it  is  obtained 
by  oxidation  (B.  26,  254). 

Trioxy-aurin  C1?H14O6  results  from  the  interaction  of  ZnCl2,  pyro- 
catechin,  and  formic  acid  (B.  26,  255).  Resaurin  C19H14O6  is  similarly 
prepared  with  resorcin  (/.  pr.  Ch.  2,  23,  547).  Orcin-aurin  C22H1«O5 
(J.  pr.  Ch.  2,  25,  277  ;  B.  13,  546).  o-Amino-aurin,  see  B.  40,  3588. 

Eupittonic  acid,  eupitton,  hexamethoxy-aurin  C^H^OCIrygOg,  is 
produced  by  oxidising  a  mixture  of  the  dimethyl  ester  of  pyrogallic 
acid  and  methyl-pyrogallic  acid.  It  is,  therefore,  an  aurin  in  which 
six  methoxyl  groups  are  present.  It  forms  orange-yellow  crystals, 
melting  with  decomposition  at  200°.  It  dissolves  with  a  deep  blue 
colour  in  alkalies,  yielding  salts  which  are  precipitated  by  excess  of 
alkali  (B.  12,  2216).  Reich enbach  (1835)  observed  the  formation  of  a 
blue-coloured  barium  salt  when  fractions  of  beechwood-tar  were 
allowed  to  stand  with  baryta  water,  and  named  it  pittical  (from  TUT™, 
tar,  and  xaAW,  beauty).  When  heated  with  ammonia,  eupittonic  acid, 
just  like  aurin,  affords  an  hexamethoxyl-rosanilin.  Tetra-  and  hexa- 
methoxy-triphenyl-carbinol,  see  B.  41,  4423. 

Alcohols  and  Aldehydes  of  Triphenyl-methane. — Few  of  them 
are  known  :  phenol-phthalol  (HOC6H4)2CHC6H4[2]CH2OH,  melting  at 
190°,  was  prepared  by  the  action  of  sodium  amalgam  upon  phenol- 
phthalem  (A.  202,  87). 

p-Diphenyl-methyl-benzaldehyde  (C6H5)2CH[4]C6H4.CHO,  boiling  at 
I9O°-I95°  (46  mm.),  results  from  the  condensation  of  tereph thai- 
aldehyde  and  benzene  with  concentrated  sulphuric  acid  (B.  19,  2029). 
Dialdehydes  have  been  prepared  by  the  condensation  of  benzaldehyde, 
m-  and  p-nitro-benzaldehyde  with  vanillin  by  means  of  ZnCl2. 

Benzal-divanUlin  C6H5CH[C6H2(OH)(OCH3)CHO]2,  m.p.  222°;  m- 
and  p-nitro-benzal-divanillin,  m.p.  266°  and  276°  with  decomposition 
(B.  36,  3975). 

Carboxyl  Derivatives  of  Triphenyl-methane.  —  Triphenyl-methane- 
carboxylic  acids  are  produced  (i)  by  reduction  of  triphenyl-carbinol- 
carboxylic  acids  ;  and  (2)  from  their  nitriles.  The  latter  are  prepared 
by  the  action  of  aluminium  chloride  upon  the  cyano-benzal  chlorides 
and  benzene. 

Triphenyl-methane-o-carboxylic  acid,  benzol  phthalin  (see  Phtha- 
lems),  (C6H5)2CH.C6H4[2]CO2H,  m.p.  162°,  is  isomeric  with  triphenyl- 
acetic  acid,  and  is  produced  by  the  reduction  of  diphenyl-phthalide 
(2),  the  lactone  of  triphenyl-carbinol-o-carboxylic  acid  (A.  202,  52),  and 
its  nitrile.  Chromic  acid  oxidises  it  to  diphenyl-phthalide,  while  it 
breaks  down  into  carbon  dioxide  and  triphenyl-methane  when  it  is 
heated  with  barium  hydroxide.  Sulphuric  acid  rearranges  it  to  phenyl- 

anthranol  C£JOH5*>CQ. 


CARBOXYL  DERIVATIVES   OF  TRIPHENYL-CARBINOL    595 

o-Cyano-triphenyl-methane  (C6H5)2CH.C6H4[2]CN  melts  at  89° 
and  boils  at  27O°-285°  (70-85  mm.).  Preparation,  see  above  (B.  24, 
2572). 

P2  -  Tetramethyl  -  diamido  -  triphenyl  -  methane  -  o  -  carboxylic  acid 
[(CH3)  gNMCeHJ  2.CH.C6H4[2]CO2H,  from  tetramethyl-diamido-di- 
phenyl-phthalide  (A.  206, 101),  melts  at  200°. 

Triphenyl-methane-p-carboxylie  acid  melts  at  161°,  and  its  nitrite 
at  91°  (B.  26,  3079).  Methyl-triphenyl-methane-earboxylie  acids,  see 
B.  16, 2364  ;  19,  3064  ;  A.  234,  242. 

Oxy-triphenyl-methane-carboxylic  acids  are  formed  in  the  reduction 
of  the  oxy-triphenyl-carbinol-carboxylic  acids.  p-Oxy-triphenyl- 

methane  -  o  -  carboxylic    acid    HO[4^6**^>CH.C6H4[2]CO2H,   melting  at 

(--6*15' 

210°  (B.  13,  1616),  and  p2-dioxy-triphenyl-methane-o-earboxylie  acid, 
phthalin  [HOMC^HJaCH.C^^CO^H,  melting  at  225°  (A.  202,  36, 
I53),  were  obtained  from  the  corresponding  oxy-triphenyl-carbinol-o- 
carboxylic  acids.  Concentrated  sulphuric  acid  converts  them  into  the 
corresponding  oxy-phenyl-anthranols. 

Hydrofluoranic  acid  C6H4|  ^CH\c!H![2]J  °'  melting  at  226°-228°, 

V[2]C02H 

results  from  the  reduction  of  fluorane  and  tribromo-fluorane.  When 
the  acid  is  distilled  over  lime,  xanthone  and  benzene  result,  while  di- 
phenylene-phenyl-methane  (B.  25,  3586)  is  produced  in  its  distilla- 
tion over  baryta  or  soda-lime. 

Fluoreseine,  p2-dioxy-hydrofluorane-earboxylie  acid,  is  the  reduction 
product  of  fluorescei'n. 

p2-Dioxy-triphenyl-methane-m2-dicarboxylic  acid  is  formed  by  con- 
densation of  benzaldehyde  with  salicylic  acid  by  means  of  gaseous 
HC1  (C.  1909,  I.  747). 

Carboxyl  Derivatives  of  Triphenyl-carbinol,  Phthalides. — The 
o-carboxyl  derivatives  of  this  class  are  especially  noteworthy.  They 
cannot  exist  free  ;  they  lose  water  and  form  lactones,  which  can  be 
regarded  as  diphenylated  phthalides. 

Diphenyl  -  phthalide,     tripkenyl-carbinol-o-carboxylic     acid     lactone 

r[i]C  =  (C6H5)2 
C6H4j         \  ,  melting  at  115°,  is  formed  (i)  by  the  oxidation  of 

triphenyl-methane-o-carboxylic  acid,  (2)  in  slight  amount  by  the  action 
of  mercury  diphenyl  upon  phthalyl  chloride,  (3)  from  phthalyl  chloride 
and  benzene  with  aluminium  chloride.  The  third  method  of  formation 
serves  for  the  preparation  of  diphenyl-phthalide,  formerly  considered 
to  be  o-phthalo-phenone,  until  it  was  discovered  to  contain  a  lactone, 
the  basis  of  the  phthaleins. 

In  the  third  method  of  producing  diphenyl-phthalide  the  phthalyl 
chloride  may  be  replaced  by  phthalic  anhydride.  In  this  case  o-benzoyl- 
benzoic  acid  will  be  the  first  product,  which  by  the  further  action  of 
benzene  and  aluminium  chloride  changes  to  diphenyl-phthalide.  The 
acetyl  derivative  of  o-benzoyl-benzoic  acid  is  better  adapted  for  the 
formation  of  diphenyl-phthalide  than  the  free  acid  (B.  14,  1865). 

Diphenyl-phthalide,  when  boiled  with  alkalies,  forms  salts  of  tri- 
phenyl-carbinol-o-carboxylic  acid,  from  the  solution  of  which  acids 
re-precipitate  diphenyl-phthalide.  Zinc  dust  in  alkaline  solution 


596  ORGANIC  CHEMISTRY 

reduces  triphenyl-carbinol-o-carboxylic  acid  to  triphenyl-methane-o- 
carboxylic  acid. 

The   anilide  C6H4|[1        (CeH5)2   ,   m.p.    189°,   and   the  hydrazide 

[  [2]CO.NH.C6H5 

C6H4J  *  ,    m.p.    230°,   are  produced  on   boiling  diphenyl- 

([2]CON2HC6H5 

phthalide  and  aniline  hydrochloride  (B.  27,  2793)  with  phenyl-hydrazin 
(B.  26,  1273). 

Dithio-diphenyl-phthalide  C6H4J       \    6   6  \  from  diphenyl-phtha- 

([2]CSS 
lide  with  sulphuretted  phosphorus,  see  C.  1900,  II.  575- 

The  nitration  of  diphenyl-phthalide  produces  two  dinitro-diphenyl- 
phthalides,  from  which  two  diamido-diphenyl-phthalides  have  been  ob- 

tained (A.  202,  66). 

r[i]C  =  [C6H4[4]N(CH3)2]2 
p2-Tetramethyl-diamido-diphenyl-phthalidec6HJ       \ 

l[2]COO 

m.p.  190°,  is  obtained  in  the  condensation  of  phthalic  anhydride  and 
dimethyl-aniline  with  ZnCl2.  If  phthalic  anhydride  be  substituted 
for  phthalyl  chloride  in  this  reaction  there  is  an  isomeric  body,  phthalyl 
green,  produced.  This  is  probably  an  anthracene  derivative,  which  is 
also  related  to  malachite  green,  and  owes  its  origin  to  an  admixture  of 
the  phthalyl  chloride  to  the  phthalylene  tetrachloride  (C.  1898,  1.  330  ; 
1903,  1.  85)  .  The  esters  of  the  colourless  tetramethyl-diamido-diphenyl- 
phthalide  form  intensely  blue  quinoid  dyeing  salts  with  acids. 

Triphenyl-carbinol-m-carboxylie  acid,  m.p.  161°,  and  triphenyl- 
carbinol-p-earboxylie  acid,  m.p.  200°,  are  formed  when  diphenyl-m- 
tolyl-methane  and  diphenyl-p-tolyl-methane  are  oxidised  with  chromic 
acid  in  glacial  acetic  acid  solution.  The  latter  also  appears  in  the 
oxidation  of  p-diphenyl-methyl-benzaldehyde,  and  of  triphenyl- 
methane-p-carboxylic  acid  (B.  16,  2369  ;  26,  3081  ;  37,  657). 

Phenyl-p-tolyl-phthalide  is  made  from  acetyl-o-benzoyl-benzoic  acid, 
toluol,  benzoyl-o-benzoic  acid  chloride  and  toluol,  toluic-o-benzoic  acid 
chloride,  and  benzene  with  aluminium  chloride  (B.  14,  1867  ;  29,  R. 
995).  Isomeric  methylated  diphenyl-phthalides  are  produced  in  the  oxi- 
dation of  diphenyl-m-  and  p-xylyl-methanes.  Ditolyl-phthalide  melts 
at  116°  (C.  1898,  1.  209  ;  A.  299,  286).  See  B.  28,  513,  for  di-biphenyl- 
([ilCO.O 

o-phthalide  c6H  J 

t[2]C=(C6H4.C6H5)2 

Carboxyl  Derivatives  of  the  Oxy-triphenyl-carbinols.  —  The  phthaleins, 
the  derivatives  of  phthalide  containing  two  phenol  residues,  are  parti- 
cularly important,  and  are  dyes  which  are  of  great  technical  value. 
A.  v.  Baeyer  discovered  them  in  1871.  The  transition  from  them  to 
diphenyl-phthalide  is  found  in  — 

,C6H4OH 


Benzol-phenol-phthalide    ^H«cob  '    m>p'    l67°'      !t    is 

prepared  from  o-benzoyl-benzoic  acid,  phenol,  and  sulphuric  acid 
(A.  354,  171).  Similarly  we  obtain  :  Resorcyl-phenyl-phthalide,  m.p. 
I09°i  pyro-cateehm-phenyl-phthalide,m.p.  161°;  hydroquinone-phenyl- 
phthalide,  m.p.  247°  ;  pyrogallol-phenyl-phthalide,  m.p.  189°  (A.  372, 


DERIVATIVES   OF   OXY-TRIFHENYL-CARBINOLS      597 

91).  Of  the  polyoxy-diphenyl-phthalides  mentioned,  the  p-substituted 
ones  dissolve  in  alkalies  with  a  red  colour,  splitting  the  lactone  ring  and 
forming  p-quinoid  salts  (cp.  Phenol-phthaleins). 

The  phthaleins  result  from  the  condensation  of  phthalic  anhydride 
(i  mol.)  with  phenols  (2  mols.)  on  heating  with  sulphuric  acid,  or,  better, 
with  SnCl2  to  120°  (or  with  oxalic  acid  at  115°). 

The  phthaleins  derived  from  di-  and  polyhydric  phenols  are  all 
anhydrides,  formed  by  the  elimination  of  water  from  two  phenol- 
hydroxyls  (A.  212,  347),  in  union  with  different  benzene  nuclei.  In 
the  condensation  of  phthalic  anhydride  and  phenol-p2-dioxy-diphenyl, 
phthalide,  or  phenol-phthalein,  is  not  the  only  product  ;  fluorane,  the 
anhydride  of  o.2-dioxy-diphenyl-phthalide,  is  also  formed.  It  is  the 
simplest  representative  of  the  phthale'in  anhydrides,  which  contain 
a  ring  similar  to  the  xanthone  ring. 

The  free  phthaleins  are  generally  colourless,  crystalline  bodies. 
They  dissolve  in  the  alkalies  with  intense  colorations,  and  are  again 
separated  from  their  solutions  by  acids  (even  CO2).  The  addition  of 
concentrated  caustic  alkali  causes  the  colours  to  disappear.  On  dilut- 
ing with  water,  the  colours  reappear. 

To  show  the  similarity  of  the  phthaleins  to  the  aurins  or  rosanilins 
in  the  formula,  it  is  assumed  that  the  free,  colourless  phthaleins  con- 
tain the  lactone  ring  ;  in  their  coloured  alkali  salt  solutions  this  ring 
is  absent,  and  the  methane  carbon  atom  and  an  oxygen  atom  form  a 
quinone-like  union  with  a  benzene  nucleus.  This  idea  is  apparently 
supported  by  the  preparation  of  phthalein-oxime  : 

C6H4.OH  XC6H4OH  /C6H4OH 


f 
\ 


[21COO  64  \  [2]C02H  1          [2]C02H 

Free  phenol-phthalein  Phenol-phthalein  in  coloured  alkali  salts. 

This  view  is  supported  by  the  fact  that  the  mm'-dioxy-ditoryl- 
phthalide,  which,  on  account  of  the  non-existence  of  m-quinones,  cannot 
be  analogously  formulated,  is  dissolved  quite  colourlessly  in  alkalies. 
Much  excess  of  alkali  decolourises  the  solutions  of  phenol-phthalein 
with  formation  of  salts  of  the  carbinol  NaO2CC6H4.C(OH)(C6H4ONa)2 
(C.  1904,  I.  1088). 

It  should  be  added  that  lactone  esters  and  ethers  have":  'also 
been  obtained  by  acidulation  and  alkylisation  of  phenol-phthalein  in 
alkaline  solution  (B.  28,  3258  ;  29,  131  ;  cp.  B.  29,  R.  552). 

The  phenol-phthaleins,  by  reduction,  yield  oxy-triphenyl-methane- 
carboxylic  acids  —  the  phthalins.  The  latter  are  changed  by  concen- 
trated sulphuric  acid  into  oxy-phenyl-anthrone  derivatives,  called 
phthalidins.  The  oxidation  of  the  latter  produces  the  phthalidelns,  or 
oxy-phenyl-oxanthrone  derivatives.  The  following  diagram  represents 
these  changes,  with  phenol-phthalein  as  the  example  : 


( 

6H4        \C-H-OH  CeH                       _  CA             C.H.OH  -_  c.H4  .H,OH 

Iwcoo    +™  IMCOOH  ~H'°  +°        ^co~  ^ 

\Jn. 

Phthalein,  Phthalin,                              Phthalidin,  Phthalidein 

pz-dioxy-diphenyl-  p2-dioxy-triphenyl-                   dioxy-phenyl-  dioxy-phenyl- 

phthalide  methane-o-carboxylic  acid                anthrone  oxanthrone 


598  ORGANIC  CHEMISTRY 

Phenol-phthalein,  p2-phthalein,  dioxy-diphenyl-phthalide  C20H14O4. 
is  a  yellow  powder,  crystallising  from  alcohol  in  colourless  crusts,  and 
melting  at  250°.  It  dissolves  in  the  alkalies  with  a  red  colour.  It  is 
used  as  an  indicator  in  alkalimetry,  especially  in  determining  carbon 
dioxide  with  baryta  (B.  17,  1907).  It  is  formed  from  phthalo-phenone 
when  nitrous  acid  acts  on  the  p-diamido-compound  ;  by  oxidising  an 
alkaline  solution  of  the  corresponding  phthalin  with  air,  or  with  potassium 
f  erricyanide  or  potassium  permanganate,  and  is  also  obtained  on  heating 
phthalic  anhydride  with  phenol  and  tin  chloride,  or  with  sulphuric  acid 
to  II5°-I2O°  for  eight  hours.  o2-Dioxy-diphenyl-phthalide  anhydride, 
insoluble  in  caustic  potash,  is  a  by-product,  sometimes  also  fluorane 
(A.  202,  68).  Boiling  caustic  potash  and  zinc  dust  reduce  phthalein 
to  phthalin,  and  it  is  decomposed  into  p2-dioxy-benzo-phenone  and 
benzoic  acid  by  fusion  with  caustic  potash. 

Derivatives  of  Phenol-phthalein.  —  Diaceto-phenol-phthalem  melts  at 
143°.  Dibenzoyl-phenol-phthalein  melts  at  169°  (B.  29,  131). 

Phenol-phthalein     methyl     ester    CH3ococ6H4.c<f^4  '°      m.p. 

\C6rl4.(Jrl 

I27°-I3O°,  orange  needles,  is  formed  by  esterification  of  phenol-phtha- 
lein  with  methyl-alcoholic  H2SO4  ;  it  dissolves  in  alkalies  with  a  violet 
colour,  and  is  easily  re-saponified  to  phenol-phthalein  (B.  40,  3484, 
3726).  The  lactoid  phenol-phthalein  mono-  and  dimethyl  ethers,  m.p. 
149°  and  100°,  are  obtained  by  alkylation  of  phenol-phthalein  in  alka- 
line solution  (B.  40,  3729).  The  latter  has  also  been  obtained  syn- 
thetically from  phthalic  anhydride,  anisol,  and  A1C13  (B.  29,  R.  550). 

f[i]C=(C6H4.OH)2 
Phenol-phthalem-anilide  C6H4  {       \  ,  m.p.  270°  (B.  26,  3077)  . 

{  [2]CONC6H5 

Phenol-phthalem-oxime  (C29H14O3)  :  NOH  (?),  a  yellow  crystalline 
powder,  melting  with  decomposition  at  221°,  and  produced  by  the  action 
of  hydroxylamine  upon  an  alkaline  phenol-phthalein  solution.  With 
dimethyl  sulphate  in  alkaline  solution  it  gives  a  dimethyl  ether.  This 
indicates  a  formula  of  the  lactame  type  C6H4{^«H*'OH)2^NOH. 

Boiling  dilute  sulphuric  acid  decomposes  the  oxime  into  p-oxy-o-ben- 
zoyl-benzoic  acid  and  p-amido-phenol  (B.  42,  2825).  Tetraehloro- 
phenol-phthalem  C20H10C14O4,  m.p.  above  300°  (C.  1909,  II.  127). 
Tetrabromo-phenol-phthalem,  m.p.  220°-230°  with  decomposition. 
Tetra-iodo-phenol-phthalein  is  used  commercially  as  an  iodoform  sub- 
stitute under  the  name  "  nosophene." 

Tetrabromo-phenol-phthalein-oxime  (B.  26,  2260;  C.  1900,  1.  1291). 
Quinoid  tetrabromo-phenol-phthalein-mono-  and  -diethyl  ether,  see  B. 
40,  1437- 

m,  m-Dioxy-p-ditolyl-phthalide,  m.p.  206°,  see  A.  354,  185. 


Fluorane,    o2-phenol  -  phthalein    anhydride  4 


melting  at  I73°-I75°,  is  produced,  together  with  p2-phenol-phthalein, 
by  the  condensation  of  phthalic  anhydride  and  phenol.  Fluorane 
yields  hydro-fluoranic  acid  by  reduction,  and  diphenylene-phenyl- 
methane  when  it  is  distilled  over  zinc  dust  (B.  25,  3586).  The  anile 

C6H4{  ]  '  \    *          melts  at  242°  (B.  27,  2793).    Tribromo-fluorane 
I  [2]CON.CflH6 


DERIVATIVES   OF   PHENOL-  PHTHALEIN  599 

C2oH19.Br3O3,  m.p.  298°-300°,  is  produced  by  the  action  of  PBr5 
upon  fluorescein,  and  is  reduced  by  alcoholic  caustic  soda  and 
zinc  dust  to  hydro-fluoranic  acid  (B.  25,  1388).  Concerning  nitro- 
fluoranes,  see  B.  31,  1739  ;  32,  1131,  2108.  3,  6-Dimethyl-fluorane, 
m.p.  213°,  see  C.  1910,  I.  449. 

The  fluoresceins  are  the  o-phthalic  anhydrides  produced  by  the 
condensation  of  phthalic  anhydrides  with  resorcin.  They  are  char- 
acterised by  a  beautiful  fluorescence  ;  this  is  especially  true  of  their 
alkaline  solutions  (Baeyer,  A.  183,  i). 

Phthalic  anhydride  may  also  be  replaced  by  the  anhydrides  of 
aliphatic  dicarboxylic  acids.  When  succinic,  maleic,  and  citraconic 
anhydrides  are  condensed  with  resorcin,  the  corresponding  fluoresceins 
are  produced.  Pyro-mellithic  and  mellithic  acids,  and  their  anhydrides, 
also  combine  with  resorcin  to  form  dyestuffs  resembling  fluoresceln, 
and  these  contain  i,  2,  or  3-fold  xanthyl  groups  (C.  1907,  I.  549). 

See  also  o-sulpho-benzoic  acid  and  naphthalic  acid  (B.  15,  883  ; 
18,2864;  24,  R.  763;  26,  R.  542;  29,2824).  Hydroquinone-sueeinein, 
C.  1908,  II.  786  ;  pyrogallol-succinein,  C.  1899,  II.  758. 

Resorcin-phthalem,  fluorescem  C20H12O5,  is  prepared  by  heating 
phthalic  anhydride  (2  parts)  with  resorcin  (7  parts)  to  200°,  or  with 
anhydrous  oxalic  acid  (B.  17,  1079)  to  iio°-ii7°.  When  precipitated 
from  its  salts  it  occurs  in  yellowish-red  flakes  C20H14O6,  which  quickly 
lose  water,  and  become  C2oH12O5,  which  dissolves  in  alcohol  with  a 
yellow-red  colour  and  green  fluorescence,  and  dries  out  as  a  red  powder. 
Upon  reduction  fluorescem  yields  fluorescin,  and  PC15  converts  it  into 
fluoresceln  chloride,  pz-dichloro-fluorane  (see  Rhodamines).  On  treat- 
ment with  alcoholic  KSH  this  yields  thio  -  fluorescem  C8H4O2  : 
(C6H3.SH)2:0(B.  32,1127). 

r[i]C=(C6H3OH)20 
Baeyer  ascribed  the  formula  C,H4-^  to  fluorescein. 

I  [2]COO 

As  there  was  a  disposition  to  assume  that  the  phthalic  acid 
residue  replaced  both  m-hydrogen  atoms  (5)  in  the  resorcin  mole- 
cules, R.  Meyer  showed  that  fluorescein  is  a  dioxy-derivative  of  o- 
phenol-phthalein  anhydride,  for  which  reason  he  gave  it  the  name 
fluorane  (above)  ;  and  that,  therefore,  the  phthalic  acid  residue  oc- 
cupied the  o-position  with  reference,  at  least,  to  each  of  the  hydroxyl 
group  of  the  resorcin  molecule,  and  between  these  hydroxyl  groups  the 
anhydride  formation  occurred.  R.  Meyer  converted  fluorescein  (i) 
by  means  of  PBr5  into  tribromo-fluorane  (2),  which,  like  fluorane  (4) 
itself,  yields  hydro-fluoranic  acid  (3)  upon  reduction.  Fluorescein  and 
fluorane  contain  a  ring,  closely  related  to  the  xanthone  ring  ;  indeed, 
hydro-fluoranic  acid  may  be  decomposed  into  xanthone  and  benzene  : 


(x)  rwo^W^^Xo         (*)  (3)  f[i]CH<'c«H«N>0         (4)  r[i] 

C,H4  >        <\C.H.(OH)[6]  j°  —  >  C.oH.Br.O,  -  >  C.H  J  \C.H4/°  <  -  C.HJ     ' 

l[2]COO  IWCOOB  \[2]COO 

The  intense  colour  of  fluorescein  led  Bernthsen  and  others  to 
ascribe  a  quinoid  constitution  to  free  fluorescein  and  its  coloured 
derivatives  (see  Phenol  -  phthalem)  .  The  assumption  of  a  free 
carboxyl  group  in  fluorescein  is  supported  by  its  solubility  in  sodium 
bicarbonate,  and  its  esterification  with  alcohol  and  sulphuric  acid 
(see  below). 


600  ORGANIC   CHEMISTRY 

The  colourless  derivatives  were  supposed  to  have  their  origin  in 
the  lactone  formula  of  fluorescein.  This  view  allies  fluorescein  and  its 
coloured  derivatives  with  the  aurins  and  rosanilins. 

When  fluorescein  is  fused  with  caustic  soda  it  breaks  down  into 
resorcinol  and  monoresorcinol-phthalein,  or  dioxy-benzoyl-benzoic 
acid.  Bromine  in  glacial  acetic  acid  changes  the  latter  to  dibromo- 
dioxy-benzoyl-benzoic  acid,  which  fuming  sulphuric  acid  rearranges 
to  dibromo-xantho-purpurin  ;  it  is  also  obtained  from  eosin.  Hence 
it  follows  that  monoresorcinol-phthalein  is  2, 4-dioxy-o-benzoyl-benzoic 
acid,  because  if  it  were  2,  6-dioxy-o-benzoyl-benzoic  acid  it  would  be 
impossible  for  an  anthraquinone  condensation  to  occur  (Heller,  B.  28, 
314;  B.  29,2623). 

Derivatives    of  Fluorescein. — Fluoreseein-anilide    and   fluoreseein- 

C(C12H803)  C(C12H303) 

phenyl-hydrazide  C6H4  — ^  and   C6H4<  ,  from   fluor- 

CONC6H6  \CON2HC6H6 

escein  on  heating  with  aniline  or  phenyl-hydrazin,  form  colourless 
crystals  ;  the  anilide  yields  a  dimethyl  ether,  m.p.  207°  (B.  28,  396  ; 

32,H33).  „„_„„ 

Fluorescein  -  carboxyl  -  methyl     ester     CH3oco[>]C6H4c/ 

m.p.  252°,  iridescent  green  crystals,  is  formed  by  the  esterification  of 
fluorescein  with  sulphuric  acid  and  methyl  alcohol  (B.  34,  2641). 
On  further  methylation  with  dimethyl  sulphate  in  nitro-benzol 
solution  it  yields  the  quinoid  fluorescein  -  dimethyl  -  ether  ester 

/C6H3OCH3 

CH3OCOC6H4C/         >O    ,  m.p.   177°,   brick-red  needles   (B.    28,   396), 
C6H3=O 

rc<C6H3(OCH3r 

besides  the  colourless  lactoid  dimethyl  ether  C6H4J  ^C6] 

(coo 

m.p.  198°,  probably  produced  by  isomerisation  (cp.  B.  40,  3603).  The 
latter  is  also  obtained  from  its  anilide  upon  heating  with  concentrated 
sulphuric  acid.  The  latter,  on  esterification  with  methyl  alcohol  and 
HC1,  passes  into  the  trimethyl  ether  of  dioxy-xanthydrol-carboxylic 
acid,  which  possesses  strong  basic  properties  and  forms,  with  acids, 
highly  coloured  salts  soluble  in  water  without  hydrolysis  (A.  371,  326), 
corresponding  to  the  coloured  salts  of  triphenyl-carbinol  (cp.  A.  370, 
142). 

Substituted  Fluoresceins. — Although  fluorescein  itself  is  not  applic- 
able as  a  dye,  by  introducing  halogens  and  nitro-groups  into  it  dyestuffs 
of  remarkable  beauty  can  be  obtained.  If  we  start  with  fluorescein, 
then  the  substitution  will  occur  in  the  resorcinol  residues. 

If  bromine  be  allowed  to  act  on  fluorescein  suspended  in  glacial 
acetic  acid,  eosin,  tetrabromo-fluorescein  C20H8Br4O5  is  produced. 
Crystallised  from  alcohol  it  forms  red  crystals.  The  potassium  and 
sodium  salts  constitute  the  eosin  of  commerce,  soluble  in  water,  and 
imparting  to  wool  and  silk  a  beautiful  rose-colour.  In  the  case  of  the 
sodium  salt  there  is  a  yellowish -red  fluorescence  (Caro,  1873). 

Erythrosin,  tetra-iodo-fluor escein  C20H8I4O5. 

Saf  rosine,  eosin  scarlet,  dibromo-dinitro-fluoresceinfC  20H8Br  2  (NO  2)  2O5 , 
is  formed  when  bromine  acts  upon  dinitro-fluorescein,  or  when  nitric 
acid  acts  upon  di-  or  tetra-bromo-fluorescein  (A.  202,  68).  See  B.  30, 


SUBSTITUTED   FLUORESCEINS  601 

333,  for  the  dinitro-fluorescein  yellow  from  dinitro-fluorescei'n  and 
ammonia. 

To  obtain  the  fluorescei'ns  substituted  in  the  phthalic  acid  residue, 
condense  the  chlorinated  phthalic  anhydrides  with  resorcinol  (Noel ting) . 
The  bromo-  and  iodo-fhiorescei'ns,  with  the  substituents  in  the  re- 
sorcinol residues,  are  at  the  same  time  prepared  from  the  chlorinated 
bodies  : 

Phloxin,  tetrabromo-dichloro-  and  tetrabromo-tetrachloro-fluorescem 
C20H4Cl4Br4O5,  rose  Bengal,  tetra-iodo-tetrachloro-fluorescem. 

Phthalic  anhydride  has  also  been  condensed  with  pyro-catechol 
(B.  40,  1442),  hydroquinones,  orcins,  and  phloro-glucin. 

Hydroquinone-pnthalem,  m.p.  226°,  is  formed  from  hydroquinone 
and  phthalic  anhydride,  as  well  as  from  fluorane,  by  transforming  into 
2,  7-dinitro-fluorane,  diamido-fluorane,  and  treating  the  latter  with 
nitrous  acid  (B.  28,  2959  ;  31,  1743).  It  shows  no  fluorescence,  and  it 
also  differs  from  fluoresce'in  in  colour  ;  it  approaches  phenol-phthalein 
in  its  behaviour  (B.  36,  2949).  In  alkalies,  hydroquinone-phthalem 
dissolves  with  a  violet  and  somewhat  unstable  colour,  o-quinoid  salts 
being  produced  with  a  probable  splitting  of  the  xanthone  ring  (cp. 
hydroquinone-benzein,  above,  and  A.  372,  133).  For  esters  of  hydro- 
quinone-phthalem, see  A.  372,  298.  The  condensation  of  phthalic 
anhydride  with  orcin  produces  three  orcin-phthaleins  ;  only  that  orcin- 
phthalein  which  contains  two  hydroxyl  groups  in  the  p-position,  i.e. 
the  phthalic  residue,  turns  out  to  be  a  perfect  analogue  of  fluorescem 
(B.  29,  2630). 

Pyrogallol-phthalein,  gallein  HOCO[2]C6H4c^^((^2o  (?)  is 
obtained  on  heating  pyrogallic  acid  with  phthalic  anhydride  to  200°. 
It  forms  crystals  with  green  colour,  dissolving  with  a  dark-red  colour  in 
alcohol  and  with  a  beautiful  blue  colour  in  excess  of  alkalies. 

It  is  converted  by  concentrated  sulphuric  acid  into  ccerule'in  (see 
A.  209,  249).  The  latter  is  a  permanent  green  anthracene  dyestuff 
(A.  209,  249  ;  C.  1900,  II.  100  ;  1901,  II.  775).  Tetrachloro-gallein, 
see  C.  1909,  II.  2161. 

Oxy-hydroquinone-phthalem,  like  the  isomeric  gallein,  and  in  con- 
trast with  phloro-glucin-phthalein,  which  does  not  contain  the  hydroxyl 
groups  in  the  ortho-position,  is  an  excellent  mordant  for  cotton.  Like 
gallein,  it  is  condensed  by  concentrated  sulphuric  acid  to  an  anthracene 
derivative  violem  ;  oxy-hydroquinone  reacts  like  resorcin  with  many 
other  i,  2-dicarboxylic  anhydrides,  with  formation  of  phthaleiin  (B.  34, 
2617,  2637  ;  35,  1782  ;  36,  1070). 

The  rhodamins,  the  phthaleins  of  m-amido-phenol  and  its  derivatives, 
are  of  special  importance.  They  are  violet-red,  magnificently  fluores- 
cent dyestuffs.  In  constitution  they  are  perfectly  analogous  to  the 
fluoresceins. 

The  simplest  rhodamin  is  formed  when  m-amido-phenol  hydro- 
chloride  and  phthalic  anhydride  are  heated  to  190°  with  concentrated 
sulphuric  acid  (B.  21,  R.  682). 

The  alkylic  rhodamins  possess  more  intense  colours.  They  are 
produced  when  rhodamin  hydrochloride  is  heated  with  alkyl  iodides. 
A  better  course  to  pursue  is  the  condensation  of  alkylic  m-amido- 
phenols  and  phenyl-m-amido-phenol  with  phthalic  anhydride  (B.  21, 


602  ORGANIC  CHEMISTRY 

R.  682,  920  ;  22,  R.  788).  Still  another  procedure  consists  in  re- 
arranging fluorescein  chloride,  melting  at  252°  (the  product  of  the 
action  of  PC15  upon  fluorescein),  by  heating  it  with  dialkylamines  (B.  22, 
R.  625,  789). 

Anisolines,  alkyl  ethers  of  the  rhodamins  (?) — see  B.  25,  R.  866. 

Suecino-rhodamin  has  been  obtained  from  succinic  anhydride  and 
m-amido-phenol  (B.  23,  R.  532). 

Di-salieylie  acid  phthalide  c6H4(Cl  ]a,  m.p.    276° 

l[2]COO 

with  decomposition,  is  formed  besides  phthaloyl-salicylic  acid  from 
phthalic  anhydride,  salicylic  ester,  and  A1C13  (A.  303,  280). 

III.  B.  p-Phenylene-bis-diphenyl-methane  C6H/^    (^5\2,  from  the 

\L,ti(i^6t±5)2 

corresponding  glycol  by  reduction  with  zinc  and  glacial  acetic  acid. 
Derivatives  of  this  hydrocarbon  are  obtained  by  the  introduction  of  the 
CH(C6H5)2  group  into  quinones  and  quinoid  substances  by  means  of 
benzo-hydrols. 

Benzo  -  quinone  -  bis  -  diphenyl  -  methane  C6H2O2[CH(C6H5)2]2,  m.p. 
250°.  Benzo-quinone-bis-tetramethyl-diamido-diphenyl-methane,  m.p. 
245°,  from  tetramethyl-diamido-benzo-hydrol  and  quinone  on  heating 
in  alcoholic  solution  (B.  32,  2146). 

p  -  Phenylene  -  bis  -  diphenyl  -  earbinol,  tetraphenyl-p-xylylene-glycol 
(C6H5)2C(OH)[i]C6H4[4]C(OH)(C6H5)2,  m.p.  169°,  is  obtained  from 
terephthalic  ester  and  C6H5MgBr.  On  boiling  with  silver,  the  benzene 
solution  of  the  bromide  (C6H5)2CBrC6H4CBr(C6H5)2  gives  tetraphenyl- 
dimethylene-quinone  (C6H5)2C  :  C6H4  :  C(C6H5)2,  orange  needles,  m.p. 
239°-242°  ;  the  latter  adds  bromine  with  decoloration,  eliminates 
iodine  from  HI,  and  is  related  to  the  methylene-quinones  (B.  37, 1463  ;  41, 
2746).  Tetraphenyl-methylene-quinones  are  also  produced  by  the  con- 
densation of  two  molecules  diphenyl-ketene  with  one  molecule  quinone, 
with  rejection  of  two  molecules  CO2  from  the  unstable  jS-dilactones 
first  formed.  On  treating  the  glycol  with  aniline  salt  or  with  phenol  in 
glacial  acetic  acid  we  obtain  p2-diamido-  and  p-dioxy-hexaphenyl-p-xylol 
H2NC6H4.C(C6H5)2C6H4C(C6H5)2C6H4NH2,  m.p.  358°,  and  HOC6H4C 
(C6H5)2C6H4C(C6H5)2C6H4OH,  m.p.  304°  (B.  37,  2001). 

III.  C.  Tetraphenyl-methane  C(C6H5)4,  m.p.  282°,  b.p.  431°  with 
sublimation,  is  formed  from  the  diazonium  sulphate  of  p-amino-tetra- 
phenyl-methane  by  boiling  with  alcohol,  and  also,  in  small  quantities, 
by  heating  triphenyl-rmethane-azo-benzol  to  100°  (B.  36,  1090).  Also 
by  transformation  of  triphenyl-chloro-methane  with  phenyl-magnesium 
chloride  (B.  39,  1463). 

p-Amido-  and  p-oxy-tetraphenyl-methane  NH2[4]C6H4C(C6H5)3, 
m.p.  245°,  and  HO[4]C6H4C(C6H5)3,  m.p.  282°,  is  easily  obtained  from 
triphenyl-carbinol  in  glacial  acetic  acid  by  heating  with  aniline  chloro- 
hydrate  and  phenol  respectively,  and  concentrated  sulphuric  acid 
(B.  35,  3018  ;  36,  407  ;  37,  659  ;  A.  363,  284). 

p-Diphenyl-methyl-tetraphenyl-methane  (C6H5)  2CH  [4] C6H4C  (C6H5) 3 , 
m.p.  231°,  is  formed  from  triphenyl-carbinol,  or  its  chloride,  by  re- 
duction with  zinc  and  stannous  chloride,  HC1,  and  glacial  acetic  acid  ; 
also  from  hexaphenyl-ethane  and  triphenyl-methyl  by  the  action  of 
HC1  (B.  37,  4790).  Also  synthetically  by  way  of  p-benzoyl-triphenyl- 
methane  C6H5COC6H4CH(C6H5)2,  m.p.  166°  (B,  41,  2421). 


HOMOLOGOUS  DI-  AND   POLY-PHENYL-PARAFFINS    603 

IV.  HOMOLOGOUS  Di-  AND  POLY-PHENYL-PARAFFINS. 

Homologous  series  are  derived  from  diphenyl-methane.  Dis- 
missing the  substitutions  in  the  benzene  residues,  this  is  attained  by 
replacing  the  H  atoms  of  the  methylene  residue  by  alkyl  groups  : 
diphenyl-methyl-,  diphenyl-dimethyl-,  diphenyl-ethyl-,  diphenyl- 
propyl-methane,  etc.,  denoted  as  "  gem-"  (geminated)  diphenyl-paraffins 
(B.  31,  2068)  ;  and  again,  it  can  be  done  by  inserting  new  C  atoms 
between  the  two  benzene  residues  :  w,  cu-diphenyl-ethane  or  dibenzyl, 
a},  oj-diphenyl-propane,  cu,  o;-diphenyl-butane,  co,  cu-diphenyl-pentane, 
etc.  The  group  of  unsym.  diphenyl-ethanes  and  the  homologous  gem- 
diphenyl-paramns  will  receive  first  attention  in  the  following  para- 
graphs. Its  members  attach  themselves  in  their  behaviour  to  di- 
phenyl-methane and  its  derivatives  ;  at  the  same  time  they  show  in 
many  ways  their  genetic  relationship  to  the  dibenzyl  group.  Compare 
benzilic  acid,  diphenyl-acetaldehyde,  stilbene,  tolane. 

After  these  there  will  follow  the  important  dibenzyl  or  sym. 
diphenyl-ethane  group,  and  then  the  cu,  co-diphenyl,  propane,  butane, 
pentane,  and  hexane  groups.  The  derivatives  alkylised  or  pheny- 
lated  in  the  benzene  nuclei,  or  in  the  side  chains  connecting  these,  are 
included  with  the  parent  hydrocarbons  of  the  individual  groups  ;  the 
saturated  are  followed  by  the  unsaturated  hydrocarbons. 

A.  Gem-diphenyl-paraffins  and  their  Derivatives  are,  as  a  rule,  formed 

(1)  by  the  condensation  of  aldehydes,  chlorinated  aldehydes,  glyoxylic 
acid,  etc.,  with  benzene  hydrocarbons,  phenols,  or  tertiary  anilines, 
just  as  the  diphenyl-methanes  are  produced  by  means  of  methylal, 
methylene  iodide,  etc.  : 

CH3CHO+2C6H6  -  >  CH3CH(C8H5)2+H20. 

(2)  Diphenyl-alkyl-carbinols    are   obtained   by   the   condensation   of 
benzo-phenone   with   magnesium-alkyl  iodides   or   from   phenyl-mag- 
nesium    bromide    with    fatty-acid    esters    and    chlorides    (Grignard's 
reaction)  .     The  carbinols  easily  split  off  water  and  form  gem-diphenyl- 
olefms,  which  are  reducible  by  Na  and  alcohol  to  gem-diphenyl-paramns  : 


(C6H5)2CO    CH,^  (C6H5)2C(OH)CH3  ^H.CO.R     2C6H5MgBr 
(C6H5)2C(OH).CH2CH3  --  >  (C6H5)2C  :  CHCH3  -         -+  C6H5CHrCH2CH3. 

All  the  substances  included  in  this  class  yield  benzo-phenone  or  its 
derivatives  when  they  are  oxidised. 

Unsym.  diphenyl-ethane  (C6H5)  2CHCH3,  b.p.  209°  (145°  at  13 
mm.),  is  made  from  benzene  and  paraldehyde  with  cold  sulphuric 
acid  ;  also  from  ethidene  chloride  CH3CHC12,  sym.  bromethyl-benzol 
CgHg.CHBr.CHg,  or  styrol  with  benzene  and  A12C16.  Chromic  acid 
oxidises  it  to  benzo-phenone,  with  the  elimination  of  the  methyl 
group.  Consult  B.  27,  3238.  Nitric  acid  nitrates  the  side  chains 
and  the  benzene  residues  of  unsym.  diphenyl-ethane.  The  products 
are  :  diphenyl-ethylene-glycol  mononitrate  (C6H5)2C(OH).CH2(ONO), 
melting  at  100°,  diphenyl-vinyl  nitrite  (C6H5)2C=CH(ONO),  melting  at 
86°,  and  a  dinitrite  melting  at  I48°-I49°.  The  latter  is  probably  a 
diphenyl-ethylene  derivative.  These  three  compounds  have  great 
crystallising  power.  They  form  yellow  crystals,  and  when  oxidised 
yield  benzo-phenone  (A.  233,  330). 


604  ORGANIC  CHEMISTRY 

Unsym.  phenol-phenyl-ethaneC6H5CH(CH3)C6H4.OH,  melting  at  58°, 
is  produced  when  sulphuric  acid  acts  upon  phenol  and  styrol  ;  the 
homologous  phenols,  naphthols,  etc.,  behave  similarly  toward  styrol 
(B.  24,  3891).  Unsym.  diphenol-ethane  (C6H4OH)2CHCH3,  melting  at 
122°,  can  be  obtained  from  aldehyde  and  phenol  (B.  19,  3009). 

Unsym.  p2-tetramethyl-diamido-diphenyl-ethane  [(CH3)2NC6H4]2 
CHCH3,  m.p.  69°,  is  split  up  by  nitrous  acid  with  formation  of  p-nitro- 
dimethyl-aniline  (C.  1899,  II.  203  ;  1900,  I.  252). 

gem-Diphenyl-propane,  -butane,  -hexane,  b.p.10  142°,  150°,  164°, 
from  the  corresponding  olefins  (see  below)  with  Na  and  alcohol  (C. 
1902,  II.  1209). 

Diphenyl-methyl-,  -ethyl-,  -propyl-,  -amyl-earbinol  (C6H5)2C(OH)R, 
m.p.  81°,  m.p.  95°,  b.p.15  185°,  m.p.  47°,  from  benzo-phenone  with 
alkyl-magnesium  iodides  or  phenyl-magnesium  bromide  and  fatty 
esters,  by  method  2  (see  above).  By  distillation  and  dehydrating 
processes  we  obtain  from  these  carbinols  :  gem-diphenyl-ethylene, 
-propylene,  -butylene,  -hexylene,  b.p.  270°,  280°,  m.p.  52°,  292°,  314° ; 
unsym.  diphenyl-ethylene  is  also  formed  from  a-diphenyl-jS-chlor- 
ethane  (see  below),  and  from  unsym.  dibromo-ethylene  with  benzene 
and  A1C13.  It  easily  splits  off  formaldehyde  by  auto-oxidation.  Gem- 
diphenyl-propylene  with  Br  immediately  gives  a-diphenyl-j3-bromo- 
propylene  (C6H5)2C  :  CBrCH3,  m.p.  49°  (B.  35,  2646  ;  37,  230,  1447  ; 
C.  1901,  I.  1337;  1902,  II.  1209).  o  -  Oxy  -  diphenyl  -  ethylene 
HO[2]C6H4C(C6H5)  :  CH2,  b.p.13  167°,  see  B.  36,  4002. 

Several  halogen  derivatives  of  mono-substituted  diphenyl-ethylenes 

p     TT      TT 

of  the  general  formula     6    5   \c  :  c<  „,     occur   in   cis-trans-isomeric 

Lx6.H.4X/  \-H-lg 

forms  which  can  be  transformed  into  each  other  by  means  of  ultra- 
violet light  (A.  342,  i  ;  B.  42,  4865). 

Unsym.  diphenyl-monochloro-ethane  (C6H5)2CH.CH2C1  is  an  oil. 
Diphenyl-dichloro-ethane(C6H5)2CH.CHCl2,melting  at  8o°,and  diphenyl- 
triehloro-ethane  (C6H5)2CH.CC13,  melting  at  64°, are  obtained  from  mono-, 
di-,  and  trichloro-acetaldehyde  (chloral)  with  benzene  and  sulphuric  acid. 
Alkali,  acting  upon  these  substances,  splits  off  hydrogen  chloride,  and 
the  products  are  : 

Unsym.  diphenyl-ethylene,  diphenyl-monochloro-ethylene  (C6H5)2C  : 
CHC1,  melting  at  42°  and  boiling  at  298°,  and  diphenyl-dichloro-ethylene 
(C6H5)2C  :  CC12,  melting  at  80°  and  boiling  at  316°,  which  is  also  found 
in  the  condensation  products  of  chloral  with  benzene  and  aluminium 
chloride  (B.  26, 1955)-  If  diphenyl-monochloro-ethane  be  heated  alone 
it  splits  off  hydrochloric  acid  and  is  rearranged  to  stilbene.  The 
latter  is  similarly  produced  by  the  reduction  and  rearrangement  of 
diphenyl-trichloro-e thane  with  zinc  dust  and  alcohol.  When  diphenyl- 
monochloro-ethylene  is  heated  with  a  sodium  ethylate  solution  it  is 
transformed  into  tolane.  Diphenyl  -  vinyl  -  ethyl  ether  (C6H5)C  : 
CHOC2H5  is  formed  simultaneously  : 

(C6H5)CH.CH2C1        -™  ->  C6H5.CH  :  CH.C6H5 
(C6H5)2CH  :  CHC1-         -->  H6C5.C  =  C.C6H5. 

These  transposition  reactions  have  been  extended  to  a  series  of 
substituted  diphenyl-mono-  and  trichloro-ethanes  and  to  diphenyl- 
monochloro-ethylene  (A.  279,  319  ;  B.  26,  R.  270). 


HOMOLOGOUS  DI-   AND   POLY-PHENYL-PARAFFINS     605 

Unsym.  diphenyl-ethylene-glycol  (C6H5)2C(OH).CH2OH,  m.p.  121°, 
is  formed  from  glycolic  ester  or  benzoyl-carbinol  by  transformation  into 
phenyl-magnesium  bromide.  Similarly  we  obtain  diphenyl-propylene- 
glycol  (C6H5)2C(OH).CH(OH).CH3,  m.p.  96°;  1, 1-diphenyl-glycerin 
(C6H5)2C(OH)CH(OH).CH2OH,  m.p.  158°;  and  diphenyl-ethylene- 
chloro-hydrin  (C6H5)2C(OH).CH2C1,  m.p.  66°,  from  lactic  ester,  glyceric 
ester,  and  chloracetic  ester  with  C6H5MgBr  respectively.  The-  latter, 
on  heating  with  sodium  ethylate,  gives  diphenyl-ethylene  oxide  (C6H5)2 

C.O.CH2,  m.p.  56°  (B.  39,  1753,  2288). 

On  heating  with  20  per  cent,  sulphuric  acid,  diphenyl-ethylene 
oxide,  distilled  in  a  vacuum,  passes  into  diphenyl-aeetaldehyde  (C6H5)2 
CH.CHO,  b.p.  166°,  oxime,  m.p.  120°,  which  is  also  formed  by  saponi- 
fication  with  glacial  acetic  acid  and  hydrochloric  acid  instead  of  di- 
phenyl-vinyl  alcohol. 

The  aldehyde  in  many  respects  behaves  analogously  to  the  oxy- 
methylene  derivatives — e.g.  when  it  is  oxidised  it  does  not  change  to 
the  acid,  but  splits  off  the  CHO  group  and  becomes  benzo-phenone 
(B.  24,  1780  ;  25,  1781).  Diphenyl-aeetaldehyde  is  also  formed  from 
the  hybro-benzoins  by  dehydrating  agents.  Anhydrides  of  the  hydro- 
benzoins  are  formed  at  the  same  time  : 

C6H5.CH.OH.CH.OHC6H5  — 'i  (C6H5)2CH.CHO. 

This  is  due  to  an  atomic  rearrangement  opposite  to  that  of  the 
transpositions  of  the  unsym.  diphenyl-chloro-ethanes  and  ethylenes  just 
indicated.  It  reminds  one  of  the  pinacolin  rearrangement  of  the 
pinacones. 

Similarly  we  obtain  from  methyl-  and  ethyl-hydrobenzoin 
C6H5CH(OH).C(Alk)OHC6H5 :  a,  a-diphenyl-propion-aldehyde  (C6H5)2C 
(CH3).CHO,  b.p.12  176°,  and  a,  a-diphenyl-butyr-aldehyde  (C6H5)2C 
(C2H5).CHO,  b.p.  314°  (C.  1907,  I.  726). 

Unsym.  diphenyl-aeetone  (C6H5)2CH.COCH3,  m.p.  45°  and  61° 
(dimorphous),  oxime,  m.p.  164°,  is  formed  on  heating  diphenyl-propy- 
lene-glycol  with  dilute  HC1  (B.  39,  2302). 

Diphenyl-ketene  (C6H5)2C  :  CO,  b.p.12  146°,  a  reddish-yellow 
liquid  solidifying  in  freezing  mixture  to  straw-yellow  crystals,  is  the 
first  and  most  closely  studied  representative  of  the  interesting  class  of 
the  ketenes  (Staudinger,  1905  ;  cp.  Vol.  I.).  It  is  formed  by  the  action 
of  zinc  upon  diphenyl-chloracetic  acid  chloride,  or  by  the  withdrawal 
of  HC1  from  diphenyl-acetic  acid  chloride  by  means  of  tertiary  bases 
(A.  356,  51).  Its  easy  formation  by  heating  azi-benzile  with  rejection 
of  N2  and  migration  of  a  phenyl  group  is  noteworthy  (B.  42,  2346)  : 

C6H5\C</N  C6H5\      /  C«H5 

C6H5CO/    XJR       ~^~*  C6H5CO/    \  C6H5 

a  reaction  which  appears  to  correspond  to  the  formation  of  stilbene 
from  diphenyl-monochloro-ethylene,  and  of  tetraphenyl-ethylene  from 
benzo-pinacolin  alcohol. 

Diphenyl-ketene  is  more  stable  than  the  aliphatic  representatives 
of  this  class  of  bodies,  and  shows  no  tendency  towards  polymerisation  ; 
but  it  shows  greater  reactivity,  (i)  With  water  it  forms  diphenyl- 
acetic  acid  or  its  anhydride.  (2)  With  alcohols  it  forms  diphenyl- 


606  ORGANIC  CHEMISTRY 

acetic  ester.  (3)  With  HC1  it  forms  diphenyl-acetic  acid  chloride.  (4) 
With  NH3,  phenyl-hydrazin,  and  primary  and  secondary  bases  it 
forms  the  corresponding  diphenyl-acetic  acid  derivatives.  (5)  With 
organic  acids  we  obtain  mixed  acid  anhydrides.  (6)  With  sodium- 
malonic  ester  we  obtain  diphenyl-acetyl-malonic  ester  (C6H5)2CH. 
COCH(CO2R)2.  (7)  With  phenyl-magnesium  bromide  we  obtain 
triphenyl-vinyl  alcohol  (C6H5)2C  :  C.(OH)C6H5.  (8)  With  Schiffs 
bases  it  unites  with  formation  of  j3-lactones  : 


(C.H5)2C=CO+C,H6CH=NC,H 


(go)  With  a/?-unsaturated  aldehydes  and  ketones  we  obtain,  on  heating 
the  components  in  indifferent  solvents,  unstable  /Mactones  which,  in 
the  nascent  state,  decompose  into  CO2  and  multiple  unsaturated 
hydrocarbons  (B.  42,  4249)  : 

(C6H5CH  :  CH)2CO  +  (C6H6)2C  :  CO  --  >  (C6H5CH  : 


(C6H5CH  :  CH)2C  :  C(C6H5)2, 


(gb)  The  quinones  react  like  the  a/3-unsaturated  ketones  ;  according  to 
the  quantities  used,  mono-  or  dilactones  of  jS-oxy-acids  are  formed, 
while  the  latter  decompose  at  once  into  2CO2  and  tetraphenyl-di- 
methylene-quinones  : 

CO.C(C6H6)2V  /C(C6H5)2.CO  -co, 

I O/  \O -  (^6^5)2^  •  ^6  "4  •    (^e^sh- 

The  monolactones  can  be  isolated,  and  are  only  split  up  into  CO2  an.d 
diphenyl-quino-methanes  on  heating. 

o-Substituents  depress  the  reactivity  of  the  quinone  groups,  so  that 
chloranile  and  anthraquinone  no  longer  unite  with  diphenyl-ketene 
(A.  380,  243). 

Diphenyl-acetic  acid  (C6H5)2CH.CO2H  is  formed  from  its  nitrile 
by  saponification  ;  by  reducing  benzilic  acid  with  hydriodic  acid  and 
phosphorus  in  glacial  acetic  acid  (A.  275,  84) ;  and  from  diphenyl- 
dichloro-ethylene  by  heating  to  180°  with  Na  alcoholate,  a  reaction 
which  may  be  generalised  (A.  306,  79).  The  acid  melts  at  146°.  When 
oxidised  with  a  chromic  acid  mixture  it  yields  benzo-phenone  ;  and 
when  heated  with  soda-lime  we  get  diphenyl-methane.  Its  ethyl  ester 
melts  at  58°  ;  the  methyl  ester  at  60°  ;  and  the  chloride  at  57°. 

Diphenyl-aceto-nitrile  (C6H5)2CH.CN  results  when  diphenyl-bromo- 
methane  is  heated  with  Hg(CN)2,  or  by  the  condensation  of  mandelic 
nitrile,  C6H5.CH(OH)CN,  and  benzene  with  tin  tetrachloride  (B.  25, 
1615).  It  melts  at  72°  and  boils  at  184°  (at  12  mm.).  The  hydrogen 
of  its  CH  group  is  readily  replaced  by  the  benzene  residue,  but  not 
by  alkyls  (A.  275,  87).  Iodide,  acting  upon  its  sodium  derivatives, 
produces  tetraphenyl-succino-nitrile. 

p2-Ditolyl-,  -dianisyl-,  and  -diphenetyl-aeetic  acid,  m.p.  144°,  110°, 
and  114°  (A.  306,  81). 

Tetranitro-diphenyl-  acetic  acid  £6^3(^2|2)>CH.co2H.  The  ethyl 
ester  is  derived  from  dinitro-phenyl-aceto-acetic  ester  and  dinitro- 


HOMOLOGOUS   DI-  AND   POLY-PHENYL-PARAFFINS     607 

phenyl-malonic  ester  by  the  action  of  o,  p-dinitro-bromo-benzol,  the 
group  CO.CH3  (and  CO2.C2H5)  being  replaced.  It  may  be  similarly 
prepared  from  dinitro-phenyl-acetic  ester  by  the  introduction  of  the 
dinitro-phenyl  residue.  It  melts  at  154°.  Alcoholic  potash  or  soda 
converts  the  ester,  by  the  substitution  of  the  hydrogen  of  the  CH 
group,  into  brilliant  metallic  salts,  dissolving  in  alcohol  and  water, 
with  a  dark -blue  colour.  Compare  tetranitro  -  phenyl  -  methane 
[(C6H3NO2)2]CH2  and  trinitro-triphenyl-methane  (C6H4NO2)3CH  (B. 
21,2476). 

p2-Diamido-diphenyl-aeetic  acid  [NHaCgHJaCHCOaH,  m.p.  234°, 
is  formed  by  the  transposition  of  dianilido-acetic  acid  (C6H5NH)^ 
CHCO2H,  on  heating  with  aniline  and  its  chlorohydrate  (B.  41,  3019, 

3031)- 

p-Oxy-diphenyl-acetie  acid,  m.p.  173°,  from  mandelic  acid  or  its 
nitrile  with  phenol  and  sulphuric  acid  (73  per  cent.),  besides  0-oxy- 

dipheayl-acetic  lactone  C6H5CH<^:^>O,  m.p.  114°.    The  latter  yields 

a  bromine  derivative  easily  transformed  into  o-oxy-diphenyl-glycocoll 
HOC6H4C(C6H5)(NH2)COOH  (B.  31,  2812). 

Tetra-oxy-diphenyl-acetie  acid  COOH.CH[C6H3(OH)2]2  has  been 
obtained  by  the  condensation  of  chloral  with  resorcin  by  means  of 
potassium  bisulphate.  It  has  a  yellow  colour.  It  dissolves  in  cold 
alkalies  with  a  red  colour,  and  forms  a  triacetyl  derivative  melting  at 
152°  (B.  29,  R.  776  ;  C.  1897,  II.  739). 

Benzilie  acid,  diphenyl-gly  colic  acid  (C6H5)2C(OH).CO2H,  m.p.  150°, 
is  produced  by  a  molecular  rearrangement  of  benzile  (q.v.)  when  digested 
with  alcoholic  potassium  hydroxide,  and  from  diphenyl-acetic  acid  by 
the  action  of  bromine  and  boiling  with  water.  We  can  prepare  it 
better  by  the  action  of  aqueous  potash  and  air  upon  benzoin  (B.  19, 
1868  ;  C.  1902,  I.  1012)  : 

C6H5COCOC6H5  -J*£~+  (C6H5)2C(OH)COOH. 

When  heated  above  its  melting-point,  benzilic  acid  takes  on  a 
blood-red  colour,  and  dissolves  with  the  same  colour  in  sulphuric  acid. 
Diphenylene-diphenyl-ethane  derivatives  are  produced  by  the  action 
of  concentrated  sulphuric  acid  upon  benzilic  acid  (B.  29,  734). 

With  phosphorus  chlorides  benzilic  acid  yields  diphenyl-ehloracetie 
acid  (C6H5)2CC1C02H,  m.p.  119°  with  decomposition  (B.  36,  145),  and 
diphenyl-ehioracetie  acid  chloride,  m.p.  50°  (A.  356,  72)  ;  with  P2O5  or 

COC12  and  pyridin  we  obtain  benzilide  (C6H5)2C<(^^C(C6H5)2,  m.p. 

196°  (B.  35,  3642).  It  yields  diphenyl-acetic  acid  when  heated 
with  hydriodic  acid  and  phosphorus.  On  distilling  its  barium  salt  it 
breaks  up  into  carbon  dioxide  and  benzo-hydrol ;  oxidation  yields 
benzo-phenone. 

p-Tolilie  acid  (CH3C6H4)2  :  C(OH)COOH  ;  anisilie  acid  (CH3OC6H4)2 
C(OH)COOH;  cuminilic  acid  (C3H7C6H4)2C(OH)COOH  ;  and  hexa- 
methoxy-benzilie  acid  [(CHgO^CgH^qOHJCOOH  are  prepared,  like 
benzilic  acid,  from  their  corresponding  substituted  benziles. 

j3,j3-Diphenyl-propionie  acid  (C6H5)2CH.CH2.COOH  is  a  homologue 
of  diphenyl-acetic  acid.  It  melts  at  149°.  It  is  formed  by  the  addi- 
tion of  phenyl-magnesium  bromide  to  cinnamic  acid  ester  (C.  1905,  I. 


608  ORGANIC   CHEMISTRY 

522).  This  is  accomplished  by  means  of  sulphuric  acid,  just  as  phenol- 
phenyl-ethane  is  obtained  from  styrol  and  phenol,  or  benzene  is 
attached  to  cinnamic  acid.  The  continued  action  of  the  sulphuric 
acid  leads  to  a  condensation  to  y-phenyl-hydrindone.  The  a-bromo- 
j8,/3-diphenyl-propionic  acid,  m.p.  about  164°,  and  especially  its  potas- 
sium salt,  decompose  on  evaporating  their  aqueous  solution  into 
CO  2,  HBr,  and  stilbene,  a  reaction  corresponding  to  the  formation  of 
this  hydrocarbon  from  diphenyl-monochloro-ethylene  (C.  1905,  II. 
1022). 

Phenyl-tolyl- ,  phenyl-xylyl-propionic  acids,  etc.,  are  prepared  just 
like  diphenyl-propionic  acid  (B.  26,  1579).  Potassium  permanganate 
oxidises  these  acids  to  benzo-phenone,  phenyl-tolyl-ketone,  phenyl- 
xylyl-ketone,  etc. 

y,  y-Diphenyl-butyric  acid  (C6H5)2CHCH2CH2COOH,  m.p.  107°, 
from  y-phenyl-butyro-laetone  or  phenyl-iso-crotonic  acid,  with  benzene 
and  A1C13  (C.  1907,  II.  2045). 

a,  a-Diphenyl-propionic  acid  (C6H5)2C(CH3)CO2H,  m.p.  173°,  and  its 
homologues  are  obtained  by  condensation  of  phenyl-pyro-racemic  acid 
with  benzene  and  its  homologues  by  means  of  concentrated  sulphuric 
acid  (B.  14,  1595).  On  heating  with  concentrated  sulphuric  acid  they 
split  off  CO  and  yield  diphenyl-carbinols,  which  in  turn  easily  decompose 
into  water  and  unsym.  diaryl-ethylenes  (B.  38,  839). 

j8-Phenyl-cinnamie  acid  (C6H5)2C  :  CH.CO2H,  m.p.  162°,  is  formed, 
like  j3-alkyl-cinnamic  acids,  from  the  condensation  product  of  benzo- 
phenone  with  bromacetic  ester  and  zinc  (B.  40,  4537  ;  41,  324),  and 
from  a-bromo-/?,  j8-diphenyl-propionic  acid  with  alcoholic  potash 
(C.  1905,  I.  522). 

y-Diphenyl-itaeonic  acid  (C6H5)2C :  C(COOH).CH2.COOH,  m.p. 
169°  with  decomposition,  is  obtained  by  the  condensation  of  benzo- 
phenone  with  succinic  ester  through  the  agency  of  sodium  ethylate. 
The  acid,  on  heating  under  reduced  pressure,  gives  an  anhydridf ,  m.p. 
I47°-I50°,  whose  soda  solution  on  acidulation  yields  diphenyl-eitraeonie 
acid  (C6H5)2CHC(COOH)  :  CHCOOH,  m.p.  iio°-ii5°  with  decom- 
position. This  acid  is  condensed  by  sulphuric  acid  to  phenyl-indone- 
acetic  acid.  With  bromine  it  gives  y-diphenyl-bromo-paraeonie  acid 

(C6H5)2C.CBr(COOH).CH2.COO,  which,  on  heating  with  water,  passes 
into  y-diphenyl-aconic  acid,  m.p.  139°,  and  further,  with  rejection  of 

CO2,  diphenyl-croto-lactone  (C6H5)2C.CH  :  CH.COO,  m.p.  131°  (A. 
308,  89).  y-Diphenyl-a,j3-dichloro-crotonic  acid  (C6H5)2CH.CC1  :  CC1 
COOH,  m.p.  152°,  is  formed  from  muco-chloric  acid  chloride  (see  Vol. 
I.),  benzene,  and  A1C13  (C.  1897,  H-  57°) •  y-Diphenyl-aeetaerylic  ester 
(C6H5)2C  :  C(COCH3)COOC2H5,  m.p.  76°,  from  benzo-phenone  chloride 
and  cu-aceto-acetic  ester,  yields  by  ketone  splitting  diphenyl-butenone 
(C6H5)2C  :  CHCOCH3,  m.p.  33°,  b.p.13  190°  (B.  32,  1433),  and  homo- 
logues are  formed  from  triphenyl-chloro-methane  and  alkyl-magnesium 
haloids  (B.  39,  2957). 

Triphenyl-acetaldehyde  (C6H5)3C.CHO,  m.p.  223°,  from  triphenyl- 
magnesium  chloride  and  formic  acid  ester. 

Triphenyl-methyl-ethyl-ketone  (C6H5)3C.COC2H5,  m.p.  104°,  from 
triphenyl-acetic  acid  chloride  and  C2H5MgI  (B.  43,  1137). 

Triphenyl-acetic  acid  (C6H5)3C.COOH  is  a  very  feeble  acid.     It  melts 


HOMOLOGOUS   DI-   AND,  POLY-PHENYL-PARAFFINS      609 

at  264°,  and  decomposes  into  triphenyl-methane-car  boxy  lie  acids.  It 
is  made  by  the  action  of  benzene  and  aluminium  chloride  upon  tri- 
chloracetic  acid,  and  when  carbon  dioxide  is  conducted  over  potassium 
triphenyl-methane  at  200°.  The  nitrite  is  produced  by  the  interaction 
of  triphenyl-chloro-  or  bromo-methane  and  mercuric  cyanide  Hg(CN)2 
(A.  194,  260  ;  B.  28,  2782),  or  by  deamidising  hydrocyano-para- 
rosanilin  (B.  26,  2225). 

P3  -  Triamido  -  triphenyl  -  acetic  nitrile,  hydrocyano-para-rosanilin, 
results  upon  digesting  para-rosanilin  salts  with  alcohol  and  potassium 
cyanide.  Hydrocyano-rosanilin  is  similarly  obtained  from  rosanilin 
salts.  According  to  Hantzsch,  quinoid  ammonium  cyanides  are  first 
generated,  and  these  transpose  themselves  into  nitriles  in  the  solution 
itself  (B.  33,  287)  : 

(NH2.C6H4)2C  :  C6H4  :  NH2CN  -    ->  (NH2.C6H4)2C(CN).C6H4.NH2. 

The  chlorohydrates  of  these  hydrocyano-compounds  decompose 
on  heating  into  HC1,  HCN,  and  the  rosanilin  salts. 

Substituted  triphenyl-acetic  acids,  especially  phenol  derivatives, 
are  easily  obtained  from  benzilic  acid  with  phenols  by  condensation 
with  tin  tetrachloride  (B.  34,  3080  ;  37,  664  ;  40,  4060)  : 


Diphenyl-p-tolyl-acetic  acid  CH3[4]C6H4(C6H5)2CCOOH,  m.p.  205°. 
p-Tritolyl-acetic  acid  (CH3C6H4)3C.CO2H,  m.p.  227°.  p-Oxy-triphenyl- 
acetic  acid  HO[4]C6H4(C6H5)2CCOOH,  m.p.  212°.  m-  and  p-Cresol- 

diphenyl-acetic  acid  lactone  A[2]C6H3(CH3)[i]C(C6H5)2CO,  m.p.  126° 
and  130°.  o-  and  m-Xylenyl-diphenyl-acetic  acid  lactone,  m.p.  178° 
and  170°.  Thymoyl-  and  earvacroyl-diphenyl-acetic  acid  HO[4]C6H0 

(CH3)(C3H7)[i]C(C6H5)COOH,  etc. 

Diphenyl-methyl-quinol-earboxylie  acid  lactone  (formula,  see  below), 
colourless  crystals,  m.p.  143°,  is  formed  by  condensation  of  diphenyl- 
ketene  with  excess  of  quinone.  On  heating,  it  decomposes  into  CO2 
and  diphenyl-quino-methane.  As  a  quinol  derivative  it  shows  the 
transposition  into  benzene  derivatives  with  migration  of  the  alkyl 
group  characteristic  of  these  compounds  ;  thus,  the  above  /Mactone 
on  illumination  in  the  solid  state  or  in  boiling  benzene  solution  passes 
into  the  isomeric  2,  5-dioxy-triphenyl-aeetic  acid  lactone,  m.p.  196°  : 

(C6H5)aC—  CO 


which  has  also  been  obtained  synthetically  from  hydroquinone  and 
benzilic  acid  by  means  of  SnCl4  (A.  380,  248). 

B.  Sym.  Diphenyl-ethane  Group.  —  Dibenzyl,  sym.  diphenyl-ethane 
C6H5.CH2.CH2.C6H5,  m.p.  52°  and  b.p.  284°,  is  prepared  (i)  by  the 
action  of  sodium  or  copper  upon  benzyl  chloride  C6H5.CH2C1,  or  (2) 
of  A1C13  upon  benzene  and  ethylene  chloride  or  co-chlorethyl-benzene 
(A.  235,  155)  ;  and  (3)  by  heating  its  oxygen  derivatives,  benzoin  and 
benzile,  and  from  the  unsaturated  hydrocarbons  tolane  and  stilbene 
VOL.  II.  2  R 


6io  ORGANIC   CHEMISTRY 

by  reduction  with  Na  and  alcohol  (B.  35,  2647),  HI,  or  H  and  Ni  at 
220°  (C.  1908,  I.  469).  Finally,  it  can  be  obtained  (4)  by  oxidation 
of  toluol  with  potassium  persulphate  (B.  32,  2531).  It  forms  stilbene 
and  tolane  when  heated  to  500°.  Chromic  acid  and  potassium  per- 
manganate oxidise  it  directly  to  benzoic  acid.  It  yields  two  dinitro- 
compounds  by  nitration. 

p,  p-Dinitro-dibenzyl  has  also  been  obtained  by  the  action  of 
stannous  chloride  upon  p-nitro-benzyl  chloride.  It  melts  at  181° 
(A.  238,  272  ;  B.  20,  909).  Also  by  the  action  of  cold  methyl-alcoholic 
potash  upon  p-nitro-toluol  (C.  1908,  I.  642).  o,  o-Dinitro-dibenzyl, 
m.p.  122°  (C.  1910,  II.  570). 

p2-Diamido-dibenzyl  can  be  used  for  the  preparation  of  tetrazo- 
dyes  in  the  same  way  as  diamido-stilbene  (C.  1899,  I-  II71)- 

Oo-Diamido-dibenzyl,  m.p.  68°,  by  reduction  of  o2--diamido-stilbene. 

CH  C  H  \ 

On  heating  its  chlorohydrate  it  gives  imido-dibenzyl  CH'C'H  /  NH> 
m.p.  110°,  which  contains  a  seven-membered  ring  (A.  305,  96). 

Homologues  of  Dibenzyl. — o2,  m2,  and  p2-Dimethyl-dibenzyl,  m.p. 
66°,  82°,  and  296°,  are  produced  by  oxidation  of  o-,  m-,  and  p-xylol 
with  potassium  persulphate  (B.  32,  2531). 

a,  j8-Diphenyl-propane  C6H5CH(CH3)CH2C6H5,  b.p.28  167°,  by 
reduction  of  a-methyl-stilbene.  a,  jS-Diphenyl-iso-butane  C6H5CH2C 
(CH3)2C6H5,  from  iso-butylene  bromide,  benzene,  and  A1C13  (C.  1901, 
II.  202). 

a,£-Phenyl-tolyl-propane  C6H5CH(CH3)CH2C6H4CH3,  and  a,j8- 
phenyl-xylyl-propane,  are  produced  when  concentrated  sulphuric  acid 
acts  upon  styrol  in  the  presence  of  xylene  or  trimethyl-benzene.  The 
homologous  benzenes,  containing  a  methyl  group,  attach  themselves 
to  the  unsaturated  linkage  in  the  styrol  (B.  23,  3269). 

Diphenyl-dimethyl-ethane  C0H?.CH(CH8)CH(CH^C6H5,  melting  at 
123°,  is  formed  when  sodium  or  zinc  dust  acts  upon  a  j8-haloid  ethyl- 
benzene  C6H5.CHX.CH3  (B.  26,  1710) ;  also  from  ethyl-benzol  with 
persulphate  (B.  32,  434). 

Stilbene,  toluylene,  sym.  diphenyl-ethylene  C6H5.CH  :  CH.C6H5, 
melting  at  124°'  and  boiling  at  306°,  crystallises  in  large,  glistening 
(oTtAjSetv,  to  glisten)  monoclinic  leaflets  or  prisms.  It  is  obtained  by 
a  great  variety  of  methods.  It  belongs  to  a  long-known  class  of 
aromatic  substances  (Laurent,  1844).  It  is  produced  : 

(1)  By  distilling  benzyl  sulphide  and  disulphide. 

(2)  By  heating  polymeric  thio-benzaldehyde  to  150°,  or  by  distilling 
trithio-benzaldehyde  with  metallic  copper  (B.  25,  600). 

(3)  By  the  action  of  metallic  sodium  upon  benzaldehyde  or  benzal 
chloride. 

(4)  From  benzaldehyde   and  phenyl-acetic  acid,  instead  of    the 
expected  phenyl-cinnamic  acid  (/.  pr.  Ch.  2.  61,  169). 

(5)  By  magnesium  organic  syntheses  stilbene  and  its  homologues 
are  formed  from  benzyl-magnesium   chloride  with   benzaldehydes  or 
aromatic  ketones,  the  benzyl-aryl-carbinols  formed  as  primary  pro- 
ducts splitting  off  water  (B.  37,  453,  1447). 

(6)  By  heating  iso-nitro-benzyl  cyanide  C6H5C(:  NOOH)CN  with 
soda  to  high  temperatures,  whereby  phenyl-iso-nitro-methane  is  first 
formed,  which  splits  off  sodium  nitrite  and  forms  stilbene  (B.  38,  502). 


HOMOLOGOUS   DI-  AND   POLY-PHENYL-PARAFFINS      611 

(7)  From  benzal-azin   C6H5CH  :  N.N  :  CHC6H5  and  phenyl-diazo- 
methane  C6H5CHN2,  by  heating  and  rejection  of  nitrogen. 

(8)  From    chlorinated,   asymmetrical   diphenyl-ethane  derivatives 
—e.g.  (C6H5)2CH.CH2C1,  (C6H5)2CH.CC13— by  a  rearrangement  caused 
by  heat  or  zinc  dust  "(B.  7,  1409  ;  /.  pr.  Ch.  2,  47,  44). 

(9)  By  the  action  of  metallic  copper,  potassium  sulphydrate  (B.  24, 
1776),  or  potassium  cyanide  (B.  11,  1219)  upon  stilbene  dihalides. 

(10)  An  interesting  method  for  its  production  is  that  of  distilling 
fumaric  and  cinnamic  phenyl  esters  (B.  18, 1945)  : 

— CaO  — COj 

C.H5OCOCH  :  CH.COOC,H5 >  C6H5.CH  :  CH.CO.OC.H, >  C6Ht.CH  :  CH.C.H, 

Diphenyl- fumaric  ester  Phenyl-cinnamic  ester  Stilbene. 

Compare  also  the  decomposition  of  chloro-benzyl-desoxy-benzoin  in 
benzoyl  chloride  and  stilbene. 

As  an  unsaturated  compound,  stilbene  can  occur  in  a  second  stereo- 
isomeric  form.  This  iso-stilbene  is  a  liquid,  b.p.12  143°,  and  has  a 
pleasant  flower-like  odour.  It  is  formed  by  the  reduction  of  tolane  or 
iso-bromo-stilbene  with  zinc  dust  and  alcohol  (A.  342,  208),  also  from 
the  ordinary  stilbene  by  illuminating  by  ultra-violet  light  in  benzene 
solution  (B.  42,  4871),  besides  the  polymeric  distilbene  C2gH24,  m.p. 
163°  (B.  35,  4129).  By  traces  of  iodine  or  bromine,  distillation  at 
ordinary  pressure,  or  vapours  of  fuming  nitric  acid,  it  passes  into  the 
stable  solid  stilbene.  Its  formation  from  tolane  indicates  for  iso- 

TTf  C  TT  TTC  f  TT 

stilbene  the  cis-configuration  H^'C"H5»  whereas          ^H6    5  represents 

the  ordinary  stilbene  as  a  trans-configuration. 

When  heated  with  hydro-iodic  acid  stilbene  yields  dibenzyl.  The 
addition  of  halogens  produces  stilbene  dihaloids,  the  haloid  esters  of 
the  hydro-benzoins.  Chromic  acid  oxidises  stilbene  to  benzaldehyde 
and  benzoic  acid.  Thionessal,  tetraphenyl-thiophene  (q.v.),  is  pro- 
duced when  stilbene  is  heated  for  several  hours  at  250°,  together  with 
sulphur.  Phenanthrene  is  formed  when  stilbene  is  heated. 

With  N2O3  and  N2O4  stilbene  combines  to  form  CUH12(N2O3)  and 
C14H12(N2O4)  ;  the  former,  on  boiling  with  glacial  acetic  acid,  is  partly 
decomposed  and  converted  into  the  latter,  which  is  to  be  regarded  as 
diphenyl-dinitro-ethane  C6H5CH(NO2).CH(NO2)C6H5,  a-mod.,  m.p. 
236°  with  decomposition,  jS-mod.,  m.p.  I50°-i52°  (B.  34,  3536). 

On  treating  with  alkali  it  splits  off  one  molecule  of  nitrous  acid  and 
passes  into  7-nitro-stilbene  C6H5CH  :  C(NO2)C6H5,  m.p.  75°,  which  is 
also  obtained  by  the  condensation  of  phenyl-nitro-methane  and 
benzaldehyde  by  means  of  aliphatic  base  (B.  37,  4509),  and  by  heating 
with  methyl-alcoholic  potash  and  then  with  HC1  through  a  number  of 
intermediate  products  into  the  isomeric  benzyl-monoxime  C6H5COC 
(NOH)C6H5  (A.  355,  269). 

a-Methyl-stilbene  C6H5C(CH3)  :  CHC6H5,  m.p.  83°,  b.p.26  183°,  and 
a-ethyl-stilbene,  m.p.  57°,  b.p.  296°,  from  desoxy-benzoin  with 
CH3MgI  and  C2H5MgI  ;  also  from  aceto-phenone  with  C6H5CH2MgCl 
(B.  37,  457,  1450  ;  C.  1904,  II.  1038). 

Stilbenes  having  the  substituents  in  the  benzene  nucleus  are 
obtained  from  substituted  benzyl  and  benzal  chlorides ;  also  by 
condensation  of  substituted  benzaldehydes  with  phenyl-acetic  acid ; 
or  of  o-chloro-benzal  chloride  with  copper. 


612  ORGANIC   CHEMISTRY 

o,  o-Dichloro-stilbene  (C1.C6H4.CH)2,  m.p.  97°;  and  chloro-nitro- 
benzyl  chloride  and  alcoholic  potash  give  rise  to  diehloro-nitro-stilbene, 
m.p.  294°  (B.  25,  79  ;  26,  640). 

o,  p-Dinitro-stilbene  (NO2)2[2,  4]C6H3CH  :  CHC6H5,  m.p.  140°,  from 
benzaldehyde  and  o,  p-dinitro-toluol  by  means  of  piperidin,  give  by 
partial  reduction  with  ammonium  sulphide  o-nitro-p-amido-stilbene, 
m.p.  in0,  and  with  stannous  chloride  o-amido-p-nitro-stilbene,  m.p. 
143°,  and  further  o,  p-diamido-stilbene,  m.p.  120°  (B.  34,  2842). 

The  action  of  alcoholic  potash  upon  o-  and  p-nitro-benzyl  chlorides 
gives  rise  to  two  physical  isomerides  in  each  case  :  two  o,  o-dinitro- 
stilbenes,  melting  at  126°  and  196°  respectively,  and  two  p,  p-dinitro- 
stilbenes,  melting  at  2io°-2i6°  and  28o°-284°  (B.  21,  2072  ;  23, 
1959  ;  26,  2232),  which  yield  corresponding  diamido-stilbenes  upon 
reduction. 

p2-Dinitro-stilbene-disulphonic  acid  is  formed  by  the  oxidation  of 
p-nitro-toluol-sulphonic  acid  with  alkaline  hypochlorite ;  oo'-dinitro- 
dibenzyl-disulphonic  acid  is  first  formed,  and  on  further  oxidation 
p-nitro-benzal-dehydro-o-sulphonic  acid  (C.  1898,  II.  94  ;  C.  1900,  I. 
1085). 

oo'-Diamido-stilbene,  melting  (cis-)  at  123°  and  (trans-)  at  168°, 
changes  to  indol  on  heating  equivalent  quantities  of  the  hydro- 
chloride  and  base ;  aniline  is  eliminated  (B.  28,  1411 ;  but  see 
o2-Diamido-dibenzyl).  The  disulphonic  acid  of  p2-diamido-stilbene 
(melting  at  227°),  by  diazotising  and  combining  with  phenol,  passes 
into  a  tetrazo-compound,  brilliant  yellow.  The  mono-ethyl  derivative 
CH.C6H3(S03H)N  :  NC6H4OH 

of  the  latter  is  the  substantive  cotton- 
CH.C6H3(S03H)N  :  NC6H4OC2H6 

dye  chrysophenin  (B.  27,  3357).  See  B.  22,  R.  311  (cp.  benzidin  dyes), 
for  additional  dye-substances.  On  the  electrolytic  reduction  of  nitro- 
stilbenes  to  cyclic  azoxy-  and  azo-stilbenes,  see  C.  1903,  I.  1414. 

o-Oxy-stilbene,  m.p.  147°  (B.  42,  825). 

p-Oxy-stilbene,  m.p.  189°,  see  A.  349,  107. 

o,  o'-Dioxy-stilbene,  m.p.  92°,  is  formed  with  other  products  from 
salicyl  aldehyde  on  boiling  with  zinc  dust  and  glacial  acetic  acid  (B.  24, 

3175). 

p2-Dioxy-stilbene,  m.p.  281°,  is  obtained  as  unsym.  diphenol- 
trichloro-ethane  (HO[4]C6H4)2CHCC13,  the  condensation  product  of 
phenol  and  chloral,  by  treatment  with  zinc  dust  or  iron  powder.  By 
attaching  bromine  at  low  temperatures  it  gives  p2-dioxy-stilbene 
dibromide,  possessing  the  character  of  a  pseudo-phenol-alcohol  bromide. 
On  treatment  with  sodium  acetate  it  splits  off  2HBr  and  yields  stilbene- 
quinone,  O  :  C6H4  :  CH.CH  :  C6H4  :  O,  bright-red  crystals,  which  can 
also  be  obtained  direct  from  the  p2-dioxy-stilbene  by  oxidation  with 
PbO2  or  FeCl3,  and  resembles  in  its  chemical  behaviour  the  simple 
methylene-quinones  (A.  335,  157  ;  B.  39,  3490).  At  higher  tempera- 
tures chlorine  and  bromine  act  upon  p2-dioxy-stilbene  as  substituents, 
forming  tetrachloro-  and  tetrabromo-p2-dioxy-stilbene  dichloride  and 
dibromide  respectively,  which,  on  treatment  with  alkali,  pass  into 
tetrabromo-  and  tetrachloro-stilbene-quinone  O  :  (C6C12H2)  :  CH.CH  : 
(C6C12H2)  :  O.  These  products  are  sparsely  soluble  and  resemble 
phosphorus  (A.  325,  19). 


ALCOHOL  AND  KETONE  DERIVATIVES  OF  DIBENZYL    613 

3,  4rMethylene-dioxy-stilbene  CH2O2C6H3CH  :  CHC6H5,  m.p.  96°, 
from  piper onal  and  benzyl-magnesium  chloride  (B.  37,  1431). 

Tolane,  diphenyl-acetylene  C6H5.C  :  C.C6H5,  m.p.  60°,  is  produced 
from  stilbene  dibromide  on  boiling  with  alcoholic  potash,  and,  further, 
together  with  diphenyl- vinyl  ether,  on  treating  unsym.  diphenyl- 
chloro-ethylene  (C6H5)2C  :  CHC1  with  sodium  alcoholate. 

The  latter  method  proceeds  more  smoothly  with  the  substituted 
tolanes.  Dimethyl-tolane,  m.p.  136°,  and  dimethoxy-tolane,  m.p.  145°, 
are  obtained  from  ditolyl-  and  dianisyl-chloro-ethylene. 

o,  o'-Dichloro-tolane,  m.p.  89°,  is  made  from  o,  o'-dichloro-stilbene 
dichloride. 

Tetrachloro-p-dioxy-tolane,  m.p.  226°,  see  A.  338,  236. 

The  tolanes  absorb  two  and  four  halogen  atoms,  the  products  being 
tolane  di-  and  tetrachlorides  (q.v.).  The  elements  of  water  are  taken 
up  by  the  action  of  glacial  acetic  acid  and  sulphuric  acid,  with  the 
formation  of  desoxy-benzoins  (below)  (cp.  Vol.  I.). 

The  action  of  nitrous  acid  gas  upon  tolane  produces  a-  and  £- 
diphenyl-dinitro-ethylene  C6H5C(NO2)  :  C(NO2)C6H5,  m.p.  i86°-i87° 
and  io5°-io7°  (B.  34,  619).  p2-Diamido-tolane,  m.p.  235°,  and  trans- 
formation products,  see  A.  325,  67. 

ALCOHOL  AND  KETONE  DERIVATIVES  OF  DIBENZYL. 

C6H5CHOH  C6H5CO  C6H5CHOH  C,H5CO  C6H5CO 

C6H5CH2  C6H5CH2  C6H5CHOH  CGH5CHOH          C6H3CO 

Stilbene  hydrate      Desoxy-benzoin     Hydro-benzoin  Benzoin  Benzile. 

Stilbene  hydrate,  benzyl-phenyl-carbinol  C6H5.CH(OH).CH2.C6H5, 
m.p.  62°,  results  upon  reducing  desoxy-benzoin  with  sodium  amalgam, 
and  from  the  action  of  benzaldehyde  upon  benzyl-magnesium  chloride. 
Similarly,  benzyl-phenyl-methyl-earbinol  C6H5.C(OH)(CH3).CH2C6H5, 
m.p.  51°,  b.p.15  175°,  is  obtained  from  benzyl-magnesium  chloride  with 
aceto-phenone,  or  from  desoxy-benzoin  with  CH3MgI  ;  the  latter 
carbinol  splits  off  water  with  greater  difficulty  than  does  the  former 
(B.  37,  456,  1450). 

Desoxy-benzoin,  phenyl-benzyl-ketone  C6H5.CO.CH2.C6H5,  m.p.  60° 
and  b.p.  314°.  It  is  obtained  by  distilling  a  mixture  of  calcium 
benzoate  and  calcium  a-toluate  ;  also  by  the  action  of  A1C13  upon  a 
mixture  of  alpha-toluic  chloride  ;  by  reducing  benzoin  with  zinc  and 
hydrochloric  acid  (B.  21,  1296  ;  35,  912)  ;  from  chloro-benzile  and 
benzile  (B.  26,  R.  585)  by  the  action  of  hydriodic  acid  or  zinc  and  HC1 ; 
and  by  heating  monobromo-stilbene  with  water  to  i8o°-i9O°.  One 
H  atom  of  its  CH2  group  can  be  replaced  by  sodium  and  alkyls,  but 
not  the  second  (B.  21,  1297  ;  23,  2072).  Methyl-,  iso-butyl-,  cetyl- 
desoxy-benzoln  melt  at  58°,  78°,  and  76°  (B.  25,  2237). 

Its  oxime  melts  at  98°.  Iso-nitroso-desoxy-benzo'in,  produced  by 
N2O3,  is  identical  with  a-benzile-monoxime.  Hydriodic  acid  converts 
desoxy-benzoin  into  dibenzyl ;  see  also  stilbene  hydrate. 

The  nitration  of  desoxy-benzoin  produces  o-nitro-desoxy-benzom 
C6H4(NO2)CH.2.CO.C6H5,  which,  upon  reduction,  yields  a-phenyl- 
indol  C6H4<™c.c6H5.  Desoxy-toluom  CH3.C6H4.CH2.CO.C6H4.CH3, 


614  ORGANIC  CHEMISTRY 

and  desoxy-anisoin  CH3O.C6H4.CH2.CO.C6H4.OCH3,  are  formed  from 
the  corresponding  tolanes  (A.  279,  335,  339)  (above).  CSC12,  or 
carbon  disulphide,  and  caustic  potash,  convert  the  desoxy-benzoins 
into  desaurins,  which  form  brilliant  golden-yellow  needles.  They 
dissolve  in  sulphuric  acid  with  a  violet-blue  colour.  The  exact  con- 
stitution of  these  bodies  is  not  yet  known.  The  simplest  desaurin 
very  probably  has  the  composition  C6H5COC(CS)C6H5  (B.  25,  1731, 
2239).  Cp.  B.  37,  1599.  Mono-  and  polyoxy-desoxy-benzoms,  see 
M.  26,  927. 

Hydro-benzoin,  toluylene-glycol  C6H5.CH(OH)CH(OH)C6H5,  has  two 
asymmetric  C  atoms,  and  occurs  in  two  optically  inactive  modifications 
(A.  259, 100)  :  hydro-benzoin,  m.p.  134°,  and  iso-hydro-benzo'in,  m.p.  119°. 
The  latter  has  been  resolved  into  two  optically  active  components 
(see  below).  Both  are  produced,  together  with  benzyl  alcohol,  when 
zinc  and  alcoholic  hydrochloric  acid  act  upon  oil  of  almonds,  or  when 
the  latter  is  treated  with  sodium  amalgam,  or  in  the  electrolytic  reduc- 
tion of  benzaldehyde  (B.  29,  R.  229).  Both  are  also  obtained  from 
stilbene  bromide  or  chloride  on  converting  the  latter  by  silver  acetate 
or  benzoate  into  esters,  and  saponifying  these  with  alcoholic  ammonia. 
With  potassium  acetate,  iso-hydro-benzoin  is  almost  the  sole  product. 
Hydro-benzoin  predominates  (with  a  little  iso-hydro-benzoin)  when 
sodium  amalgam  acts  on  benzoin.  This  is  also  the  best  method  for 
its  preparation  (A.  248,  36). 

Hydro-benzoin  dissolves  with  difficulty  in  water,  crystallises  in 
rhombic  plates,  melting  at  134°,  and  sublimes  without  decomposition. 
The  diacetate  is  obtained  from  benzaldehyde  and  acetyl  chloride  by 
means  of  zinc  dust  (B.  16,  636)  ;  it  melts  at  134°. 

Iso-hydro-benzo'in  is  more  readily  soluble  in  water.  It  crystallises 
in  prisms  which  contain  water  of  crystallisation  and  rapidly  effloresce 
on  exposure.  Its  diacetate  is  dimorphous,  and  crystallises  in  shining 
leaflets,  melting  at  118°,  or  in  rhombic  prisms,  melting  at  106°. 

C6H5CH.O.CH.C6H5 

Dimolecular  anhydrides  \  (?),  melting  at   132°  and 

C6H5.CH.O.CH.C6H5 

102°,  are  obtained,  together  with  diphenyl-acetaldehyde  (C6H5)2CH. 
CHO,  from  both  hydro-benzoins  by  the  action  of  sulphuric  acid  or  P2O5. 

By  crystallisation  from  ether  iso-hydro-benzoin  has  been  resolved 
into  enantiomorphous  dextro-  and  Isevo-rotatory  crystals  (B.  30,  1531). 
Chromic  acid  or  potassium  permanganate  changes  both  hydro-benzoins 
into  benzaldehydes,  and  nitric  acid  converts  them  into  benzoin  (B.  24, 
1776).  PBr5  changes  both  to  the  same  stilbene  dibromide  C6H5.CHBr. 
CHBr.C6H5,  melting  at  237°,  which  has  also  been  made  by  the  action 
of  bromine  upon  stilbene  and  dibenzyl.  Stilbene  and  bromine  yield 
not  only  the  body  (the  a-)  melting  at  237°,  but  also  a  j8-variety,  melting 
at  no0.  This  is  more  readily  soluble.  It  passes  into  the  higher-melting 
variety  under  the  influence  of  heat,  and  this  again  reverts  by  alcoholic 
potash  into  liquid  monobromo-stilbene,  whereas  the  /^-modification 
by  similar  treatment  changes  to  a  solid  monobromo-stilbene  (B.  28, 
2693) .  Both  hydro-benzoins  are  changed  by  PC15  into  a-  and  /3-stilbene 
dichloride,  melting  at  192°  and  93°.  The  a-compound  is  also  produced 
when  chlorine  acts  upon  stilbene  dissolved  in  chloroform.  When 
heated  to  200°  the  j8-  passes  into  the  a-variety. 


ALCOHOL  AND  KETONE  DERIVATIVES  OF  DIBENZYL    615 

Diphenyl-oxethylamine  C6H5.CH(OH)CH(NH2)C6H5,  melting  at  163°, 
and  iso-diphenyl-oxethylamine,  melting  at  129°,  are  produced  together 
by  the  reduction  of  benzoin-oxime,  also  from  benzaldehyde  and  benzyl- 
amine,  as  well  as  by  the  condensation  of  benzaldehyde  and  glycocoll, 
together  with  phenyl  -  a  -  amido  -  lactic  acid.  This  last  reaction  is 
explained  by  the  condensation  of  benzaldehyde  with  benzylidene- 
glycocoll  in  two  directions  according  to  the  following  scheme  : 

T    C6H5CH  :  NCHCOOH  .  C6H5CHN  :  CHCOOH 

HO.CHC6H5  -C'H5CI          'H2CC  ^C6 


I.  is  split  up  into  benzaldehyde  and  phenyl-amido-lactic  acid  ;  II.  into 
glyoxylic     acid     and     diphenyl-oxethylamine.       The     two     isomeric 
diphenyl-oxethylamines  can  be  separated  by  means  of  their  benzylidene 
compounds.     Nitrous  acid  converts  them  both  into  iso-hydro-benzoin. 
Iso-diphenyl-oxethylamine  has    been  split  up  into   optically  active 
components,    [a]D=  ±109-6°   (A.   307,   79;     B.   32,   2377;    36,    976). 
The  quaternary  ammonium  bases  obtained  from  the  two  dimethyl- 
oxethyl  -  amines     by     thorough     methylation     have     the     formula 
C6H5CH(OH).CH(C?H5)N(CH3)3OH,  and  are  broken  up   by  heating 
with  water  into  trimethylamine,  water,  and  diphenyl-ethylene  oxide 
C6H5CH.O.CHC6H5,  m.p.  69°,  and  iso-diphenyl-ethylene   oxide,  m.p. 
42°  (B.  43,  884). 

Diphenyl  -  ethylene  -  diamine,  stilbene-diamine  C6H5CH(NH2)CH 
(NH2)C6H5,  melting  at  91°,  is  produced  by  reducing  benzile-dioxime 
with  sodium  and  alcohol.  It  is  resolved  by  crystallisation  of  its 
bitartrate  into  two  optically  active  components  (B.  28,  3167). 

The  reduction  of  diphenyl-dinitro-ethanes  and  ethylenes  with  zinc 
dust  and  acetic  acid  produces  tetraphenyl-diethylene-diamine,  tetra- 
phenyl-piperazin  NH[CH(C6H5).CH(C6H5)]NH  (B.  34,  627). 

The      dieso  -  anhydride      of      an       o,  o  -  dioxy  -  hydro  -  benzoin 

O.C6H4.CH.CH.C6H4O,  has  been  obtained  in  two  modifications,  melting 

at  68°  and  114°,  by  the  reduction  of  salicyl-aldehyde  with  zinc  dust 
and  glacial  acetic  acid. 

Benzoin,  benzoyl-phenyl-carbinol  C6H5.CH(OH).CO.C6H5,  melting 
at  134°,  is  produced  when  the  hydro-benzoins  are  oxidised  with 
concentrated  nitric  acid,  and  by  the  condensation  of  two  molecules 
of  benzaldehyde  with  potassium  cyanide  in  aqueous  alcoholic 
solution. 

This  reaction  is  also  shown  by  other  aromatic  aldehydes  (see  B.  25, 
293  ;  26,  60  ;  C.  1908,  II.  1689).  The  products  are  ketone  alcohols— 
e.g.  aniso'in  CH3O.C6H4CH(OH)CO.C6H4.OCH3  ;  cuminom,  etc.,  from 
anisic  aldehyde,  cuminol  (see  Furfurol,  Phenyl-glyoxal)  —  and  reduce 
Fehling's  solution,  being  at  the  same  time  oxidised  to  the  corresponding 
benziles. 

d-  and  1-Benzoin  have  been  obtained  by  transformation  of  d-  and 
1-mandelic  acid  amide  with  phenyl-magnesium  bromide  (C.  1909, 

II.  2005). 

Chromic  acid  oxidises  benzoin  to  benzaldehyde  and  benzoic  acid, 
while  nitric  acid  changes  it  to  benzile  ;  nascent  hydrogen  reduces  it 
to  hydro-benzoin.  The  latter  and  benzile  are  produced  when  benzoin 


616  ORGANIC  CHEMISTRY 

is  boiled  with  alcoholic  potash.  If  air  be  simultaneously  introduced, 
benzile  is  the  chief  product,  and  it  is  further  changed  to  benzilic  acid. 
By  heating  with  concentrated  alkali  it  is  partly  split  up  into  benzyl 
alcohol  and  benzoic  acid.  Prolonged  action  also  yields  hydro-benzoin, 
stilbene  hydrate,  etc.  (B.  35,  1982). 

Benzoin  hydrazone  melts  at  75°  (/.  pr.  Ch.  2,  52,  124).  Semi- 
carbazone,  m.p.  206°  (A.  339,  257).  The  phenyl-hydrazones  melt  at 
158°  and  106°  (B.  28,  R.  788)  ;  the  a-oxime  at  152°,  the  £-oxime  at 
99° ;  by  oxidation  with  chromic  acid  the  acetyl-/3-benzoin-oxime 
passes  into  the  acetyl-y-benzile-oxime,  which  determines  its  configura- 
tion (B.  38,  69). 

Alcohols  and  hydrochloric  acid  alkylise  benzoin  :  methyl-benzoin 
C6H5CH(OCH3)COC6H5  melts  at  50°,  and  ethyl-benzoin  at  62°  (B.  26, 
2412).  Iso-propyl-benzom,  m.p.  72°-75°  (B.  26,  2412;  C.  1700, 

I-  454)- 

The  HC1  ester  of  benzoin,  desyl-chloride  C,3H5CHC1COC6H5,  m.p. 
68°,  is  formed  by  heating  of  benzoin  with  thionyl  chloride  (B.  42, 

2348). 

Desyl-bromide  C6H5.CHBrCOC6H5,  m.p.  55°,  is  obtained  from 
desoxy-benzoin  (see  below)  and  bromine.  Aniline  converts  it  into 
desyl-anilide,  benzom-anilide  C6H5CH(NHC6H5)CO.C6H5,  m.p.  99°, 
which  is  also  produced  when  aniline  is  heated  together  with  benzoin. 
When  heated  together  with  aniline  hydrochloride  to  160°,  the  product 
is  benzom-anile-anilide  C6H5CH(NH.C6H5)C(NC6H5)C6H5,  m.p.  125° ; 
and  when  with  aniline  and  zinc  chloride  at  still  higher  temperatures, 

NH.C6H4 

diphenyl-indol         I      I          (B.  26,  1336,  2640). 
C6H5C=C.C6H5 

Benzom-p-toluide  C6H5CH(NHC6H4.CH3)CO.C6H5,  m.p.  145°,  is 
formed  in  the  condensation  of  benzaldehyde-toluidin  by  means  of 
potassium  cyanide  (B.  29,  1736).  o-Diamines  and  benzoin  condense 
to  dihydro-quinoxalins  ;  urea  and  thio-ureas  with  benzoin  yield  gly- 
oxalins,  while  oxazoles  are  produced  in  the  condensation  of  benzoin 
with  acid  nitriles.  For  the  condensation  products  of  benzoin  with 
acetone  and  aceto-phenone,  consult  B.  26,  65. 

Benzile,  dibenzoyl,  diphenyl-glyoxal  C6H5.CO.CO.C6H5,  m.p.  90° 
and  b.p.  347°,  consists  of  beautiful  yellow  prisms.  It  is  the  most 
easily  obtained  a-diketone.  It  is  produced  on  boiling  stilbene  bromide 
with  water  and  silver  oxide,  and  by  digesting  benzoin  with  concen- 
trated nitric  acid. 

/yNH\ 

Benzile  andhydrazin  hydrate  form  hydra-benzile  C6H5cl  <^  |     JCO.C6H6 


C6H5C( 


and   bis  -  hydrazi  -  benzile      C6H5C  <J          ,   which   yield   azi  -  benzile 


/  /N\  /  /N\l 

C6H5d<J|jco.C6H5  and  bis-azi-benzile     c.H5.cmij      on  oxidation 

(B.  29,  775).  On  heating  in  indifferent  solvents  the  azi-benzile 
decomposes  into  nitrogen  and  diphenyl-ketene  (B.  42,  2346).  Benzile- 
mono-semi-earbazone,  m.p.  175°,  heated  with  alcohol,  splits  off  water 
and  forms  diphenyl-oxytriazin  ;  benzile-di-semi-carbazone,  m.p.  244° 
(A.  339,  243). 


ALCOHOL  AND  KETONE  DERIVATIVES  OF  DIBENZYL    617 

Benzile-osazone  (C6H5)2.C2(NNH.C6H5)2,  m.p.  225°,  becomes  tri- 
phenyl-oso-triazole  on  heating  (A.  232,  230  ;  B.  26,  R.  198).  An  iso- 
meric  modification  of  benzile-osazone,  m.p.  208°,  has  been  obtained  by 
the  action  of  iodine  and  sodium  ethylate  upon  benzal-phenyl-hydra- 
zone.  Derivatives  have  been  similarly  obtained.  When  heated  above 
its  melting-point  it  changes  to  the  higher-melting  modification  (B.  29, 
R.  863  ;  35,  3519  ;  A.  305,  170;  324,  310  ;  C.  1909,  I.  739). 

One  molecule  of  hydroxylamine,  acting  upon  benzile,  produces  two 
isomeric  monoximes,  the  a-  melting  at  134°,  and  the  y-  at  113°.  The 
former  passes  into  the  latter  by  heating  it  to  100°  with  alcohol,  or 
upon  dissolving  it  in  glacial  acetic  acid  with  hydrochloric  acid. 

a-Monoxime  and  hydroxylamine  form  a-benzile-dioxime,  while  the 
y-monoxime  yields  y-benzile-dioxime  (B.  22,  540,  709).  Compare  B.  26, 
792,  R.  52,  for  their  behaviour  with  phenyl-hydrazin. 

Both  monoximes  break  down,  upon  heating,  into  benzo-nitrile  and 
benzoic  acid.  The  behaviour  of  the  benzile-monoximes  in  the  Beckmann 
oxime  rearrangement  is  very  interesting.  It  is  effected  by  means  of 
PC15  :  a-monoxime  (i)  yields  benzoyl-benzimide  chloride  (2),  readily 
decomposing  into  benzo-nitrile  and  benzoyl  chloride,  while  the  y-mon- 
oxime (3)  yields  benzoyl-formic-acid,  anilide  chloride  (4)  (A.  296,  279  ; 
B.  37,  4295)  : 

(i)  C6H5CCOC6H5        (2)  C6H5CC1  (3)  C6H5CCOC6H5        (4)  C1CCOC6H5 

NOH  ttCOCH;  HON  *  CHtt 


In  the  first  instance  the  hydroxyl  exchanged  positions  with  the 
phenyl  residue,  in  the  second  with  the  benzoyl  residue,  which  led  to 
the  above  accepted  configuration  of  the  monoximes. 

Two  molecules  of  hydroxylamine  convert  benzile  into  two  isomeric 
benzile-dioximes,  the  a-  melting  at  237°,  and  the  /?-  at  207°.  A  third 
y-benzile-dioxime  has  been  prepared  from  y-benzile-monoxime  ;  it 
melts  at  163°.  The  ^-dioxime  is  the  most  stable  ;  the  other  modifica- 
tions rapidly  change  to  it.  Under  certain  conditions  the  y-dioxime 
rearranges  itself  into  the  a-form  (A.  274,  33). 

Three  different  esters  are  produced  with  acid  anhydrides  :  benzile- 
dioxime  diacetates  —  the  a-form  melting  at  148°,  the  j8-  at  124°,  and  the 
y-  at  114°.  Sodium  hydroxide  saponifies  the  a-  and  jS-diacetates  to 

C  H  C  *  N 
their  oximes,  while  the  y-acetate  yields  the  anhydride         6|       ^>O, 

v^^JriE\w/  I  JN 

diphenyl-furazane  (q.v.),  which  also  results  from  all  three  dioximes  by 
the  exit  of  water.     Potassium  ferricyanide,  in  alkaline  solution,  oxidises 

C6H6C=N—  O 
all  three  to  the  peroxide  \  \  ,  melting  at  114°.     This,  when 

O6  HgC  =  N  —  O 
rapidly  distilled,  breaks  down  into  two  molecules  of  phenyl  cyanate. 

A  complete  picture  is  also  afforded  by  the  behaviour  of  the  three 
dioximes  in  the  Beckmann  rearrangement,  which  has  led  to  a  formula 
for  the  present  case  of  isomerism  on  the  assumption  that  the  oxime 
hydroxyls  invariably  exchange  positions  with  the  atomic  groups 
adjacent  to  them  (A.  274,  i)  : 

I.  a-Benzile-dioxime  yields  chlorides  with  PC15  by  a  change  in 
position  first  of  the  one  and  then  of  the  second  hydroxyl,  which  can  be 
converted  into  the  anhydrides  :  dibenzenyl-azoxime  and  diphenyl-oxy- 


618  ORGANIC   CHEMISTRY 

biazole  (q.v.),  whose  hydrates  are  included  in  the  following  diagram  for 
the  sake  of  clearness  : 

C6H5C C.C6H6          C6H5COJH       HO|N  N N 

II  II  >  II    II >          II    II 

N.OH     HON  N — CC6H5     C6H5.CQ|H       HO|C.C6H5 

a-Benzile-dioxime  Dibenzenyl-azoxime  Diphenyl-oxy-biazole. 

II.  y-Benzile-dioxime  in  the  first  stage  of  the  reaction  also  yields 
dibenzenyl-azoxime,  but  by  a  second  change  in  position  phenyl-benzoyl- 
urea  is  produced  : 

C6H5C C.C6H6  HO.C N 

II  II  >  II  II 

HO.N       HON  C6H5.N       HOC.C6H5 

y-Benzile-dioxime  Phenyl-benzoyl-urea  (pseudo-form). 

III.  j8-Dioxime  by  a  double  change  in  position  yields  oxanilide  : 

CjHgC C.CgHg  HOC COH 

II          II  >  II          II 

HO.N        N.OH  C6H5.N        NC6H5 

y-Benzile-dioxime  Oxanilide. 

The  ready  transition  of  the  y-diacetate  into  furazane  is  not  in 
harmony  with  the  preceding  configuration  of  the  dioximes  ;  this  might 
rather  be  expected  from  the  a-diacetate. 

The  analogy  of  the  benzile-dioximes  with  the  osazones  of  dioxo- 
succinic  ester  is  rather  remarkable  (I.  528).  These  osazones  also  occur 
in  three  forms,  one  of  which  is  stable  and  the  other  two  unstable, 
so  that  the  assumption  of  similar  causes  for  the  isomerism  is  not  yet 
excluded  (B.  28,  64). 

Aniline  and  benzile  heated  to  200°  yield  benzile-monanile  C6H5CO. 
C(NC6H5)C6H5,  melting  at  106°  ;  on  adding  P2O5  the  product  is  benzile- 
dianile  C6H5C(NC6H5)C(NC6H5)C6H5,  melting  at  142°  (B.  25,  2600  ; 
26,  R.  700).  Benzile,  being  an  o-diketone,  is  particularly  well  adapted 
for  the  formation  of  heterocyclic  rings.  It  condenses  with  ethylene- 
diamine  to  a  dihydw-pyrazine  derivative,  with  ortho-diamines  to 
quinoxalins,  with  o-amido-diphenylamine  to  a  stilbazonium  base  (see 
this),  with  ureas  and  thio-ureas  to  ureins  and  diure'ins,  with  semi- 
carbazide  to  o%y-diphenyl-triazine,  etc.  Hydriodic  acid  reduces  it  to 
desoxy-benzoin,  while  chromic  acid  oxidises  it  to  benzoic  acid.  On 
standing  with  potassium  cyanide  and  alcohol  it  breaks  down  into 
benzoic  acid  and  benzaldehyde.  See  B.  28,  R.  465  ;  29,  R.  645,  865  ; 
C.  1897,  I.  596  ;  1903,  I.  877  ;  1905,  II.  243,  for  the  condensation  of 
benzile  with  malonic  ester  and  aceto-acetic  ester. 

The  conversion  of  benzile  into  benzilic  acid  by  fusion  with  caustic 
potash  or  upon  boiling  with  alcoholic  potash  is  important  : 

C6H5COCOC6H5  -5£~*  (C6H5)2C(OH)COOH. 

Phosphorus  pentachloride  changes  benzile  to  ehloro-benzile  C6H5. 
COCC12C6H5,  m.p.  61°,  and,  later,  to  tolane  tetrachloride  C6H5CC12CC12 
C6Hg,  m.p.  163°.  The  latter  has  also  been  obtained  synthetically  on 
heating  benzo-trichloride  with  copper,  whereas  benzile  is  produced 
when  it  is  heated  together  with  glacial  acetic  acid  or  sulphuric  acid. 

As  benzile  is  obtained  from  benzoin,  so  anisile  (CH3O.C6H4CO)2, 


ALCOHOL   DERIVATIVES   OF   STILBENE  619 

melting  at  133°,  cuminile  (C3H7.C6H4CO)2,  melting  at  84°,  have  been 
prepared  by  the  action  of  nitric  acid  upon  anisoin  and  cuminoin.  Ani- 
sile  and  a  hexamethoxy-benzile  [(CH3.O)3C6H2CO]2,  m.p.  189°,  have 
been  obtained  by  alkaline  reducing  agents  from  anisamide  and  tri- 
methyl-gallamide  (B.  24,  R.  523). 

These  benziles,  when  fused  with  caustic  potash,  yield  : 

Anisilic  acid,  cumilic  acid,  and  hexamethoxy-benzilic  acid  (see 
above) . 

The  osazones  of  several  substituted  benziles,  like  salicile,  cuminile, 
anisile,  piperile,  like  benzile-osazone  itself,  have  been  obtained  by  the 
action  of  atmospheric  oxygen  upon  the  alkaline  alcoholic  solutions  of 
the  phenyl-hydrazones  of  the  corresponding  aldehydes  :  salicyl-alde- 
hyde,  piperonal,  etc.  (A.  308,  i). 

p2-Tetramethyl-diamido-benzile  (CH8)  2NC6H4.CO.COC6H4N(CH3)  2, 
m.p.  198°,  is  obtained  by  heating  oxalyl  chloride  with  excess  of 
dimethyl- aniline  (B.  42,  3487). 

ALCOHOL  DERIVATIVES  OF  STILBENE  are  not  known  in  a  free 
condition  ;  when  their  esters  are  saponified,  isomeric  ketones  are 
obtained  for  the  most  part  (see  Phenyl-vinyl  alcohols)  : 

Bromo-stilbene  C6H5CBr :  CHC6H5  -Jl?0— >  C6H5CO.CH2C6H5  benzofn" 

Iso-benzile  C6H5C(OCOC6H6) :  C(OCOC6H5)C6H5  ->  C6H5CO.CH(OH)C5H5  Benzoin. 

However,  benzoin  reacts  in  most  cases  as  if  it  were  an  unsaturated 
glycol  with  the  formula  C6H5C(OH)  :  C(OH)C6H5. 

Monoehloro-stilbene  C6H5CH  :  CC1.C6H5  is  an  oil  boiling  at  320°- 
324°.  It  is  produced  when  PC15  acts  upon  desoxy-benzom,  and  by 
the  action  of  alcoholic  potash  on  stilbene  dichloride.  When  boiled 
with  glacial  acetic  acid  it  is  transformed  into  an  isomeric  modification, 
melting  at  54°.  Chlorine  and  bromine  convert  it  into  ehloro-stilbene 
dichloride  C6H5CC12.CHC1.C6H5,  m.p.  103°,  and  chloro-stilbene  di- 
bromide,  m.p.  127°  (C.  1897,  I.  858).  Methyl-chloro-stilbene  C6H5C 
(CH3)  :  CC1C6H5  is  obtained  from  methyl-desoxy-benzoin,  and  behaves 
similarly.  It  is  an  oil,  and  melts  at  118°  (B.  25,  2237  ;  29,  R.  34). 
Monobromo-stilbene,  m.p.  31°,  results  on  treating  jS-stilbene  dibromide, 
m.p.  110°,  with  alcoholic  potash  ;  whereas  the  stilbene  dibromide,  m.p. 
237°,  yields  an  iso-bromo-stilbene,  m.p.  19°.  On  the  application  of 
heat  the  latter  passes  into  the  solid  isomeride.  Reduction  with  zinc 
and  alcohol  converts  iso-bromo-stilbene  into  liquid  iso-stilbene. 

Diacetyl-dioxy-stilbene,  stilbene-glycol  diacetate  C6H5C(OCOCH3)  : 
C(OCOCH3)C6H5,  a-modification,  m.p.  153°,  ^-modification,  m.p.  110°, 
is  formed  by  the  reduction  of  benzile  in  acetic  anhydride  and  sulphuric 
acid  with  zinc  dust  (A.  306,  142). 

Iso-benzile,  stilbene-glycol  dibenzoate  C6H5C(O.COC6H5)  :  C(OCOC6Hg) 
C6H5,  colourless  needles,  m.p.  156°,  is  obtained  by  the  action  of  metallic 
sodium  upon  the  ethereal  solution  of  benzoyl  chloride  (Vol.  I.).  It  is 
a  polymeride  of  benzile.  When  saponified  with  caustic  potash  it 
is  resolved  into  benzoic  acid  and  benzoin  (B.  24, 1264). 

Diehloro-stilbene,  tolane  dichloride  C6H5CC1  :  CC1.C6H5,  exists  in 
two  modifications  :  a-,  m.p.  143° ;  j8-,  m.p.  63°.  Both  are  formed 
by  the  addition  of  chlorine  to  tolane,  or  by  the  reduction  of  tolane 
tetrachloride  with  iron  and  acetic  acid,  as  well  as  from  chloro-stilbene 


620  ORGANIC   CHEMISTRY 

dichloride  (see  above)  with  caustic  potash.  Chloro-bromo-stilbene 
CgHgCCl  :  CBrC6H5,  m.p.  174°,  is  similarly  prepared  from  chloro- 
stilbene  dibromide.  Dibromo-stilbenes,  a-  melting  at  208°,  and  j8-  melting 
at  64°,  are  obtained  from  tolane  and  bromine.  Concerning  p2-dioxy- 
derivatives  of  dichloro-stilbene,  and  their  conversion  into  the 
methylene-quinones  of  the  dibenzyl  series,  see  /.  pr.  Ch.  2,  59,  228  ; 
A.  325,  67. 

CARBOXYLIC  ACIDS  OF  THE  DIBENZYL  GROUP. — These  consist 
of  :  (a)  those  in  which  the  carboxyl  group  is  in  the  benzene  nucleus  ; 
(b)  such  as  have  the  carboxyl  group  in  the  side  chain  :  diphenylated 
fatty  acids. 

The  first  group  is  composed  chiefly  of  a  series  of  o-carboxylic  acids 
produced  by  phthalic  anhydride  condensations  : 

Dibenzyi-o,  o'-  and  -p,  p'-dicarboxylie  acid  CO2HC6H4CH2. 
CH2C6H4CO2H,  m.p.  231°  and  over  320°,  are  formed  by  the  oxidation 
of  o-  and  p-toluic  acid  with  potassium  persulphate  (B.  37,  3215). 

o-Desoxy-benzom-carboxylicacidC6H5.CH2.CO.C6H4.COOH(+H2O), 
melting  at  75°,  is  formed  when  boiling  alkalies  act  on  the  corresponding 

lactone.  Benzylidene-phthalide,  benzal-phthalide  C6H4.CH  :  <ic6H4COC), 
melting  at  99°,  which  results  from  the  condensation  of  phthalic 
anhydride  and  phenyl-acetic  acid  with  the  elimination  of  CO2. 

By  means  of  nitro-benzal-phthalide,  benzal-phthalide  can  be  changed 

to  iso- benzal-phthalide  C6H5C  :  CH.C6H4.COO,  melting  at  91°,  the 
anhydride  of  /?,  o-desoxy-benzoin-earboxylic  acid  C6H5.CO.CH2.C6H4. 
CO2H,  melting  at  163°.  The  latter  is  made  by  decomposing  /?-phenyl- 
hydrindone  with  caustic  soda,  and  from  homo-phthalic  anhydride  with 
benzene  and  A1C13  (B.  31,  377).  Benzal-phthalide  sustains  a  different 
rearrangement  under  the  influence  of  sodium  alcoholate  ;  the  sodium 
salt  of  j3-phenyl-diketo-hydrindene  is  then  produced  : 


C6H5.C  :  CH.C6H4.COO  < C6H5CH  :  C.C6H4.COO >  C6H4CH.CO.C6H4.CC)6 

Iso-benzal-phthalide  Benzal-phthalide  Phenyl-diketohydrindene. 

Hydrazin    converts    benzal-phthalide    into    benzyl  -  phthalazone 

N NH 

II  I     .     By  reduction  with  glacial  acetic  acid  and  zinc  it 

C6H6.CH2.C.C6H4.60 

passes  into  benzyl-phthalimidine  C6H5CH2.iHC6H4.CO.NH,  melting  at 
137°.  It  can  also  be  obtained  by  the  reduction  of  benzal-phthalimidine 
(B.  29,  1434,  2743).  Homologues  of  benzal-phthalide,  see  B.  32, 
1104,  etc. 

o,  o-Desoxy-benzoin-dicarboxylic  acid  COOH.C6H4.CH2.Cq.C6H4. 
COOH,  melting  at  239°,  is  obtained  upon  heating  monophthalic  acid 
and  sodium  acetate  (B.  24,  2820).  The  reduction  of  desoxy-benzom- 
mono-  and  dicarboxylic  acids  yields  dibenzyl-mono-  and  dicarboxylie 
acids,  melting  at  131°  and- 225°.  The  oxidation  of  o-desoxy-benzoin- 
carboxylic  acid  produces  o-benzile-carboxylic  acid  C6H5.CO.CO.C6H4. 
COOH,  occurring  in  two  modifications,  one  yellow  in  colour,  melting 
at  141°,  and  another  white,  melting  at  i25°-i3o°  (B.  23,  1344,  2079  ; 
29,  2745  ;  C.  1898,  II.  481). 

o,  o-Benzile-diearboxylie  acid,  diphthalylic  acid  (COOHC6H4CO)2  or 


CARBOXYLIC   ACIDS   OF  THE   DIBENZYL   GROUP     621 


6COC6H4C(OH).C(OH)C6H4CO6,  m.p.  273°,  gives  with  acetyl  chloride 
a  diacetyl  derivative ;  the  acid  esters  are  colourless,  like  the  acid  itself, 
while  the  neutral  esters  are  yellow.  Diphthalide  acid  is  formed  by  the 
oxidation  of  chryso-quinone  and  chryso-ketone  (A.  311,  264).  The  acid 
is  formed  from  phthalic  anhydride  with  zinc  dust  and  acetic  acid  and 

subsequent  oxidation,  or  by  the  oxidation  of  diphthalyl  O.OC.C6H4C  : 

CC6H4COO,  melting  at  334°.  This  latter  body  has  been  produced  by 
the  condensation  of  phthalide  and  phthalic  anhydride  with  potassium 
cyanide  (see  formation  of  benzoin,  p.  615) .  Tetramethoxy-diphthalyl 

6.0C.C6H2(OCH3)2C:CC6H2(OCH3)COO  (B.  24,  R.  820;  cp.  B.  26, 
540)  is  similarly  made  by  the  condensation  of  opianic  ester. 

Tetramethoxy-diphthalyl  OOCC6H2(OCH3)2C  :  CC6H2(OCH3)2COO 
(B.  24,  R.  820  ;  26,  540). 

Dithio-diphthalyl  SCO.C6H4C  :  CC6H4COS,  yellow-green  needles, 
m.p.  333°,  see  B.  31,  2646.  

Dihydro-diphthalyl-di-imide  NH.CO.C6H4.CH.CHC6H4CO.NH,  melt- 
ing with  decomposition  at  284°,  results  from  the  condensation  of  two 
molecules  of  phthalic  anhydride  with  methyl-alcoholic  ammonia.  This 
substance  is  isomeric  with  indigo  white  (cp.  B.  29,  2745). 

Hydro-diphthalyl-lactonie  acid  HOOCCeH4CH2.CHC6H4COO,  m.p. 
198°,  is  formed  on  heating  homo-phthalic  acid  to  230°  (B.  31,  376). 

Dibenzyl-earboxylic  acid  a-phenyl-hydro-cinnamic  acid,  a,  jS- 
diphenyl-propionic  acid,  benzyl-pheny  I- acetic  acid  C6H5CH2CH(C6H5) 
COOH,  appears  in  three  physical  isomerides,  melting  at  95°,  89°,  82°, 
boiling  at  335°  (B.  25,  2017) .  Its  nitrile  results  upon  introducing  benzyl 
into  benzyl  cyanide.  a-Phenyl-o-amido-hydro-cinnamic  acid,  melting 
at  148°,  is  obtained  in  the  reduction  of  a-phenyl-o-nitro-cinnamic  acid 
(B.  28,  R.  391).  It  changes  very  readily  into  its  lactame — B-phenyl- 

/CH2— CH(C6H5)CO 
kydrocarbo-styrile  C6H4<^ — ,  melting  at  174°. 

a/3-Diphenyl-valerie  acid  C2H5CH(C6H5)CH(C6H5)COOH,  m.p.  178° ; 
its  nitrile,  m.p.  115°,  is  formed  by  attaching  C2H5MgI  to  a-phenyl- 
cinnamic  acid  nitrile  (C.  1906,  II.  46). 

Stilbene-earboxylic  acid,  a-phenyl-cinnamic  acid  C6H5CH  :  C(C6H5) 
C02H,  melting  at  172°,  is  formed  in  the  condensation  of  benzaldehyde 
with  phenyl-acetic  acid.  Allo-phenyl-cinnamic  acid,  m.p.  137°  (C.  1897, 
II.  663)  is  also  formed  ;  also  stilbene  on  heating  and  expulsion  of  CO2 
(/.  pr.  Ch.  2,  61,  i).  a-Phenyl-cinnamic  nitrite,  m.p.  86°,  from  benzyl 
cyanide,  benzaldehyde,  and  sodium  ethylate.  By  reduction  it  becomes 
a-phenyl-hydro-cinnamic  acid,  but  does  not  add  bromine.  The  action 
of  bromine  upon  the  sodium  salt  produces  bromo-stilbene  (B.  26,  659). 
a-Phenyl-o-amido-einnamic  acid,  m.p.  186°,  the  reduction  product 
of  o-nitro-a-phenyl-cinnamic  acid,  obtained  in  the  condensation  of 
o-nitro-benzaldehyde  with  phenyl-acetic  acid,  yields  j8-phenanthrene- 
carboxylic  acid  (q.v.)  (B.  29,  496)  when  its  diazo-derivative  is  shaken 
with  copper  in  powder  form.  The  nitrile  of  phenyl-o-amido-cinnamic 


622  ORGANIC   CHEMISTRY 

acid  is  easily  transposed  into  a-amido-j8-phenyl-quinolin,  so  that  syn- 
thesis gives  the  latter  instead  of  the  nitrile  (B.  32,  3399).  The  lactone 
of  phenyl-o-oxy-cinnamic  acid,  a-phenyl-cumarin  C6H4/^^H  :  ^6Hs, 

m.p.  140°,  is  formed  from  salicyl-aldehyde  and  phenyl-acetic  acid  (/. 
pr.  Ch.  2,  61,  178).  o-,  m-,  and  p-Oxy-benzal-benzyl  cyanide  HOC6H4 
CH  :  C(CN)C6H5,  m.p.  104°,  107°,  and  192°  (B.  37, 3163). 

a-Stilbene-methyl-ketone,  3,  ^-diphenyl-butenone-2  C6H5CH  :  C(C6H5) 
COCH3,  m.p.  51°,  from  benzaldehyde  and  phenyl- acetone  with 
gaseous  HC1.  It  does  not  add  bromine,  but  gives  on  reduction  with 
sodium  amalgam  3, 4-diphenyl-butanone  C6H5CH2.CH(C6H5)COCH3, 
b.p.  310°  (M.  22,  659). 

Stilbene  -  propionic  acid,  y,  %-diphenyl-alyl-acetic  acid  C6H5CH  : 
C(C6H5).CH2.CH2COOH,  m.p.  106°,  from  sodium-a-phenyl-glutarate 
with  benzaldehyde  and  acetic  anhydride  (B.  34,  4177). 

Desyl-acetic  acid,  fifi-phenyl-benzoyl-propionic  acid  C6H5.COCH 
(C6H5).CH2.COOH,  m.p.  161°,  is  obtained  as  ester  from  the  interaction 
of  sodium  desoxy-benzoin  and  bromacetic  ester  (A.  319,  164)  ;  it  is 
also  formed  from  phenyl-succinic-j8-methyl  ester  acid  chloride  with 
benzene  and  A1C13.  By  treatment  with  acetic  anhydride  sulphuric 
acid  in  the  cold  the  acid  gives  unstable  diphenyl-A2-eroto-laetone 

C6H5C  :  C(C6H5)CH2COO,  m.p.  100°,  which,  on  boiling  with  acetic  an- 
hydride or  treatment  with  alkalies,  passes  into  the  stable  diphenyl- 

A^croto-laetone  C6H5CH.C(C6H5)  :  CHCOO,  m.p.  152°.  Both  lactones, 
treated  with  alkalies,  regenerate  desyl-acetic  acid  ;  by  the  action  of 
permanganate  or  bromine  the  stable  diphenyl-croto-lactone  gives 
desylene-acetic  acid  C6H5CO.C(C6H5)  :  CHCOOH,  m.p.  139°,  which 
has  also  been  obtained  from  desylene-malonic  ester,  the  condensation 
product  of  benzile  withmalonic  ester  (A.  319, 155).  Desyl-acetic  acid 
and  the  stable  diphenyl-croto-lactone  are  also  formed  from  diphenyl- 
a-keto-butyro-lactone  (i),  the  condensation  product  of  phenyl-pyro- 
racemic  acid  and  benzaldehyde,  which,  on  reduction,  first  yields  an 
oxy-lactone  (2),  and  from  the  latter,  by  rejection  of  water,  diphenyl- 
croto-lactone  (3)  (B.  31,  2218  ;  36,  2344  ;  A.  333,  160). 

(J)  (2)  (3) 

C6H5CH.CH(C6H5)\CO  _^  C6H5CH.CH(C6H5)\  CHQH  ^  CCH5CH.C(C6H5)\CH 
6—        —CO/  6 CO/  O CO/ 

Dibenzyl  -  diearboxylie     acid,     sym.     diphenyl  -  suceinic     acid 

C6H5.CH.COOH 

occurs    similarly    to    the    dialkvl-succinic    acids    in 
C6H5.CH.COOH 

two  isomeric  forms.  The  a-acid  (+H2O)  is  produced  on  heating 
phenyl-bromacetic  acid  (2  mols.)  with  alcoholic  CNK,  also  (together 
with  the  jS-acid,  m.p.  229°)  from  stilbene-dicarboxylic  acid  with  sodium 
amalgam.  The  acid,  containing  one  molecule  of  water,  melts  at  185° 
when  rapidly  heated  ;  it  loses  water  and  remelts  at  220°.  When  heated 
to  200°  with  hydrochloric  acid  it  changes  to  the  j8-acid.  Its  anhydride, 
melting  at  116°,  is  readily  produced  by  means  of  acetyl  chloride. 

The  j8-acid  yields  an  anhydride  (but  with  more  difficulty)  when  heated 
with  acetyl  chloride  (B.  23, 117,  R.  574  ;  A.  259,  61).  It  melts  at  112°. 

The  nitrites  C6H5CH(CN)CH(CN)C6H5,  the  a-  melting  at  160°  and 


CARBOXYLIC   ACIDS   OF  THE  DIBENZYL   GROUP       623 

the  j8-  melting  at  240°,  result  from  the  condensation  of  phenyl-aceto- 
nitrile  with  mandelo-nitrile  by  means  of  potassium  cyanide  (B.  25, 
289  ;  26,  60).  Both  nitriles  yield  the  jS-acid  when  they  are  saponified. 

a,  p  -  Diphenyl -  glutaric  acid  C6H5CH(CO2H)CH(C6H5)CH2CO2H, 
m.p.  231°  ;  its  ester  is  obtained  by  attaching  phenyl-acetic  ester  to 
cinnamic  acid  ester  by  means  of  sodium  ethylate  (B.  42, 4497  ;  C.  1908, 

I.  1776). 

J8,  y-Diphenyl-adipic  acid  CO2HCH2CH(C6H5)CH(C6H5)CH2CO2H, 
two  modifications,  m.p.  270°  and  170°.  Dimethyl  esters,  m.p.  175° 
and  73°,  are  formed  by  the  reduction  of  cinnamic  acid  ester  with  Al 
amalgam,  together  with  nydro-cinnamic  acid  ester.  The  great  simi- 
larity to  truxillic  acid  is  noteworthy  (A.  348, 16  ;  B.  39,  4089). 

Stilbene-dicarboxylic  acid,  diphenyl-malele  acid,  decomposes  im- 
mediately when  separated  from  its  salts,  like  the  dialkylic  maleic  acids, 

C6H5.C.C(\ 
into  water  and   its   anhydride  \\       ">O,  m.p.    155°.     The   latter 

C6H5.C.CO 
condenses,  like  phthalic  anhydride,  with  phenyl-acetic  acid  and  quickly 

CTT     f*            f^- ,/-*TT    f^     TT 
g.LljjV^ V^ : ^Xi.Vx^JTLe 

changes  to  benzal-diphenyl-maleide  ,  which  behaves 

C6H5C— CO/ 

just  like  benzal-phthalide  (B.  24,  3854).  The  salts  of  diphenyl- 
maleic  acid  are  formed  when  dicyano-stilbene  C6H5C(CN)  :  C(CN)C6H5, 
m.p.  158°,  are  saponified  with  alcoholic  potash.  This  nitrile  is  pro- 
duced when  phenyl-chloraceto-nitrile  is  treated  with  CNK  or  NaOC2H3, 
or  by  the  action  of  sodium  alcoholate  and  iodine  upon  phenyl-aceto- 
nitrile  (B.  25,  285,  1680). 

Stilbene-succinic  acid,  y-benzylidene-y-phenyl-pyro-tartaric  acid,  from 
benzoin  with  succinic  ester  and  sodium  alcoholate.  With  Br  the  acid 
gives  a  bromo-lactonic  acid,  which  on  heating  yields  an  unsaturated 

lactonic  acid  C6H5CH.C(C6H5)  :  C(COO)CH2COOH  and  a  dilactone 
C6H5CH.C(C6H5).CH(COO)CH2COO  (A.  308,  156). 

4,  5-Diphenyl-octane-2,  7  -  dione,  ajS  -  diacetonyl-dibenzyl 
C6H5.CH.CH2.CO.CH3 

r  J.WrW  rnm  '  m'P'  l6l°  and  b'P'  335°-340°,  may  be  regarded 

L6H3.CH.Cii2.CU.CJtl3 

as  a  derivative  of  dibenzyl.  It  might  be  designated  aj8- diacetonyl- 
dibenzyl  It  results  in  the  reduction  of  two  molecules  of  benzyl- 
idene-acetone  in  feebly  acid  or  neutral  solution  (B.  29,  380,  2121). 
Homologous  diketones  are  formed  from  homologous  benzylidene- 
ketones  by  reduction  (B.  35,  966). 

C.  Tri-,  Tetra-,  Penta-,  and  Hexaphenyl-ethane  Group. — Triphenyl- 
ethane  (C6H5)2CHCH2C6H5,  b.p.  348°  (B.  37,  1455),  by  reduction 
of  triphenyl-ethylene,  a-phenyl-stilbene  (C6H5)2C  :  CHC6H5,  m.p.  68°, 
b.p.  221°  ;  also  by  extracting  water  from  benzyl-diphenyl-carbinol 
(B.  37,  1429,  1455). 

Triphenyl-ethanone,  or  triphenyi-vinyl  alcohol  (C6H5)2.CH.CO.C6H5 
or  (C6H5)2.C  :  C(OH)C6H5,  m.p.  136°,  results  from  the  action  of  benzene 
and  aluminium  chloride  upon  chloral,  upon  dichloro-  or  trichoro-acetyl 
chloride  (B.  29,  R.  292  ;  A.  296,  219  ;  368,  92)  ;  also  from  triphenyl- 
ethylene-glycol  (C6H5)2C(OH)CH(OH)C6H5,  m.p.  164°,  the  product  of 
the  action  of  C6H5MgBr  upon  benzoin  or  mandelic  ester  (B.  37,  2762), 


624  ORGANIC   CHEMISTRY 

on  heating  with  25  per  cent.  H2SO4  (C.  1908,  I.  830).  Potassium 
permanganate  oxidises  it  to  benzo-phenone  and  benzoic  acid,  while 
alcoholic  potash  resolves  it  into  diphenyl-methane  and  benzoic  acid. 
With  hydroxylamine  chlorohydrate  it  yields  an  oxime,  m.p.  182°  (C. 
1906,  II.  1061).  With  acetyl  chloride  and  benzoyl  chloride  we  obtain 
triphenyl- vinyl  acetate  and  benzoate  derivatives  of  the  alcohol  form. 

Bromine  in  carbon  disulphide  converts  it  into  triphenyl-brom- 
ethanone  (C6H5)2CBrCOC6H5,  m.p.  97°,  in  glacial  acetic  acid;  however, 
by  replacement  of  bromine  with  hydroxyl  triphenyl-oxy-ethanone, 
phenyl-benzo'in  (C6H5)2C(OH)COC6H5,  m.p.  84°,  results.  This  is  also 
obtained  by  the  oxidation  of  diphenyl-ethanone  with  HNO3,  and  from 
benzile  with  CgH5MgBr  (B.  32,  650  ;  37,  2758).  Reduction  of  triphenyl- 
ethanone  or  its  bromination  product  gives  triphenyl-ethanol,  benzo- 
hydryl-,  phenyl-,  carbinol  (C6H5)2CH.CH(OH)C6H5,  m.p.  87°,  isomeric 
with  benzyl-,  diphenyl-carbinol  (see  above)  (C.  1897,  II.  66 1). 

Triphenyl  -  methyl  -  ethane,  a,  a,  fi-triphenyl-propane  (C6H5)  2CH. 
CH(CH3)C6H5,  is  probably  the  product  obtained  by  the  reduction  of 
diphenyl-indone  with  phosphorus  and  hydriodic  acid.  Diphenyl- 
indone  is  an  intermediate  product  in  the  condensation  of  benzo- 
phenone  chloride  with  phenyl-acetic  ester,  whereby  there  results — 

Triphenyl-aerylie  ester  (CgH5)2C  :  C(C6H5)COOR.  The  acid,  melting 
at  213°,  corresponding  to  this  ester  is  obtained  from  its  nitrite,  melting 
at  163°,  the  condensation  product  of  benzo-phenone  chloride  and  benzyl 
cyanide  (B.  28,  1784 ;  29,  2841)  The  acid  is  also  obtained  from 
triphenyl  -propionie  acid  (C6H5)2CH.CH(C6H5)CO2H,  m.p.  211°,  the 
product  of  attachment  of  C6H5MgBr  to  a-phenyl-cinnamic  ester,  by 
bromination  and  rejection  of  HBr  (C.  1905,  I.  824  ;  B.  34,  1963). 
When  diphenyl-indone  is  fused  with  caustic  potash  it  yields  an  acid, 
melting  at  186°,  which  is  isomeric  with  triphenyl-acrylic  acid.  It  is 
probably — 

a,^-Diphenyl-vinyl-o-benzoicacidCOOH[2]C6H4C(C6H5)  :  CH.C6H5. 
Both  acids,  when  heated  with  ZnCl2,  revert  again  to  diphenyl-indone 
(B.  30,  1282). 

Tetra-phenyl-ethane  (C6H5)2CH.CH(C6H5)2,  melting  at  209°  and 
boiling  at  37o°-383°,  is  formed  when  benzo-phenone  or  benzo-hydrol 
chloride  (C6H5)  2CHC1  is  heated  with  zinc,  and  thio-benzo-phenone  with 
copper  ;  further,  by  the  reduction  of  tetraphenyl-ethylene  with  sodium 
and  alcohol,  of  benzo-pinacone  or  benzo-pinacolin  (see  below)  with 
hydriodic  acid  and  phosphorus,  as  well  as  by  the  condensation  of 
stilbene  bromide,  of  tetrabromo-ethane,  or  of  chloral  with  benzene  and 
A1C13  (B.  18,  657  ;  26,  1952  ;  A.  296,  221). 

Unsym.  tetraphenyl  -  ethane  (C6H5)3C.CH2C6H5,  m.p.  144°,  is 
formed  by  the  action  of  C6H5CH2MgCl  upon  triphenyl-chloro-methane, 
or  of  (C6H5)3CMgCl  or  (C6H5)3CK  upon  benzyl  chloride  (B.  41,  435). 

Tetraphenyl-ethylene  (C6H5)2C  :  C(C6H5)2,  melting  at  221°,  is 
formed,  together  with  tetraphenyl-ethane,  from  benzo-phenone,  and  is 
also  obtained  on  heating  benzo-phenone  chloride  with  silver  or  with 
zinc  dust,  together  with  the  benzo-pinacolins  (B.  29,  1789),  also  by 
heating  benzo-phenone  chloride  with  diphenyl-methane  (B.  43,  2958). 
By  oxidation  it  is  split  up  into  two  molecules  of  benzo-phenone.  It 
unites  with  chlorine  in  CC14  solution  to  form  tetraphenyl-ethylene 
diehloride  (C6H5)2CC1.CC1.(C6H6)2,  m.p.  186°,  which  is  also  obtained 


PHENYL-ETHANE  GROUP  625 

from  benzo-phenone  chloride  by  the  action  of  molecular  silver  or  mercury 
as  well  as  sodium  iodide  in  acetone  solution.  With  two  molecules  of 
CHC13  or  CC14  it  gives  crystalline  addition  products.  Two  chlorine 
atoms  in  the  tetraphenyl-ethylene  dichloride  are  very  loosely  bound. 
On  heating  alone  it  splits  up  into  tetraphenyl-ethylene  and  chlorine, 
the  latter  partly  acting  as  a  substituent.  Upon  boiling  with  water  we 
obtain  a-benzo-pinacolin ;  with  methyl  alcohol,  j8-benzo-pinacolin. 
The  action  of  A1C13  upon  the  benzene  solution  brings  about  rejection  of 
2HC1  and  formation  of  9,  lo-diphenyl-phenanthrene  (B.  43, 1533,  2940). 
Tetra  -  methyl  -  diamido  -  tetraphenyl  -  ethylene  (CH3)  2NC6H4(C6H5)C  : 
C(C6H5)C6H4N(CH3)2,  m.p.  225°,  by  reduction  of  dimethyl-amido- 
benzo-phenone  with  tin  and  HC1.  In  acid  solution  with  oxidising 
agents  like  FeQ3  it  gives  intensely  red  colorations  (B.  39,  3765). 

The  alcohols  of  the  tetraphenyl  group  are  the  pinacones  of  benzo- 
phenone  and  its  homologues.  They  are  formed,  like  the  pinacones 
of  the  aliphatic  series,  from  the  ketones,  together  with  secondary 
alcohols,  by  the  action  of  nascent  hydrogen. 

Benzo  -  pinacone,  tetraphenyl  -  ethylene  -  glycol  (C6H5)  2C(OH)C(OH) 
(C6H5)2,  melts  at  185°  and  splits  into  benzo-phenone  and  benzo-hydrol. 
It  sustains  a  like  change  when  boiled  with  alcoholic  potash.  It  is 
formed  from  benzo-phenone  by  the  action  of  zinc  and  sulphuric  acid 
or  by  the  decomposition  of  sodium  benzo-phenone  (B.  25,  R.  15),  or  by 
condensation  of  oxalic  methyl  ester,  or  benzilic  acid  ester,  with 
C6H5MgBr  (C.  1903,  I.  967  ;  B.  37,  2761).  By  heating  with  con- 
centrated HC1  or  dilute  sulphuric  acid  to  200°,  benzo-pinacone,  like 
the  ordinary  pinacone  (Vol.  I.),  passes  with  rejection  of  water  and 
migration  of  a  phenyl  group  into  the  so-called  jS-benzo-pmacolin 
(C6H5)3C.COC6H5,  m.p.  170°,  which  is  also  obtained  synthetically  by 
the  action  of  triphenyl-methyl-magnesium  chloride  upon  benzaldehyde 
and  subsequent  oxidation,  as  well  as  from  triphenyl-acetyl  chloride 
and  phenyl-magnesium  bromide  (B.  43,  1140)  ;  its  constitution  is 
proved  not  only  by  these  syntheses,  but  also  by  the  splitting  up  into 
triphenyl-methane  and  benzoic  acid  on  heating  with  soda  lime  and  by 
the  formation  of  triphenyl-carbinol  and  benzoic  acid  during  oxidation. 
j3-Benzo-pinacolin  can  also  be  obtained  direct  from  benzo-phenone 
with  zinc  dust  and  acetyl  chloride  besides  the  isomeric  a-benzo- 
pinacolin,  m.p.  203°,  which  is  easily  converted  by  acids  into  £-benzo- 

pinacolin  and  is  probably  tetraphenyl-ethylene  oxide  (C6H5)2C.O.C(C6H5)2 
(B.  29,  2158  ;  43,  1153).  By  heating  with  zinc  ethyl  j3-benzo-pinacolin 
can  be  reduced  to  benzo-pinaeolm  alcohol  (C6H5)3C.CH(OH)C6H5, 
m.p.  151°,  which  on  heating  with  acetic  anhydride  passes  into  tetra- 
phenyl-ethylene with  return  of  the  phenyl  group  (B.  23,  R.  769) 
(cp.  the  analogous  formation  of  tetramethyl-ethylene  from  pinacolin 
alcohol,  Vol.  I.).  p4-Tetrachloro-benzo-pinacolin,  see  C.  1907,  I.  475. 

Pentaphenyl-ethane  (C6H5)3C.CH(C6H5)2,  m.p.  179°,  in  CO2 
atmosphere,  is  formed  by  the  transposition  of  diphenyl-methyl-mag- 
nesium  bromide  (C6H5)2CH.MgBr  with  triphenyl-chloro-methane  (B.  39, 
1466),  as  well  as  the  action  of  zinc  upon  a  mixture  of  diphenyl-bromo- 
methane  and  triphenyl-chloro-methane  in  acetic  ester  (B.  43,  2945).  It 
is  not  so  stable  as  the  entirely  stable  tetraphenyl-ethane,  and  in  that 
respect  approaches  the  easily  dissociated  hexaphenyl-ethanes.  On 

VOL.  II.  2  S 


626  ORGANIC   CHEMISTRY 

heating  in  the  air  it  is  decomposed  with  absorption  of  oxygen.  By 
boiling  its  solutions  in  anisol  or  benzoic  acid  ester  it  is  split  up  into 
triphenyl,  methyl-,  or  hexaphenyl-ethane  and  sym.  tetraphenyl- 
ethane  (B.  43,  3541)- 

2(C6H3)3C-CH(C6H5)2  -     ~>  [(C6H6)3C-]2+[-CH(C6H5)2]2. 

Similarly,  it  decomposes  on  heating  with  benzene  and  HC1,  or  by  the 
action  of  sulphuryl  chloride  (B.  40,  367  ;  43,  2945). 

Pentaphenyl-ethyl  alcohol  (C6H5)3C.C(OH)(C6H5)2,  m.p.  179°,  from 
/3-benzo-pinacolin  and  C6H5MgBr  (B.  43,  1145). 

Hexaphenyl-ethane,  m.p.  about  95°  :  this  exceedingly  interesting 
hydrocarbon  was  first  obtained  by  Gomberg  (1900,  B.  33,  3150)  by  the 
action  of  zinc  upon  benzene  solution  of  triphenyl-chloro-methane 
(see  A.  372,  17).  It  is  distinguished  by  its  great  reactivity,  which 
makes  it  appear  as  an  unsaturated  compound.  In  solution  it  greedily 
absorbs  atmospheric  oxygen  with  the  formation  of  a  peroxide 
[(C6H5)3C]2O2,  m.p.  185°,  which  on  treatment  with  concentrated 
sulphuric  acid  gives  triphenyl-carbinol.  Iodine  solution  is  also 
instantly  decolourised  with  formation  of  triphenyl-iodo-methane 
(B.  35,  1824).  With  benzene,  ether,  acetic  ester,  etc.,  hexaphenyl- 
ethane  forms  crystal  compounds  which  are  easily  dissociated  (B.  38, 
I333»  2447)-  Colourless  in  the  solid  state,  hexaphenyl-ethane  has  a 
yellow  colour  when  dissolved.  This  colour,  on  shaking  with  air, 
disappears  with  a  precipitation  of  the  peroxide  mentioned,  but  the 
colour  reappears  in  a  short  time.  The  substance  therefore  exists  in 
solution  in  a  colourless  and  a  yellow  modification,  in  a  state  of  equili- 
brium dependent  upon  the  solvent  and  the  temperature.  Only  the 
coloured  modification  shows  characteristic  unsaturated  behaviour  of 
hexaphenyl-ethane  (Schmidlin,  B.  41,  2471).  It  is  assumed  that  by 
the  binding  of  the  six  unsaturated  phenyl  groups  the  affinities  of  the 
ethane-carbon  atoms  are  so  much  engaged  that  the  affinities  required 
for  binding  these  two  carbon  atoms  do  not  suffice  for  a  solid  and 
normal  binding,  and  that  therefore  the  hexaphenyl-ethane  passes  in 
solution  partly  into  the  yellow  unsaturated,  and  therefore  very  reactive 
free  radicle,  triphenyl-methyl : 

(C6H5)3C-C(C6H5)3  nz^  2(C6H5)3C-. 

Triphenyl-methyl  is  therefore  the  first  example  of  a  compound  in 
which  one  carbon  atom  only  binds  three  univalent  atomic  groups,  and 
in  which,  therefore,  carbon  appears  as  a  trivalent  element.  Hexa- 
phenyl-ethane therefore  shows  a  behaviour  parallel  with  that  of 
nitrogen  tetroxide,  which,  while  colourless  at  low  temperatures,  de- 
composes on  heating  into  the  coloured  and  very  reactive  hemimeric 
nitrogen  dioxide.  From  this  point  of  view  it  is  remarkable  that  the 
organic  radicle  (C6H5)3C  unites  with  the  inorganic  radicles  NO  and  NO2 
to  form  a  colourless  triphenyl-nitroso-methane  (C6H5)3C.NO  and 
triphenyl-nitro-methane  (C6H5)3C.NO2,  m.p.  147°,  which,  on  heating, 
easily  decompose  into  their  components  (B.  44,  1169). 

The  action  of  concentrated  HC1  converts  hexaphenyl-ethane  and 
triphenyl  -  methyl  into  p  -  diphenyl  -  methyl  -  tetraphenyl  -  methane 
(C6H5)2CHC6H4C(C6H5)3  (B.  37,  4790). 


PHENYL-ETHANE  GROUP  627 

Besides  the  methods  indicated,  the  following  have  also  been  used 
for  preparing  hexaphenyl-ethane  :  (i)  from  triphenyl-methyl-mag- 
nesium  chloride  and  triphenyl-chloro-methane  (B.  41,  423)  ;  (2)  by 
electrolysis  of  triphenyl-bromo-methane  in  SO2  solution  (A.  372,  n)  ; 
(3)  from  hydrazo-triphenyl-methane  (C6H5)3C.NH.NH.C(C6H5)3  by 
oxidation  with  potassium  hypo-bromite  by  way  of  the  unstable  azo- 
compound  (B.  42,  3020). 

While  solid  hexaphenyl-ethane  does  not  pass  into  triphenyl-methyl, 
and  even  its  solution  does  so  only  in  small  quantities  (see  B.  37,  2041  ; 
42,  3028),  the  tribiphenyl-methyl  (C6H5.C6H4)3C,  obtained  by  withdrawal 
of  halogen  from  tribiphenyl-chloro-methane  by  means  of  powdered 
copper,  which  is  dark  violet  even  in  the  solid  condition,  only  exists 
in  solution  in  the  form  of  the  free  radicle,  as  indicated  by  the  molecular 
weight.  In  contrast  with  these,  a  hydrocarbon  obtained  from  the 

similarly  built  biphenylene-biphenyl-chloro-methane  ?624\xi(C6H4c6H5) 

^e-"*' 

is  colourless  even  in  solution  and  incapable  of  uniting  with-  oxygen  or 
halogen.     It  must  therefore  be  regarded  as  undissociated  dibiphenyl- 

ene-dibiphenyl-ethane  C*H*\C  -  c<624-     Between    these    two 

6   4 


extremes  the  similarly  obtained  hydrocarbons,  diphenylene-diphenyl- 
ethane,  tetraphenyl-dibiphenyl-ethane,  and  diphenyl-tetrabiphenyl- 
ethane  occupy  a  middle  position,  decomposing  in  solution  with  more 
or  less  ease  into  the  hemimeric  triaryl-methyls  (Schlenk,  A.  372,  I  ; 
B.  43,  1753)- 

Tetraphenyl  -  ethane  -  diearboxylie  acid,  tetraphenyl  -  succinic    acid 

//->  TT  \   /->  (~>r-\/"\TiJ' 

'  V  ,  melting  at  261°  with  decomposition  (its  ethyl  ester  at  89°), 

(L/gtlg)  2(-'.v-/O(J.ri. 

is  obtained  from  diphenyl-chloracetic  ester  by  the  action  of  silver 
(B.  22,  1538).  Its  nitrite,  melting  at  215°,  is  formed  by  the  interaction 
of  the  nitrile  of  diphenyl-acetic  acid  with  sodium  and  iodine. 

The  dilactone  of  a  benzo-pinacone-o2-dicarboxylic  acid  O.CO.C6H4C 

(C6H5).C(C6H5)C6H4COO,  melting  at  265°,  is  formed  on  boiling  o-benzoyl- 
benzoic  acid  with  hydriodic  acid  and  phosphorus  (B.  29,  R.  498). 

D.  co,  aj-Diphenyt-propane  Group.  —  Dibenzyl-methane,  a,  y-diphenyl- 
propane  C6H5.CH2.CH2.CH2.C6H5,  boiling  at  29O°-3OO°,  results  by  the 
reducing  action  of  hydriodic  acid  upon  dibenzyl-ketone  (see  below). 

a,  y-Diphenyl-propylene  C6H5CH2.CH  :  CHC6H5,  b.p.15  179°,  an 
oil  with  an  odour  of  hyacinth,  is  formed  from  a,  y-diphenyl-propyl 
alcohol,  b.p.12  193°,  with  anhydrous  oxalic  acid  ;  also  from  j8-bromo- 
dibenzyl-acetic  acid  by  heating  with  dilute  soda  solution  (B.  39,  3046). 

Tetraphenyl-allene  (C6H5)2C  :  C  :  C(C6H5)2  (?),  m.p.  164°,  from  the 
dry  distillation  of  barium-diphenyl  acetate  (B.  39,  1024). 

"  Dibenzyl-ketone  C6H5.CH2.CO.CH2.C6H5,  melting  at  40°  and  boiling 
at  330°  (B.  24,  R.  946).  This  body  is  produced  in  the  distillation  of 
calcium-phenyl-acetate.  One  hydrogen  atom  of  each  of  the  two 
CH2  groups  can  be  replaced  by  alkyls.  It  condenses  with  oxalic  ester 
and  sodium  ethylate  to  a  triketo-R-pentene  derivative,  oxalyl-dibenzyl- 
ketone.  With  benzal-aniline  it  yields  an  addition  product  which  takes 
various  forms  (C.  1899,  II.  664).  With  PC15  it  yields  1,  3-diphenyl-2- 
ehloro-propylene  C6H5CH2.CC1  :  CHC6H5,  b.p.12  181°,  and  di-iso- 


628  ORGANIC   CHEMISTRY 

nitroso-dibenzyl-ketone  C6H5C(NOH).COC(NOH)C6H5,  with  nitrous 
acid,  m.p.  133°  (B.  37,  1134). 

Sodium  reduces  dibenzyl-ketone  to  dibenzyl-earbinol  (C6H5.CH2)2 
CH.OH,  boiling  at  327°.  It  combines  to  dibenzyl-diphenol-methane 
(C6H5CH2)2C(C6H4OH)2  (B.  25,  1271)  with  phenol. 

Dibenzyl-phenyl-earbinol  (C6H5CH2)2C(OH)C6H5,  m.p.  87°,  and 
tribenzyl-earbinol  (C6H5CH2)3C(OH),  m.p.  115°,  from  benzoic  acid  ester 
and  phenyl-acetic  ester  with  two  molecules  C6H5CH2MgCl  (B.  37, 1456). 

Benzyl-aeeto-phenone  C6H5CH2.CH2.CO.C6H5,  m.p.  73°,  is  isomeric 
with  dibenzyl-ketone.  It  is  produced  on  reducing  benzylidene-aeeto- 
phenone  C6H5CH  :  CH.CO.C6H5,  m.p.  58°,  b.p.  346°,  with  zinc  dust 
and  acetic  acid.  This  latter  compound  is  the  condensation  product 
of  benzaldehyde  and  aceto-phenone.  By  means  of  sodium  methylate 
it  yields  two  stereo-isomeric  oximes,  m.p.  75°  and  116°,  the  latter  of 
which  on  Beckmann's  transposition  gives  cinnamic  anilide  (A.  351, 172) . 
With  HC1  it  unites  to  form  chloro-benzyl-aeeto-phenone  C6H5CHC1CH2 
COC6H5 ;  with  bromine,  a  dibromide  C6H5CHBr.CHBr.COC6H5,  m.p. 
157°,  which,  with  alcoholic  potash,  yields  monobromo-benzylidene 
aceto-phenone  C6H5.CBr  :  CHCOC6H5,  m.p.  44°  (A.  308,  219).  The 
action  of  nitrous  gases  upon  benzal-aceto-phenone  gives  various 
products,  of  which  we  may  mention  the  sub-nitride  (C15H12O)N2O4, 
which,  on  treatment  with  dilute  soda,  gives  benzal-nitro-aeeto-phenone 
C6H5CH  :  C(N02)COC6H5,  m.p.  90°.  The  reduction  of  the  latter  with 
stannous  chloride  and  HC1  in  methyl  alcohol,  produces  benzyl-iso- 
nitroso-aceto-phenone  C6H5CH2.C(NOH).COC6H5,  m.p.  126°,  an  oxime 
of  the  diphenyl-diketo-propane  which  is  isomeric  with  dibenzoyl-methane 
(B.  36,  3015  ;  A.  340,  63). 

p2-Diehloro-benzylidene-aeeto-phenone,  m.p.  157°,  yields,  with 
PC15  in  benzene  solution,  a  keto-chloride  C1C6H4CH  :  CH.CC12C6H4C1, 
m-P-  55°>  in  which  one  of  the  chlorine  atoms  occupies  the  middle 
position,  is  exceedingly  mobile,  and  can  easily  be  replaced  by  hydroxyl 
or  methoxyl  on  treatment  with  moist  silver  oxide  or  methyl  alcohol. 
The  compounds  dissolve  in  concentrated  sulphuric  acid  with  intense 
coloration  (B.  42,  1804)  (cp.  also  dibenzylidene-acetone) . 

o-,  m-,  p-Oxy-benzylidene-aceto-phenone,  from  the  corresponding 
oxy-benzaldehydes  and  aceto-phenone, melt  at  154°  with  decomposition, 
at  160°  and  183°. 

The  isomeric  benzylidene-o-,  m-,  and  p-oxy-aceto-phenones,  m.p. 
89°,  126°,  and  173°  respectively,  are  formed  from  benzaldehyde  and 
the  oxy-aceto-phenones.  Coloration  of  the  isomers,  see  B.  32,  1921. 
Several  poly-oxy-benz3>lidene-aceto-phenones  are  found  in  nature, 
usually  in  the  form  of  glucosides. 

Butein  (HO)2[3,  4]C6H3CH  :  CH.COC6H3[2',  4/J(OH)2,  orange-yellow 
needles,  m.p.  214°,  as  a  glucoside  in  the  flowers  of  Butea  frondosa  ; 
this  is  split  up  on  boiling  with  potash  into  proto-catechuic  acid  and 
resaceto-phenone  (C.  1904,  II.  451).  Naringenin  HO[4]C6H4CH  :  CH. 
COC6H2[2/,  4',  6'](OH)3,  m.p.  248°,  and  hesperitin  (HO) [3] (CH3O) [4] 
C6H3CH  :  CH.COC6H2[2',  4',  6'](OH)3,  m.p.  224°,  are  formed  by  break- 
ing up  the  glucosides  naringin  and  hesperidin  (q.v.)  with  dilute  acids, 
On  boiling  with  potash  they  yield  phloro-glucin  and  p-cumaric  acid 
and  iso-ferulic  acid  respectively.  Isomers  of  hesperitin  are  homo-erio- 
dictyol  HO[4](CH30)[3]C6H3CH  :  CH.COC6H2[2',  4',  6'](OH3),  b.p. 


CD,  co-DIPHENYL-PROPANE   GROUP  629 

223°,  and  eriodietyol  (HO)2[3,  4]C6H3CH  :  CH.COC6H2[2',  4',  6^OH)3, 
m.p.  267°,  from  the  leaves  of  Eriodictyon  californicitm  (C.  1911,  I.  150). 
On  boiling  with  mineral  acids  the  benzylidene-o-oxy-aceto-phenones 

r  /^\  _  PTT  f*  TT 

are  transformed  into  the  isomeric  flavanones  c«H*\coCH'       5>  a  re~ 

action  which  has  been  used  for  the  synthesis  of  numerous  vegetable 
dyes  belonging  to  this  group  ;  cp.  quercetrin,  fisetin,  luteolin,  etc. 
Alcoholic  potash  converts  acety-o-oxy-benzylidene-aceto-phenone 

into  benzoyl-cumarone  (q.v.)  C6H4<^CH^C.CO.C6H5.     Reduction  changes 

o-oxy-  benzylidene-aceto-phenone  into  a-phenyl-y-(o-oxy-phenyl)-propyl 
alcohol  HO.C6H4.CH2.CH2.CH(OH)—  C6H5,  m.p.  97°,  which  is  con- 


x2.2 

densed  by  HC1  in  methyl  alcohol  to  a-phenyl-cumaran  C6H4< 

^O  —  CH.CjHg 
(B.  29,244,375). 

o-Oxy-styryl-diphenyl-earbinol  HO[2]C6H4CH  :  CHC(OH)(C6H5)2, 
m.p.  i64°-i66°,  from  cumarin  with  two  molecules  C6H6MgBr  (C.  1903, 
I.  1179  ;  B.  37,  496). 

The  condensation  of  two  molecules  of  aceto-phenone  by  heat  alone, 
or  by  zinc  ethide  or  zinc  chloride,  yields  a  homologue  of  benzal-aceto- 
phenone  called  dypnone  C6H5.C(CH3)  :  CH.COC6H5,  m.p.  225°  (22  mm.), 
which  sustains  the  same  relation  to  aceto-phenone  as  mesityl  oxide 
bears  to  acetone  (B.  27,  R.  339)  ;  heating  splits  up  dypnone  with 
formation  of  unsaturated  hydrocarbons,  diphenyl-furfurane,  and  tri- 
phenyl-benzol  (C.  1899,  II.  96).  On  standing  in  alcoholic  solution, 
dypnone  combines  with  hydroxylamine  to  form  dypnone-hydroxylamine 
C6H5C(CH3)(NHOH).CH2COC6H5,  m.p.  110°  ;  under  other  conditions 
two  dypnone  oximes  are  formed,  C6H5C(CH3)  :  CHC(NOH)C6H5,  m.p. 
78°  and  134°,  the  latter  of  which  yields  by  Beckmann's  transposition 
the  anilide  of  j3-methyl-cinnamic  acid  (B.  37,  730). 

Benzaldehyde  condenses  as  readily  as  aceto-phenone  with  desoxy- 
benzoin  under  the  influence  of  alkalies,  forming  benzylidene-desoxy- 
benzoln  C6H5CH  :  C(C6H5)CO.C6H5,  m.p.  101°;  this  is  also  formed  from 
benzamarone  by  distillation,  besides  iso-benzylidene-desoxy-  benzoin, 
m.p.  89°.  The  latter  is  easily  converted  into  the  isomeride  of  higher 
melting-point.  It  is  also  formed  by  condensation  of  benzaldehyde 
and  desoxy-benzoin  by  means  of  HC1  and  chloro-benzyl-desoxy- 
benzoin,  m.p.  172°,  which  is  easily  converted  by  alkalies  into  benzal- 
desoxy-benzoin,  m.p.  101°  ;  but  it  is  split  up  by  distillation  into  stilbene 
and  benzoyl  chloride  (B.  26,  447,  818  ;  34,  3897  ;  35,  3865)  : 

C6H5CH  _  C6H5CHC1 

C6H5CCOC6H6  *  CGH5CHCOC6H5 

By  reduction,  benzal-desoxy-benzoin  yields  benzyl-desoxy-benzoin 
C6H5fCH2.CH(C6H5)COC6H5,  m.p.  120°,  which  can  also  be  obtained 
direct  by  benzylating  desoxy-benzoin. 

)3j8-Diphenyl-propio-phenone  C6H5COCH2.CH(C6H5)2,  m.p.  96°,  by 
attachment  of  one  molecule  phenyl-magnesium  bromide  to  benzal- 
aceto-phenone  (C.  1904,  II.  445).  Correspondingly,  we  obtain  from 
phenyl-magnesium  bromide  and  benzylidene-  desoxy-benzoin  in  ether 
solution  : 

a,  0,  ft  -  Triphenyl-  propio  -  phenone     C6H5COCH(C6H5)CH(C6H5)2, 


630  ORGANIC  CHEMISTRY 

m.p.  182°,  which  is  also  formed  from  a-phenyl-cinnamic  ester  with  gases 
of  phenyl-magnesium  bromide.  In  ligroin  solution  it  is  found  possible  to 
isolate,  as  the  first  addition  product,  the  tetraphenyl-propinol  C6H5C(OH) : 
C(C6H5)CH(C6H5)2,  which,  at  95°-ioo°,  melts  with  transformation  into 
triphenyl-propio-phenone.  It  greedily  absorbs  oxygen,  with  formation 
of  a  peroxide,  m.p.  127°,  which,  on  heating,  decomposes  into  diphenyl- 
aceto-phenone  and  benzoic  acid  (C.  1906,  II.  1059). 

Benzoyl  -  dibenzyl  -  methane,  dibenzyl  -  aceto  -  phenone  C6H6COCH 
(CH2C6H5)2,  m.p.  78°,  is  formed  by  heating  aceto-phenone  with  benzyl 
chloride  and  caustic  potash  to  i6o°-i70°  (A.  310,  322). 

By  condensation  of  o-phthal-aldehydic  acid  with  aceto-phenone  we 

/CHCH2COC6H6 

obtain  phenacyl-phthalide  C6H4<^  \  ,  m.p.  182°  (C.  1898,  II. 

coo 

980). 

Benzoyl-phenyl-aeetylene  C6H5COC  :  CC6H5,  m.p.  50°,  from  sodium- 
phenyl-acetylene  and  benzoyl  chloride  in  ether.  This  is  split  up  by 
alkalies  into  aceto-phenone  and  benzoic  acid,  and  by  concentrated 
sulphuric  acid  into  dibenzoyl-methane  (A.  308,  276  ;  C.  1900,  I.  1290). 
Phenyl-acetylene-phenyl-earbinol  C6H5C ;  C.CH(OH)C6H6,  b.p.  221°, 
from  sodium-phenyl-acetylene  and  benzaldehyde  (C.  1902,  I.  629). 

Dibenzoyl-methane  C6H5CO.CH2.COC6H6  or  C6H5C(OH)  :CHCOC6H5 
(cp.  Proc.  Chem.  Soc.,  20,  48),  m.p.  81°,  is  formed  by  boiling 
dibenzoyl-acetic  ester  with  water,  by  condensation  of  benzoic  acid 
ester  and  aceto-phenone,  or  by  transposition  of  the  aceto-phenone-O- 
benzoate  C6H5C(OCOC6H5)  :  CH2  obtained  from  aceto-phenone  by  heat- 
ing with  benzoyl  chloride,  the  transposition  being  effected  by  boiling 
with  sodium  in  benzene  solution  (B.  36,  3674).  It  is  soluble  in  alkali, 
forms  a  sparsely  soluble  copper  salt  and  a  red  iron  salt,  and  is  easily 
attacked  by  potassium  permanganate.  On  treatment  with  benzoyl 
chloride  and  pyridin  it  yields  an  0-benzoate  C6H5C(OCOC6H5)  : 
CHCOC6H5,  m.p.  109°  (B.  36,  3679).  Nitrous  acid  converts  it  into  an 
iso-nitro  so-derivative  (C6H5.CO)2C  :  N.OH,  which  may  be  converted  into 
the  corresponding  diphenyl-triketone  C6H5.CO.CO.CO.C6H5,  b.p.  289°, 
(175  mm.  pressure).  It  solidifies  to  a  golden-yellow  mass,  melting  "at 
70°.  It  combines  with  water  to  a  colourless  hydrate  (B.  23,  3378). 

Dibenzoyl-aeetyl-methane,  dibenzoyl-acetone,  occurs  in  two  forms, 
one  of  which  probably  represents  the  diketo-hydroxyl  form  (C6H5.CO)2 
C  :  C(OH)CH3  (a-,  m.p.  80°),  the  other  the  triketo  form  (C6H5CO)2.CH. 
COCH3  (/?-,  m.p.  i07°-iio°).  It  results  from  benzoyl-acetone  and 
benzoyl  chloride  with  soda.  Similarly,  dibenzoyl-methane  yields  (jB)- 
tribenzoyl-methane  (C6H5CO)3CH,  m.p.  225°.  By  boiling  with  potash 
and  acetic  ester  this  /^-modification  is  changed  to  the  a-form(C6H5CO)  2C : 
C(OH)C6H5,  soluble  in  alkalies  (A.  291,  25).  The  latter  combines  with 
one  molecule  diazo-benzol  chloride  to  form  a  yellow  diazo-oxy-com- 
pound  (i),  m.p.  125°,  which  is  easily  split  up  by  mineral  acids.  On 
heating,  it  first  turns  into  the  red  C-azo-compound  (2),  m.p.  164°, 
stable  in  the  presence  of  acids,  and  further,  by  migration  of  a  benzoyl 
group,  into  the  colourless  benzoyl- phenyl-hydrazone  of  diphenyl-tri- 
ketone (3),  m.p.  203°  (B.  41,  4012) : 

(C6H5CO)2:C  (C6H6CO)2 :  C.N  :  NC6H5         (C6H5CO)2 :  C  :  N.NC,H5 

(i)        C6H5C.O.N:NC6H5         (2)      C6H5  CO  (3)  CaH6  CO 


co,  co-DIPHENYL-PROPANE  GROUP  631 

This  process  corresponds  to  the  transposition  of  fatty  aromatic  azo- 
compounds  into  aryl-hydrazones,  and  to  a  reversal  of  the  conversion 
of  the  quinone-acyl-phenyl-hydrazones  into  O-acylated  oxy-azo- 
compounds.  » 

Carboxy lie  Acids. — Dibenzyl-acetic  acid  (C6H5.CH2)2CH.COOH,  m.p. 
87°,  is  formed  from  a-benzyl-cinnamie  acid  C6H5CH  :  C(CH2C6H5) 
COOH,  m.p.  159°,  the  condensation  product  of  benzaldehyde  with  hydro- 
cinnamic  acid  by  reduction  with  Na  amalgam  (/.  pr.  Ch.  2,  62,  545). 
It  is  also  derived  from  dibenzyl-malonic  acid  (C6H5CH2)2C(COOH)2,  the 
ester  of  which  is  produced  by  benzylating  malonic  ester. 

X^TT  ^-*TT  f^T-T 

o,  o-Dinitro-benzyl-acetic  acid  C6H,/  2^>C6H4,  made 

\N02    COOH       N02/ 

in  an  analogous  manner,  may  be  condensed  by  reduction  with  zinc 
dust  to  tetrahydro-naphthinolin  (q.v.)  (B.  27,  2248  ;    29,  636). 

Dibenzoyl-malo-nitrile  (C6H5CH2)C(CN)2,  m.p.  130°  and'b.p.  360°,  is 
obtained  from  the  corresponding  nitrilo-acid  amide,  which  is  prepared 
from  cyanacetamide.  Sodium  and  alcohol  reduce  the  nitrile  with 
elimination  of  a  cyanogen  group  to  dibenzyl-ethylamine  (C6H5CH2)2CH. 
CH2.NH2,  whose  hydrochloride  melts  at  190°  (B.  29,  R.  mi). 

Dibenzyl-glyeolic  acid  (C6H5.CH2)2C(OH).CO2H,  oxatolylie  acid,  is 
produced  by  saponification  of  its  nitrile,  the  HCN  addition  product  of 
dibenzyl-ketone,  and  when  vulpic  and  pulvic  acids  are  boiled  with 
dilute  alkalies.  It  melts  at  156°.  When  boiled  with  concentrated 
potassium  hydroxide  it  decomposes  into  oxalic  acid  and  two  molecules 
of  toluol  (A.  219,4i). 

a-Phenyl-j8-benzoyl-propionic  acid,  phenyl-phenacyl-acetic  acid, 
C6H5CO.CH2.CH(C6H5)COOH,  melts  at  153°.  Its  nitrile  melts  at 
127°.  Its  ester  is  formed  from  phenyl-succinic-a-methyl  ester  acid 
chloride  with  benzene  and  A1C13.  The  acid  is  produced  when  CNK  acts 
upon  chloro-benzyl-aceto-phenone.  If  heated  with  acetic  anhydride 
it  yields  the  lactone  of  isomeric  a,  y-diphenyl-y-oxy-erotonie  acid 

CeH5C  :  CH.CH(C6H5)COO,  melting    at    110°,  while   upon   reduction 
with     sodium      amalgam,      a,  y  -  diphenyl  -  butyro  -  lactone     C6H5. 

CH.CH2.CH(C6H5)COO  (A.  284,  i). 

a,  y-Diphenyl-aceto-aeetie  acid  is  isomeric  with  phenyl-phenacyl- 
acetic  acid.  Its  ester ,  C6H5.CH2.CO.CH(C6H5)CO2C2H5,  melting  at  79°, 
is  formed  when  two  molecules  of  phenyl-acetic  ester  are  condensed  with 
sodium  ethylate.  Concentrated  sulphuric  acid  condenses  the  ester  to 
a  naphthalene  derivative — phenyl-naphtho-resorcinol  (A.  296,  I.) 

0-Phenyl-y-benzoyl-butyrie  acid  C6H5CO.CH2.CH(C6H5).CH2.COOH, 
m.p.  153°,  is  formed  by  attachment  of  aceto-phenone  to  cinnamic  ester, 
by  means  of  sodium  ethylate,  and  by  transformation  of  the  addition 
product  of  malonic  ester  and  benzylidene-aceto-phenone  (B.  34,  653). 

Benzylidene-benzoyl-aeetic  ester,  m.p.  98°,  from  benzaldehyde, 
benzoyl-acetic  ester,  and  piperidin  (C.  1903,  I.  1420  ;  II.  1270). 

Dibenzoyl-aeetic  acid  (C6H5.CO)2CH.COOH  melts  at  109°.  Its 
ester,  from  benzoyl-acetic  ester  and  benzoyl  chloride,  yields  CO2  and 
dibenzyl-methane  by  dry  distillation,  and  aceto-phenone,  carbon 
dioxide,  and  benzoic  acid  when  digested  with  sulphuric  acid.  Its 
nitrile,  obtained  from  cyan-aceto-phenone  with  benzoyl  chloride,  shows 


632  ORGANIC   CHEMISTRY 

very  acid  properties.  The  silver  salt  gives,  with  methyl  iodide  and 
methyl  ether,  C6H5COC(CN)  :  C(OCH3)C6H5,  m.p.  118°;  with  benzoyl- 
chloride,  tribenzoyl-aceto-nitrile  (C6H5CO)3C.CN  or  C6H5COC(CN)  : 
C(OCOC6H5)C6H5,  m.p.  138°  (/.  pr  .Ch.  2,  58,  151). 

y-Phenyl-£-benzylidene-a-keto-butyro-lactone    c  H  ^6H  5  <^_co/co> 

m.p.  167°  ;  this  keto-lactone,  in  the  form  of  yellow  crystals,  is  obtained 
by  condensation  of  two  molecules  benzaldehyde  with  pyro-racemic 
acid  by  means  of  gaseous  HC1  (B.  32,  1450  ;  34,  817)  ;  on  reduction 
with  sodium  amalgam  it  gives  y-phenyl-j3-benzyl-keto-butyro-lactone, 
in  two  modifications,  m.p.  134°  and  137°  (also  from  benzyl-pyro-racemic 
acid  with  benzaldehyde).  The  isomeric  jS-phenyl-y-benzyl-a-keto- 
butyro-laetone,  m.p.  171°,  is  formed  from  two  molecules  phenyl-pyro- 
racemic  acid  with  rejection  of  CO2  (B.  35,  1942). 

f*  M  P"H"  \  /POOTT 

y-Benzyl-y-benzylidene-pyro-raeemie  acid  ^CH  XCH\CH,COOH' 
m.p.  147°  ;  its  ester  is  formed  by  condensation  of  dibenzyl-ketone  and 
succinic  ester  by  sodium  alcoholate  (A.  308,  175). 


from  succinic  acid  ester  and  benzal  aceto-phenone  by  means  of  NaOC2H5; 
its  dimethyl  ester  is  easily  further  condensed  to  pentacyclic  diketone- 

carboxylic  ester     6    *     '**     VTJ™  ^TJ  »  which  is  in  turn  easily  split 

U6ri5L/rl ^JtlLAJ2^H3 

up  by  sodium  methylate  to  an  acyclic  dimethyl  ester  (A.  326,  347). 

a,  j8,  y-Triphenyl-glutaric  acid  C6H5CH[CH(C6C5)COOH]2,  m.p.  237°; 
the  nitrite,  m.p.  138°,  of  this  acid  is  formed  by  the  combination  of  benzal- 
benzyl  cyanide  with  the  second  molecule  of  benzyl  cyanide  (B.  31, 

3059)- 

E.  co,  ay-Diphenyl-butane  Group. — Dibenzyl-ethane,  a,  S-diphenyl- 
butane  C6H5.CH2.CH2.CH2.CH2.C6H5,  melting  at  52°,  is  formed  by  the 
reduction  of  A2-diphenyl-butylene  C6H6.CH  :  CH.CH2.CH2.C6H5,  which 
is  produced  from  diphenyl-butadiene  and  diphenyl-butenin  with  Na 
amalgam  (A.  342, 253),  or  from  a-phenyl-cinnamenyl- aery  lie  acid  nitrile 
with  Na  and  alcohol  (B.  23,  2857). 

a,  8-Diphenyl-butadiene,  diphenyl-diethylene  C6H6CH  :  CH.CH  : 
CHC6H5,  is  known  in  its  three  theoretically  possible  stereo-isomeric 
forms  :  a-form  (trans-trans),  m.p.  151°  ;  j8-form  (cis-cis),  m.p.  70-5°  ; 
y-form  (cis- trans),  oily.  Of  these  the  a-form  is  most  stable,  and  the 
other  forms  pass  into  it  on  standing,  and  do  so  rapidly  in  sunlight. 
The  a-form  is  obtained  (i)  by  heating  a-phenyl-cinnamenyl-acrylic  acid 
or  dibenzal-propionic  acid  ;  (2)  from  the  dibromide  of  A2-diphenyl- 
butylene  by  means  of  quinolin  ;  (3)  in  small  quantity  on  reduction  of 
phenyl-acetylene  with  zinc  dust  and  alcohol ;  (4)  by  the  action  of 
magnesium  upon  co-bromo-styrol  (B.  43, 1232).  The  jS-form  is  obtained 
from  diphenyl-diacetylene,  the  y-form  from  diphenyl-butenin  (m.p.  97°) 
by  reduction  with  zinc  dust  and  alcohol  (A.  342,  238).  With  bromine 
in  chloroform  the  diphenyl-butadiene  gives  dibromide,  m.p.  141°, 
which  is  also  obtained  by  attachment  of  two  molecules  HBr  of  diphenyl- 
butenin,  and  probably  contains  the  bromine  atoms  in  the  i,  4-position 
(A.  342,  244).  With  two  molecules  NO2  it  also  combines  with  i,  4- 
addition  to  diphenyl-dinitro-butylene  C6H5CH(NO2).CH  :  CH.CH(NO2) 
C6H5,  m.p.  158°,  colourless  needles  from  which,  by  action  of  alkalies, 


a>,  co-DIPHENYL-BUTANE   GROUP  633 

nitrous  acid  is  split  off  to  form  diphenyl-a-nitro-butadiene  C6H5C(NO2)  : 
CH.CH  :  CHC6H5,  m.p.  112°,  in  golden-yellow  columns  (A.  360,  299). 

Diphenyl-butenin  C6H5CH  :  CH.C  :  CC6H5  also  occurs  in  two  stereo- 
isomeric  forms,  of  which  the  stable  trans-form,  m.p.  97°,  is  formed  by 
solution  of  phenyl-acetylene-copper  in  glacial  acetic  acid,  and  the 
unstable  liquid  cis-form,  b.p.12  188°,  by  partial  reduction  of  diphenyl- 
diacetylene  with  zinc  dust  and  alcohol.  Illumination  or  traces  of  . 
iodine  convert  the  unstable  form  into  the  stable  form  (A.  342,  225). 

Diphenyl-diacetylene  C6H5C  ;  C.C  ;  C.C6H5,  melting  at  88°.  This 
is  made  by  shaking  copper  phenyl-acetylide  CgH^C  ;  C.Cu  in  am- 
moniacal  solution  with  air,  or  by  the  action  of  potassium  ferricyanide. 
It  is  the  parent  hydrocarbon  of  indigo-blue.  Its  o,  o-dinitro-  derivative 

C6H4<^  ;,C'~:5fX6H4  (from  o-nitro-phenyl-acetylene)  is  rearranged  by 

xJNvJo     ^-^2  4. 

concentrated  sulphuric  acid  into  the  isomeric  di-isatogen  (q.v.),  which 
becomes  indigo-blue  :  CeH4<>C  :  C<XW4>  by  reduction   with 


ammonium  sulphide  (B.  15,  53). 

The  action  of  Br  in  CS2  solution  produces  a  dibromide,  m.p.  42°,  and  a 
tetrabromide,  m.p.  173°,  but  bromination  in  ether  or  acetic  acid  solution 
produces  ring-closure  and  tribromo-phenyl-naphthalin  (A.  342,  229). 

a  a,  S-Triphenyl-butadiene  (C6H5)aC  :  CH.CH  :  CHC6H5,  m.p.  102°, 
and  a,  a,  p,  S-tetraphenyl-butadiene  (C6H5)2C  :  C(C6H5).CH  :  CHC6H5, 
m.p.  147°,  are  formed  by  attaching  diphenyl-ketone  to  cinnamic  alde- 
hyde and  benzal-aceto-phenone  respectively,  with  rejection  of  CO2 
(B.  42,4249). 

a,  a,  3,  5  -  Tetraphenyl  -  butadiene  (C6H5)  2C  :  CH.CH.C  :  C(C6H5)  2, 
m.p.  202°,  from  tetraphenyl-tetramethylene-glycol  (C6H5)2C(OH).CH2. 
CH2.C(OH)(C6H5)2,  m.p.  208°,  the  condensation  product  of  succinic 
ester  with  phenyl-magnesium  bromide  (C.  1903,  I.  967). 

Ketones.  —  Phenethyl-benzyl-ketone,  i,  ^-diphenyl-butanone  C6H5. 
CH2.CH2.CO.CH2.C6H5,  boiling  at  234°-238°,  is  produced  when  hydro- 
cornicularic  acid  is  distilled  with  lime  ;  also  by  distillation  of  calcium- 
phenyl  acetate  and  hydro-cinnamate.  It  is  obtained  pure  by  the 
reduction  of  1,  4-diphenyl-butenone,  styryl-benzyl-ketone  C6H5CH  : 
CHCOCH2C6H5,  m.p.  71°,  formed  from  benzaldehyde  and  phenyl- 
acetone  by  alkaline  condensation  (M.  22,  659,  749). 

Phenyl-iso-erotone-phenone  C6H5CO.CH2.CH  :  CHC6H5,  m.p.  93°,  is 
obtained  by  the  reduction  of  diphenyl-a-nitro-butadiene  with  SnCl2  and 
HC1  ;  it  dissolves  in  alkalies  with  formation  of  salts  of  diphenyl-oxy- 
butadiene  C6H5C(OH)  :  CH.CH  :  CHC6H5  ;  with  benzaldehyde,  it  con- 
denses and  forms  dibenzal-propio-phenone  C6H5COC(  :  CHC6H5).CH  : 
CHC6H5,  m.p.  117°  (B.  40,  4825).  o-Oxy-styryl-benzyl-ketone  HO[i] 
C6H4CH  :  CHCOCH2C6H5,  b.p.12  2i7°-2i9°,  from  cumarin  with  benzyl- 
magnesium  chloride  (B.  37,  498). 

Diphenaeyl,  dibenzoyl-ethane  C6H5CO.CH2.CH^.COC6H5,  m.p.  145°, 
from  phenacyl-benzoyl-acetic  ester  by  ket  one-splitting,  and  by  reduc- 
tion of  dibenzoyl-ethylene  and  various  halogen  diphenacyls  ;  as  a 
y-diketone  it  easily  forms  diphenyl-furfurane,  thiophene,  and  pyrrol. 

y-Chloro-  and  y-bromo-diphenacyl  C6H5COCHC1.CH2COC6H5  and 
C6H5COCHBr.CH2COC6H5,  m.p.  141°  and  139°,  are  formed  from  di- 
benzoyl-ethylene with  halogen  hydrides,  which  are  easily  split  off  ;  with 


634  ORGANIC   CHEMISTRY 

potassium  iodide  they  are  easily  transposed  to  y-iodo-diphenacyl 
C6H5COCHI.CH2COC6H5,  m.p.  121°.  Isomeric  halogen  diphenacyls 
are  formed  by  the  action  of  alcoholic  potash  upon  phenacyl  haloids, 
C6H5COCH2X  ;  in  contrast  with  the  above  compounds  they  show  no 
ketone  or  diketone  reactions  and  are  marked  by  the  ease  of  addition  of 
carboxylic  acid  haloids  and  halogen  hydrides.  They  are  regarded  as 
the  various  stereo-isomeric  forms  of  the  corresponding  di-enol  forms  of 
the  halogen  diphenacyls  C6HC(OH)  :  CX.CH  :  C(OH)C6H5.  On  reduc- 
tion they  yield  diphenacyl.  a-  and  j8-Chloro-diphenaeyl,  m.p.  117°  and 
155°,  a-'  and  jS-bromo-diphenacyl,  m.p.  129°  and  161°,  a-,  j3-,  and  8- 
iodo-diphenacyl,  m.p.  82°-83°  with  decomposition,  m.p.  113°  with  de- 
composition, and  m.p.  I50°-I53°  with  decomposition.  If  metallic 
sodium  is  made  to  act  upon  the  ether  solution  of  phenacyl  iodide,  we 

obtain  tribenzoyl-trimethylene  C6H5COCH<C^^625  (B-  36»  2386>  2425)- 

\CrlCUL/6rl5 

Dibenzoyl-ethylene  C6H5COCH  :  CHCOC6H5,  cis-form,  m.p.  134°, 
trans-form,  m.p.  m°,  is  produced  by  heating  dibenzoyl-malic  acid, 
which  splits  off  2CO2  and  H2O.  The  cis-form  is  converted  by  HC1  into 
the  trans-form,  and  the  latter,  by  illumination,  back  into  the  cis-form. 
The  cis-form  reacts  more  easily  than  the  trans-form  with  hydrazin, 
forming  diphenyl-pyridazin,  and  it  also  forms  addition  products  more 
readily  (B.  35,  168). 

Phenaeyl-benzyl-ketone  C6H5COCH2COCH2C6H5,  m.p.  54°-56°,  from 
phenyl-acetic  ester  and  aceto-phenone  with  sodium  in  ether.  It  is 
isomeric  with  diphenacyl  (B.  34,  1479). 

Desyl-aceto-phenone,a,  fi-dibenzoyl-phenyl-ethane  C6H5CO.CH(C6H5) . 
CH2.COC6H5,  melting  at  126°,  is  produced  in  the  condensation  of  benzoin 
and  aceto-phenone  with  potassium  cyanide  (B.  23,  R.  636  ;    26,  60). 
See  B.  29,  R.  171,  for  the  action  of  hydrazin. 
C6H5.COCH.C6H5 

Bidesyl  I  ,   dibenzoyl-dibenzyl,    results    when    desyl- 

C6H5.CO.CH.C6H6 

bromide  or  iodine  acts  upon  sodium  desoxy-benzoin  (B.  21,  1355  ;  25, 
285).  It  melts  at  255°.  Iso-bidesyl,  formed  simultaneously,  melts  at 
161°.  Bidesyl  yields  tetraphenyl-pyrrol  and  tetraphenyl-furfurane, 
the  so-called  lepidene. 

a,j8-Dibenzoyl-styrol,  anhydro-aceto-phenone-benzile  C6H5CO.CH  :  C 
(C6H5)COC6H5,  m.p.  129°,  is  obtained  from  benzile  and  aceto-phenone 
by  the  action  of  caustic  potash.  When  heated  it  rearranges  itself  by 
the  migration  of  a  phenyl  group  into  the  isomeric  triphenyl-croto- 
lactone,  m.p.  118°  : 

C6H5CO.C(C6H5)  :  CHCOC6H5 >  CO.C(CeH5)2.CH  :  C(6)C6H5 

Dibenzoyl-styrol  a,  a,  y-Triphenyl-croto-lactone. 

Dibenzoyl-stilbene,  acicular  oxy-lepidene  C6H5CO.C(C6H5)  :  C(C6H5) 
COC6H5,  m.p.  220°,  resulting  from  the  oxidation  of  lepidene  (see  above) 
with  nitric  acid,  or  of  thio-nessal  with  potassium  chlorate  and  hydro- 
chloric acid,  also  yields,  on  heating,  tetraphenyl-croto-lactone,  tabular 
oxy-lepidene,  m.p.  136°  : 

C6H5COC(C6H5)  :  C(C6H5)COC6H5 >COC(C3H5)2.C(C6H5  :  )C(6)C6H5 

Dibenzoyl-stilbene  a,  a,  j8,  y-Tetraphenyl-croto-lactone 

Bidesyl  results  from  the  reduction  of  dibenzoyl-stilbene. 


w,  co-DIPHENYL-BUTANE  GROUP  635 

Diphenyl-tetraketone  C6H5.CO.CO.CO.CO.C6H5(+H2O),  m.p.  87°, 
is  red  in  colour  when  hydrous  and  yellow  when  anhydrous.  It  is 
formed  in  the  oxidation  of  benzoyl-formom  C6H5.CO.CO.CH(OH) 
COC6H5)  m.p.  170°,  which  is  produced,  like  benzoin,  from  benzaldehyde 
by  condensing  two  molecules  of  phenyl-glyoxal  with  potassium  cyanide. 
Benzoyl-formoin  also  results  readily  from  the  action  of  soda  upon  iso- 
nitroso-aceto-phenone  acetate  C6H5.CO.CH  :  NO.COCH3.  Substituted 
diphenyl-tetraketones  have  been  similarly  prepared  (B.  25,  3468). 

Diphenyl-tetraketone  is  a  member  of  the  following  CO  homologous 
series  : 

Diphenyl-ketone,  benzo-phenone     C6H5COC6H5 
Diphenyl-diketone,  benzile  C6H5COCOC6H5 

Diphenyl-triketone  C6H5COCOCOC6H5 

Diphenyl-tetraketone  C6H5COCOCOCOC6H5. 

Hydroxylamine  forms  but  one  i,  ^-dioxime  [C6H5C(NOH)CO]2,  m.p. 
176°  with  decomposition  ;  the  2, 3-dioxime  or  dibenzoyl-glyoxime 
C6H5.COC(NOH)C(NOH)CO.C6H5,  m.p.  108°  with  decomposition, 
results  from  the  reduction  of  its  peroxide,  which  is  formed  in  the 
interaction  of  nitric  acid  and  aceto-phenone.  Hydroxylamine  con- 
verts the  2,  3-dioxime  into  diphenyl  -  tetraketoxime  C6H5[C(NOH)]4 
C6H5,  m.p.  225°  (B.  26,  528). 

Carboxylic  Acids. — From  diphenyl-butadiene  the  following  two 
acids  are  derived  : 

a-Phenyl-cinnamenyl-acrylic  acid,  cinnamylidene-phenyl-acetic  acid 
C6H5C(CO2H)  :  CH.CH  :  CHC6H5,  m.p.  188°,  from  cinnamic  aldehyde 
and  phenyl  -  acetic  acid,  and  dibenzal-propionic  acid  C6H5CH  :  C 
(COOH).CH  :  CHC6H5,  obtained  from  benzaldehyde  and  y-phenyl- 
iso-crotonic  acid  by  Perkin's  synthesis.  These  two  diolefm-carboxylic 
acids  have  been  closely  examined  by  Thiele,  as  they  furnished  material 
for  his  theory  of  conjugate  double  bindings  (A.  306,  87-246  ;  but  see 
B.  37,  1121). 

The  a-phenyl-cinnamenyl-acrylic  acid  gives  with  bromine  a 
dibromide,  m.p.  175°  with  decomposition,  containing  the  Br  atoms  in 
the  i,  4-position,  since  with  alkali  it  yields  a,  a-diphenyl-dihydro- 
furfurane  and  a  brominated  acid.  On  the  other  hand,  the  dibromide 
heated  with  diethyl-aniline  is  transposed  into  the  lactone  of  eorni- 
cularic  acid  C6H5C(COQH)  :  CH.COCH2C6H5,  m.p.  123°,  which  is  also 
produced  by  the  reduction  of  vulpic  acid.  The  reduction  of  phenyl- 
cinnamenyl-acrylic  acid  produces  first  2, 5-diphenyl-pentenic-acid 
C6H5CH(COOH)CH  :  CHCH2C6H5,  m.p.  101°,  which  with  alkali  is 
isomerised  to  the  a,  jS-unsaturated  acid,  and  with  glacial  acetic  sul- 
phuric acid  to  the  lactone  of  tetrahydro-eornicularic  acid  C6H5CH 
(COOH)CH2.CH(OH)CH2C6H5.  Bromine  converts  the  2,  5-diphenyl- 
pentenic  acid  into  1, 3-phenyl-benzyl-A1-eroto-lactone 

CgHeC  :  CH.CH. CHoCfiHc       i  •  i        -.1      n     i-      •  i  i     i      i  •      i      •          •  j 

co ^  5,  which  with  alkali  yields  hydro-cormculanc  acid 

(A.  319,  211). 

Dibenzal-propionic  acid  also  yields  a  i,  5-dibromide,  which  is  easily 
converted  into  bromo-lactone  and  a  diolefin-lactone  :  benzal-phenyl- 

eroto-lactone  C«H*CH  :  ^Q1^0'115'  m.p.  150°.  a-Phenacyl-cinnamic 
acid  C6H5CH  :C(COOH)CH2COC6H5,  m.p.  171°,  is  produced  from  the 


636  ORGANIC  CHEMISTRY 

former  by  alkali.  Reduction  of  the  bromo-lactone  and  diolefin- 
lactone  gives  an  unstable  lactone  (i),  m.p.  101°,  and  a  stable  lactone 
(2),  m.p.  67°,  both  of  which  yield  with  alkali  a-phenacyl-hydro-cinnamic 
acid  (3)  : 

(!)  CO O  (3)  COOH  (2)  CO O 

C6H5CH2.CH.CH  :  CC6H5— >C6H5CH2CHCH2COC6H5<— C6H5CH2C  :  CH.CHC6H5. 

Reduction  of  diphenyl-propionic  acid  gives  a-benzyl-phenyl-iso- 
erotonic  acid  C6H5.CH2CH(COOH)CH  :  CHC6H5,  m.p.  124°,  distin- 
guished by  the  ease  with  which  it  produces  naphthalin  derivatives. 
With  bromine  it  splits  off  HBr  and  produces  phenyl-bromo-tetrahydro- 
naphthoic  acid. 

From  the  nitrile  of  cinnamenyl-phenyl-acrylic  acid  is  derived 
p2-diamido-diphenyl-cyano-butadiene  NH2[4]C6H4CH  :  CH.CH  :  C(CN) 
C6H4[4]NH2,  m.p.  196°,  which,  like  benzidin  and  p2-diamido-stilbene, 
is  a  generator  of  substantive  cotton  dyes  (B.  34,  3109). 

Diphenyl  -  butadiene  -  acetic  acid  C6H5CH  :  CH.CH  :  C(C6H5)CH2 
COOH,  m.p.  190°,  from  cinnamic  aldehyde  and  phenyl-succinic  acid, 
on  boiling  with  acetic  anhydride,  yields  diphenyl-phenol  (B.  36,  1407). 

The  ester  of  benzoyl-phenacyl-aeetic  acid,  a,  /3-dibenzoyl-propionie 
acid  C6H5.CO.CH2.CH(CO.C6H5)COOR,  is  obtained  from  benzoyl-acetic 
ester  with  phenacyl  bromide.  In  the  ketone  decomposition  it  yields 
diphenacyl  ;  and  by  the  acid  decomposition,  benzoyl-propionic  acid 
and  benzoic  acid.  Iso-oxalyl-dibenzyl-ketone,  melting  at  24o°-242°, 
may  be  referred  to  benzoyl-oxalyl-phenyl-acetic  acid  C6H5.CH2.CO. 
CO.CH(C6H5).COOH,  isomeric  with  dibenzoyl-propionic  acid.  It  is 
formed  on  heating  oxalyl-dibenzyl-ketone  beyond  its  melting-point 
(A.  284,  293)  : 

C6H5C  :  C(OH).CO.CH.C6H5  __        C6H5C  :  C(OH).C  :  CH.C6H5 


CO 


Alkalies  convert  isoxalyl-benzyl-ketone,  just  like  pulvic  acid  richer 
in  CO2,  into  dibenzyl-glycollic  acid. 

Dibenzylidene-succinic  acid  C6H5CH  :  C(COOH).C(COOH)  : 
CHC6H5,  melting  with  decomposition  at  201°,  and  benzylidene-y- 
diphenyl-itaeonie  acid  (C6H5)2C  :  C(COOH).C(COOH)  :  CH.C6H5,  are 
obtained  by  the  condensation  of  succinic  ester  (i)  with  two  molecules 
of  benzaldehyde,  and  (2)  with  benzo-phenone  and  benzaldehyde  by 
means  of  sodium  ethylate  (B.  30,  94  ;  37,  2240).  By  reduction  with 
Na  amalgam  they  form  a  mixture  of  two  cis-trans  isomeric  diphenyl- 
and  triphenyl-butane-dicarboxylic  acids  (B.  37,  2662).  By  illumina- 
tion the  dibenzylidene-succinic  anhydride  is  oxidised  and  converted 
into  the  anhydride  of  i-phenyl-naphthalin-2,  3-dicarboxylic  acid 
(B.  40,  3374)  : 

C6H5CH:C—  C0\     _    c  R  /CH=rC.CO\ 
C6H5CH  :  C—  CO/  4\C(C6H5)  :  C.CO/ 

C6H5.CO.CH.C02H 

Dibenzoyl  -  succinic     acid  .       Its     ethyl     ester, 

C6H5.CO.CH.C02H 

melting  at  129°,  is  obtained  from  sodium-benzoyl-acetic  ester  by  the 
action  of  iodine,  just  as  we  form  diaceto-succinic  ester  from  aceto-acetic 
ester.  By  the  elimination  of  water  there  results  diphenyl-furfumne- 


co,  oj-DIPHENYL-BUTANE   GROUP  637 

dicarboxylic  ester.  The  esters  of  the  acid  appear  in  three  forms,  of  which 
the  unstable  variety,  soluble  in  alkalies,  is  probably  the  enol-form  C6H5 
C(OH)  :  C(COOH)  :  C(COOH)  :  C(OH)C6H5,  while  the  other  two  repre- 
sent the  syn-  and  anti-modifications  of  the  keto-form  (B.  29,  R.  962). 

Dibenzoyl-maleic  acid  ester  c^'coCco^H5'  m'p'  75°'  from 
disodium-dibenzoyl-succinic  acid  ester  with  iodine,  is  transposed  by 
heat  into  dibenzoyl-fumarie  acid  'J5?^S^ff*,  m.p.  88°.  The 

UVJ2l^2-"5'"'*-'*-"-'6-"-5 

maleinoid  ester  condenses  more  easily  than  the  fumaroid  with  hydrazin 
to  form  diphenyl-pyridazin-carboxylic  ester  (q.v.).  The  potassium  salts 
produced  by  the  acidulation  of  the  esters  give,  on  acidulation,  a 
hydrate  of  dibenzoyl-ethylene-dicarboxylic  acid,  the  so-called  dibenzoyl- 

malic  acid  c6H5coCHCOCH2H  (?)'  which  on  heatinS  loses  water  and 
2CO2,  and  passes  into  dibenzoyl-ethylene  (B.  33,  3784). 

Diphenyl-oxalyl-diacetie  acid,  diphenyl-ketipic  acid  COOH.CH(C6H5) 
CO.CO.CH(C6H5)COOH  is  isomeric  with  dibenzoyl-succinic  acid.  Its 
dinitrile,  melting  at  270°  with  decomposition,  is  produced  by  the  con- 
densation of  oxalic  ester  with  two  molecules  of  benzyl  cyanide.  When 
saponified  with  hydrochloric  or  sulphuric  acid  it  yields  not  the  free 
acid,  but  passes  at  once  into  its  anhydride,  a  monolactone,  pulvic  acid 

OOC.CH(C6H5)CO.C  :  C(C6H5)COOH,  melting  at  214°,  and  a  dilactone 
OOC.C(C6H5)  :  C.C  :  C(C6H5)COO.  Pulvic  acid  may  also  be  prepared 

from  vulpic  acid,  C19H14O5,  consisting  of  yellow  prisms,  melting  at  110°, 
and  found  in  a  certain  moss  and  in  the  lichen  Cetraria  vulpina,  by  boiling 
it  with  lime-water.  Sodium  ethylate  converts  pulvic  acid  back  into 
salts  of  vulpic  acid.  The  latter  is  therefore  very  probably  to  be 
regarded  as  a  methyl  ether  of  pulvic  acid  (B.  27,  R.  869  ;  A.  288,  14). 
Zinc  dust  and  ammonia  reduce  pulvic  acid  to  hydro-cornieularic  acid, 
a,  §-diphenyl-lcevulinic  acid  C6H5.CH2.CO.CH2.CH(C6H5)COOH,  melting 
at  134°.  Distilled  with  lime,  it  yields  phenyl-ethyl-benzyl-ketone,  and 
when  heated  with  caustic  potash  the  products  are  toluene  and  phenyl- 
succinic  acid.  Boiling  alkalies  decompose  pulvic  and  vulpic  acids  into 
2CO2  and  dibenzyl-glycollic  acid.  If  it  be  assumed  that  diphenyl- 
ketipic  acid  is  formed  at  first,  then  this  reaction,  discarding  the  evolu- 
tion of  CO  2,  is  an  analogue  of  the  benzilic  acid  transposition  : 

C6H5.CH(COOH)  .CO  C6H6.CH2X 

|    ±5£ >  >C(OH)COOH. 

C6H5.CH(COOH).CO         -2CO»         C6H5.CH/ 

Ethane-dibenzoyl-o2-diearboxylic  acid  COOH.C6H4CO.CH2.CH2 
CO.C6H4.COOH,  is  another  isomeride  of  dibenzoyl-succinic  acid.  It 

melts  at  166°.     It  is  made  by  boiling  ethine-diphthalyl  6.OC.C6H4.C  : 

CH.CH  :  C.C6H4.COO,  melting  above  350°,  the  dilactone  corresponding 
to  it,  with  alkalies.  Ethine-diphthalyl  results  from  the  condensation 
of  two  molecules  of  phthalic  anhydride  with  succinic  acid  when  two 
molecules  of  carbon  dioxide  are  split  off  (B.  17,  2770).  Sodium  alcohol- 
ate  rearranges  it  into  bis-diketo-hydrindene. 

F.  cu,cu  -  Diphenyl-pentane    Group.  —  y  -  Diphenyl  -  methylene  -  a, 


638  ORGANIC   CHEMISTRY 

e-diphenyl-pentadiene    (C6H5CH  :  CH)2  :  C  :  C(C6H5)2,    sulphur-yellow 
crystals,  m.p.  174°,  from  diphenyl-ketene  and  dibenzal-acetone  (B.  41, 


Ketones.  —  i.  The  diolefin  -  ketones  of  this  group  are  generally 
obtained  by  condensation  of  benzaldehydes  (two  molecules)  with 
ketones  (one  molecule)  which  contain  the  group  —  CH2COCH2  —  : 

2C6H5CHO+CH3COCH3=C6H5.CH  :  CHCOCH  :  CHC6H5+2H2O. 

Dibenzylidene  -  acetone,  dibenzal  -  acetone  C6H5CH  :  CH.COCH  : 
CHC6H5,  yellow  needles,  m.p.  112°  ;  oxime,  m.p.  143°,  gives  two 
isomeric  hydroxylamine  oximes  C6H5CH  :  CHC(NOH)CH2.CH(NHOH) 
C6H5,  m.p.  165°  and  201°  (C.  1900,  1.  336)  by  the  reduction  of  a  second 
molecule  of  hydroxylamine. 

The  dibenzyl-acetone  gives  with  HC1  not  only  the  normal  colourless 
addition  products,  but  also  a  yellow  unstable  monochlorohydrate 
which  in  solution  partly  splits  up  into  its  components  and  unites  with 
a  second  molecule  HC1  or  metallic  salts  like  ferric  or  mercuric  chloride 
to  intensely  red  double  compounds  (B.  37,  3277,  3364). 

By  the  action  of  acetic  anhydride  and  concentrated  sulphuric  acid, 
dibenzal-acetone  takes  up  water  and  is  changed  into  diphenyl-eyelo- 

pentenolone  c^C^H*))00'  m'P-  r76°  (B-  37>  "33). 

Dibenzal-acetone  dichloride,  dicinnamenyl-dichlow-methane  (C6H5 
CH  :  CH)2CC12,  m.p.  77°,  produced  by  the  action  of  PC15  upon  dibenzal- 
acetone  in  benzene  solution,  shows  in  its  properties  a  far-reaching 
analogy  with  triphenyl-chloro-methane.  It  dissolves  in  concentrated 
sulphuric  acid  with  a  violet  colour,  and  gives,  with  metallic  salts  like 
mercuric  and  stannic  chloride,  double  compounds  of  the  same  colour. 
Its  purple  solution  in  SO2  contacts  the  electric  current.  One  of  the 
two  chlorine  atoms  is  very  lightly  bound  and  can  easily  be  exchanged 
for  other  groups  like  OH,  OCH3,  etc.  The  dieinnamenyl-ehloro- 
carbinol  (C6H5CH  :  CH)2C(OH)C1,  m.p.  56°,  formed  by  treatment  with 
moist  silver  oxide,  is  very  stable  and  resembles  triphenyl-carbinol. 
Like  the  latter,  it  dissolves  with  an  intense  colour  in  concentrated 
sulphuric  acid.  It  is  very  easily  esterified  (methyl  ether,  m.p.  55°), 
and  is  easily  converted  by  gaseous  HC1  into  the  dichloride,  and  by 
HBr  into  chloro-bromide  in  which  the  bromine  atom  shows  the  chief 
reaction.  The  reason  for  this  property  is  to  be  found  in  the  particu- 
larly strong  valency  binding  by  the  cinnamenyl  group,  which  surpasses 
that  of  the  phenyl  group,  since  in  the  benzo-phenone  chloride  C6H5CC12 
C6H5  no  loosening  of  the  chlorine  atom  is  to  be  observed,  whereas  the 
dichloride  of  the  benzylidene-aceto-phenone  C6H5CH  :  CH.CC12C6H5 
shows  similar  phenomena  (B.  39,  2977  ;  40,  2689  ;  A.  370,  315). 

Benzal-benzyl-acetone  C6H5CH  :  CHCOCH2CH2C6H5,  m.p.  53°,  from 
benzaldehyde  and  benzyl-acetone  with  soda.  Sodium  amalgam 
reduces  it  to  dibenzyl-acetone  (C6H6CH2CH2)2CO,  b.p.130  28o°-285° 
(A.  330,  185).  p2-Dinitro-dibenzyl-acetone,  see  B.  37,  1993. 

o-Oxy-dibenzal-acetone,  yellow  flakes,  m.p.  139°  (B.  31,  728). 

o2-Dioxy-dibenzal-acetone,  o-dicumarketone,  m.p.  160°,  p2-dioxy- 
dibenzal-acetone,  m.p.  238°,  orange-yellow  crystals,  the  unstable 
modification  consisting  of  dark-green  flakes  (B.  26,  129).  Dibenzal- 
diethyl-ketone,  m.p.  122°  (B.  31,  1886). 


o>,  oj-DIPHENYL-PENTANE  GROUP  639 

Cmnamylidene-aceto-phenone  C6H5CH  :  CH.CH  :  CHCOC6H5,  m.p. 
103°,  from  cinnamic  aldehyde  and  aceto-phenone.  Its  oxime,  m.p.  131°, 
is  condensed  by  heating  to  a1a1-diphenyl-pyridin  (B.  28,  1730)  ; 
homologues,  see  B.  35,  1065. 

Dibenzoyl-propane  CH2(CH2COC6H5)2,  m.p.  67°,  is  formed  from 
glutaryl-chloride-benzene  and  A1C13.  Also  by  splitting  up  a1a1- 
dibenzoyl-glutaric  ester  obtained  from  benzoyl  -  acetic  ester  with 
CH2I2  or  formaldehyde. 

Dibenzoyl-diphenyl-propane  CH2[CH(C6H5)COC6H5]2,  m.p.  146°, 
from  formaldehyde  and  desoxy-benzoin.  The  reduction  of  its  i,  5- 
diketone  produces  cyclic  pinacones  of  the  pentamethylene  group 
(B.  24,  R.  323  ;  A.  302,  215,  223). 

i,  5-Diketones  of  this  group  are  obtained  by  condensing  benzalde- 
hydes  (one  molecule)  and  aceto-phenones  (two  molecules)  with  sodium 
hydroxide  :  benzylidene  -  diaceto  -  phenone  C6H5CH(CH2.CO.C6H5)2, 
m.p.  85°,  and  o-oxy-benzylidene-diaceto-phenone  (OH)[2]C6H4(CH2. 
CO.C6H5)2,  melting  at  131°.  By  varying  the  conditions  and  condensing 
two  molecules  of  benzaldehyde  with  three  molecules  of  aceto-phenone, 
two  isomeric  dibenzylidene-triaceto-phenones  (C6H5CH)2(CH2COC6H5)3, 
melting  at  198°  and  256°  respectively,  are  produced. 

Benzamarone,  benzylidene-bis-desoxy-benzom  C6H5COCH(C6H5)CH 
(C6H5).CH(C6H5)COC6H5  (?),  exists  in  two  modifications,  melting  at 
219°  and  180°.  It  is  prepared  by  condensing  benzaldehyde  with 
desoxy-benzoin,  as  well  as  by  the  addition  of  desoxy-benzoin  to  benzyl- 
idene-desoxy-benzoin  by  the  aid  of  sodium  ethylate.  Similarly,  desoxy- 
benzoin  attaches  itself  to  the  unsaturated  unions  of  other  olefin 
derivatives — e.g.  a-phenyl-cinnamo-nitrile,  benzal-aceto-acetic  ester, 
benzal-benzoyl-pyro-racemic  ester,  etc.  (B.  25,  1087).  By  decom- 
position with  sodium  ethylate,  benzamarone  yields  the  sodium  salt  of 
amaric  acid  C23H20O3,  and  with  sodium  iso-butylate  it  forms  dimethyl- 
amaric  acid  C25H26O3  (A.  275,  50). 

The  dry  distillation  of  benzamarone  produces  desoxy-benzoin, 
benzylidene-desoxy-benzoin,  and  a  body  isomeric  with  the  latter  (B. 
26,  818).  Hydroxylamine  changes  it  quite  readily  into  pentaphenyl- 
pyridin. 

Carboxyl  Derivatives  of  the  a>,  a)-Diphenyl-pentane  Group. — Styryl- 

(-   TJ  (^TJ-  .  P"H"\ 

phenaeyl-propionic  acid  r5;;5;; „  '  rp  >CHCH2COOH,  m.p.  125°,  from  the 

v^6r!5^U.v^rl2  / 

condensation  product  of  cinnamylidene-aceto-phenone  with  malonic 
ester  by  saponincation  and  rejection  of  CO2.  On  reduction  it  yields 
phenacyl-succinic  acid  C6H5COCH2CH(COOH).CH2COOH  (C.  1903, 
II.  944). 

Diphenyl-acetic  acid  (C6H5COCH2)2CHCO2H,  m.p.  133°,  from 
diphenacyl-malonic  ester  (C6H5COCH2)2C(CO2R)2  or  diphenacyl-aceto- 
acetic  ester  (C6H5COCH2)2C(COCH3)COOC2H5,  m.p.  83°,  the  products 
of  the  action  of  phenacyl  bromide  upon  malonic  ester  and  aceto-acetic 
ester  (B.  22,  3225).  It  is  also  formed  by  alkaline  condensation  of 
aceto-phenone  with  glyoxylic  acid,  as  well  as  the  action  of  cold  soda 
upon  benzoyl-acrylic  acid,  wherein  the  latter  splits  up  into  aceto- 
phenone  and  glyoxylic  acid  (C.  1909,  II.  125).  Diphenacyl-acetic  acid, 
being  an  e-diketone,  forms  with  ammonia  a  pyridin  derivative  (B.  29, 


640  ORGANIC   CHEMISTRY 

Dibenzyl-aeetone-dicarboxylie  ester  C6H5CH2(C02R)COCH(CO2R) 
CH2C6H5  is  formed  on  benzylating  acetone-dicarboxylic  ester  (Vol.  I.), 
besides  the  monobenzylated  and  tribenzylated  product  (B.  34,  1996). 

Acetone-diphthalide  CO[CH2CHC6H4[2]COO]2,  m.p.  137°,  from 
phthal-aldehydic  acid  and  acetone,  besides  acetonyl-monophthalide 
(C.  1898,  II.  980). 

Benzylidene-bis-benzoyl-acetic  ester  C6H5CH[CH(CO2R)COC6H5]2 
from  benzal-benzoyl-acetic  ester  with  benzoyl-acetic  ester.  It  is  easily 
split  by  alcoholic  sodium  ethylate  into  these  components  (B.  33,  3183). 

G.  w,  aj-Diphenyl-hexane  Group  and  Higher  Homologues. — 1,  6- 
Diphenyl-hexadiene  C6H5CH  :  CH.CH2.CH2.CH  :  CHC6H5,  m.p.  82°,  is 
formed,  besides  an  isomeric  liquid  hydrocarbon,  by  the  action  of  Mg 
upon  cinnamyl  chloride  C6H5CH  :  CH.CH2C1  (B.  43,  172).  Tetra- 
phenyl-hexatriene  C6H5CH  :  CH.CH  :  CH.C(C6H5)  :  C(C6H5)2,  yellow 
prisms,  m.p.  159°,  from  diphenyl-ketone  and  cinnamylidene-aceto- 
phenone  (B.  42,  4249).  Hydro-cinnamoin  C6H5CH  :  CH.CH(OH). 
CH(OH).CH  :  CHC6H5,  m.p.  154°,  is  obtained,  besides  other  products, 
by  the  reduction  of  cinnamic  aldehyde  with  copper  zinc  in  alcohol 

(B.   32,   1296).      Dibenzoyl-diphenyl-butadiene   9'^c    ^ :  ^6S5    (?), 

L^g-TLgULJU-n.  .  Ut^gJtl5 

m.p.  192°,  from  benzile  and  aceto-phenone,  can  be  converted  by  reduc- 
tion into  tetraphenyl-benzol  and  its  derivatives  (A.  302,  195). 

Oxalyl-diaeeto-phenone  C6H5COCH2COCOCH2COC6H5,  m.p.  180°, 
is  formed  in  the  condensation  of  two  molecules  of  aceto-phenone  and 
oxalic  ester  with  sodium  alcoholate.  Consult  B.  28,  1206,  for  the 
reduction-products  of  this  tetraketone. 

w,  oj-Diphenyl-diketo-hexane  (C6H5COCH2CH2)  2.  Diphenyl-diketo- 
octane  (C6H5COCH2CH2CH2)2,  and  diphenyl-diketo-nonane  (C6H5CO. 
CH2.CH2.CH2)2CH2,  are  prepared  from  the  chlorides  of  adipic  acid, 
sebacic  acid,  and  azelaic  acid  by  means  of  benzene  and  aluminium 
chloride  (B.  29,  R.  1157).  Cinnamylene-benzylidene-acetone  C<.H5CH  : 
CH.CH  :  CH.COCH  :  CHC6.H5,  m.p.  106°,  is  derived  from  6o,co-diphenyl- 
heptane.  It  is  formed  from  cinnamylene-acetone  and  benzaldehyde 
(B.  29,  615).  Cinnamylene-benzylidene-acetone  C6H5CH  :  CH.CH  :  CH. 
COCH  :  CHC6H5,  m.p.  106°,  is  derived  from  o>,  cu-diphenyl-heptane. 
It  is  formed  from  cinnamylene-acetone  and  benzaldehyde  (B.  29,  615). 
Diphenyl-butadiene,  diphenyl-octa-tetrene  C6H5CH  :  CH.CH  :  CH.CH  : 
CH.CH  :  CHC6H5,  m.p.  225°  with  decomposition,  golden  -  yellow 
flakes,  is  formed  besides  dicinnamylidene  -  succinic  anhydride 

QH'CH  :  CtLCH  :  Cco)°'  m'P'  2I5°'  brick-red  needles,  by  condensa- 
tion of  cinnamic  aldehyde  with  sodium  succinate  by  acetic  anhydride 
(A.  331,  165).  A  stereo-isomeric  (?)  white  diphenyl-octa-tetrene,  m.p. 
124°,  is  formed  from  cinnamic  aldehyde,  succinic  ester,  and  sodium 
ethylate,  besides  other  products  (B.  34,  2190).  Illumination  converts 
the  yellow  into  the  white  hydrocarbon  (B.  42,  565). 

B.  CONDENSED  NUCLEI. 

The  condensed  nuclei  to  be  discussed  in  the  following  section  are 
characterised  by  the  fact  that  in  them  C  atoms  of  the  benzene  nuclei 
participate  in  the  formation  of  other  carbocyclic  rings. 


CONDENSED   NUCLEI  641 

Substances  to  which  bicyclic  formulae  are  attributed  have 
already  been  mentioned.  Compare  bicyclo-pentane,  bicyclic  ketone, 
carone,  thujone,  pinene,  camphene,  tricyclene,  camphor,  fenchone, 
etc.  It  should  be  noted  that  the  capacity  of  forming  bicyclic 
combinations  in  the  hydro-aromatic  substances  is  more  varied 
than  in  the  benzene  derivatives  proper,  and  is  not  confined  to  the 
i,  2-position. 


The    bicyclic    system    of    carone    |  I  yC  7,  representing   the 

c  —  c  —  c/ 

321 

condensed  benzene-trimethylene  ring,  and  whose  hypothetical  hydrogen 
compound  is  called  norcarane,  has  been  made  accessible,  in  a  more 
general  synthetic  manner,  by  heating  diazo-acetic  ester  with  benzene 
or  its  derivatives  (Buchner,  B.  33,  3453  ;  34,  982  ;  36,  3502  ;  37,  931)  : 

CH=CH—  CH     K  CH=CH—  CHV 

||     +  ||  >CHC02C2H5=|  I      >CHC02C2H5+NZ. 

CH=CH—  CH     N/  CH=CH—  CH/ 

A2'4  -Norcaradiene-7-earboxylic  ethyl  ester,  pseudo-phenyl-acetic  ester, 
followed  by 

A^Norcaradiene  -  7  -  carboxylic  ethyl  ester,  pseudo-phenyl-acetic 
ester  C6H6CHCO2C2H5,  is  formed  from  benzene  and  diazo-acetic  ester 
by  heating  under  pressure  to  I35°-I4O°.  The  raw  ester,  b.p.13  108°, 
partly  converted  into  j3-cyclo-heptatriene-carboxylic  ester,  gives, 
with  concentrated  sulphuric  acid,  a  red  colour  passing  into  indigo  blue. 
With  ammonia  we  obtain  the  crystalline  amide,  m.p.  141°,  which  on 
saponification  with  sulphuric  acid  gives  the  oily,  free  acid.  The  latter 
with  bromine  gives  a  dibromide,  m.p.  160°  with  decomposition,  and  a 
tetrabromide,  m.p.  235°  with  decomposition.  Oxidation  with  per- 
manganate is  complicated.  It  results  in  benzoic  acid,  o-,  and  p- 
phthalic  acid,  and  trimethylene-tricarboxylic  acid  (splitting  of  the 
benzene  ring).  Heating  under  pressure  transposes  the  ester  into 
j3-cyclo-heptatriene-carboxylic  ester,  while  boiling  the  ester  or  amide 
with  alkalies  produces  a-cyclo-heptatriene-carboxylic  acid  (splitting  of 
the  trimethylene  ring  between  i  and  6).  Treatment  with  concentrated 
sulphuric  acid  transposes  the  amide  into  phenyl-acetamide  C6H5.CH2 
CONH2  (splitting  of  the  trimethylene  ring  between  i  and  7). 

A2,4-3-Methyl-norcaradiene-carboxylic  ester,  pseudo-tolyl-acetic  ester 
CH3.C6H5  :  CHCO2C2H5,  b.p.12  I22°-I26°,  from  toluol  and  diazo-acetic 
ester,  amide,  m.p.  131°,  gives  on  boiling  with  30  per  cent,  sulphuric  acid, 
p-tolyl-acetic  acid  ;  by  prolonged  shaking  with  ammonia,  methyl- 
cyclo-heptatriene-carboxylic  ester,  m.p.  108°. 

3,  5-Dimethyl-norcaradiene-earboxylie  ester,  pseudo-xylyl-acetic  ester 
(CH3)2C6H4  :  CHCO2C2H5,  b.p.10  I25°-I35°,  from  m-xylol  and  diazo- 
acetic  ester,  amide,  m.p.  142°,  gives,  with  sulphuric  acid,  2,  4-dimethyl- 
phenyl-acetic  acid  (A.  258,  i). 

1,  7  -  Norcarane  -  dicarboxylic  ester  CO2C2H5.C6H9  :  CHCO2C2H5, 
b.p.18  160°,  from  A1-tetrahydro-benzoic  ester  with  diazo-acetic  ester  ; 
the  acid,  m.p.  153°,  gives  an  anhydride,  m.p.  87°. 

C6H4          CH. 

Benzo-norearadiene-carboxylic  ester  i  |    NcHCO2c2H5,  b.p.u 

CH  =CH  —  CH/ 
VOL.  II.  2  T 


642  ORGANIC   CHEMISTRY 

i63°-i64°,  from  naphthalene  with  diazo-acetic  ester.  Acid,  m.p.  166°  ; 
amide,  m.p.  217°.  Oxidation  produces  carboxy-phenyl-trimethylene- 
diearboxylic  acid  C°2H-C6H4CH  \CHCOgH>  which  has  been  further  dis- 

CO2H.CH/ 

integrated  to  trimethylene-tricarboxylic  acid.  In  this  connection 
some  substances  should  be  mentioned  which  are  derived  from  a  con- 
densed benzene  and  heptamethyl  ring,  benzo-cyelo-heptane. 

Benzo-cyclo-heptanone  C6H4{^^2'™2^CH2'  b-P-  27°°>  is  formed 

v.  |_2jv-<VJ  .  Crlg/ 

by  condensation  of  A-phenyl-valeric  acid  chloride  by  means  of  A1C13  ; 
its  oxime,  m.p.  109°,  gives  on  reduction  benzo-a-amino-cyclo-heptane, 
whose  chlorohydrate,  on  heating,  decomposes  into  sal  ammoniac  and 


benzo-cyclo-heptene  C6H4^~2:H2,  b.p.  234°.     The  latter  is 

L  l_2JL/xl  -  \stis  » 

split  up  by  oxidation  to  o-phenylene-butyro-carboxylic  acid  (C.  1903, 
I.  586,  882). 

Benzo-eyclo-heptadione  c6H4]'2H2,  m.p.  46°,  is  formed  by 


ketone-splitting  of  phthalyl-glutarie  esters  C- 

obtained  by  condensation  of  phthalic  ester  and  glutaric  ester  by  means 
of  sodium  alcoholate  (B.  32,  2227). 

Benzo-eyclo-heptadienone  ^{|*S|  ;  £^>co,  m>p'  67°'  is  formed 
from  its  dicarboxylic  acid,  m.p.  210°.  The  diethyl  ester,  m.p.  95°,  is 
formed  by  condensation  of  o-ph  thai-aldehyde  with  acetone-dicarboxylic 
ester  by  means  of  diethylamine. 

#0wo/ogw£s  of  benzo-cyclo-heptadienone  are  formed  by  the  condensation 
of  o-ph  thai-aldehyde  with  methyl-ethyl-ketone,  diethyl-ketone,  dibenzyl- 
ketone,  etc.,  together  with  acyl-hydrindones.  Sodium  and  alcohol 
reduce  them  to  the  corresponding  benzo-cyclo-heptanols  (A.  377,  i). 

Of  greater  importance  are  the  combinations  of  the  benzene  nuclei 
with  five-member  ed  nuclei,  and  of  benzene  nuclei  with  each  other  : 


/ 

CH 

C  CH 

pTT                                        PTT 

,/CH\                      /CH\ 

CH        C  C          CH 

XH^  /CH^ 
CH         C           CH 

C'H 

II         II 
C        CH 

JH 

II      II        1 

C^/C          CH 

CH 

II 
C 

- 

s 

-W/VLT 
^Jnr       L/rl2 

V 

H/  CH^CH^ 

xct 

[/      NQP 

-i// 

Indene 

Fluorene 

Naphthalene 

CH=CH 

v^Jri  —  v^jri                        i^i-j          /^T-T          c*\^ 

CH             C— 

—  C 

CH          CH         C    \ 

Y 

%CH 

\           / 
CH—  C 

\      /'        1       II  i 

C  CH              CH         C    1 

C 

JH 

\H 

=^ 

H/^C 

H/ 

Phenanthrene  Anthracene. 

Although  these  condensed  nuclei,  as  a  rule,  continue  to  manifest 
their  aromatic  character,  they  exhibit  in  their  behaviour,  in  har- 
mony with  their  peculiar  structure,  a  series  of  wide  differences  from 
the  true  benzene  compounds  (see  Naphthalene).  They  are  eventually, 
by  suitable  oxidations,  changed,  like  the  homologues  of  benzene,  into 
benzene-carboxylic  acids.  The  parent  hydrocarbons  of  these  groups 


INDENE  AND   HYDRINDENE  GROUP  643 

occur,  like  benzene,  chiefly  in  coal-tar,  from  which  they  are  obtained 
in  greater  or  lesser  amount.  Naphthalene  is  technically  important  ; 
this  is  especially  true  of  anthracene,  the  hydrocarbon  of  alizarin. 

I.  INDENE  AND  HYDRINDENE  GROUP. 


Indene  Hydrindene. 

Indene  has  received  its  name  from  indol,  because  of  its  similarity 
to  the  latter  in  structure.  By  introducing  NH  into  the  methylene 
group  of  indene  the  formula  of  indol  results. 

Indene  C9H6  is  an  oil,  boiling  at  178°  ;  its  specific  gravity  is 
1-040  at  15°.  It  occurs,  together  with  cumarone,  to  which  it  is  very 
similar  in  its  behaviour  (B.  28,  114),  in  that  fraction  of  coal-tar  boiling 
at  i76°-i82°,  and  can  be  extracted  from  it  by  means  of  its  picric  acid 
derivative  (B.  23,  3276).  Very  appreciable  amounts  of  indene  are  also 
present  in  the  condensation  products  resulting  from  the  chilling  of 
illuminating  gas  (B.  28,  1331).  It  can  also  be  obtained  by  the  dis- 
tillation of  the  calcium  salt  of  synthetic  hydrindene-carboxylic  acid 
(B.  27,  R.  465)- 

It  is  best  formed  by  heating  a-hydrindamine  chlorohydrate. 
Indene  absorbs  oxygen  from  the  air  and  polymerises  to  indene  resin 
on  standing,  heating,  or  treatment  with  concentrated  sulphuric  acid. 
It  seems  partly  to  be  decomposed  into  truxene  and  hydrindene  (B.  33, 
2257  ;  36,  640).  With  chlorine  and  bromine  it  combines  to  form 
dichloro-  and  dibromo-hydrindene.  It  also  forms  nitroso-chloride  and 
nitrosite  like  the  terpenes  (B.  28,  1331).  By  treatment  with  sodium 
and  alcohol,  indene  is  reduced  to  hydrindene.  At  incandescent  heat 
two  molecules  indene  give  up  four  H  atoms  to  form  chrysene. 

The  hydrogen  atoms  of  the  CH?  group  in  indene  show  a  similar 
reactivity  to  those  in  cyclo-pentadiene.  With  oxalic  ester  it  forms 
indene-oxalic  ester,  and  with  aldehydes,  by  alkaline  condensation,  in- 

xCl_  CH8 
tensely  colouredhy  drocarbons  derived  from  benzo-f  ulvene  C6H4<^  \CH  . 

Heating  with  halogen  alkyl  and  caustic  alkali  produces  mono-  and  di- 
alkylated  indenes.  It  is  remarkable  that  the  benzyl-indene  obtained 
by  reducing  benzylidene-indene  with  aluminium  amalgam,  which  must 

Q  —  —  CH  H  C 
be  regarded  as  C8H4/       /CH*       5  on  account  of  its  condensation  with 

Crio 

/CH\ 

benzaldehyde,  is  identical  with  the  a-benzyl-indene  C6H4<        >CH 

XCH/CH2C6H5 

obtained  by  benzylating  indene.  There  is  therefore  no  isomerism 
between  the  a-  and  y-alkyl-indenes  (A.  347,  249). 

With  benzaldehyde,  indene  combines  to  oxy-benzyl-indene,  which 
partly  passes  into  benzylidene-indene  C9H6  :  CHC6H5,  m.p.  88°,  yellow 
flakes,  and  partly  combines  with  the  second  molecule  of  benzaldehyde 
to  oxy-benzyl-benzylidene-indene  C9H5.CH(OH)C6H5(:  CHC6H5),  m.p. 
135°,  yellow  crystals.  Cinnamylidene-indene  C9H6  :  CH.CH  :  CHC6H5, 
m.p.  190°,  yellowish-red  needles. 


644  ORGANIC  CHEMISTRY 

Bz.-bromo-indene  C6H3Br(C2H4),  b.p.  243°,  is  formed  from  hydrin- 
dene  and  bromine  (B.  26,  2251).  It  yields  bromo-phthalic  acid  upon 
oxidation. 

Indene  derivatives  are  obtained  synthetically  by  the  following 
methods,  which  to  some  extent  recall  the  syntheses  of  the  penta- 
methylene  compounds  : 

i.  Benzene  compounds,  having  the  group  C6H5.C.C.CO,  split  off 
water  and  condense  to  indene  derivatives  :  (a)  Nitro-a-alkyl-cinnamic 
aldehydes  yield  amido-j8-alkyl-indenes  (B.  22,  1830)  : 


Nitro-a-methyl-cinnamo-aldehyde      Amido-/3-methyl-indene. 

Similarly,  benzyl-acetone  and  benzyl-aceto-acetic  ester  yield 
y-methyl-indene  and  y-methyl-indene-j8-carboxylic  acid  (B.  20,  1574  ; 
A.  247,  157)  when  they  are  heated  with  sulphuric  acid  : 


5X  2  --  /CH;.       C6H5v  >CH.CO2H  --  >C6H 

XCH/  XH«  XCH/  CI 

Benzyl-acetone  •)  -Methyl-indene  Benzyl  -acetic  acid  Methyl-indene-carboxylic 

acid. 

(b)  Substituted  cinnamic  acids  yield  indone  derivatives  when  they 
are  treated  with  hot  sulphuric  acid,  just  as  the  hydro-cinnamic  acids, 
alkylised  in  the  nucleus  and  in  the  side  chain,  yield  dihydro-indones. 
Cinnamic  and  hydro-cinnamic  acids  themselves  react  with  as  little 
readiness  as  cinnamic  aldehyde  (A.  247,  140  ;  B.  25,  2095,  2129)  : 

HOCO\  __  /CO  \ 

C«H'\CBr=,/CBr  C«H*\CBr/CBr  ' 

Dibromo-cinnamic  acid  Dibromo-indone. 

HOCCK  /CO 


a-Phenyl-hydro-cinnamic  acid  /S-Phenyl-hydrindone. 

2.  The  hydrindene  derivatives  have  been  obtained  in  the  same 
manner  as  the  tetra-  and  pentamethylene  derivatives  :  by  the  action  of 
xylylene  halides  upon  malonic  ester  and  sodium  alcoholate  (B.  17,  125  ; 
18,  378)  : 

/CH2Br  C02R  /CH2 


3«.  The  formation  of  ay-diketo-hydrindenes  from  p-phthalic  esters 
and  fatty-acid  esters  or  ketones  (A.  252,  72  ;  B.  27,  104,  R.  19)  corre- 
sponds to  the  condensation  of  oxalic  esters  to  pentamethylene 
derivatives  : 


*  T  T  "O 

36.  The  phthalide  compounds,   of    the   formula 

formed  from  phthalic  anhydride  and  fatty  acids,  are  transposed  by 
sodium  alcoholates  into  the  sodium  derivatives  of  the  isomeric  diketo- 
hydrindenes  (B.  26,  954,  2576)  : 


INDENE   AND   HYDRINDENE  GROUP  645 

40.  The  formation  of  dihydrindones  by  the  distillation  of  salts  of 
o-phenylene-diacetic  acid  and  o-hydro-cinnamic  acid  (B.  26,  222, 
R.  708)  corresponds  to  the  cyclic  ketone  formation  of  dicarboxylic 
acids  of  the  adipic  acid  series  : 

/CH2.COOH  _  /CH2\ 

C«H4\CH.COOH  '  C6H*\CH/ 


46.  Corresponding  to  the  cyclic   aceto-acetic   ester   condensation 
(P-  5)>  we  have  the  formation  of  hydrindone-carboxylic  esters  by  the 
action  of  Na  or  Na  alcoholate  upon  the  esters  of  o-phenylene-diacetic 
acid  or  o-hydro-cinnamo-carboxylic  acid  : 
CH2.CH2COOR 


/ 
C«H4\ 


COOR  '    ~«"*\CO  /~H-C( 

Similarly,  we  obtain  from  the  o-phenylene-diaceto-nitrile,  by  means 
of  sodium  alcoholate,  a-cyano-j3-imino-hydrindene  (C.  1908,  I.  1274)  : 

/CH2CN  /CH2\C=NH 

Ce    4\CH2CN  6    ,4\CH^_CN 

5.  Hydrindone  derivatives  are  formed  by  alkaline  condensation 
from  o-phthal-aldehyde  with  methyl-ketones  and  methyl-ketone- 
carboxylic  acids  (A.  347,  112  ;  369,  287)  : 


6.  The  formation  of  indene  derivatives  from  naphthalene  deriva- 
tives is  rather  remarkable  ;  a  six-membered  benzene  ring  is  rearranged 
to  a  ring  of  five  members  —  similar  to  the  production  of  pentamethylene 
derivatives  from  the  benzenes,  or  fluorene  compounds  from  phen- 
anthraquinone.  This  change  occurs  by  the  action  of  chlorine  or  hypo- 
chlorous  acid  upon  the  naphthols,  naphtho-quinones,  amido-naphthols, 
etc.  The  first  product  consists  of  naphthalene  keto-derivatives  with 
the  groups  —  CO.  CO  —  or  CO.CC12  —  ;  these  sustain  the  decomposition 
(B.  20,  2890  ;  21,  2719).  Thus,  dichloro-j8-naphtho-quinone  yields 
dichloroxy-indene-carboxylic  acid  : 

,C02H 

/CO—  CO  /C(OH) 

C6H4<  -  >  C6H4< 

x:ci=cci  xcci 

Dichloro-/S-naphtho-quinone      Dichloroxy-indene-carboxylic  acid. 

Indene  Derivatives.  —  y  (a)-Methyl-indene  C6H4  :  C3H3.CH3,  b.p.  206°, 
is  formed  by  methylating  indene,  and,  synthetically,  from  benzyl- 
acetone,  also  from  its  carboxylic  acid  by  splitting  off  CO2. 
y  (a)-Benzyl-indene  C6H4  :  C3H3.CH2C6H5,  b.p.13  184°.  a,  y-Dibenzyl- 
indene  C6H4  :  C3H2(CH2C6H5)2,  m.p.  63°,  by  benzylating  indene,  also 
by  reduction  of  benzyl-benzylidene-indene,  m.p.  137°,  with  aluminium 
amalgam  (A.  347,  262).  1,  2,  3-Triphenyl-indene,  m.p.  135°  (C.  1908, 
II.  1736).  1,  1,  3-Triphenyl-indene,  m.p.  135°  (B.  39,  1030).  Bz.-amido- 
jS-methyl-,  -ethyl-,  -iso-propyl-indene,  m.p.  98°,  89°,  84°. 

j3-Nitro-indene  C6H4  :  C3H3NO2,  m.p.  141°,  yellow  crystals,  from 
indene  nitrosite  by  distillation  with  water  vapour.  Zinc  dust  and 
glacial  acetic  acid  reduce  it  to  /Miydrindone-oxime  (A.  336,  i). 


646  ORGANIC   CHEMISTRY 

/Mndene-earboxylic  acid  C6H4C3H3COOH,  m.p.  222°-23o°,  from 
hydrindene-carboxylic  acid  with  bromine.  y-Methyl-/Mndene-car- 
boxylic  acid,  m.p.  200°,  from  benzyl-aceto-acetic  ester. 

Indene-oxalic  ethyl  ester  C6H4  :  C3H3.COCOOC2H5,  m.p.  87°,  orange- 
red  needles,  from  indene-oxalic  ester  and  sodium  ethylate,  gives,  on 
reduction  with  aluminium  amalgam,  indene-oxy-acetie  ester  C6H4  : 
C3H3.CH(OH)CO2C?H5,  b.p.13  172°,  which,  by  saponification  and 
loss  of  water,  gives  benzo-fulvene-earboxylie  acid  C6H4  :  C3H2  : 
CHCO2H,  decomposing  at  175°,  orange  flakes.  The  latter,  on  reduction, 
yields  indene-acetic  acid  C6H4  :  C3H3.CH2CO2H,  m.p.  96°,  w^ich,  on 
further  condensation,  passes  into  benzo-fulvene-carboxylic  acetic  acid 
C6H4  :  C3H(:  CHCO2H)CH2CO2H,  m.p.  245°  with  decomposition 
(A.  347,  275). 

j8,  y-Dichloro-a-oxy-indene-carboxylic  acid,  melting  at  100°,  is 
obtained  from  j8-dichloro-naphtho-quinone.  Chromic  acid  oxidises  it 
to  dichlorindone.  It  is  changed  to  chlorindone-carboxylic  acid  when 
digested  with  concentrated  sulphuric  acid  (B.  28,  R.  279). 

a,  jS-Diphenyl-indone    C6H4<(^^^C(C6H5),    garnet-red    crystals, 

melting  at  151°,  is  produced,  together  with  triphenyl-acrylic  acid,  when 
benzo-phenone  chloride  is  condensed  with  phenyl-acetic  ester.  It 
yields  triphenyl-propane  upon  reduction.  It  is  decomposed  into 
a,  jS-diphenyl-vinyl-o-benzoic  acid  when  fused  with  caustic  potash. 
It  can  be  recovered  from  this  as  well  as  from  triphenyl-acrylic  acid  on 
heating  with  zinc  chloride  (B.  30,  1281). 

j8-Phenyl-o-,  m-,  and   p-nitro-indone 

139°,  205°,  and  2i5°-2i7°,  from  o-,  m-,  and  p-nitro-phenyl-a-phenyl- 
cinnamic  acid  (C.  1900,  II.  1276). 

Indone-^-acetic  acid  c6H4<^CHyC.CH2co2H,  m.p.  99°,  from  phenyl- 

itaconic  acid  with  concentrated  sulphuric  acid,  lemon-yellow  prisms. 
It  is  isomerised,  by  prolonged  action  of  mineral  acids,  to  saturated 
colourless  lactone,  m.p.  123°  (B.  41,  3983).  Similarly  we  obtain 
y-methyl-y-phenyl-indone-j3-aeetic  acid  and  y-phenyl-indone-/2-pro- 
pionic  acid,  m.p.  155°,  167°,  and  168°  respectively,  from  methyl-phenyl- 
itaconic  acid,  diphenyl-itaconic  acid,  and  a-methyl-yy-diphenyl-ita- 
conic  acid. 

y-Bromindone  C6H4 :  C3BrHO,  m.p.  64°,  f$,  y-diehloro-  and  dibromo- 
indone  C6H4  :  C3Br2O,  m.p.  90°  and  123°,  are  obtained  synthetically 
from  monobromo-dichloro-  and  dibromo-cinnamic  acid  (B.  32,  2477  ; 
33,  2426).  The  jS-halogen  atom  is  easily  replaced  by  OH  and  NHR  : 
£-ehloro-  and  j8-bromo-y-oxy-indone,  m.p.  114°  and  119° ;  y-anilido- 
indone,  m.p.  105°  with  decomposition,  is  converted  into  diketo- 
hydrindene  by  HC1.  A  halogen  atom  also  easily  reacts  with  Na-malonic 
and  acetic  esters,  etc.,  the  resulting  substances  being  feebly  yellow, 
but  giving  fine  purple  colours  with  alkalies,  resembling  cochineal 
(B.  31,  2079,  2903  ;  33,  2418,  2425  ;  35,  2938). 

Perchlorindone  C6C14  :  C3C12O,  m.p.  149°,  from  a  monocyclic 
pentene  derivative,  hexachloroxy-cyclo-pentene-carboxylic  acid,  pro- 
duced by  the  splitting  of  hexachloro-diketo-cyclo-hexene,  by  warming 
with  water,  or  sodium  acetate  solution  (A.  367,  i). 


INDENE  AND   HYDRINDENE   GROUP  647 

Hydrindene  Derivatives. — Hydrindene  C6H4  :  C3H6  is  an  oil,  boiling 
at  177°.  It  results  when  indene  is  reduced  with  sodium  and  alcohol. 
For  other  methods,  see  B.  33,  735  ;  34,  1247  '•  C.  1903,  II.  989. 

Dichloro-hydrindene  is  an  oil.  Dibromo-hydrindene  C6H4 :  C3H4Br2 
melts  at  44°.  They  yield  ehlor-  and  bromoxy-hydrindenes,  melting  at 
129°  and  131°,  when  digested  with  water.  Ammonia  converts  the 
latter  bodies,  in  the  cold,  into  amido-oxy-hydrindene,  melting  at  133°, 
which  nitrous  acid  transposes  into  j8,  y-dioxy-hydrindene,  hydrindene- 
glycol  C6H4  :  C3H4(OH)2,  melting  at  99°  (B.  26,  1539  ;  32,  30). 

Hydrindene- jS-carboxylic  acid  C6H4(CH2)2CH.CO2H,  melting  at 
130°,  is  converted  by  distillation  of  its  salts  into  indene,  by  bromine 
into  indene-carboxylic  acid,  and  is  oxidised  by  KMnO4  to  o-carbo- 
phenyl-glyoxylic  acid.  It  results  when  CO2  is  eliminated  from 
hydrindene-/?-dicarboxylic  acid,  melting  at  199°.  The  ester  of  the 
latter  acid  may  be  obtained  synthetically  from  xylylene  bromide  and 
malonic  ester. 

j8-Aeeto-hydrindene-carboxylic  ester  caH4(CH2)2c/^c^13  is  obtained 

from  xylylene  bromide  and  aceto-acetic  ester. 

y-Methyl-hydrindene-j3-carboxylic  acid,  m.p.  86°;  see  C.  1906, 
I.  1699. 

Hydrindene-jS-methyl-,  ethyl-,  and  phenyl-ketones  are  formed  in 
the  distillation  of  hydrindene-carboxylic  acid  with  benzoic  acid, 
propionic  acid,  and  acetic  acid  (B.  26,  1539). 

</->TJT  v 
^2^>CH2,  melting  at  41°  and  boiling 

at  244°,  is  obtained  in  the  dry  distillation  of  o-carbohydro-cinnamic 
acid  as  well  as  from  o-cyan-hydro-cinnamic  ester  upon  digesting  with 
concentrated  hydrochloric  acid.  The  phenyl-hydrazone  melts  at  131°. 
The  oxime,  melting  at  146°,  is  changed,  by  reduction,  to  a-amido- 
hydrindene,  hydrindamine,  melting  at  220°. 

The  chlorohydrate  decomposes  almost  quantitatively  into  AmCl 
and  indene,  on  heating. 

N2O3  converts  it  into  a-oxy-hydrindene,  melting  at  54°  (B.  26,  R.  708). 
Phosphorus  pentachloride  converts  a-hydrindone-oxime  into  hydro- 
carbo-styril  (Beckmann's  transposition)  (B.  27,  R.  598)  : 

/CH2 x  /CH2— CH8 

CeH4\C(NOH)/C  C'H4\NH-CO  ' 

Hydrindone-azine  C9H8  :  N.N  :  C9H8,  melting  at  165°,  results  from 
the  action  of  hydrazin  upon  the  oxime.  Nitrous  acid  converts 

hydrindone  into  iso-nitroso-hydrindone    C6H4<^^2^>C=NOH,  melting 

with  decomposition  at  210°.  This  phenyl-hydrazin  changes  to  a 
osazone,  melting  at  229°.  The  latter  is  isomeric  with  the  dihydrazone 
obtained  from  a,  y-diketo-hydrindene.  It  yields  /2-amido-a-hydrindone 
when  it  is  reduced  (B.  29,  2605,  R.  869  ;  C.  1897,  I.  860). 

Concentrated  H2SO4  produces  Beckmann's  transposition,  and  forms 
homo-phthalamidic  acid  (C.  1907,  I.  727).  With  benzaldehyde  (B.  34, 
412)  a-hydrindene  gives  a  benzylidene  compound  C9H6O  :  CHC6H5, 
yellow  crystals,  m.p.  114°,  also  yielded  by  a-benzyl-cinnamic  acid,  with 
concentrated  sulphuric  acid  ;  two  molecules  hydrindone  condense  to 


648  ORGANIC   CHEMISTRY 

anhydro-bis-hydrindone  C9H6O  :  C9H8,  m.p.  143°,  which,  on  further 
condensation,  gives  the  hydrocarbon  tru%ene  (C9H6)a.  (C.  1894,  II.  92  ; 
B.  31,  720  ;  33,  3085  ;  36,  645).  With  o-phthal-aldehyde  a-hydrindone 
condenses  to  iso-naphtho-fluorenone  C?6H*  \co  (A.  369,  288). 

Ci0H6/ 

When  o-,  m-,  and  p-methyl-hydro-cinnamic  acids  are  heated  they 
yield  o-,  m-,  and  p-methyl-a-hydrindones.  The  constitution  of  the 
latter  is  deduced  from  their  oxidation  to  the  various  methyl-o-phthalic 
acids.  Bz.-Chloro-,  bromo-,  iodo-,  and  nitro-hydrindones  behave 
similarly  (B.  25,  2095). 

jS-Methyl-a-hydrindone,  melting  at  168°  (n  mm.),  and  jS-phenyl-a- 
hydrindone,  melting  at  78°,  are  obtained  from  a-methyl-  and  phenyl- 
hydro-cinnamic  acids.  When  its  ethereal  solution  is  shaken  with 
caustic  soda  jS-phenyl-hydrindone  is  changed  partly  to  jS-phenyl-oxy- 
hydrindone,  melting  at  129°,  and  in  part  by  rupture  of  the  ring  into 
desoxy-benzoin-o-carboxylic  acid  C6H4(CO.OH).CH2.COC6H5  (B.  26, 
2095).  y-Phenyl-a-hydrindone,  melting  at  78°,  is  prepared  from 
j3,  jS-diphenyl-propionic  acid  (B.  26,  2128). 

j8j8-Dimethyl-a-hydrindone     C6H4<™2>C(CH3)2,     m>p.  ^     from 


aa-dimethyl-jS-phenyl-propionic  acid  chloride  and  A1C13,  or  by  methy- 
lation  of  a-hydrindone  by  means  of  NaNH2  and  CH3L  On  heating 
with  NaNH2  in  benzene  solution,  it  is  split  into  the  amide  of  aa-dimethyl- 
j3-phenyl-propionic  acid.  j3/?-Diethyl-a-hydrindone,  m.p.  7°,  b.p.13 
138°  (C.  1910,  II.  39). 

Tetrachloro-a-hydrindone  CgH4  :  C3C14O,  melting  at  108°,  is  the  addi- 
tion product  of  chlorine  and  dichlorindone.  It  is  readily  decomposed 
by  digestion  with  alcoholic  sodium  hydrate  into  o-trichloro-vinyl- 
benzoic  acid.  Chloro-dibromo-hydrindone-y-earboxylic  acid  C6H4  : 
[C3ClBr2O(COOH)],  melting  at  171°,  is  made  from  chlorindone-y-car- 
boxylic  acid  and  bromine.  It  is  similarly  decomposed  into  bromo- 
chloro-methylene-homo-phthalic  acid. 

/?-Nitro-a-hydrindone    C6H4<^™*^>CH  .NO2,  sulphur-yellow  needles, 

m.p.  117°  with  decomposition,  is  formed  by  condensation  of  o-phthal- 
aldehyde  with  nitro-methane  and  sodium  ethylate  (A.  377,  15). 

j8-Hydrindone,  fi-indanone  C6H4(CH2)2CO,  m.p.  61°,  b.p.  220°-225° 
with  decomposition,  is  formed  by  the  distillation  of  calcium  o-phenylene 
diacetate,  and  by  heating  hydrindene-glycol,  or  its  monomethyl  ether, 
with  sulphuric  acid.  Hydrazone,  m.p.  120°.  Oxime,  m.p.  155°,  gives, 
by  reduction,  j8-amido-hydrindene  (B.  26,  R.  709).  Di-iso-nitroso-j8- 
hydrindone  C6H4[C(NOH)]2CO2,  m.p.  233°  with  decomposition.  Like 
the  a-hydrindone  and  the  diketo-hydrindene,  the  j3-hydrindone  easily 
condenses  to  anhydro-bis-j8-hydrindone  C9H60  :  C9H8,  m.p.  170° 
(B.  32,  28). 

Tetrachloro-jS-hydrindone  C6H4  :  C3C14O,  m.p.  98°,  is  formed  by  the 
action  of  bleaching  -  lime  upon  tetrachloro-2,  3-diketo-tetrahydro- 
naphthalin.  Monobromo-,  a,  y-dibromo-,  and  tetrabromo-hydrindone, 
m.p.  91°,  in0,  and  173°,  by  bromination  of  j8-hydrindone  in  benzene 
solution.  Tetrachloro-  and  tetrabromo-hydrindone  on  heating  with 
alkalies  pass  into  phthalide-carboxylic  acid  (benzilic  acid  transposition) 
(A.  334,  346  ;  C.  1908,  II.  1183). 


INDENE  AND   HYDRINDENE  GROUP  649 

jS-Acetyl-  and  jS-benzoyl-a-hydrindone,  m.p.  76°  and  98°  (A.  347, 
112)  ;  a-hydrindone-/3-oxalie  acid,  m.p.  212°  (A.  369,  287). 

a.y-Diketo-hydrindene  C6H4(CO)2CH2,  melting  with  decomposition 
at  130°,  is  obtained  from  its  carboxylic  acid  (below).  It  consists  of 
colourless  needles,  which  dissolve  readily  with  a  yellow  colour  in  alkalies. 
The  hydrogen  atoms  of  the  methylene  groups  placed  between  the  two 
keto-groups  have  an  acid  nature.  Phenyl-hydrazin  converts  it  into 
a  monohydrazone,  melting  at  163°,  and  a  dihydrazone  C6H4(C  :  NNH 
C6H5)2CH2,  melting  at  171°.  Diazo-benzene  chloride  converts  the 
monohydrazone  into  a  triketo-hydrindene  C6H4(CO)2C  :  NNHC6H5, 
which  is  also  prepared  by  the  decomposition  of  benzal-diketo-hydrindene 
C6H4(CO)2C=CHC6H5,  a  condensation  product  of  benzaldehyde  and 
diketo-hydrindene,  with  phenyl-hydrazin. 

3,  4-Dioxy-benzal-diketo-hydrindene,  melting  at  257°,  and  prepared 
by  the  condensation  of  proto-catechuic  aldehyde  and  diketo-hydrindene, 
is  a  dye  (B.  30,  1185). 

With  p-amido-benzaldehydes,  also,  feebly  basic  dyes  are  obtained. 
o-Amido-benzaldehyde  yields  the  so-called  quinolene-phenylene- 
ketone  c.H4{  W£H=  £—  }c6H4,  m.p.  175°  (B.  34,  2467). 

With  orthoformic  ester,  indane-dione  condenses  to  the  compounds 
C6H4(CO)2C  :  CHOH  and  C6H4(CO2)C  :  CH.CH(CO2)C6H.  With  am- 

monia we  obtain  from   this  dibenzoylene-pyridin 


(C.  1903,  II.  950).  With  ethoxy-methylene-aceto-acetic  ester  (Vol.  I.), 
indane-dione  forms  indane-dione-methenyl-aceto-acetic  ester,  m.p.  118°, 
which  is  condensed  by  concentrated  alkali  to  3-oxy-diphenylene- 
ketone-2-carboxylie  acid  (C.  1906,  I.  849).  By  heating  diketo-hydrin- 
dene by  itself  or  boiling  with  water,  anhydro-bis-diketo-hydrindene- 
bindone  C6H4(CO)2C=C<^^4^>CO  is  formed,  yielding  intensely  coloured 

metallic  compounds.  Heated  with  aromatic  amines,  it  gives,  like 
coerulignone,  beautiful  blue  dyes  (B.  30,  3137).  Phenyl-hydrazin 
splits  it  into  two  molecules  diketo-hydrindene-dihydrazone  (A.  277,  362  ; 
B.  34,  3269).  The  anhydro-bis-diketo-hydrindene  can  undergo  higher 
condensation  (B.  31,  2935  ;  33,  2433). 

jS-Methyl-diketo-hydrindene  C6H4(CO)2CHCH3,  m.p.  85°,  is  formed 
from  its  carboxylic  acid.  Its  sodium  compound  gives,  with  methyl 
iodide,  ^-dimethyl-diketo-hydrindene  C6H4(CO2)C(CH3)2.  £-Phenyl- 
diketo-hydrindene,  m.p.  145°,  from  benzal-phthalide.  The  isatin- 
diphthalyl,  m.p.  above  350°,  violet  needles,  similarly  obtained  by  trans- 
position of  ethine-diphthalyl,  is  now  regarded  as  derived  from  a  hydro- 
carbon, naphthacene  C16H12  compound  of  two  naphthalene  nuclei,  and 


has  the  structure  C.H4<  :    -^^  (R  31>  I2?2)      ^  £-Diethyl- 


diketo-hydrindone  C6H4(CO)2C(C2H5)2,  b.p.10  i43°-i56°,  oxime,  m.p. 
143°,  from  benzene,  diethyl-malonyl  chloride,  and  A1C13  (A.  373,  291). 

jS-Diehloro-diketo-hydrindene  C6H4(CO)2CC12,  m.p.  125°,  by  the 
action  of  chlorine  upon  y-oxy-chlorindone.  It  is  split  up  into  o-phthalic 
acid  by  dilute  soda  (B.  21,  491,  2380). 

£-Bromo-diketo-hydrmdene  C6H4(CO)2CHBr  is  identical  with  0- 
bromo-y-oxy-indone  and  is  formed  also  from  diketo-hydrindene-car- 
boxylic  ester  by  bromination  and  saponification.  Boiling  with  water 


650  ORGANIC   CHEMISTRY 

gives  dibromo-diketo-hydrindene  C6H4(CO)2CBr2  and  finally  tris-diketo- 
hydrindene  C6H4(CO)2C[CH(CO)2C6H4]2  ;    see  also  B.  33,  2433;    34, 

2145- 

Diketo-hydrindene-earboxylic  ester  C6H4(CO)2CH.COOR,  m.p.  75°- 
78°,  from  phthalic  ester  with  acetic  ester  and  Na  alcoholate,  is  easily 
converted  into  diketo-hydrindene.  Other  derivatives,  see  B.  31,  2084  ; 
M.  31,  62. 

/?-Acetyl  and  jS-benzoyl-diketo-hydrindene  C6H4(CO)2CH.COR,  m.p. 
110°  and  108°,  from  phthalic  ester  with  acetone  and  aceto-phenone. 
Easily  split  up  by.  alkalies  (B.  27,  104). 

Indacene  is  the  name  of  a  tricyclic  combination  of  a  benzene  nucleus 
with  two  cyclo-pentene  nuclei.  From  m-xylylene-diaceto-acetic  ester, 
with  80  per  cent.  H2SO4,  we  obtain  dimethyl-indacene-carboxylic  acid 

C02Hc(^H3)Nc6H2/^H^")cco2H;   from  pyro-mellithic  ester,  acetic 

XUrig  -  /  XGHg  -  • 

ester,  and  Na  tetraketo-hydrindacene-dicarboxylic  ester  CO2RCH(CO)2 
C6H2.(CO)2CHCOOR  (B.  34,  2779). 

Fluorene  is  a  dibenzo-pentene  resulting  from  the  union  of  the  pentene 
nucleus  with  two  benzene  nuclei.  It  will  be  considered  in  conjunction 
with  chrysene-fluorene  and  picene-fluorene  after  the  condensed  nuclei 
of  the  phenanthrene  group  —  phenanthrene,  chrysene,  and  picene,  —  to 
which  the  two  first-named  bodies  are  intimately  related. 

II.  NAPHTHALENE  GROUP. 

Garden  (1816)  discovered  naphthalene  C10H8,  among  the  distillation 
products  of  coal-tar.  It  shows  great  similarity  to  benzene,  from  which 
it  differs  in  constitution  by  C4H2.  Like  benzene,  it  is  produced  by  the 
action  of  intense  heat  upon  various  carbon  compounds  ;  hence  its 
occurrence  in  coal-tar.  Numerous  derivatives  are  obtained  from  it  by 
the  replacement  of  its  hydrogen  atoms  ;  they  are  very  similar  to  the 
benzene  compounds.  Only  the  most  important  of  them  will  be  con- 
sidered in  the  following  sections. 

Constitution  of  the  Naphthalene  Nucleus. 

The  behaviour  of  naphthalene  is  satisfactorily  explained  by  the 
formula  first  suggested  by  Erlenmeyer,  sen.  (A.  137,  346)  : 

H     H 

YYY 


H     H 

It  consists  of  two  benzene  nuclei,  having  in  common  two  carbon 
atoms  occupying  the  ortho-position.  Graebe  (1866)  proved  the  correct- 
ness of  the  formula  (A.  149,  20). 

The  oxidation  of  napthalene  to  o-phthalic  acid  shows  the  presence 
of  a  benzene  nucleus.  Further,  the  oxidation  of  dichloro-naphtho- 
quinone  C6H4  :  C4C12O2  also  yields  o-phthalic  acid.  If,  however,  di- 
chloro-naptho-quinone  is  converted  by  PC15  into  tetrachloro-naphtha- 
lene,  this,  upon  oxidation,  will  become  tetrachlor-o-phthalic  acid.  In  the 
second  instance,  therefore,  the  benzene  nucleus,  which  in  the  first  case 
was  unattacked,  is  now  oxidised.  A  precisely  similar  method  of  de- 


NAPHTHALENE  GROUP  651 

monstration,  to  which  reference  has  already  been  made,  is  as  follows  : 
Nitro-naphthalene,  obtained  by  nitration  of  naphthalene,  yields  nitro- 
o-phthalic  acid  ;  whereas  amido-naphthalene,  resulting  from  the  re- 
duction of  the  preceding  nitro-naphthalene,  yields  o-phthalic  acid  : 

NH2  NO2  NO2 

"i_i/xri___i/YooH 


Hence  it  follows  that  naphthalene  must  consist  of  two  symmetri- 
cally condensed  benzene  nuclei.  For  other  formulae,  like  the  central 
formula  of  Bamberger,  the  formula  of  Armstrong,  etc.,  consult  B.  23, 
R.  337,  692  ;  24,  R.  651,  728  : 


i\  y  /i 
I/  -L  \l 
V  \\/\\/ 

Bamberger.  Armstrong. 

Isomerisms  of  the  Naphthalene  Derivatives.  —  The  isomerisms  of  the 
derivatives  of  naphthalene  conditioned  by  this  formula  agree  with  the 
facts.  The  substituents  are  designated  according  to  the  diagram  : 


• 


a4       a, 

f 


The  replacement  of  an  H  atom  in  naphthalene  can  give  rise  to  two 
isomeric  mono-derivatives,  distinguished  as  a-  and  fl-derivatives  accord- 

\C/ 
ing  as  the  substituent  is  adjacent  to  the  complex      ||      common  to 

both  groups,  or  separated  from  it  by  a  CH  group.  The  positions  i,  4,  5, 
8  (alf  a2,  a3,  a4)  on  the  one  side,  and  2,  3,  6,  7  (fa,  j32,  £3,  j34)  are  equi- 
valent. Liebermann  (A.  183,  254)  and  Atterberg  (B.  9,  1736)  have 
adduced  proof  of  the  equivalence  of  the  four  a-positions.  The  method 
adopted  is  similar  to  that  followed  in  demonstrating  the  equal  value 
of  the  benzene  hydrogen  atoms. 

Whether  a  substituent  occupies  the  a-  or  j3-position  is  mainly  de- 
termined by  its  oxidation  to  a  corresponding  o-phthalic  acid  derivative. 
Thus,  if  [i,  2,  3]-nitro-phthalic  acid  is  obtained  from  a-nitro-phthalene, 
the  nitro-group  must  consequently  be  adjacent  to  the  contact  position 
of  the  second  benzene  nucleus  in  naphthalene.  The  constitution  of  a- 
oxy-naphthalene  or  a-naphthol  is  evident  also  from  its  synthesis  by 
means  of  phenyl-iso-crotonic  acid  C6H5.CH  :  CH.CH2.COOH.  Be- 
sides, only  a-derivatives  of  naphthalene  can  be  converted  into  quinones 
analogous  to  p-benzo-quinone,  as  these  alone  possess  a  free  H  atom  in 
para-position  with  reference  to  the  substituent.  This  latter  circum- 
stance also  determines  still  other  peculiarities  in  the  behaviour  of  the 
compounds  of  naphthalene  —  e.g.  the  power  of  the  naphthols  and 
naphthylamines  to  unite  with  diazo-bodies,  etc. 

The  di-substitution  products  of  naphthalene,  when  the  substituents 
are  similar,  can  exist  in  ten  isomeric  forms,  which  are  designated  by 
numbers  or  prepositions  (B.  26,  R.  533).  In  the  following  diagram  the 


652  ORGANIC   CHEMISTRY 

double  hexagon  of  naphthalin  is  replaced  by  two  parallel  lines,  as 
was  similarly  done  with  benzene  : 

R  R  R  R  R  R         RR 


1,2  1,3          1,4         1,5  1,6          1,7          1,8         2,3  2,6          2,7 

Ortho-     Meta-     Para-     Ana-         Epi-       Kata-      Peri-  Amphi-     Pros- 

On  the  calculation  of  the  isomeric  possibilities  of  the  naphthalin 
derivatives,  see  B.  33,  2131. 

The  position  of  the  substituents  in  the  di-derivatives  can  very  often 
be  determined  by  the  oxidation  method,  if  thereby  it  can  first  be  ascer- 
tained whether  the  substituents  are  in  the  same  nucleus  (isonuclear) 
or  in  different  nuclei  (heteronuclear)  .  Isonuclear  substitution  products 
with  adjacent  substituents,  show  in  general  the  same  behaviour  as 
the  ortho-substitution  products  of  benzene,  inasmuch  as  they  form 
similar  condensation  products.  However,  a  difference  appears  to  exist 
between  positions  like  I,  2  and  2,  3.  Thus,  only  those  amido-naph- 
thalenes  manifest  the  ability  to  form  naphtho-quinolin  rings,  in  which 
the  pyridene  ring  can  attach  itself  to  a,  ft-  C  atoms.  It  must  be 
assumed  that  the  double  linkages  in  naphthalene  are  not  so  easily  dis- 
placed as  in  benzene.  The  behaviour  of  the  I,  8-  or  peri-derivatives  is 
remarkable.  Like  the  o-di-derivatives,  they  exhibit  a  series  of  hetero- 
ring  formations. 

Naphthalene-ring  Formations. 

Naphthalene  is  produced  by  pyrogenic  condensation  from  a  series 
of  carbon  compounds,  like  ethylene,  acetylene,  ether,  etc.  Methods  of 
producing  the  naphthalene  nucleus  by  processes  in  which  one  benzene 
nucleus  pre-exists  are  more  important  : 

1.  A  mixture  of  benzene  and  acetylene  conducted  through  a  tube 
heated  to  redness  yields  naphthalene  (Bull.  7,  306). 

2.  It   is   derived   from   phenyl-butylene   C6H5.CH2.CH2.CH  :  CH2 
and  its  dibromide,  on  leading  their  vapours  over  heated  lime  : 

/CH2—  CH2  /CH=CH 

C6H/  |         =  C6H4<  |      +4H. 

CH2=CH  \CH-CH 

Similar  reactions  result  in  the  formation  of  phenyl-dihydro-naphthoic 
acid  from  dibenzal-propionic  acid  with  glacial  acetic-sulphuric  acid  ; 
of  phenyl-bromo-tetrahydro-naphthoic  acid  from  benzyl-phenyl-iso- 
crotonic  acid  with  Br  ;  and  of  i-phenyl-tribromo-naphthalene  by  the 
bromination  of  diphenyl-diacetylene  (A.  341,  198). 

3.  Phenyl-propiolic  acid,  on  heating  with  acetic  anhydride  or  treat- 
ing with  POC13,  passes  into  the  anhydride,  while  phenyl-propiolic  ester, 
on  heating  to  200°,  forms  the  ester  of  i-phenyl-naphthalene-2,  3-dicar- 
boxylic  acid.     This  anhydride  is  also  formed  by  illumination  of  dibenzal- 
succinic  anhydride  in  benzene  solution  : 

/C=CH.COOH  ,CH=C.CO  CGH5CH  :  C.CCX 

C6H/  -  >  C8H4<  >  <  --  >0. 

C=CH.COOH  \C=C.CO/  C6H5CH  :  C.CCX 

C6H5  C6H5 


NAPHTHALENE  GROUP  653 

4.  Xylylene  bromide  and  sodium-acetylene-tetracarboxylic  ester  pro- 
duce tetrahydro-naphthalene-tetracarboxylic  ester,  which,  on  saponi- 
fication,  yields  tetrahydro-naphthalene-dicarboxylic  acid,  whose  silver 
salt  passes  by  distillation  into  naphthalene  (Baeyer  and  Perkin,  B.  17, 
488  ;  cp.  formation  of  the  tetramethylene  and  indene  rings)  : 


/CH2Br     NaC(CO,R)2  /2— 

C.H4/  +1  =  C6H4< 

xCH2Br     NaC(CO2R)2  X:H2—  C(CO2R)2 

5.  o-Xylylene  cyanide  condenses  in  the  presence  of  Na  ethylate 
with  oxalic  ester   and  a-diketones  to  form  naphthalene  derivatives 
(B.  43,  1300)  : 

/CH2CN  ,  ROCO  _  /C(CN)  :  COH 

^^  \CH2CN     ROCO  6    4\C(CN)  :  COH 

/CH2CN  ,  OCR     _  /C(CN)  :  CR 

C'    4\CH2CN  "'"OCR  6    4\C(CN)  :  CR' 

6.  What  is  further  noteworthy  is  the  formation  of  a-naphthol  from 
phenyl-iso-crotonic  acid  when  heated  (Fittig  and  Erdmann,  B.  16,  43  ; 
A.   247,  372  ;  255,  263  ;  275,  284  ;  cp.  formation  of  indene  deriva- 

tives) : 


CH 


/CH= 
C8H/  =  C6H4<  +H20. 

OC(OH)— CH2  XC(OH)=CH 

Phenyl-iso-crotonic  acid  a-Naphthol. 

In  a  perfectly  similar  manner  5-,  6-,  and  fj-chloro-i-naphthols  are  obtained 
from  o-,  m-,  and  p-chloro-phenyl-paraconic  acids',  2-and ^-methyl-naphthols 
from  a-  and  ^-methyl-par aconic  acids  ;  a-naphthol-3-methyl-ketone 


(B.  26,  345)  from  B-benzal-lfevulinic  acid  C6H/ 

OC(OH)  -  CH2 
and  2-phenyl-i,  3-dioxy-naphthalene  is  produced  when  a,  y-diphenyl- 

CH2  -  CO 
aceto-acetic   ester    C9U/  is    digested    with    concen- 

ROCO—  CH(C6H5) 
trated  sulphuric  acid  (A.  296,  14). 

Similarly,  phenacetyl-malonic  ester  gives  I,  3-dioxy-naphthalene- 
2-carboxylic  ester  (A.  298,  374),  and  cinnamylidene-hippuric  acid, 
or  its  decomposition  product,  cinnamyl  -  pyro  -  racemic  acid,  gives 

/pTT  _  /->TT  J 

C'Hs    COIC^.CH,  «-naPhthoic  acid  (B.  35,  384)- 

7.  y-Phenyl-f$-imino-butyro-nitrile  condenses  under  the  action  of 
concentrated  H2SO4  to  i,  3-diamido-naphthalene  (C.  1909  I,  857)  : 

/CH2—  C  :  NH  /CH=C.NH2 

C6H/  -  >  C6H4< 

CN—  CH2  N:(NHa)  :  CH 

Similarly,   we    get    from    y-phenyl-y-imino-a-cyano-butyric    ester 


C.H         ;         'Vr  o  the  i.  4-diamido-naphthalene-2-carboxylic  ester, 

- 


and,  from  the  imino-nitriles  obtained  by  the  condensation  of  o-tolu- 

7C(  :  NH).CHC6H5 
nitrile  with  benzyl  cyanide  or  cyano-acetic  ester  C6U^<f  I 

x)H  CN 


and  C6H4<  -2j   the   ^  3.diamido-2-phenyl-napthalin  and 


654  ORGANIC  CHEMISTRY 

i,  3-diamido-naphthalin-2-carboxylic    ester   respectively   (C.    1907,   I. 
728  ;  II.  68,  539,  2053). 

8.  An  interesting  formation  of  a-naphthylamine  consists  in  heating 
aniline  with  pyro-mucic  acid  and  zinc  chloride  to  300°  (B.  20,  R.  221)  : 
C02H.C=^CH  XCH=CH 


Aniline    Pyro-mucic  acid  a-Naphthylamine. 

a-Naphthylamine  is  similarly  formed  on  heating  aniline  hydro- 
chloride  with  mannitol  under  pressure. 

9.  Two  molecules  of  styrolene  alcohol  or  phenyl-glycol  can  be  con- 
densed by  dilute  H2SO4  to  jS-phenyl-naphthalene  (A.  240,  137)  : 

/CH(OH).CH2(OH) 
+ 
CH2(OH)—  CH(OH)C6H 


C.H/  + =  C6H4<  |  +4H20. 

XCH— C.C6H5 


Phenyl-acetaldehyde  is  an  intermediate  product. 

10.  The  formation  of  a  naphthalene  derivative  in  the  oxidation 
of  bromo-proto-catechuic  acid  with  nitric  acid  is  peculiar.  There  is 
produced  thereby  a  dibromo-j3-naphtho-quinone-carboxylic  acid 
(A.  293,  120)  : 

CO— CO 

2COOH.C6H2Br(OH),  >  COOH.C6H2Br< 

xCH=CBr. 

Decompositions  of  the  Naphthalene  Ring. 

Naphthalene  and  most  of  its  derivatives  are  converted  by  energetic 
oxidants  into  o-phthalic  acid  and  substituted  o-phthalic  acids  with  de- 
struction of  one  benzene  nucleus.  The  oxidation  is  made  easier  by  the 
introduction  of  an  amido-group  into  the  nucleus  which  is  to  be  oxidised. 
Naphthols  and  their  derivatives  are  decomposed  by  heating  with 
alkalies,  and  oxidising  metallic  oxides  to  form  phthalic  and  benzoic 
acids  (C.  1903,  I.  1106). 

In  many  instances  it  has  been  possible,  by  moderating  the  oxidising 
action,  to  arrest  the  intermediate  products  of  this  reaction,  or  even  the 
primary  products  in  the  breaking-down  of  the  ring. 

i.  Decomposition  by  Mild  Oxidation. — (a)  Potassium  permanganate 
oxidises  naphthalene  to  phthalic  acid  and  phenyl-glyoxyl-o-carboxylic 
acid  (B.  28,  R.  490)  : 

/CH^CH  /CO.COOH 

C6H4<(  | >  C6H4< 

XCH=CH  XCOOH 

Naphthalene          Phenyl-glyoxyl-o-carboxylic  acid. 

(b)  a-  and  j8-Naphthols,  oxidised  with  an  alkaline  permanganate 
solution,  also  yield  o-carbo-phenyl-glyoxylic  acid.  /S-Naphthol  with 
most  careful  oxidation  becomes  o-cinnamo-carboxylic  acid,  along  with 
other  products  (M.  10.  115). 

Besides  these  reactions  we  have  the  decomposition  of  sodium-nitroso- 
j8-naphthol  by  heating  to  250°,  forming  o-cyano-cinnamic  acid  : 

rw/CH=COH           _^  r  u  /COOHCOOH     r  „  /  C(NO).CONa  ^^u/CN     COONa 

C'McH=CH     "          "C'H'toH=CH        ;CaHMCH=CH  ^QHMcH=CH 

/3-Naphthol                   o-Cinnamo-carboxylic    Nitroso-/3-naphthol  o-Cyano-cinnamic  acid, 
acid. 


NAPHTHALENE  GROUP  655 

In  the  oxidation  of  a-nitro-naphthalene  with  potassium  perman- 
ganate products  appear  which,  in  the  process  of  reduction,  yield,  among 
other  things,  isatin-carboxylic  acid  NH2[3]C6H3  {  ^£^OH  (B.  28, 

1641).     Naphthalic  acid  becomes  phenyl-glyoxyl-dicarboxylic  acid. 

(c)  The  decomposition  of  hydrogenised  naphthalene  derivatives 
occurs  with  special  readiness  ;  thus,  permanganate  changes  dihydro- 
/3-naphthol  into  dihydro-iso-cumarin-carboxylic  acid,  while  potassium 
bichromate  oxidises  tetrahydro-naphthylene-glycol,  in  the  cold,  to 
phenylene-o-diacetic  acid  (B.  26,  1833)  : 

CH2—  CHOH  /CH2—  CH 


2—  CHOH  /C 

-  >  C.H/ 
=CH  XC 


OO   COOH 
Dihydro-jS-naphthol          Dihydro-iso-cumarin-carboxylic  acid. 

CH2—  CHOH  /CH2.COOH 

|  -  *  C6H4< 

H2—  CHOH  XCH2.COOH 

Tetrahydro-naphthylene-glycol     o-Phenylene-diacetic  acid. 

Potassium  permanganate  oxidises  ac-tetrahydro-naphthylamine  to 
o-hydro-cinnamo-carboxylic  acid  ;  ar-tetrahydro-naphthylamine,  how- 
ever, because  of  the  oxidation  of  its  amided  benzene  nucleus,  is  changed 
to  adipic  acid  together  with  oxalic  acid  (B.  22,  767)  : 

,CH(NH2)—  CH,  /COOH    COOH 

r     TT     /  V  2'  I  2       _   ^       r     TT     /  | 

C6HX  -  >   C6H4< 

\CH2  -  CH2  XCH2  -  CH2 

ac-Tetrahydro-naphthylamine  o-Carbohydro-cinnamic  acid. 

/CH2—  CH2  HOOC     HOOC.CH2—  CH2 

NH2.C6H3<(  |  -  >  1  + 

XCH2—  CH2  HOOt     HOOC.CH2—  CH2 

ar-Tetrahydro-naphthylamine  Oxalic  acid       Adipic  acid. 

2.  Decomposition  by  Simultaneous  Chlorination  and  Oxidation.  — 
The  ring-decompositions,  produced  by  the  action  of  chlorine  or  hypo- 
chlorous  acid  upon  jS-naphtho-quinone  and  its  derivatives,  are  very 
numerous.  They  proceed  on  lines  analogous  to  the  benzene-ring  de- 
compositions. Two  groups  may  be  distinguished  in  these  changes  : 
either  the  naphthalene  ring  first  resolves  itself  into  an  indene  ring, 
which  subsequently  by  decomposition  is  converted  into  o-di-derivatives 
of  benzene,  as  in  the  case  of  dichloro-naphtho-quinone  (see  below),  or  the 
break-down  proceeds  without  the  intermediate  formation  of  indene, 
as  in  the  case  of  j3-naphtho-quinone  or  nitro-j3-naphtho-quinone  (see 
below)  (Zincke,  B.  27,  2753,  etc.).  Examples:  (a)  j8-Naphtho-quinone, 
by  the  action  of  hypochlorous  acid,  becomes  dioxy-diketo-tetrahydro- 
naphthalene,  which  by  the  decomposition  of  the  ring  changes  to  the 
lactone  of  o-phenyl-glycerol-carboxylic  acid  (B.  25,  3599)  : 

CO  ,CO—O     COOH 


,      -  ,—^ 

C6H4<  I  —*  C6H4<  \| 

XCHOH—  CHOH  XCHOH—  CH 


/9-Naphtho-quinone          Dioxy-diketo-tetrahydro-  o-Phenyl-glycerol-car- 

naphthalene  boxylic  acid  lactone. 

(b)  With  chlorine,  nitro-j3-naphtho-quinone  first  forms  a  chlorine 
addition  product,  which  by  ring-decomposition  readily  passes  into 


656  ORGANIC   CHEMISTRY 

o-  (a,  j8-dichloro-nitro-ethyl)  -benzoyl-f  ormic  acid .  Chromic  acid  oxidises 
the  latter,  with  loss  of  hydrochloric  acid  and  carbon  dioxide,  to  nitro- 
chloro-methyl-phthalide,  which  can  be  directly  formed  by  treating  nitro- 
quinone  with  chlorine  and  water  (B.  25,  R.  732)  : 

co— co  xo — co  .CO.COOH  /co">o 

C"H    X;H=C.No7~~""    *       XJHCLCONQJ  '    *\CHC1.CHC1N02  *\CH— CHC1NO, 

Nitro-/3-naphtho-  Chlorine  addition          o-(a,  /3-Dichloro-nitro-ethyl)-      Nitro-chloro-methyl- 

quinone  product'  benzoyl-f  ormic  acid'  phthalide. 

(c)  Alkalies  rearrange  3, 4-dichloro-j3-naphtho-quinone  to  dichloroxy- 
indene-carboxylic  acid.  The  latter  can  be  decomposed  (i)  by  changing 
it  to  dichlorindone  with  CrO3,  and  tetrachloro-hydrindone,  the  chlorine 
addition  product,  when  acted  upon  with  alcoholic  soda,  becomes  o-tri- 
chloro-vinyl-benzoic  acid ;  or  (2)  if  the  acid  be  heated  to  ioo°-iio°  with 
oil  of  vitriol  it  is  converted  into  j3-chlorindone-y-carboxylic  acid.  The 
bromine  addition  product  of  the  latter  acid  is  decomposed  by  alkalies 
with  the  formation  of  a-chloro-bromo-methylene-homo-phthalic  acid 
(B.  28,  R.  279)  : 

/CO. CO  i  /C0\  /CO  \  /COOH 

p     TT     /  k       r*     TT     /  \/~>n  ^      C*     IT    /  X/~*^1  ^      r     1J      S 

*\CC1:CC1 
Dichloro-naph- 
tho-quiiione 


C(OH).COaH 


C6H4 


CeH4< 

\CC1=CC12 
Dichlorindone  Tetra-chloro-hy-  o-Trichloro-vinyl- 


drindone  benzoic  acid 


2 


'C.COOH  /CBr  COOH 


./COOH 


C8H 


4\CO/C-C1  4\CO/>CBrC1  \COOH 


Dichlor-oxy-indene  j8-Chlorindone-      Dibromo-chloro-a-hydrin-   Bromo-chloro-methylene- 

carboxylic  acid  y-carboxylic  acid      done-y-carboxylic  acid  homo-phthalic  acid. 

(d)  2,  3-Dioxy-naphthalin  (i)  yields  under  the  action  of  chlorine 
tetrachloro-2,  3-diketo-tetrahydro-naphthalin  (2),  which  is  converted 
by  bleaching-lime  into  tetrachloro-/3-hydrindone  (3)  ;  the  latter  is  split 
up  by  alkalies  to  phthalide-carboxylic  acid  (4),  and  by  concentrated 
HNO3  to  phthalonic  acid  (5)  (A.  334,  342)  : 

(i)  (2)  (3)  (4)  -  -  /CH-^°2H 

/CH  :  coH__r2H  /ccit.co_^r_wyca, 

/CO.COOH 


3.  A  transformation  of  the  naphthalin  nucleus  into  the  indene 
nucleus  has  also  been  effected  by  the  liquid  nitrous  acid  upon  a-naphtho- 
quinone  ;  this  first  forms  diketo-hydrindene-nitrosite,  which,  on  careful 
treatment  with  water,  passes  into  a,  y-diketo-hydrindene  (B.  33,  543)  : 

CO—  CH 


4.  When  perchloro-naphthalene  is  heated  with  SbCl5  to  28o°-3oo° 
it  is  resolved  into  perchloro-benzene,  tetrachloro-methane,  and  hexa- 
chloro-ethane  (B.  9,  1486)  : 


6-« 

1\CC1=CC1  CC14 

Perchloro-naphthalene. 

5.  Decomposition  by   Reduction  in   Alkaline  Solution.  —  A   ring-de 
composition  analogous  of  that  of  salicylic  acid  (p.  49)  is  that  under 


NAPHTHALENE  GROUP  657 

gone  by  2,  i-  and  2,  3-oxy-naphthoic  acids  (p.  679)  when  their  alcoholic 
solutions  are  acted  upon  by  metallic  sodium  (A.  286,  268)  : 

/C(COOH)  :  COH  CH2.COOH  OH.C=CH, 

C6H4<(  ->C6H4/  COOH«-  >C6H4 

\CH  =.CH  COOH.C=CH/ 

CH2  -  CH2 

2-Oxy-i-naphthoic  acid      o-Phenylene-aceto-propionic     2-Oxy-3-naphthoic  acid. 

acid 

6.  Naphthalene-disulphonic  acids,  naphthylamine-  and  naphthol- 
sulphonic  acids,  containing  the  substituents  in  the  I,  3-position,  sustain 
a  remarkable  decomposition  into  o-toluic  acid  when  they  are  fused  with 
caustic  potash  (B.  28,  R.  364)  : 

/C(S03H):CH  CH 

C6H4\CH=C(S03H) 


Naphthalene-i-3-  disulphonic  acid  o-Toluic  acid. 

m-Cresol  (Ch.  Z.  1895,  No.  48)  is  similarly  produced  on  fusing  i,  3,  6- 
and  1,3,  8-naphthalene-trisulphonic  acids  with  caustic  potash. 

Naphthalene  C10H8,  melting  at  79°  and  boiling  at  218°,  occurs  in  coal- 
tar,  and  is  obtained  by  crystallisation  from  that  portion  boiling  from 
i8o°-3OO°.  It  is  purified  by  distillation  with  steam  and  sublimation. 
It  dissolves  with  difficulty  in  cold  alcohol,  readily  in  hot  alcohol  and  in 
ether.  It  crystallises  and  sublimes  in  shining  plates.  It  is  charac- 
terised by  its  great  volatility  and  possesses  a  peculiar  odour.  It  forms 
a  crystalline  compound  C10H8.C6H2(NO2)3.OH  with  picric  acid,  which 
melts  at  149°  (Fritzsche,  J.  1857,  456).  m-  and  p-Dinitro-benzene,  tri- 
nitro-benzene,  trinitro-toluene,  etc.,  form  similar  double  compounds. 

Naphthalene  is  applied  technically  in  the  preparation  of  phthalic 
acid  and  dye-substances.  It  is  also  used  in  carburetting  water-gas.  It 
is  employed  for  itch,  moths,  etc.,  because  of  its  strong  antiseptic  pro- 
perties and  its  stupefying  effect  upon  the  lower  animals. 

As  naphthalene  has  unsaturated  linkages  it  will,  under  favourable 
conditions,  take  up  hydrogen  and  chlorine  ;  the  compounds  thus  pro- 
duced will  be  discussed  in  conjunction  with  other  hydro-naphthalene 
derivatives  at  the  conclusion  of  the  naphthalene  group.  Naphthalene, 
like  benzene,  is  chlorinated,  nitrated,  and  sulphonated  by  halogen, 
nitric  acid,  and  sulphuric  acid. 

Naphthalene  Homologues.  —  The  methylated  naphthalenes  are  pre- 
sent in  coal-tar.  Alkylic  naphthalenes  also  result  from  the  bromo- 
naphthalenes  by  the  action  of  alkylogens  and  sodium,  and  from  naph- 
thalene by  means  of  alkyl  iodides  or  bromides  and  A1C13  : 

M.p.  B.p. 


a-Methyl-naphthalin    . 

C10H7-a-CH3 

.           -20° 

240°-2430 

^-Methyl-naphthalin    . 

C10H7-£-CH3 

•        +32°-5 

24I°-24201 

i,  4-Dimethyl-naphthalin 

C10H6-i,  4-(CH3)2 

liquid 

262°-264°  2 

a-Ethyl-naphthalin 

C10H7-a-C2H5 

»» 

258° 

/8-Ethyl-naphthalin      . 

C10HV^-C2H5 

.        -19° 

251° 

a-n-Propyl-naphthalin    . 

C10H7-a-(CH2)2CH3 

liquid 

274° 

j3-n-Propyl-naphthalin    . 

C10H7-0-(CH2)2CH3 

,, 

278° 

ct-n-Butyl-naphthalin 

C10H7-a-(CH2)3CH3 

,, 

282° 

/?-n-Butyl-naphthalin 

C10H7-£-(CH2)3CH3 

• 

284° 

1  B.  25,  R.  857.    2  B.  28,  R.  619. 
VOL.  II.  2  U 


658  ORGANIC   CHEMISTRY 


M.p.  B.p. 

uid 


a-Iso-butyl-naphthalin  C10H7-a-CH2CH(CH3)2  .  liquid  137°  (n  mm.) 

/S-Iso-butyl-naphthalin  C10H7-/3-CH2CH(CH3)2  112°  (  6  mm.) 

a-Phenyl-naphthalin    .  C10H7-a-C6H5       .  o°  325° 

0-Phenyl-naphthalin    .  C10H7-/5-C6H5       .  102°  347°. 

a-  and  j3-Phenyl-naphthalenes  have  been  prepared  by  the  action 
of  diazo-benzene  chloride  upon  naphthalene  in  the  presence  of  A12C16. 

Similarly,  nitro-phenyl-naphthalene,  melting  at  129°,  is  obtained  from 
sodium  nitro-phenyl-nitrosamine  with  naphthalene  (B.  29, 168). 

j3-Phenyl-naphthalene  is  also  formed  on  conducting  the  vapours  of 
bromo-benzene  and  naphthalene  through  tubes  heated  to  redness  ;  also 
in  the  condensation  of  two  molecules  of  phenyl-glycol  (B.  26,  1119, 
1748),  and  in  the  distillation  of  jS-phenyl-hydroxy-a-naphtho-quinone 
with  zinc  dust  (A.  296,  28).  The  constitution  of  the  two  isomeric 
phenyl-naphthalenes  can  be  deduced  from  their  oxidation  products  : 
a-phenyl-naphthalene  yields  o-benzoyl-benzoic  acid,  whereas  j3-phenyl- 
naphthalene  yields  phenyl-a-naphtho-quinone  : 

XCH=CH  yCOOH  xCH=CH  /CO— CH 

C«H4\C(C6H5)  =iH  -"C'H4\CO.C6H5;  ^^\CH=t.C.H«       •H*\CO-i.G?H, 

o-Phenyl-naphtha-          o-Benzoyl-  /3-Phenyl-  Phenyl-a-naphtho 

lene  benzoic  acid  naphthalene  quinone. 

Olejftn  -  naphthalins. — a- Vinyl  -  naphthalin  C10H7.CH  :  CH2,  b.p.15 
137°,  from  a-naphthyl-magnesium  bromide  and  acetaldehyde.  a-Alyl- 
naphthalin  C10H7.CH2.CH  :  CH2,  b.p.  266°,  from  allyl  bromide  and 
a-naphthyl-magnesium  bromide.  On  heating  with  alcoholic  KOH  it 
is  transposed  into  the  isomeric  a-propenyl-naphthalin  C10H7.CH.CH  : 
CH3,  b.p.10  138°,  which  is  also  formed  from  a-naphthaldehyde,  pro- 
pionic  anhydride,  and  Na  propionate  (C.  1897,  II.  800  ;  1908,  II.  1779). 
a-  and  /Mso-propenyl-naphthalin  C10H7.C(:  CH2)CH3,  a-  b.p.8  125°, 
j8-  m.p.  45°-47°,  b.p.7 139°,  are  formed  from  a-  and  j8-naphthyl-methyl- 
ketone  with  CH3MgI  ;  the  j8-compound  direct,  and  the  a-compound 
by  way  of  a-naphthyl-dimethyl-carbinol  with  acetic  anhydride  (C.  1901, 
I.  1321). 

Substituted  Naphthalenes. 

i.  Halogen  Derivatives, — These  are  formed  (i)  by  the  direct  sub- 
stitution of  the  hydrogen  atoms  by  halogens  ;  (2)  by  the  replacement 
of  NH2  groups  in  amido-naphthalenes  by  halogens,  following  Griess' 
reaction  (p.  60)  ;  (3)  by  the  replacement  of  OH  as  well  as  of  SO3H  and 
NO 2  groups  in  oxy-,  nitro-,  or  sulpho-derivatives  of  naphthalene  on 
heating  them  with  PC15.  The  latter  reaction  is  useful  for  determining 
positions  in  naphthalene-  and  naphthol-sulphuric  acids. 

The  union  of  the  halogen  atoms,  and  also  that  of  the  other  sub- 
stituents,  like  NO2,  SO3H  (cp.  B.  26,  3028),  in  naphthalene  derivatives 
are,  as  a  rule,  less  stable  than  in  the  corresponding  benzene  derivatives. 

Fluoro-naphthalenes  C10H7F  :  the  a-form  boils  at  216°,  the  )3-  melts 
at  59°  and  boils  at  213°. 

Chloro-naphthalenes  C10H7C1  :  the  a-  boils  at  263°,  while  the  j8- 
melts  at  56°  and  boils  at  265°.  a-Chloro-naphthalene  is  produced  (i) 
in  chlorinating  boiling  naphthalene  ;  further,  (2)  by  action  of  alcoholic 
potash  upon  naphthalene  dichloride  ;  (3)  from  naphthalene-a-sulphonic 
acid  and  PC15  ;  (4)  from  a-amido-naphthalene.  j3-Chloro-naphthalene 


NAPHTHALENE  GROUP  659 

is  prepared  from  /3-amido-naphthalene  or  from  j8-naphthol.  Dichloro- 
naphthalenes  C10H6C12  :  The  ten  possible  isomerides  are  known  : 
i,  2-  melts  at  35°  and  boils  at  281°  ;  I,  3-  melts  at  61°  and  boils  at  289°  ; 
i,  4-  melts  at  68°  and  boils  at  287°  ;  i,  5-  melts  at  107°  ;  i,  6-  melts 
at  48°  ;  i,  7-  melts  at  62°  and  boils  at  286°  ;  i,  8-  melts  at  83°  ;  2,  3- 
melts  at  120°  ;  2,  6-  melts  at  135°  and  boils  at  285°  ;  2,  7-  melts  at  114° 
(B.  24,  3475,  R.  653,  704,  709  ;  26,  R.  536). 

Triehloro-naphthalenes. — There  are  fourteen  isomerides ;  see  B. 
29,  R.  227. 

Pentachloro-naphthalene  C10H3C15  melts  at  168°.  Perehloro- 
naphthalene  C10C18  melts  at  203°  and  boils  at  403°. 
\YBromo-naphthalenes  C10H7Br  :  the  a-variety  melts  at  5°  and  boils 
at  279°,  while  the  j3-variety  melts  at  59°  and  boils  at  282°.  lodo-naph- 
thalenes  C10H7I  :  the  a-body  is  an  oil,  boiling  at  305°  ;  the  /2-body 
melts  at  54-5°.  a-Iodo-naphthalene  is  obtained  by  the  introduction  of 
iodine  into  a  carbon  bisulphide  solution  of  mercury  dinaphthyl 
Hg(C10H7)2.  See  B.  29,  1408,  for  the  bromo-iodo-naphthalenes,  and 

B.  27,  599,  for  the  naphthyl-iodo-chlorides  and  iodoso-naphthalenes. 
Consult  B.  29,  1573,  for  jS-iodo-naphthalene.     lodo-naphthalene  and 
naphthyl-phenyl-iodonium   hydroxide,   see    B.    29,    1573  ;    33,    692 ; 

C.  1901,  II.  750. 

2.  Nitro-naphthalenes. — a-Nitro-naphthalene  C10H7-a-NO2  consists 
of  yellow  needles,  melting  at   61°   and  boiling  at   304°.     It  is  pro- 
duced on  treating  naphthalene  with  nitric  acid  at  the  ordinary  tempera- 
ture.    When  heated  with  PC15  it  yields  a-chloro-naphthalene.     Chromic 
acid  oxidises  it  to  v-nitro-phthalic  acid.     jS-Nitro-naphthalene,  melting 
at  79°,  is  derived  from  jS-mtro-naphthylamine  by  replacing  the  NH2 
group  by  hydrogen,  or,  better,  from  jS-diazo-naphthalene  nitrite  C10H7N 
=N.O.NO,  by  means  of  Cu2O  (B.  20, 1494  ;  36, 4157).     Transformation 
into  4,  i-  and  2,  i-nitroso-naphthol,  see  A.  355,  299.     Different  dinitro- 
naphthalenes  are  obtained  by  the  nitration  of  naphthalene  at  high 
temperatures.     Consult  B.  29, 1243, 1521,  for  the  separation  of  the  i,  5- 
and  i,  8-compounds.     The  i,5~(a-)  compound  melts  at  216°  ;  the  i,  8- 
(j8-)  body  melts  at  170°,  and  when  heated  with  potassium  cyanide  yields 
potassium    naptho-cyaminate   C28H17N8O9K.      The   two   dinitro-naph- 
thalenes,  when  heated  with  sulphuric  acid  and  reducing  agents,  form 
naphthazarin   or   dioxy-naphtho-quinone   (B.   27,  R.   959).     1,  3-(y-) 
Dinitro-naphthalene,  melting    at    144°,  is    obtained  from  amido-di- 
nitro-naphthalene.     At  very  low  temperatures  (—50°  to  —55°)  nitric 
acid  and  naphthalene  form  various  dinitro-naphthalenes  (B.  26,  R.  362). 
When  naphthalene  or  dinitro-naphthalenes  are  boiled  for  some  time 
with  fuming  nitric  and  sulphuric  acids  (B.  28, 367)  tri-  and  tetranitro- 
naphthalenes  are  produced.     These  explode  partly  with  violence  on 
heating. 

3.  Nitroso  -  naphthalenes.  —  Mononitroso  -  naphthalene     C10H7.NO, 
melting  at  89°  and  decomposing  at  134°,  results  from  the  action  of 
nitrosyl  bromide  upon  mercury  dinaphthyl,  or  by  oxidation  of  naphthyl- 
hydroxylamine  with  Ag2O  or  PbO2  (B.  41,  1937). 

1, 4-Dinitroso-naphthalene  is  a  powder  exploding  at  120°,  and  is 
produced  when  a-naphtho-quinone-dioxime  is  oxidised  with  red  prus- 
siate  of  potash.  1,  2-Dinitroso-naphthalene,  melting  at  127°  (B.  19, 
349  ;  21,  434),  is  similarly  formed  from  jS-naphtho-quinone-dioxime. 


660  ORGANIC  CHEMISTRY 

4.  Amido-naphthalenes,  Naphthylamines. — (a)  Primary  Amines. 
— The  naphthylamines,  in  contrast  to  the  anilines,  are  very  easily 
obtained  by  heating  the  oxy-naphthalenes  or  naphthols  with  ammonia- 
zinc  chloride. 

They  are  also  formed  by  fusing  naphthalene-sulphonic  acids  with 
sodium  amide.  Naphthalene  itself  in  the  presence  of  phenol  at  220° 
yields  a-naphthylamine  and  I,  5-naphthylene-diamine  (B.  39,  3011). 

The  acid  sulphurous  acid  esters  of  naphtholene  and  naphthol  deriva- 
tives are  transformed  by  treatment  with  ammonia  in  aqueous  solution 
into  naphthylamines  at  temperatures  as  low  as  100°.  This  action  is 
reversed  by  boiling  with  alkaline  bisulphite  (/.  pr.  Ch.  2,  69,  49)  : 

NH, 

C10H7.OSO2Me  ^_          ~*  C10H7.NH2. 

SO  jti  Me 

a-Naphthylamine  C10H7-a-NH2,  melting  at  50°  and  boiling  at  300°, 
results  from  the  reduction  of  a-nitro-naphthalene,  or  on  heating 
a-naphthol  with  ZnCl2  or  CaCl2-ammonia  to  250°,  and  is  synthetically 
produced  when  aniline  and  zinc  chloride  are  heated  with  pyro-mucic 
acid.  It  crystallises  in  flat  needles,  which  are  especially  beautiful  when 
they  separate  from  aniline.  It  acquires  a  red  colour  on  exposure  to 
the  air,  sublimes  readily,  and  possesses  a  pungent  odour.  In  general,  it 
behaves  exactly  like  the  phenylamines. 

Sodium  in  amyl  alcohol  reduces  it  to  a-tetrahydro-naphthylamine. 
It  is  oxidised  to  a-naphtho-quinone  when  boiled  with  chromic  acid. 
Oxidising  agents  (chromic  acid,  ferric  chloride,  silver  nitrate)  produce 
an  azure-blue  precipitate  in  the  solutions  of  its  salts  :  oxy-naphthyl- 
amine  C10H9NO  (A.  129,  255). 

In  a-naphthylamine  derivatives  the  amido-group  can  be  replaced 
by  the  hydroxyl  group  by  treating  with  H2SO3  and  alkali  (C.  1900, 

II.  359). 

j8-Naphthylamine,  melting  at  112°  and  boiling  at  294°,  results  from 
jS-naphthol  and  ZnCl2-ammonia.  It  is  odourless,  and  is  not  coloured  by 
ferric  chloride  and  the  like.  Potassium  permanganate  oxidises  it  to 
phthalic  acid.  /3-Tetrahy dro-naphthylamine  is  formed  by  its  reduction . 

Secondary  and  Tertiary  Naphthylamines. — Naphthyl-alkylamines  are 
formed,  analogous  to  the  alkyl-anilines,  from  the  naphthylamines  with 
alkylogens,  or  upon  heating  the  naphthylamine  hydrochlorides  with 
alcohols.  Also  from  the  sulphurous  esters  of  naphthols  by  heating 
with  aliphatic  amines.  The  /?-naphthol,  but  not  the  a-naphthol  esters, 
react  in  this  way  with  aromatic  amines  (/.  pr.  Ch.  2,  70,  345  ;  71,  433). 

a-Naphthyl-methylamine  C10H7NH.CH3,  boils  at  293° ;  a-naphthyl- 
ethylamine  boils  at  303° ;  j8-naphthyl-dimethylamine  C10H7-jS-N(CHa)l 
melts  at  46°  and  boils  at  305°  (B.  13, 2053).  The  phenyl-naphthylamines 
C10H7.NH.C6H5  are  formed  when  the  hydrochlorides  of  a-  and  /3- 
naphthylamines  are  heated  with  aniline  and  zinc  chloride.  On  heating 
the  naphthylamines  with  zinc  chloride  or  with  HC1  to  i8o°-i90°,  or 
with  a-  and  jS-naphthol,  various  dinaphthylamines  result.  /3,  f$- 
Dinaphthylamine  C10H7-j3-NH-jS-C10H7,  melting  at  171°  and  boiling 
at  471°,  occurs  as  a  by-product  in  the  technical  manufacture  of  /3- 
naphthylamine.  Heated  to  150°  with  concentrated  hydrochloric  acid, 
it  breaks  down  into  j8-naphthylamine  and  /3-naphthol.  Heated  with 
sulphur  it  forms  thio-dinaphthylamine  NH(C10H6)2S,  corresponding  to 


NAPHTHALENE   GROUP  661 

thio-diphenylamine.  When  sulphuric  acid  (80  per  cent.)  acts  upon 
j3-naphthylamine  in  the  presence  of  oxidising  agents,  two  naphthalene 
nuclei  unite  and  naphthidine  (C10H6.NH2)2  results  (B.  25,  R.  949). 

The  acid  derivatives  of  the  naphthylamines  show  great  similarity  to 
those  of  the  anilines.  The  naphthyl-benzene  sulphamides  C10H7.NH. 
SO2.C6H5  manifest  a  rather  remarkable  deportment,  similar  to  that  of 
the  naphthols,  in  that  they  dissolve  in  the  alkalies,  and  unite  similarly 
with  diazo-salts,  etc.  (B.  27,  2370).  Consult  B.  25,  R.  9,  upon  naphthyl- 
carbamine-chlorethyl  esters  C10H7.NH.COOC2.H4C1  and  their  trans- 
position products.  See  B.  29,  R.  184,  for  the  a-naphthylamine  de- 
rivatives of  succinic,  tartaric,  and  citric  acids. 

Substituted  Naphthylamines. — Haloid  naphthylamines  result  by 
direct  substitution,  or  by  the  action  of  ammonia  upon  substituted 
naphthols.  1,  2-  and  1,  4-nitro-naphthylamines  are  formed  by  the 
nitration  of  aceto-a-naphthylamine  and  its  subsequent  saponification. 
The  i,  ^-body  melts  at  191°.  It  is  oxidised  to  a-naphtho-quinone.  It 
forms  a-nitro-naphthalene  by  the  elimination  of  the  NH2  group. 
Boiling  potassium  hydroxide  converts  a-nitro-naphthalene  into  I,  4- 
nitro-naphthol  (B.  19,796;  25,  R.  432).  The  i,  2-compound  melts  at 
144°,  and  yields  j3-nitro-naphthalene  and  2,  i-nitro-naphthol. 

l-Nitro-2-naphthylamine,  melting  at  127°,  is  formed  by  the  nitration 
of  aceto-j8-naphthylamine  and  subsequent  saponification  of  the  acetc- 
derivative.  Nitrous  acid  and  alcohol  convert  it  into  a-nitro-naphtha- 
lene. 2,  5-  and  2,  8-Nitro-naphthylamines  (B.  25,  2076)  are  produced 
when  /?-naphthylamine  nitrate  is  introduced  into  concentrated  sulphuric 
acid. 

Naphthylene  Diamines.  —  Diamido-naphthalenes,  naphthylene-dia- 
mines,  are  obtained  by  the  reduction  of  dinitro-  and  nitro-amido- 
naphthalenes,  also  by  the  decomposition  of  amido-azo-naphthalenes, 
and  when  dioxy-naphthalenes  and  amido-oxy-naphthalenes  are  heated 
with  ammonia  (B.  21,  R.  839  ;  22,  R.  42  ;  26,  188). 

The  o-naphthylene-diamines  adapt  themselves  like  the  o-phenylene- 
diamines  to  condensation  reactions,  in  that  they  form  naphtho-deriva- 
tives  of  heterocy die  rings.  To  a  certain  degree  the  o-naphthylene-dia- 
mines in  this  respect  resemble  the  i,  8-  or  ^>m"-compounds  (p.  651). 

1,  2-Naphthylene-diamine,  melting  at  98°,  is  obtained  by  reduc- 
tion from  jS-nitro-a-naphthylamine  and  j8-naphtho-quinone-dioxime. 
2,  3-Naphthylene-diamine,  melting  at  191°,  is  derived  from  2,  3-dioxy- 
naphthalene  by  the  action  of  ammonia  at  240°.  These  two  bodies 
yield  naphtho-azimides  with  nitrous  acid,  anhydro-bases  with  car- 
boxylic  acids,  quinoxalins  with  o-diketones,  etc.  (B.  25,  2714  ;  26, 
188  ;  27,  761).  Perfectly  similar  hetero-ring-formations  are  exhibited 
by  1,  8-  (peri-)  naphthylene-diamine,  melting  at  67°  and  obtained  from 
i,  8-dinitro-  or  i,  8-dioxy-naphthalene  ;  however,  it  does  not,  in 
contrast  to  the  o-diamines,  condense  with  o-diketones,  like  phen- 
anthra-quinones,  forming  azines  (B.  22,  861). 

1, 3-Naphthylene-diamine  melts  at  96°  ;  has  been  obtained  by  nuclear 
synthesis  by  the  action  of  concentrated  H2SO4  upon  y-phenyl-/3-imino- 
butyro-nitrile  (B.  28,  1953).  i,  3~(w)- Naphthylene-diamine  derivatives 
are  derived  from  naphthylamine-sulphonic  acids,  which  contain  the 
SO3H  group  in  the  meta-position  with  reference  to  NH2,  by  the  action 
of  amines. 


662  ORGANIC   CHEMISTRY 

(1,  4)-Naphthylene-diamine,  melting  at  120°,  results  from  the  re- 
duction of  a-nitro-naphthylamine,  and  the  decomposition  of  a-amido- 
azo-naphthalene,  by  tin  and  hydrochloric  acid.  Ferric  chloride  con- 
verts it  into  a-naphtho-quinone,  and  bleaching-lime  changes  it  to 
naphtho-quinone  dichlorimine. 

1,  5-Naphthylene-diamine,  m.p.  189°,  has  also  been  obtained  from 
a-naphthylamine,  and  i,  6-naphthylene-diamine,  m.p.  78°,  from  )3- 
naphthylamine  by  fusing  with  NaNH2  (B.  39,  3021). 

1,  7-Naphthylene-diamine,  m.p.  117° ;  see  B.  25,  2082.  2,  6-Naph- 
thylene-diamine,  m.p.  216° ;  see  A.  323, 130.  2, 7-Naphthylene-diamine, 
m.p.  159°  (J.pr.  Ch.  2,  69,  89). 

5.  Diazo-  and  Azo-compounds  of  Naphthalene. — By  the  action  of 
HNO2  and  NaNO2  upon  the  salts  of  naphthylamines,  diazo-compounds 
are  obtained  which,  like  the  benzene-diazo-compounds,  form  azo-dyes 
with  anilines  and  phenols.  The  diazo-amido-compounds  probably 
formed  cannot  be  isolated.  But  a-  and  /3-naphthalene-diazonium 
chloride  and  aniline  give  a-  and  jS-naphthalin-diazo-amido-benzol, 
naphthyl-phenyl-triazene  C10H7N  :  N.NHC6H5,  m.p.  84°  and  150° 
with  decomposition.  The  a-body  has  also  been  obtained  by  other 
methods  (B.  40,  2400). 

j8-Diazo-naphthalin-imide,  m.p.  33°;  seeC.  1908, 1.  527  (/.  pr.  Ch. 
2,  76,  461).  l-Nitro-2-diazo-naphthalin-imide  Ci0H6[i]NO2[2]N3,  m.p. 
117°,  decomposes  on  heating  with  alcohol  or  glacial  acetic  acid  into  N2 
and  i,  2-dinitroso-naphthalene  (C.  1908,  I.  526). 

j8-Diazo-naphthalene  acid,  fi-naphthyl-nitramine  C10H7-/3-NH.NO2, 
yields  on  transposition  2-amido-i-nitro-naphthalene  (B.  30,  1262). 

Azo-naphthalenes. — The  reduction  of  nitro-naphthalenes  to  azoxy- 
and  azo-naphthalenes  is  less  straightforward  than  in  the  case  of  the 
nitro-benzols.  a-Nitro-naphthalene  gives  on  reduction  with  zinc  dust  in 
neutral  solution  naphthyl-hydroxylamine  and  aa-azoxy-naphthalene 
C10H7[a]N2O[a]C10H7,  m.p.  127°.  The  latter  on  further  reduction 
yields  aa-azo-naphthalene,  m.p.  190°,  red  needles  (A.  321,  61). 

j8£-Azo-naphthalene,   m.p.    208°,   red   flakes,   is    formed   besides 

C10H6— N 
dinaphtho-ortho-diazin    I  II   and  2,  2-diamido-i,  i-dinaphthyl  by 

C10H6 — N 
reduction  of  jS-nitro-naphthalene  (B.  36,  4153). 

Benzol-azo-naphthalene  C10H7.N2C6H5,  m.p.  65°. 

o-Toluene-azo-naphthalene  C10H7.N2.C7H7  melts  at  52°  (B.  26,  143), 

Naphthyl-azo-aeetie  ester  C10H7.N2.CH(COCH3)CO2R,  melting  at  94°, 
is  formed  from  diazo-naphthalene  chloride  and  sodium  aceto-acetic 
ester.  Caustic  potash  changes  it  to  naphthyl-acetone,  and  by  the  acid 
decomposition  it  is  resolved  into  naphthyl-azo-acetic  acid  (B.  24,  R.  571). 

A  mido-azo-naphthalenes — a- Amido-azo-naphthalene  C10H7-a-N  2-a- 
C^Hg-c^-NHg,  melting  at  175°,  is  formed  by  adding  sodium  nitrite 
(i  mol.)  to  the  aqueous  solution  of  naphthylamine  hydrochloride 
(2  mol.)  ;  the  diazo-amido-naphthalene  C10H7.N2.NH.C10H7  first 
formed  undergoes  a  molecular  rearrangement.  Tin  and  hydrochloric 
acid  resolve  a-amido-azo-naphthalene  into  a-naphthylamine  and 
(i,  4)-naphthylene-diamine.  Naphthalene  red  belongs  to  the  safranine 
dyes  and  is  produced  when  a-amido-azo-naphthalene  is  heated  with 
Na-naphthylamine  hydrochloride. 


NAPHTHALENE  GROUP  663 

j8-Amido-azo-naphthalene,  from  j8-naphthylamine,  melts  at  156° 
(B.  19,  1282). 

a-Naphthylamine-azo-benzene-sulphonic  acid  C6H4(Sp3H).N2.C10H6. 
NH2,from  sulphanilic  acid  and  naphthylamine  hydrochloride,  is  coloured 
orange  by  caustic  potash  and  red  by  acids  (test  for  nitrous  acid). 

The  o-azo-compounds  of  jS-naphthyl-alphylamines,  like  benzene- 

azo-/3-naphthyl-phenylamine  C10H6<{  f1^  '    '  •   5,  when  oxidised  form 

li|_2j.N  I  W  .L/gJrlj 

ammonium  bases  of  the  pseudo-azimide  group,  and  when  heated  they 
split  off  aniline,  forming  naphtho-phenazines  (A.  28,  328)  : 

/N:N.C,HS     o  /N\  /N  :  N.C.H, 

C"H'<NH.C.H5    :r^l>*  ;  C"H<NH.C.H8    ' 
/  \ 

HO       c.H6 

Compare  further  B.  18,  3132  ;  20,  1167  ;  24,  R.  765,  for  the  con- 
stitution of  the  products  resulting  from  the  action  of  diazo-salts  upon 
jS-napthylamines,  which  are  sometimes  viewed  as  j3-quinone  derivatives. 

6.  Hydrazin    Derivatives   of  Naphthalene.— Hyfaazo  -  naphthalene 
C10H7.NH.NH.C10H7,  melting  at  275°,  corresponds  to  hydrazo-benzene. 
It  is  formed  on  boiling  azo-naphthalene  with  alcoholic  sodium  hydroxide 
and  zinc  dust.     When  digested  with  hydrochloric  acid  it  changes  to  the 
isomeric  naphthidin  or  diamido-dinaphthyl  and  i,  i-diamido-2,  2-di- 
naphthyl  or  dinaphthylin  (B.  38,  136)  ;    J3j3-hydrazo-naphthalin,  m.p. 
141°,  is  transposed  into  2,  2-diamido-i,  i-dinaphthyl  by  both  acids  and 
alkalies  (cp.  benzidin  transposition). 

Naphthyl-hydrazins  C10H7.NH.NH2  are  derived  from  the  diazo- 
chlorides  of  the  two  naphthylamines  by  the  action  of  stannous  chloride 
and  hydrochloric  acid  (B.  19,  R.  303).  The  a-compound  melts  at  117°, 
the  /^-modification  at  125°.  They  unite  with  the  aldehydes  and  ketones 
forming  hydrazones  ;  these  form  naphthindol  compounds  by  condensa- 
tion, and  manifest  throughout  the  tendency  to  form  derivatives  and 
hetero-ring  formations  similar  to  those  shown  by  the  phenyl-hydrazins 
(B.  19,  R.  831 ;  22,  R.  672).  On  jS-naphthyl-hydrazones  of  sugars,  see 
B.  35,  1841.  2,  3-Naphthylene-dihydrazin  C10H6[2,  3](NHNH2)2, 
m.p.  156°,  see  B.  38,  266  ;  /.  pr.  Ch.  2,  76,  205. 

7.  Sulphonic  Acids. — On  digesting  naphthalene  with  sulphuric  acid 
we  have  formed   a-  and   /?-naphthalene-sulphonie  acids.    At   lower 
temperatures  (80°)  the  a-acid,  melting  at  90°,  predominates,  while  at 
about  1 60°  and  with  an  excess  of  sulphuric  acid  the  j3-acid,  melting  at 
161°,  is  the  chief  product.     When  heated  with  sulphuric  acid  the  a-acid 
passes  into  the  j8-variety.     They  may  be  separated  by  means  of  the 
calcium  or  lead  salts.     The  free  acids  are  crystalline,  and  deliquesce 
readily.     The   a-acid   decomposes   upon  heating  with   dilute  hydro- 
chloric acid  to  200°  into  naphthalene  and  sulphuric  acid,  whereas  the 
j3-acid  remains  unaltered. 

The  a-sulpho-chloride  melts  at  66°  and  boils  at  185°  (13  mm.).  The 
fi-sulpho-chloride  melts  at  76°  and  boils  at  201°  (13  mm.)  (/.  pr.  Ch. 
2,  47,  49).  Protracted  heating  of  naphthalene  with  concentrated 
sulphuric  acid  produces  two  isomeric  disulpho-acids  :  2,  6-  and  2,  7-. 

Naphthalene-disulphonie  Acids. — They  are  separated  by  crystallising 
their  chlorides  from  benzene  (B.  9,  592).  Additional  disulphonic  acids 
of  naphthalene  have  been  prepared  by  sulphonating  the  naphthalene- 


664  ORGANIC  CHEMISTRY 

monosulphonic  acids,  by  oxidising  thio-naphthol-sulphonic  acids,  from 
the  naphthylamine-disulphonic  acids,  etc.  A  series  of  naphthalene- 
trisulphonic  acids  has  been  made  by  similar  indirect  methods  (B.  24,  R. 
654, 707,  715 ;  27,  R.  81 ;  32, 3186 ;  Proc.  126, 168) .  Chloro-naphthalene- 
sulphonic  acids  have  been  obtained  in  part  by  sulphonating  the  chloro- 
naphthalenes,  and  in  part  by  replacing  the  NH2  group  of  the  naphthyl- 
amine-sulphonic  acids  by  halogens  (B.  24,  R.  658,  707  ;  25,  2479  * 
Ch.  Z.  1895, 1114).  Nitro-naphthalene-sulphonic  acids  are  obtained  by 
sulphonating  the  nitro-naphthalenes  or  nitrating  the  chlorides  of  the 
sulphonic  acids  (B.  26,  R.  536). 

Some  naphthylamine-sulphonic  acids  possess  technical  value,  inas- 
much as  they  form  desirable  and  valuable  dyes  by  combining  with  the 
tetrazo-compounds  of  the  benzidine  series  : 

(a)  a-Naphthylamine,  treated  at  130°  with  an  excess  of  concentrated 
sulphuric  acid,  forms  1,  4-naphthylamine-sulphonic  acid,  naphthionic 
acid,  which  can  also  be  prepared  from  nitro-naphthalene  with  ammon- 
ium sulphite  by  simultaneous  reduction  and  sulphonation  (Ch.  Z.  1895, 
1114;    A.  78,  31).     The  acid  crystallises  with  |H2O  and  dissolves 
sparingly  in  water.     Its  sodium  salt  has  the  formula  C10H6(NH2)SO3Na 
+4H2O.     When   the   acid   combines   with   the   tetrazo-derivative   of 
benzidine  Congo  red  is  produced.     Tin  and  hydrochloric  acid  decom- 
pose  the   latter   with   the   formation   of   i,    2-naphthylene-diamine-<\- 
sulphonic  acid.     See  B.  29,  1978,  for  additional  naphthylene-diamine- 
sulphonic  acids. 

If  a-naphthylamine  be  digested  with  sulphuric  acid  at  130°  for 
some  time  there  results,  instead  of  the  i,  4-acid,  1,  5-napthylamine- 
sulphonic  acid,  naphthal-idinic  acid,  and  this  finally  gives  place  to 
the  i,  6-acid  (B.  26,  R.  534).  1,  8-  or  Peri-naphthylamine-sulphonic 
acid  is  obtained  from  peri-nitro-sulphonic  acid.  The  derivatives  of  the 
i,  8-acid  show  a  tendency  to  part  with  water  with  the  production  of 

/SO, 
sultams — e.g.    (SO3H2)C10H4</  |     ,  1,  8-naphth-sultam,  2,  4-disulphonic 

/SO2 
acid    (S03H)3c10H3<^  |      ,  1,  8-naphth-sultam-trisulphonic  acid  (B.  27, 

NH2 

2137).  Peri-amido-naphthol  derivatives  are  produced  when  these 
sultams  are  fused  with  caustic  potash  (B.  28,  R.  636). 

Dimethyl-a-naphtnylamine-sulphonic  acids  (CH3)2NC10H6SO3H,  see 
B.  35,  976.  Naphthionates  condense  easily  with  aldehydes  to  RCH  : 
NC10H6SO3Me  (C.  1901,  II.  903). 

(b)  Four  different,  isomeric,   fl-naphthylamine-sulphonic  acids   (A. 
275, 262)  are  produced,  according  to  the  temperature,  when  ^S-naphthyl- 
amine  is  sulphonated  : 

S03H 
-J — Lso3H  J — L  J — L  so3H- 


TH, 


NH2  NH2 

a-acid  /?-acid  F-  or  <5-acid  y-acid 

(Baden  acid)  (Bronner's  acid)  (Dahl's  acid). 

These  acids  can  also  be  prepared  by  the  action  of  ammonia  upon  the 
corresponding  naphthol-sulphonic  acids  (p.  669).  The  j8-  and  the  F-  or 
8-acids  are  particularly  valuable,  because  by  their  combination  with 


NAPHTHALENE   GROUP  665 

o-tetrazo-ditolyl  beautiful  red  dyes  having  a  blue  tinge  result.    Certain 
fi-naphthylamine-disulphonic  acids  are  technically  important  : 


H03< 

H03S-1 i— 

HN2  NH2 

Amido-sulphonic  acid  G      Amido-sulphonic  acid  R      d-Amido-sulphonic  acid 
(B.  24,  R.  716)  (B.  24,  R.  707)  (B.  24,  R.  715)- 

See  B.  27,  1193,  for  additional  jS-naphthyl-amido-poly-sulphonic 
acids.  These  /?-naphthylamine-sulphonic  acids,  which  contain  a 
sulpho-group  in  the  m-position  with  reference  to  the  NH2  group, 
readily  exchange  the  sulpho-group  for  the  amine  residue  when  they  are 
heated  with  amines  (B.  28,  R.  311). 

1,  4-Diazo-naphthalene-sulphonic   acid   c^H^^^O,   diazo-naph- 

thionic  acid,  is  produced  by  the  action  of  nitrous  acid  upon  naphthionic 
acid.  It  forms  rocellin  by  combining  with  a-naphthol,  and  azorubin 
S  by  its  union  with  a-naphthol-a-sulphonic  acid. 

By  the  union  of  various  azo-naphthalene-diazo-sulphonic  acids — e.g. 

/N    \ 
CjoHjNsj.CjoHs^g^  />O  —  with   naphthol-monosulphonic   acid,   azo-black 

dyes — e.g.  naphthol-black,  wool-black,  etc. — result. 

8.  N  aphthalene-sulphinic  acids  are  derived  by  the  reduction  of  the 
chlorides  of  sulpho-acids  ;   on  treating  naphthalene-diazonium   salts 
with  SO  2  and  powdered  Cu  ;  or  by  the  action  of  SO2  upon  naphthalene 
in  the  presence  of  A1C13  (B.  32,  1141  ;  41,  3319).     a-Naphthalene- 
sulphinic  acid  C10H7.SO2H  melts  at  84°,  while  the  £-acid  melts  at  105° 
(B.  26,  R.  271).     These  acids  behave  just  like  the  benzene-sulphinic 
acids  (B.  25,  230).     Mixed  naphthyl-sulphones  are  prepared  from  their 
salts  by  the  action  of  alkyl  bromides  (B.  29,  R.  979). 

9.  Naphthols. — The  oxy-derivatives  of  naphthalene  or  naphthols  in 
general  show  a  deportment  similar  to  that  of  the  phenols.     However, 
their  hydroxyl  group  is  more  reactive.     They  readily  yield  naphthyl- 
amines  with  ammonia.     They  form  esters  and  ethers  more  easily  than 
the  phenols  (B.  15,  1427  ;   C.  1900,  I.  131,  349).     The  naphthols  occur 
in  coal-tar  (A.  227,  143). 

a-Naphthol  C10H7-a-OH  melts  at  95°,  boils  at  278°-28o°,  and  results 
from  a-naphthalene-sulphonic  acid  by  fusing  with  potash,  and  from 
a-naphthylamine  by  means  of  the  diazo-compound,  and  upon  fusing 
a-naphthalene-sulphonic  acid  with  alkalies.  Its  formation  from 
phenyl-iso-crotonic  acid  is  very  noteworthy.  It  is  soluble  with 
difficulty  in  hot  water,  readily  in  alcohol  and  ether,  crystallises  in 
shining  needles,  has  the  odour  of  phenol,  and  is  readily  volatilised. 
Ferric  chloride  precipitates  violet  flakes  of  dinaphthol  C20H12(OH2)  from 
its  aqueous  solution.  Nitrous  acid  converts  it  into  2, 1-  and  4,  i-nitroso- 
naphthol  ;  chlorine  in  acetic  acid  changes  it  to  various  chlorinated 
naphthols  and  keto-hydro-naphthalenes  ;  potassium  chlorate  and 
hydrochloric  acid  oxidise  it  to  dichloro-naphtho-quinone  (A.  152,  301) ; 
metallic  sodium  and  alcohol  reduce  it  to  ar-tetrahydro-naphthol 
(p.  412),  while  potassium  permanganate  in  alkaline  solution  breaks  it 
down  into  carbo-phenyl-glyoxylic  acid.  The  acetate  C10H7-a-O.C2H3O 
melts  at  46°.  See  B.  28,  3049,  for  the  carbonate  and  phosphate. 


666  ORGANIC   CHEMISTRY 

j8-Naphthol  C10H7-£-OH,  melting  at  122°  and  boiling  at  286°,  is 
derived  from  jS-naphthalene-sulphonic  acid,  or  /3-naphthylamine.  It  is 
readily  soluble  in  hot  water  and  crystallises  in  leaflets.  Ferric  chloride 
imparts  a  greenish  colour  to  the  solution  and  separates  a  dinaphthol. 
Nitrous  acid  and  j9-naphthol  yield  I,  2-nitroso-naphthol.  The  acetate 
C10H7-/3-OC2H3O  melts  at  70°.  On  mixing  glacial  acetic  solution  of 
/3-naphthol  and  mercury  acetate  we  obtain  jS-oxy-naphthyl-mercuric 
acetate  Ci0H6(OH).Hg.OCOCH3  (B.  31,  2624). 

The  bismuth  salt  of  /3-naphthol  has  been  recommended,  under  the 
name  of  orpholum,  as  an  intestinal  antiseptic. 

N '  aphthol-alkyl  ethers  are  formed  when  the  naphthols  are  heated 
with  alcohols  and  hydrochloric  acid  to  150°  (B.  15,  1427),  or  from 
naphthol-alkali  salts  with  halogen  alkyls  or  alkyl  sulphates  (B. 
34,  3172) 

a-Naphthol-ethyl  ether  boils  at  277°.  jS-Naphthol-methyl  ether  and 
ethyl  ether  have  been  called  Jara-Jara  and  neroline  and  been  used  in 
perfumery  (B.  26,  2706).  a-  and  jS-Dinaphthyl  ethers  melt  at  110°  and 
106°  (B.  13,  1840  ;  14,  195  ;  C.  1906,  I.  364).  a-  and  /KNaphthyl- 
phenyl  ether,  m.p.  55°  and  93°,  from  the  diazo-naphthalenes  with 
phenol  (C.  1902,  II.  1470).  a-  and  /3-Naphthoxy-acetie  acid  C10H7 
OCH2COOH,  cp.  B.  34,  3191. 

Naphthol  homologues,  such  as  2, 1-  and  3, 1-methyl-naphthol  C10H6 
(CH3)OH,  melting  at  80°  and  92°,  have  been  prepared  from  phenyl-a- 
and  -jS-methyl-iso-crotonic  acids  (A.  255,  272).  1, 4-Dimethyl-3- 
naphthol  C10H5(CH3)2OH,  melting  at  136°,  is  obtained  from  santonin 
(p.  724)  (B.  28,  R.  116,  619  ;  31, 1675).  1,  2-Methyl-naphthol  C10H6[i] 
CH3[2]OH,  m.p.  110°,  from  /Minaphthol-methane  by  reduction  with 
zinc  dust  and  soda.  HNO2  has  a  peculiar  action  upon  i,  2-methyl- 
naphthol  and  its  substitution  products,  producing  either  o-quinitrols  or 
o-methylene-quinones.  1,  2-Methyl-naphtho-quinitrol  C10H6[2]  :  O[i] 
(N02)CH3,  m.p.  60°,  heated  above  its  m.p.,  gives  1,  2-methyl-naphtho- 
quinol,  m.p.  89°,  also  obtained  direct  from  i,  2-methyl-naphthol  by 
oxidation  with  CrO3  in  glacial  acetic  acid  (C.  1907,  II.  1415).  1,  2- 
Naphtho-methylene-quinone  C10H6[2]  :  O[i]  :  CH2,  m.p.  132°,  yellow 
needles,  shows  a  reaction  inertia  resembling  that  of  the  o-methylene- 
quinones  of  the  benzene  series  (B.  39,  435  ;  41,  2614). 

Substituted  Naphthols. — Substituted  a-naphthols  can  be  synthesised 
from  the  substituted  phenyl-iso-crotonic  acids  (cp.  B.  26,  R.  537). 
Otherwise  they  are  made  by  methods  similar  to  those  adopted  with  the 
substituted  phenols  (p.  193). 

Nitro-naphthols.— 4, 1-Nitro-naphthol  C10H6[4](NO2)[i]OH,  melting 
at  164°,  and  2,  1-nitro-naphthol  C10H6[2]NO2[i]OH,  melting  at  195°, 
result  from  the  oxidation  of  4,  i-  and  2,  i-nitroso-naphthol  with 
potassium  ferricyanide  or  nitric  acid  (B.  25,  973),  or  by  boiling  the 
corresponding  nitro-naphthylamines  with  caustic  potash. 

2,  4-Dinitro-a-naphthol,  melting  at  138°,  is  produced  by  the  action 
of  nitric  acid  upon  these  nitro-naphthols  or  upon  naphthalene-a- 
sulphonic  acid,  a-naphthylamine,  and  a-naphthol-disulphonic  acid  (A. 
152,  299).  It  is  almost  insoluble  in  water,  sparingly  soluble  in  alcohol 
and  in  ether,  decomposes  alkaline  carbonates,  and  forms  yellow  salts 
with  one  equivalent  of  base.  The  salts  dye  silk  a  beautiful  golden 
yellow.  The  sodium  salt  C10H5(NO2)2.ONa-f  H2O  finds  use  in  dyeing, 


NAPHTHALENE  GROUP  667 

under  the  name  of  naphthalene  yellow  (Martius  yellow),  and  is  frequently 
used  to  colour  foods.     The  potassium  salt  of  dinitro-naphthol-sulphonic 

acid,  CioH4(N02)2{W°*K  (B    24,  R.  709),  obtained  by  the  nitration 

of  naphthol-trisulphonic  acid,  is  naphthol  yellow. 

Trinitro-a-naphthol  melts  at  177°. 

a-Nitro-j8-naphthol,  melting  at  103°,  is  produced  in  the  oxidation 
of  a-nitroso-^S-naphthol,  or  from  nitro-j8-naphthylamine  by  the  action 
of  caustic  potash.  See  B.  25,  2079,  R.  670,  and  31,  2418,  for  other 
nitro-/3-naphthols  and  -naphthol  ethers. 

Amido-naphthols.  —  These  are  derived  by  the  reduction  of  nitro- 
naphthols,  by  the  action  of  ammonia  upon  dioxy-naphthalenes,  the 
decomposition  of  naphthol-azo-compounds,  etc.,  etc.,  from  dioxy- 
naphthalenes  with  NH3,  from  naphthylamino-sulphonic  acids  by  fusion 
with  potash,  from  naphthol-sulphonic  acids,  and  direct  from  naphthalene 
by  fusion  with  Na  amide  (B.  39,  3006). 

In  the  isonuclear,  particularly  the  i,  3-amido-naphthols,  the 
NH2  group  is  more  readily  displaced  than  in  the  heteronuclear 
isomerides. 

(1,  4)-Amido-a-naphthol  C10H6(NH2).OH  results  from  the  reduc- 
tion of  (i,  4)-nitro-naphthol,  and  by  the  decomposition  of  a-naphthol 
orange  C10H6(OH).N2.C6H4.SO3H.  It  is  very  unstable.  It  yields 
a-naphtho-quinone  by  oxidation. 

Its  ethyl  ether  C10H6(OC2H5)NH2  melts  at  96°.  ^-Acetamido-i- 
naphthol,  naphthacetol,  melting  at  187°,  is  especially  well  adapted  for 
the  production  of  pure  naphthol-azo-dyes.  ^-Acetamino-i-naphthol- 
ethyl  ether,  naphthacetin,  melts  at  189°  (B-.  25,  3059). 

2-Amido-a-naphthol,  from  2,  i-nitro-naphthol,  oxidises  in  the 
air  to  imido  -  oxy  -  naphthylamine  or  B  -  naphtho  -  quinonimide 
O  ,NH 


6^  |T 


,  C10H6<        ,  forming  violet  leaflets. 


2,  i-Amido-naphthol  yields  anhydro-bases  or  naphtho  xazoles  (see 
B.  25,  3430)  with  carboxylic  acids,  etc. 

{/N 
2J  \N,  yellow 
[i]  :  O 

needles,   m.p.   77°,   from    i-chloro-2-naphthalene-diazonium    sulphate 
on    standing   in    aqueous   solution  ;    cp.  quinone    diazide    (C.    1903, 

1.  401). 

l-Amido-/2-naphthol,  from  the  reduction  of  i-nitro-  or  nitroso-j3- 
naphthol,  or  by  the  decomposition  of  jS-naphthol  orange,  can  be  oxi- 
dised to  jS-naphtho-quinone.  1,  3-Amido-naphthol  decomposes  at 
185°  (B.  28,  1952).  1,  3-Amido-naphthol  decomposes  at  185°  (B.  28, 
1952).  2,  3-Amido-naphthol,  melting  at  234°,  is  produced  by  the 
action  of  concentrated  ammonia  at  I35°-I40°  (B.  27,  763)  upon 

2,  3-dioxy-naphthalene. 

1,  6-Amido-naphthol,  m.p.  186°,  obtained  from  jS-naphthol,  2,  6- 
and  2,  8-naphthol-sulphonic  acids.  1,  5-Amido-naphthol,  from  a- 
naphthol  and  i,  5-naphthol-sulphonic  acid  on  fusion  with  Na  amide. 
1,  8-(peri-)-Amido-naphthol,  m.p.  96°,  from  i,  8-naphthylamine-sul- 
phonic  acid  by  fusion  with  potash  (B.  39,  3331  ;  42,  4748).  1,  7-Amido- 
naphthol,  m.p.  165°,  see  B.  42,  350. 


668  ORGANIC   CHEMISTRY 

Azo-naphthols.  —  The  naphthols  can  be  readily  combined  with  all 
diazo-compounds  to  azo-derivatives.  The  a-naphthols  add  the  diazo- 
group  as  easily  to  the  para-(4-)  as  to  the  ortho-(2-)  position.  However, 
the  p-position  is  preferred,  and  it  is  only  when  this  is  occupied  that  the 
o-position  is  assumed  (B.  29,  2945  ;  30,  50  ;  31,  2156).  The  final 
products  are  o,  p-dis-azo-compounds.  With  the  j8-naphthols  the 
diazo-group  attaches  itself  only  to  the  a-position  referred  to  the 
OH  group. 

From  a-naphthol  we  obtain  in  the  first  instance  1,  4-Naphthol-azo- 
benzol  (OH)[i]C10H6[4]N  :  NC6H5  and  l-naphthol-2,  4-dis-azo-benzol 
(OH)[i]C10H5[2,  4](N  :NC6H5)2;  from  j8-naphthol,  2-naphthol-l-azo- 
benzol  (OH)[2]C10H6[i]N  :  NC6H5. 

These  same  compounds  are  also  obtained  by  the  action  of  phenyl- 
hydrazin  upon  the  naphtho-quinones.  a-Naphtho-quinone-phenyl- 
hydrazone  is  identical  with  i-naphthol-4-azo-benzene.  jS-Naphtho- 
quinone  and  phenyl-hydrazin  form  a  compound  which  probably  is 
l-naphthol-2-azo-benzene,  melting  at  128°,  which  cannot  be  directly 
made  from  a-naphthol,  because  it  is  converted  by  diazo-benzene 
chloride  into  i-naphthol-2,  4-dis-azo-benzene. 

In  spite  of  this  formation,  the  azo-naphthols,  like  the  azo-phenols, 
must  be  regarded  as  true  oxy-azo-compounds.  In  i-naphthol-2-azo- 
benzol,  the  tendency  towards  the  azo-structure  is  so  strong  that  the 
acyl-phenyl-hydrazones  immediately  transpose  into  the  iso'meric 
O-acyl-compounds,  which  are  also  obtained  direct  by  acylation  of 
the  l-naphthol-2-azo-benzol  (A.  359,  353): 


TT 

H 


l°« 


/O 


N.N(Ac)C6H 


The  naphthol-azo-dyes  are  of  great  importance  in  the  colour  in- 
dustry. They  are  prepared  almost  exclusively  in  the  form  of  their 
sulpho-acids,  which  are  formed  (i)  by  the  union  of  the  naphthols  with 
diazo-sulphonic  acids  —  e.g.  a-naphthol  orange  OH[i]C10H6[4].N2.C6H4. 
S03H,  jS-naphthol  orange  OH[2]C10H6[i]N2C6H4SO3H,  roeellin  OH[2] 
C10H6[i]N2.C10H6.SO3H,  Bieberich  scarlet  OH[2]C10H6[i]N2.C6H3 
(SO3H)N2.C6H4SO3H,  forms  a-  and  j3-naphthols  with  diazo-benzene- 
sulphonic  acid,  diazo-naphthalene-sulphonic  acid,  and  sulpho-benzene- 
azo-benzene-sulphonic  acid  ;  (2)  by  the  combination  of  diazo-salts 
with  naphthol-sulphonic  acids.  Cp.  B.  29,  2945,  for  the  dye- 
stuffs  obtained  from  naphthacetol  and  diazo-compounds. 

Amido-naphthols,  together  with  amines,  are  obtained  by  the  reduc- 
tion of  azo-naphthols.  The  benzene-azo-p-naphthol  ethers,  when 
reduced  with  SnCl2,  yield  2-anilido-i,  4-amido-naphthol  ethers  Ci0H5 
(OR)(NH2)(NHC6H5)  ;  the  aniline  residue  enters  consequently  into 
the  nucleus  (B.  25,  1013)  ;  cp.  semidin  rearrangement  (p.  146). 

(d)  Naphthol-sulphonic  acids  have  been  made  in  great  numbers  and 
introduced  into  trade.  In  method  of  preparation  and  chemical 
behaviour  they  exhibit  nothing  new,  when  compared  with  the  phenol- 
sulphonic  acids.  In  the  following  paragraph,  therefore,  a  table  alone 
of  the  representatives  of  these  groups  which  possess  a  technical 
value  will  be  introduced  :  * 

*  Cp.  Nietzki,  Organische  Farbstoffe. 


NAPHTHALENE  GROUP 


669 


a-Naphthol-mono-sulphonic  acids  : 

C10H6OH.SO3H 

i       2      Schaeffer's    a-acid,    A. 

152,  293- 

i       3      B.  26,  R.  31. 
i       4      Neville   and   Winther's 

acid,  B.24,3157;  27, 
3458  ;  A.  273,  102. 

i       5      L-acid,  A.  247,  343. 

i       7      B.  22,  993- 

i  8  Schollkopf's  acid,  A. 
247,  306  ;  B.  23, 3088. 


a-Naphthol-disulphonic  acids  : 

C10H5OH.S03H.S03H 

124  Disulphonic  acid 
for  Martius' 
yellow. 


I 

2 

7 

B."25,  1400. 

I 

3 

8 

e  -Disulphonic 

acid,      B.    22, 

3227. 

I 

4 

6 

DR.P.  41,957- 

I 

4 

7 

B.    24,    R.    709; 

29,38. 

I 

4 

3 

Disulphonic  acid, 

S,  B.  23,  3090. 

a-Naphthol-trisulphonic  acids  : 
C10H4OH.S03H.S03H.S03H 


Sulphonic 
acid    for 
naphthol 
yellow 
p.  (401). 

Sulphonic 
acid  for 
Chromo- 
trope,  B. 
24.  R. 
485. 


fi-Naphthol-mono-sulphonic  acids  : 

C10H6.OH.SO3H 

2         6     Schaeffer's    /?-acid,    A. 

152,  296. 
2         8     Crocein    acid,    B.    22, 

453  ;  24,  R.  654. 
2         5     y-Mono-sulphonic  acid, 

B.  22,  R.  336. 
2         7     F-    or    5-acid,    B.    20, 

1426;  22,  724- 


fi-Naphthol-disulphonic  acids : 

3OH.S03H.S03H 

236  R-acid,     B.     22, 

396. 

237  8-Disulphonic 

acid,     B.     20, 

2906. 
248     Disulphonic  acid, 

C,    B.    26,    R. 

259- 
268    G-acid,  B.  24,  R. 

707. 


ft-Naphthol-trisulphonic  acids : 

C10H4OH.SO3H.SO3H.SO3H 

2         3         6         8      B.  16,  462. 


(Consult  B.  27,  1207,  1209,  for  other 
,5-naphthol-trisulphonic  acids.) 


It  is  the  acid  of  Neville  and  Winther — of  all  these  acids — which 
is  principally  used  in  the  making  of  azo-dyes.  It  corresponds  to 
naphthionic  acid.  It  is  obtained  in  its  present  state  by  the  action  of 
concentrated  sulphuric  acid  upon  a-naphthyl  carbonate.  The  R-acid 
and  G-acid  also  meet  with  application.  They  unite  with  benzene  and 
naphthalene  diazo-salts  to  form  a  series  of  Ponceau-  and  Bordeaux- 
dyes  of  the  most  varying  hues.  The  most  important  sulphonic  acids 
of  jS-naphthol  are  produced  together  or  one  after  the  other  in  the 
sulphonation  of  jS-naphthol  in  the  manner  represented  in  the  following 
diagram  : 

Schaeffer's  jS-acid  R-acid 


2]-0-Naphthol { 


2,3,6,8 


Croceiin  acid 


G-acid. 


The  naphthol-sulphonic  acids  containing  an  OH  and  SO3H 
group  in  the  i,  8-  or  peri-position  give  rise  to  anhydrides  having  a 
lactone  nature  ;  these  are  the  sultones  (cp.  sultames). 


670  ORGANIC  CHEMISTRY 

Naphtho-sultone  C10H  J       |     ,  melting  at  154°  and  boiling  above  360°, 

I  [8]SO, 

is  formed  by  decomposing  the  diazo-derivative  of  peri-naphthylamine- 
sulphonic  acid.  The  sultone  dissolves  in  hot  alkalies,  forming  salts  of 
peri-naphthol-sulphonic  acid.  Sultones  have  also  been  obtained  from 
i,  3,  8-  and  i,  4,  8-naphthol-di-  and  i,  3,  6,  8-trisulphonic  acids. 

Amido-naphthol-sulphonic  Acids  are  produced  in  the  decomposition, 
by  reduction,  of  the  azo-derivatives  of  naphthol-sulphonic  acids,  and 
from  nitroso-naphthols  by  reduction  and  sulphonation,  both  of  which 
processes  can  be  worked  in  common  if  the  nitroso-naphthols  be  treated 
with  sulphurous  acid  (B.  27,  23,  3050).  In  this  way  i,  2-nitroso- 
naphthol  yields  1,  2, 4-amido-naphthol-sulphonie  acid  C10H5[i]NH2[2] 
OH[4]S03H.  The  isomeric  2,  i,  4-acid  Ci0H5[i]OH[2]NH2[4]SO3H 
produces,  even  when  oxidised  in  the  air,  imido-oxy-naphthalene-sul- 

phonic  acid  SO3H.C10H5/  |     .     This  dye  is  black-violet  in  colour,  and 

is  fast  to  light  and  alkalies  (B.  25,  1400  ;  26,  1279).  The  2,  i,  6-acid 
C10H5[i]OH[2]NH2[6]SO3H  is  used  as  a  photographic  developer  under 
the  name  of  eikonogen.  Important  dyes,  from  the  technical  point  of 
view,  are  2-amido-8-naphthol-6-sulphonic  acids  G  (B.  25,  R.  830  ;  29, 
2267)  and  i-amido-8-naphthol-3, 6-disulphonic  acid  H  (B.  26,  R. 
460,  917).  Also  2-amido-5-naphthol-7-sulphonic  acid  (C.  1907,  II. 
1467),  and  some  i,  8-amido-naphthol-sulphonic  acids  for  black  wool 
dyes ;  2-amido-5-naphthol-i-sulphonic  acid  (C.  1911,  I.  1263). 
Farther  amido-naphthol-sulphonic  acids,  see  /.  pr.  Ch.  2,  80,  201. 

Dioxy-naphthalenes. — Nine  of  the  ten  possible  isomerides  are  known. 
The  hydro-naphtho-quinones  resulting  from  the  reduction  of  the 
naphtho-quinones  are  worthy  of  mention  : 

jS-Hydro-naphtho-quinone  C10H6[i,  2](OH)2,  melting  at  60°, 
separates  when  a  solution  of  j3-naphtho-quinone  is  boiled  with  sul- 
phurous acid.  It  is  strongly  corrosive.  It  dissolves  in  the  alkalies 
with  a  yellow  colour,  which  becomes  an  intense  green  upon  exposure. 

a-Hydro-naphtho-quinone  C10H6[i,  4](OH)2,  melting  at  173°,  is 
obtained  from  a-naphtho-quinone  on  boiling  with  hydriodic  acid  and 
phosphorus,  or  with  zinc  and  hydrochloric  acid.  Chromic  acid  readily 
oxidises  it  to  a-naphtho-quinone. 

2, 6-Dioxy-naphthalene,  m.p.  218°,  from  Schaeffer's  ^-naphthol- 
sulphonic  acid  by  fusion  with  potash,  passes  into  the  2,  6-  or  amphi- 
naphtho-quinone  on  oxidation  with  PbO2.  From  this  it  is  recovered  by 
reduction  with  dilute  HI  (B.  40,  1410). 

2, 3-Dioxy-naphthalene  melts  at  216°  (B.  27,  762).  Its  mono- 
methyl  ether,  m.p.  108°,  acts  physiologically  like  guaiacol  (B.  27,  762  ; 
C.  1902,  II.  554,  744).  Also  cp.  A.  247,  356  ;  B.  23,  519,  etc. 

1, 3-Dioxy-naphthalene,  naphtho-resorcinol,  melting  at  124°,  is 
obtained  from  i,  3,  4-amido-naphthol-sulphonic  acid.  It  yields  o-toluic 
acid  when  fused  with  caustic  potash  (see  B.  29,  1611). 

2-Phenyl-i,  ^-dioxy-naphthalene,  melting  at  166°,  is  made  by  the 
action  of  concentrated  sulphuric  acid  upon  a,  y-diphenyl-aceto-acetic 
ester  (p.  653).  It  absorbs  oxygen  and  changes  readily  to  phenyl- 
hydroxy-a-naphtho-quinone.  I,  7 '-Dioxy '-naphthalene  melts  at  175°  ; 
see  B.  29,  40  ;  2,  j-dioxy-naphthalene,  see  B.  30,  1119. 


NAPHTHALENE  GROUP  671 

1,  8-(Peri-)  dioxy-naphthalene,  m.p.  140°,  from  naphtho-sultone  by 
fusion  with  potash  (A.  247,  356).  The  i,  8-dioxy-naphthalene-3,  6- 
disulphonic  acid  ("  chromo-tropic  acid  ")  is  obtained  by  fusing  the 
naphthol-trisulphonic  acid  \vith  potash.  It  is  a  component  of  valuable 
o-oxy-azo-dyes  (B.  31,  2156). 

Trioxy-naphthalenes. — Two  trioxy-naphthalenes,  a-  and  j8-hydro- 
juglones,  occur  in  green  walnut  shells  oijuglans  regia  (B.  18,  463,  2567). 
a-Hydro-juglone  C10H5[i,  4,  5](OH)3,  melting  at  169°,  is  produced  by 
the  reduction  of  juglone.  In  the  air  it  rapidly  oxidises  to  juglone.  If 
it  be  distilled  it  changes  to  j3-hydro- juglone,  melting  at  97°,  which 
does  not  yield  juglone  upon  oxidation.  It  reverts  again  to  a-hydro- 
juglone  when  boiled  with  dilute  alcoholic  hydrochloric  acid. 

1,  2,  4-Trioxy-naphthalene,  m.p.  154°,  is  obtained  as  a  triacetate, 
m.p.  134°,  by  the  action  of  acetic-anhydride-sulphuric  acid  upon 
a-  and  £-naphtho-quinone  (A.  311,  345).  1,  3,  6-Trioxy-naphthalene, 
m.p.  95°,  see  B.  38,  3945. 

1,  2,  5,  6-Tetraoxy-naphthalene,  m.p.  154°,  by  reduction  of  naphtha- 
zarin  (see  below)  (B.  28,  R.  543).  Reduction  of  iso-naphthazarin  gives 
1,  2,  3,  4-tetraoxy-naphthalene,  and  on  further  reduction  a  1,  2,  3- 
trioxy-naphthalene,  naphtho-pyrogallol  (A.  307,  16). 

Thio-naphthols  have  been  prepared  by  the  reduction  of  the  chlor- 
ides of  naphthalene  -  sulphonic  acids  or  from  diazo- naphthalenes. 
Thio  -  naphthol,  naphthyl  -  mercaptan  C10H7.SH  ;  the  a -form  is  liquid 
and  boils  at  286°.  The  jS-variety  melts  at  81°  and  boils  at  286° 
(B.  22,  821 ;  23,  R.  327).  Phenyl-jS-naphthyl  sulphide,  melting  at  51° 
(B.  24,  2266),  is  formed  when  the  lead  salt  (C10H7-j8-S) 2Pb  is  heated, 
together  with  bromo-benzene.  Different  dinaphthyl  sulphides  have 
been  prepared  by  heating  the  naphthyl  -  lead  mercaptides.  Other 
methods  have  been  employed  in  making  them  (B.  26,  2816).  Sulphur 
chloride  and  ^-naphthol  yield  dioxy-dinaphthyl  sulphide  S(C10H6.OH)2, 
melting  at  211°.  This  can  be  readily  oxidised  to  a  ^/ry^ro-compound 

C10H60 

I   (B.  27,  2993  ;  28,  114)  (cp.  quinones  with  two  nuclei). 

C10H6O 

Naphthalene  disulphydrates  C10H6(SH)a ;  see  B.  25,  2735. 

10.  Quinones. — On  the  basis  of  the  diketone  formula  for  the 
quinones,  six  different  naphtho-quinones  are  theoretically  conceivable, 
comprising  three  single-nucleus  quinones,  corresponding  to  the  benzo- 
quinones,  and  three  double-nucleus  quinones  : 

\\     f     1IS     if     4°     if 

b  6 

a-Naphtho-         /3-Naphtho-        2,  3-Naphtho-        i,  5-Naphtho-       Amphi-naphtbo-       i,  7-Naphtho- 
quinone  quinone  quinone  quinone  quinone  quinone. 

Out  of  these,  only  the  i,  4~(a)-,  the  i,  2-(/?)-  and  the  2,  6-(amphi-) 
naphtho-quinone,  and  a  derivative  of  the  2,  3-naphtho-quinone,  have 
hitherto  been  prepared. 

a-Naphtho-quinone  O=[i]C10H6[4]=:O,  melting  at  125°,  crystallises 
from  alcohol  in  yellow  plates,  subliming  under  100°.  It  possesses  the 
usual  quinone  odour,  and  is  very  volatile  in  a  current  of  steam.  It  is 


672  ORGANIC  CHEMISTRY 

formed  (i)  by  oxidising  naphthalene  in  glacial  acetic  acid  solution  with 
chromic  acid  ;  (2)  in  the  oxidation  of  I,  4-diamido-  or  I,  4-dioxy- 
naphthalene,  I,  4-amido-naphthol  (A.  286,  70),  a-naphthylamine,  etc., 
with  sodium  bichromate  and  sulphuric  acid  (B.  20,  2283)  ;  and  (3)  when 
benzene-azo-naphthol  is  treated  in  the  cold  with  PbO2  and  sulphuric 
acid  it  is  decomposed  into  diazo-benzene  sulphate  and  a-naphtho- 
quinone  (B.  24,  R.  733). 

Nitric  acid  oxidises,  a-naphtho-quinone  to  phthalic  acid,  while 
a-hydro-naphtho-quinone  is  produced  in  its  reduction.  See  the 
nitrogen-quinone  derivatives  for  its  phenyl-hydrazin  and  hydroxyl- 
amine  derivatives. 

Substituted  a-Naphtho-quinones.  —  a-Naphtho-quinone  takes  up  two 
atoms  of  chlorine  or  bromine  ;  the  addition  products  readily  part  with 
hydrochloric  and  hydrobromic  acids  and  become  j8-chloro-  and  j8-bromo- 
a-naphtho-quinones,  melting  at  117°  and  130°.  2,  3-Diehloro-  and 
2,  3-dibromo-naphtho-quinone,  m.p.  189°  and  218°. 

In  these  halogen  quinones,  as  in  the  ajS-dihalogen  indones,  the 
halogen  atoms  are  easily  replaced  by  other  groups.  Thus,  from  the 
dihalogen-a-naphtho-quinones  we  obtain  with  sodium-aceto-acetic 
ester  and  sodium-malonic  ester,  with  intermediate  beautiful  red  and 
blue  colorations,  such  compounds  as 

CGH4\  /*    ]         -\  /*  TT  \  '  m-P-  I02°.  bromo-a-naphtho-quinone-malonic  ester. 

\CO  —  C.CH(CO2C2H5)2 

'  m-p-  ^ 


H5'  m'P'   '°7°'  cMoro-a-naphtho-qulnone-aceto- 
acetic  ester. 

From  these  compounds  many  derivatives  of  the  naphtho-quinone 
series  can  be  obtained  by  further  transformations  (B.  33,  566,  2402  ; 
34,  1543).  Condensation  of  2,  3-dichloro-a-naphtho-quinone  with 
resorcin  or  orcin  and  sodium  ethylate  produces  derivatives  of  phenylene- 
naphthylene  oxide  C6H4<^'£  ^C^OH,  which  are  closely  related 
to  some  decomposition  products  of  brasilin,  the  so-called  brasanes 
(B.  32,  924  ;  41,  2373). 

Hypochlorous  acid  converts   a-naphtho-quinone  into  diketo-tetra- 

CO—CH, 
hydro-naphthylene  oxide  C6H/          |      >o,  which,  by  the  breaking  down 

OvJ  -  0x1 

of  the  ethylene-oxide  union,  readily  takes  up  the  elements  of  water, 
hydrogen  chloride,  and  NH2C6H5.  The  primary  addition  products 
sustain  the  most  varied  transpositions  with  great  readiness,  and  form  : 
oxy-naphtho-quinone,  chloroxy-naphtho-quinone,  anilido-oxy-naphtho- 
quinone,  oxy-naphtho-quinone-anile,  and  other  bodies  ;  cp.  B.  25,  3599. 
Amido-derivatives.  —  Alkyl-  or  alphyl-amido-naphtho-quinones  are 
produced  on  heating  primary  amines  together  with  a-naphtho-quinone  : 
2-anffldo-a-naphtho-quinone  C10H5O2[2]NH.C6H5  consists  of  red 
needles,  melting  at  191°.  2-Amido-a-naphtho-quinone,  melting  at  203°, 
is  formed  together  with  the  isomeric  oxy-a-naphtho-quinone-imide  on 
boiling  amido-a-naphtho-quinone-imide  with  water  (B.  27,  3337  ; 
B.  28,  348). 


NAPHTHALENE  GROUP  673 

Oxy-naphtho-quinones. — 2-Oxy-a-naphtho-quinone,  naphthalic  acid 
C10H5O2[2]OH,  melting  at  188°,  is  produced  when  anilido-naphtho- 
quinone  (see  above)  is  boiled  with  dilute  sodium  hydroxide  or  oxy- 
naphtho-quinone-anile  with  alcohol  and  sulphuric  acid.  j8-Phenyl- 
/^-oxy-a-naphtlio-quinone,  melting  at  147°,  is  prepared  from  jS-phenyl- 
i,  3-dioxy-naphthalene  by  oxidising  it  in  alkaline  solution  with  air 
(A.  296, 18) .  lodo-oxy-naphtho-quinone,  iodo-naphthalic  acid  C10H4O2[2] 
OH [3] I,  results  from  the  iodation  of  naphthalic  acid  (B.  28,  348).  Dyes 
of  the  paroxazine  and  paradiazine  series  are  easily  made  from  the 
o-oxy-  and  o-amido-naphtho-quinone  derivatives  (cp.  also  the  cor- 
responding naphtho-quinone-aniles  and  o-diamines)  (B.  28,  353). 

5-Oxy-a-naphtho-quinone,  juglone,  consists  of  yellow  needles,  melt- 
ing with  decomposition  about  I5o°-i55°.  The  best  method  to  obtain 
it  consists  in  oxidising  a-hydro- juglone  with  ferric  chloride.  It  may 
be  synthetically  prepared  by  oxidising  (i,  5)-dioxy-naphthalene  with 
chromic  acid  (B.  20,  934).  It  dissolves  in  alkalies  with  a  violet  colour. 
Nitric  acid  converts  it  into  dinitro-oxy-phthalic  acid  (juglonic  acid) 
(B.  19,  164). 

Oxy-juglone,  dioxy-a-naphtho-quinone,  melting  with  decomposition 
at  220°,  is  produced  by  the  oxidation  of  the  alkaline  solution  of  juglone 
on  exposure  to  the  air.  An  isomeric  5,  6-dioxy-a-naphtho-quinone, 
naphthalizarin  or  naphthazarin,  is  formed  on  heating  various  a-dinitro- 
naphthalenes  with  concentrated  sulphuric  acid  in  the  presence  of 
reducing  agents  (B.  27,  3462,  R.  959  ;  A.  286,  26).  It  corresponds  to 
alizarine,  which  may  be  imagined  to  have  arisen  from  naphthazarin 
by  the  addition  of  a  benzene  nucleus.  It  is  a  valuable  mordant  dye. 

Oxidation  with  MnO2  and  sulphuric  acid  yields  the  naphthazarin 
called  naphtho-purpurin,  5,  7, 8-trioxy-a-naphtho-quinone  (C.  1899, 

ii.  1053). 

1 so-naphthazarin  is  probably  a  2,  3-dioxy-a-naphtho-quinone.  It 
is  produced  from  j8-naphtho-quinone  by  the  action  of  a  little  bleaching- 
lime  as  well  as  when  2,  3-oxy-anilido-a-naphtho-quinone  (see  above)  is 
heated  with  bromine  (B.  25,  409,  3606). 

Iso-naphthazarin,  on  reduction,  gives  tetra-  and  trioxy-naphthalene, 
and,  on  oxidation,  tetra-keto-naphthalene  C6H4(CO)4,  which  partly 
regenerates  iso-naphthazarin,  and  phenyl-glyoxal-o-carboxylic  acid, 
with  hydroxylamine  or  dioxime,  m.p.  228°,  which,  on  oxidation,  yields 
dinitroso-a-naphtho-quinone  C6H4[C4O2(NO)2](A.  307,  i).  Closely 
related  to  iso-naphthazarin  is  carminazarin,  from  oxidation  of  carminic 
acid.  On  6,  7-Dioxy-a-naphtho-quinone,  see  C.  1902,  IL  744. 

/2-Naphtho-quinone  C10H6[i,  2]O2  is  produced  on  oxidising  /?-amido- 
a-naphthol  with  ferric  chloride  (B.  17,  R.  531  ;  21,  3472).  It  consists 
of  red  needles,  which  decompose  at  Ii5°-I20°.  It  is  distinguished 
from  the  para-quinones  by  being  odourless  and  non-volatile.  It  closely 
resembles  anthraquinone,  and  especially  phenanthraquinone  ;  like  the 

/CH  •  CH 

latter,  it  must  be  considered  an  ortho-diketone  C6HX  ~T  '    ™ 

\OO  .  OU- 

Like  a-naphtho-quinone,  it  can  add  two  atoms  of  chlorine  and 
bromine,  and  by  the  elimination  of  halogen  hydrides  ehloro-  and  bromo- 
j8-naphtho-quinones  are  formed. 

3, 4-Dichloro-  and  dibromo-/S-naphtho-quinone,  m.p.  91°  and  173° ; 
jS-naphtho-quinone-malonie  ester  C6H4[C4O2H.CH(COOR)2],  m.p.  108°. 

VOL.  II.  2  X 


674  ORGANIC  CHEMISTRY 

3-Chloro-j8-naphtho-quinone-aceto-acetie  ester,  m.p.  175°,  see  B.  32, 
264,  2412. 

A  little  bleaching-lime  converts  j8-naphtho-quinone  into  iso- 
naphthazarin  (together  with  various  other  products,  A.  286,  59).  This 
is  a  dioxy-a-naphtho-quinone.  Such  a  rearrangement  of  4~oxy-  or 
4-amido-j8-naphtho-quinone  derivatives  into  oxy-a-naphtho-quinone 
compounds  is  a  phenomenon  that  has  been  frequently  observed  (cp. 
oxy-a-naphtho-quinone-anile).  An  excess  of  bleaching-lime  will 
produce  a  rupture  in  the  ring  of  /2-naphtho-quinone  and  convert  it 
into  the  lactone  of  o-phenyl-glycerol-carboxylic  acid. 

Similarly,  3-nitro-l,  2-naphtho-quinone,  melting  at  158°,  and 
obtained  by  the  nitration  of  j3-naphtho-quinone,  is  changed,  on  treating 
it  with  chlorine  and  water,  into  o-di-derivatives  of  benzene. 

3,  4-Diehloro-l,  2-naphtho-quinone,  on  the  contrary,  is  first 
rearranged  by  alkalies  into  dichlor  -  indene  -  oxy  -  carboxylic  acid. 
Potassium  permanganate  oxidises  jS  -  naphtho  -  quinone  to  phthalic 
acid,  while  sulphurous  acid  reduces  it  to  j8-naphtho-hydroquinone, 
and  hydriodic  acid  to  jS-naphthol  (B.  26,  R.  586). 

6-Bromo-4-ehloro-l-methyl-2,  3-naphtho-quinone  C10H3[6]Br[4]Cl 
[i]CH3[2,  3]O2,  yellow  prisms,  decomposing  at  220°,  has  been  obtained 
from  the  lead  salt  of  the  corresponding  2,  3-dioxy-naphthalene  by  the 
action  of  iodine.  It  is  odourless  and  non-volatile.  Zinc  dust  and 
glacial  acetic  acid  partly  reduce  it  to  the  corresponding  dioxy-naphthal- 
ene.  With  o-phenylene-diamine  it  combines  like  the  ortho-diketones 
to  form  a  derivative  of  naphtho-phenazene  (B.  42,  3375). 

2,  6  -  (amphi-)  Naphtho  -  quinone  C10H6[2,  6]O2,  reddish  -  yellow 
crystals,  decomposed  at  I3O°-I35°,  is  formed  by  the  oxidation  of 
2,  6-dioxy-naphthalene  with  PbO2  in  benzene  solution.  It  is  odourless 
and  non-  volatile,  and  distinguished  by  its  strong  oxidising  action. 
Dilute  HI  reduces  it  to  2,  6-dioxy-naphthalene,  with  which  it  unites 
molecularly  to  a  blue  green  quin-hy  'drone,  decomposing  at  124°.  More 
stable  than  amphi-naphtho-quinone  itself  is  its  dichloro-substitution 
product,  1,  5-dichloro-amphi-naphtho-quinone,  m.p.  206°,  obtained 
similarly  from  i,  5-dichloro-2,  6-dioxy-naphthalene  (B.  40,  1406,  3971). 

Nitrogen  Derivatives  of  the  Naphtho-quinones. 

i  .  Naphtho  -  quinone  -  phenyl  -  hydrazones.  —  Unlike  the  benzene 
quinone,  both  the  a-  and  /?-naphtho-quinones  unite  with  phenyl- 
hydrazin  and  form  phenyl-hydrazones  (B.  28,  2414).  The  quinone- 
phenyl-hydrazones  are  identical  with  the  benzol-azo-naphthols  (B.  32, 
3100).  The  results  of  the  action  of  unsym.  acyl-phenyl-hydrazins 
upon  /3-naphtho-quinone  must  probably  be  regarded  as  O-acylated  azo- 
naphthols  (B.  40,  2153  ;  A.  359,  353).  On  the  other  hand,  a-naphtho- 
quinone  with  unsym.  benzoyl-  and  methyl-phenyl-hydrazin  have 
yielded  products  C10H6<£N(COC«H°>C«H°  and  ^^^(CH.)^ 
differing  from  those  obtained  by  methylating  and  benzoylating  i,  4- 


naphthol-azo-benzol     C10H6  .  and  C10H6  «*  (C.  1900, 


I.  3i). 

2.   A'  itroso-naphthols  or  Naphtho-quinoximes.  —  These  are  produced 
when  the  alcoholic  solutions  of  the  a-  and  jS-naphtho-quinones  are 


NAPHTHALENE   GROUP  675 

boiled  with  hydroxylamine  hydrochloride,  and  by  the  action  of  nitrous 
acid  upon  the  naphthols ;  hence  they  can  be  regarded  as  nitroso- 
naphthols  C10H6(O)(NOH)  or  C10H6(OH)(NO)  (cp.  nitroso-phenols, 
p.  198).  Three  isomeric  bodies  are  formed  ;  their  relation  is  expressed 
by  the  following  diagram  : 


N,O,_ 

OH  NOH 


roH 

a-Naphtho-       a-Naphthoquinone- 
quinone  oxime 

a-Nitroso-  a-naphthol 

O  O 


It0- 


NOH 


•It 


a-Naphthol  0-Naphthol  a-Nitroso- 

/?-naphthol 
0-Naphtho- 
N'°«  quinpne- 

/?-Naphtho-    /?-Naphthoquinone- 
quinone  )5-oxime 

/S-Nitroso-a-naphthol 

The  three  isomerides  are  weak  acids.  Oxidation  converts  them  into 
the  corresponding  nitro-naphthols. 

a-Nitroso-a-naphthol,  a-naphtho-quinone-oxime,  melting  at  190°, 
and  jS-nitroso-a-naphthol,  j3-naphtho-quinone-/?-oxime,  melting  at  152°, 
are  colourless  compounds.  /3-Naphtho-quinone-oxime  is  best  made 
from  i-oxy-2-naphthoic  acid  with  nitrous  acid,  when  the  carboxyl 
group  is  split  off  (B.  26,  1280).  a-Nitroso- j8-naphthol,  f$-naphtho- 
quinone-a-oxime,  consisting  of  yellow-brown  prisms,  melting  at  106°, 
precipitates  different  metals  from  their  salts,  and  may  be  used  to 
separate  nickel  from  cobalt,  iron  from  aluminium,  and  for  the  deter- 
mination of  copper  (B.  18, 2728  ;  20, 283) .  Naphthol  green  (B.  24, 3741) , 
a  wool  dye,  is  the  iron  salt  of  a-nitroso-/3-naphtnol-sulphonic  acid 
C10H5(SO3H)O(NOH),  obtained  by  the  action  of  nitrous  acid  upon 
Schaeffer's  j8-naphthol-sulphonic  acid.  Consult  B.  30,  187,  for  the 
product  obtained  in  the  action  of  NO2  vapours  upon  Schaeffer's  /?-acid. 

The  ethers  of  the  nitroso-naphthols,  derived  from  the  silver  salts 
with  methyl  iodide  and  partly  from  the  quinones  with  alkyl-hydroxyl- 
amines,  are  reduced  to  amido-naphthols  by  tin  chloride  (B.  18,  715, 
2225),  a  proof  of  the  "  oxime  formula  "  of  the  nitroso-naphthols. 

a-Naphtho -quinone-dioxime  c10H6-i,  4-\^Qu     *s  formed  from  a- 

nitroso-a-naphthol  with  hydroxylamine  hydrochloride.  It  melts  at 
207°  (B.  21,  433). 

)3-Naphtho- quinone-dioxime    c10H6-i,  2-^^        is    derived    from 

j3-nitroso-a-naphthol  and  from  a-nitroso-/2-naphthol  by  the  action  of 
hydroxylamine  hydrochloride  (B.  17,  2064,  2582).  It  melts  at  149°. 

After  the  manner  of  the  glyoximes  it  forms  the  anhydride  C10H6/pj;y>o, 

melting  at  78°,  when  digested  with  alkalies.  This  compound  may  also 
be  designated  naphtho-furazane.  The  reduction  of  the  dioximes  gives 
rise  to  naphthylene-diamine. 

3.   N aphtho-quinone   Chlorimides. — These  are  made  from  amido- 


676  ORGANIC   CHEMISTRY 

naphthols,  and  the  dichlorimides  from  the  naphthylene  diamines  with 
a  bleaching-lime  solution  (B.  27,  238).  They  resemble  the  benzo- 
quinone  chlorimides,  but  do  not  exhibit  the  same  dyestuff  condensa- 
tions as  the  former  (B.  27,  242). 

a-Naphtho-quinone-chlorimide  C10H6[i,  4](NC1)O  melts  at  109°. 

a-Naphtho-quinone-diehlorimide,  C10H6[i,  4] (NCI) 2  melts  at  137°. 

/3-Naphtho-quinone-a-ehlorimide,  melting  at  87°,  and  jS-naphtho- 
quinone-/3-ehlorimide,  decomposing  at  98°,  are  derived  from  2,  i-  and 

1,  2-amido-naphthols  ;     they    yield   ft,  a-   and   a,  j8-nitroso-naphthols 
with  hydroxylamine.     j8-Naphtho-quinone-dichlorimide  melts  at  105°. 

4.  Naphtho-quinone-imines  and  Aniles. — The  indo-phenol  and  indo- 
aniline  dyes  of  the  naphthalene  series  belong  to  this  group — e.g. 
a-naphthol  blue  or  indo-phenol  C10H6[i]O[4]N.C6H4N(CH3)2— which 
results  when  naphthol  interacts  with  dimethyl-p-phenylene-diamine  or 
nitroso-dimethyl-aniline.  The  simple  a-naphtho-quinone-imide  is  not 
known.  2-Amido-l,  4-naphtho-quinone-imine,  di-imido-naphthol  C10H5 
[2]NH2[i]O[4]NH  (A.  154,  303)  is  produced  in  the  oxidation  of  i-oxy- 

2,  4-diamido-naphthalene.     Boiling  water  changes  di-imido-naphthol 
to  2-oxy-l,  4-naphtho-quinone-imine,  melting  at  195°  (B.  23,  2454)  ; 
aniline  to  2-amido-l,  4-naphtho-quinone-anile  C10H5[2]NHC6H5[i]O[4] 
NCgHg,  melting  at  187°  (B.  13,  123  ;    21,  391,  676) ;   and  further  to 
2-anilido-l,  4-naphtho-quinone-anile  (C.  1910,  I.  926)  ;  with  hydroxyl- 
amine an  oxy-naphtho-quinone-oxime,  which  consists  of  two  modifica- 
tions, red  and  yellow,  which  can  be  changed  one  into  the  other  (B. 
29,  1415). 

a-Naphtho-quinone-anile  C10H6[i]O[4]NC6H5,  red  columns,  m.p. 
100°,  and  j8-naphtho-quinone-anile  C10H6[i]O[2]NC6H5,  m.p.  103°, 
dark-green  needles,  are  formed  by  alkaline  condensation  of  nitroso- 
benzol  with  a-  and  j8-naphthol  respectively  (B.  39,  1035). 

2-Oxy-l,  4-naphtho-quinone-anile,  melting  at  240°  with  decom- 
position, is  produced  by  the  action  of  aniline  in  the  cold  upon  jS-naphtho- 
quinone-4-sulphonic  acid,  the  oxidation  product  of  i,  2-amido-naphthol- 
4-sulphonic  acid.  This  is  an  instance  of  the  rearrangement  of  a  ft-  into 
an  a-naphtho-qumone  derivative.  The  p-diamines  react  in  a  manner 
similar  to  aniline,  so  that  in  this  way  hydroxyl-indaniline  dyes  (see 
above)  can  be  obtained  (B.  27,  25,  3050). 

a-Naphtho-quinone-phenyl-di-imide  C10H6(NH)(NC6H5),  melting  at 
129°,  is  formed  upon  oxidising  p-amido-naphthyl-phenyl-amine  with 
mercuric  oxide  (A.  286,  186). 

^S-Naphtho-quinone-imides,  also  called  imido-oxy-  or  imido-ketone 
naphthalenes,  e.g.  C10H6-i,  2-O(NH),  are  produced  when  the  alkaline 
solutions  of  i,  2-amido-naphthols  are  oxidised  with  air. 

ii.  ALCOHOLS  OF  THE  NAPHTHALENE  SERIES  AND  THEIR 
OXIDATION  PRODUCTS. 

A.  Alcohols.—  Naphtho-benzyl  alcohols,  naphthyl-carbinols  C10H7. 
CH2.OH,  the  a-  melting  at  60°  and  boiling  at  301°,  and  the  ft-  melting 
at  80°,  result  when  their  amines  are  treated  with  nitrous  acid  (B.  21, 
257).  The  naphtho-benzyl  chlorides  C10H7CH2C1,  the  a-  boiling  at  178° 
(25  mm.)  and  the  ft-  melting  at  47°,  are  formed  when  chlorine  acts  upon 
the  two  methyl-naphthalenes  at  a  boiling  temperature  (B.  24,  3928). 


NAPHTHALENE   GROUP  677 

Naphtho-benzyl-amines  menaphthyl-amines  C10H7.CH2.NH2,  the  a- 
boiling  at  292°  and  the  jS-  melting  at  60°,  have  been  made  by  the 
reduction  of  the  corresponding  naphthoic  acid  thiamides,  as  well  as  of 
the  naphtho-nitriles. 

a-  and  jS-Naphthyl-nitro-methane  C10H7.CH2NO2,  m.p.  73°  and  72°, 
show  isomeric  phenomena  similar  to  those  of  phthalyl-nitro-methane. 
They  have  been  obtained  from  the  naphthyl-aceto-nitriles  by  the  action 
of  ethyl  nitrate  and  sodium  ethylate  and  splitting  up  of  the  resulting 
nitro-aceto-nitriles  by  boiling  with  soda  (B.  38,  508). 

a-Naphthyl-dimethyl-carbinol  C10H7[a]C(OH)(CH3)2,  m.p.  80°,  from 
a-naphthyl-methyl-ketone  with  CH3MgI,  and  from  a-naphthyl-mag- 
nesium  bromide  and  acetone.  a-Naphthyl-phenyl-carbinol  C10H7CH 
(OH)C6H5,  m.p.  86°,  and  a-naphthyl-diphenyl-carbinol  C10H7C(OH) 
(C6H5)2,  m.p.  133°,  from  a-naphthyl-magnesium  bromide,  with  benzalde- 
hyde  and  benzo-phenone  respectively  (B.  37,  625,  2755).  Other 
naphthyl-carbinols,  see  C.  1910,  I.  1144. 

B.  Aldehydes,  Ketones. — When  the  naphthyl-methyl  alcohols  are 
oxidised,  the  products  are  : 

a-Naphthaldehyde  C10H7.CHO,  boiling  at  291°,  and  /3-naphthalde- 
hyde,  melting  at  59°  (B.  20,  1115  ;  22,  2148  ;  44,  447).  a-Naphthyl- 
acetaldehyde  C10H7.CH2.CHO,  b.p.13  i63°-i66°,  from  a-vinyl-naphtha- 
lene  with  HgO  and  I  (C.  1908,  II.  1780). 

a-  and  /3-Naphthyl-methyl-acetaldehyde  C10H7CH(CH3)CHO,  b.p.4 
132°  and  m.p.  53°,  by  condensation  of  a-  and  /?-naphthyl-methyl-ketone 
with  chloro-acetic  ester  and  sodium  ethylate,  the  resulting  glycide  esters 
being  saponified  with  loss  of  CO2  (C.  1908,  I.  644).  The  a-compound 
has  also  been  obtained  by  the  action  of  HgO  and  I  upon  a-propenyl- 
naphthalene  (C.  1908,  II.  1780). 

a-Naphthyl-methyl-ketone,  aceto-naphthone  C10H7.CO.CH3  is  derived 
from  naphthalene  and  acetyl  chloride  by  means  of  aluminium  chloride. 
It  melts  at  34°  and  boils  at  about  295°.  Its  chloride  splits  off  hydrogen 
chloride  and  becomes  a-naphthyl-acetylene  C10H7.C  :  CH.  Potassium 
permanganate  oxidises  the  ketone  to  a-naphthyl-glyoxylic  acid  C10H7 
CO.COOH,  melting  at  113°,  which  is  also  formed  by  the  saponification 
of  naphthol  cyanide  obtained  from  a-naphthoyl  chloride. 

a-Naphthoyl-o-benzoie  acid  C10H7COC6H4COOH,  m.p.  173°,  from 
phthalic  anhydride,  naphthalene,  and  A1C13  (B.  33,  448).  The  action 
of  Na  amide  and  alkylene  iodide  produces  trialkyl-aceto-naphthones, 
corresponding  to  aceto-phenones  (C.  1910,  II.  83).  Other  acyl- 
naphthyl-ketones,  see  C.  1908,  II.  948.  Phenyl-naphthyl-ketones 
C10H7COC6H5.  see  C.  1908,  II.  1357. 

1,  4-  and  2, 1-Naphthol-aldehyde  C10H6(OH)CHO,  m.p.  181°  and  81°, 
are  best  obtained  by  Gattermann's  method  in  the  form  of  aldimines 
(B.  32,  284  ;  C.  1901,  I.  1010).  1,  2-naphthol-aldehyde,  m.p.  59°,  has 
been  obtained  by  the  condensation  of  a-naphthol  with  isatin  chloride 
(M.  29,  382  ;  30,  277).  From  naphthol-sulphonic  acids,  naphthol- 
aldehyde-sulphonic  acids  are  obtained  by  Reimer's  aldehyde  synthesis 
(C.  1898,  II.  799). 

l-Naphthol-3-methyl-ketone  C10H6[i](OH)[3](CO.CH3),  melting  at 
174°,  is  formed  from  j8-benzal-laevulinic  acid  by  condensation  (B.  24, 
3201).  See  B.  28,  1946,  for  1,  2-naphthol-methyl-ketone. 

Peri-dioxy-naphthyl-ketones  (HO)2[i,  8]C10H5COR,  from  peri-dioxy- 


678  ORGANIC   CHEMISTRY 

naphthalene  with  carboxylic  acids,  and  zinc  chloride,  are  lac-forming 
mordant  dyes  (C.  1901,  II.  1287). 

C.  Naphthalene-monocarboxylic  Acids. — a-Naphthoie  acid  C10H7-a- 
CO2H,  melting  at  160°,  is  derived  from  a-naphtho-nitrile  by  saponifica- 
tion  (B.  20,  242  ;  21,  R.  834)  ;  by  fusing  a-naphthalene-sulphonic  acid 
with  sodium  formate  ;  by  the  action  of  sodium  on  a  mixture  of  a- 
bromo-naphthalene  and  chloro-carbonic  ester  ;  and  from  naphthalene, 
urea  chloride,  and  aluminium  chloride  (B.  23, 1190).  j8-Naphthoie  acid, 
melting  at  182°,  is  formed  from  /?-naphtho-nitrile  (B.  24,  R.  725),  as 
well  as  by  the  oxidation  of  /S-alkyl-naphthalenes  (B.  17,  1527  ;  21, 
R.  355)-  Both  acids  are  decomposed  when  heated  with  baryta  into 
CO 2  and  naphthalene. 

Homologous  Naphthalene-carboxylic  Acids. — a-Naphthyl-acetic  acid 
C10H7-a-CH2.COOH,  melting  at  131°,  has  been  made  by  the  reduction 
of  a-naphthyl-glyoxylic  acid,  while  the  fi-acid,  melting  at  139°,  has  been 
prepared  by  means  of  the  cyanide  from  /3-naphtho-benzyl  chloride 

(B.  29,2373). 

a-  and  £-Naphthyl-aerylie  acids  C]0H7.CH  :  CHCOOH,  m.p.  205°  and 
196°  respectively,  are  found  by  Perkin's  synthesis  from  the  naphth- 
aldehydes  with  Na  acetate  and  acetic  anhydride.  With  Na  propionate, 
propionyl-naphthalene  is  mostly  obtained,  with  loss  of  C02  (C.  1897, 

fCH  :CH 
II.  800).     a-  and  /?-Naphtho-eumarin  C10H6-          I     ,  m.p.   141°  and 

1^  Cy LxV-) 

118°,  and  their  alkylated  derivatives,  have  been  obtained  by  the  general 
cumarin  methods  from  malic  acid,  aceto-acetic  ester,  etc.  with  H2S04, 
and  from  the  naphthaldehydes  by  Perkin's  synthesis  (B.  36,  1966  ;  37, 
4484  ;  M.  30,  280). 

/?-Phenyl-  and  /3-naphthyl-a-naphthoic  acids  are  the  chrysenic  and 
picenic  acids  (see  Chrysene  and  Picene). 

Substituted  Naphthoic  Acids. — The  nitration  of  a-naphthoic  acid 
produces  1,5-  and  1, 8-nitro-naphthoic  acids,  melting  at  239°  and 
275°  respectively.  Boiling  nitric  acid  converts  them  into  I,  5-(a)- 
and  i,  8-(j3-)  dinitro-naphthalene.  1,  4-Nitro-naphthoic  acid,  melting 
at  220°,  results  upon  saponifying  the  nitrile,  which  is  formed 
on  treating  the  diazo-derivative  of  i,  4-nitro-naphthyl-amine  with 
potassium  cuprous  cyanide. 

Ferrous  sulphate  and  ammonia  reduce  the  i,  5-acid  to  a  stable 
amido-naphthoie  acid  (1,  5)-,  melting  at  212°  (B.  19,  1981),  whereas  the 
same  reagents  reduce  the  i,  8-acid  to  (i,  8)-  or  peri-amido-naphthoic 
acid,  which,  when  free,  passes  like  the  i,  8-amido-sulphonic  acids  quite 

readily  into  its  inner  anhydride,  naphtho-styril  C10H6/^^?.  melting 

L  L°J-'^'  -H 

at  179°  (B.  19,  1131).     1,  4- Amido-naphthoie  acid  melts  at  177°  (B. 

28, 1842). 

See  B.  24,  R.  637,  for  the  nitro-/2-naphthoie  acids.     2,  3-Amido- 

naphthoic  acid,  melting  at  214°,  results  upon  treating  the  corresponding 
oxy-naphthoic  acid  with  ammonia  (B.  28,  3089).  Further  nitro-  and 
amido-naphthoie  acids,  see  C.  1899,  I.  288.  1,  3-  and  1,  4-Diamido-/3- 
naphthoic  acids,  m.p.  85°  and  185°,  decompose  into  CO2  and  i,  3-  or 
i,  4-naphthylene-diamine.  Their  esters  have  been  obtained  by  nuclear 
synthesis  (C.  1907,  II.  68,  539). 

Oxy-naphthoic  acids,  naphthol-carboxylic  acids,  containing  the  OH- 


NAPHTHALENE   GROUP  679 

and  COOH-groups  in  the  ortho-position,  are  prepared  like  the  ortho- 
phenol-carboxylic  acids — i.e.  by  heating  the  sodium  naphtholates  with 
CO  2  under  pressure. 

1,  2-(a-)  Naphthol-earboxylie  acid  C10H6[i](OH)[2](COOH),  melting 
at  186°,  is  formed  from  a-naphthol  and  from  ^-naphthol-sodium  with 
carbon  dioxide  and  pressure  at  I2o°-i45°  ;  2,  l-(j8)-naphthol-carboxylie 
acid,  melting  with  decomposition  at  156°,  is  similarly  produced ;  while 
if  j8-naphthol-sodium  be  heated  more  strongly,  2oo°-25o°,  in  a  current 
of  carbon  dioxide,  the  product  will  be  2,  3-naphthol-carboxylic  acid, 
melting  at  216°.     The  2,  i-(j3)-naphthol-carboxylic  acid  is  distinguished 
by  the  easy  mobility  of  its  carboxyl  group.     Heated  alone,  or  when 
boiled  with  water,  it  changes  to  j3-naphthol  ;   nitrous  acid  converts  it 
into  a-nitroso-j3-naphthol,  and  diazo-benzene  salts  into  benzene-azo-j3- 
naphthol,  etc.     The  2,  3-acid,  on  the  other  hand,  is  very  stable,  and 
resembles  salicylic  acid.     Because  of  its  striking  and  remarkable  yellow 

XCH2— CO 
colour  the  formula  of  a  keto-dihydro-naphthoic  acid  C,H4<r 

\CH  =C.COOH 

has  been  proposed  for  this  acid.  The  behaviour  of  the  acid  toward 
phenyl-hydrazin  supports  this  view  :  it  is  very  probable  that  at  first 
a  hydrazin  is  produced,  which  subsequently,  owing  to  indol  condensa- 
tion, forms  a  pheno-naphtho-carbazol-carboxylic  acid  (B.  29,  265 ;  cp. 
also  M.  31,  917).  With  thionyl  chloride,  a-  and  /?-naphthol-carboxylic 
acids  yield  the  corresponding  chlorides  (C.  1901,  II.  1119).  The  2,  3- 
naphthol-carboxylic  acid  with  PC15  gives  colourless  2-chloro-3-naphthoic 
acid  chloride,  m.p.  56°,  b.p.160  248°  (B.  34,  4158). 

From  i,  2-naphthoic  acid  chloride  and  acetyl-2,  3-naphthoic  acid 
chloride,  transposition  with  sodium-malonic  ester  yields  /2-oxy-  1,  2-  and 
2, 3-naphtho-cumarin-naphtho-tetronic  acid  CIOH,{^  _^,  m.p. 
258°  and  240°  (A.  367,  253  ;  368,  43). 

Naphtho-xanthones  C10H6<^     ^>C10H6  (B.   25,   1642)    are  produced 

when  the  three  o-naphthol-carboxylic  acids  are  heated  with  acetic 
anhydride. 

(1,  8)-  or  peri-naphthol-earboxylie  acid  is  derived  from  (i,  8)-amido- 
naphthoic  acid  by  means  of  the  diazo-compound.  It  breaks  down  into 

water  and  its  y-lactone  C10H6 1  fg3co/»  melting  at  169°. 

2,  3-Oxy-naphthoic  acid  and  diazo-benzene  chloride  yields  a  mixed 
azo-compound.     Reduction     converts    this    into     1, 2, 3-amido-oxy- 
naphthoie  acid,  which,  on  boiling  with  sulphuric  acid,  becomes  1,  2,  3- 
dioxy-naphthoic   acid.     This  can  also  be   obtained  from  /?-naphtho- 
hydroquinone  and  carbon  dioxide,  and  by  oxidation  it  is  changed  to 
jS-naphtho-quinone-carboxylie  acid   (B.   28,  3089).     From  sodium  a- 
naphtho-hydroquinone  and  CO2  we  obtain  1,  4-dioxy-2-naphthoic  acid, 
m.p.  186°  with  decomposition,  and  also  a  condensation  product  of  the  • 
anthracene  series  (/.  pr.  Ch.  2,  62,  47).     1,  3-Dioxy-2-naphthoic  acid, 
naphtho-resorcin-carboxylic  acid,  m.p.  145°  with  decomposition,  has  been 
obtained  by  saponifying  its  ethyl  ester,  m.p.  83°,  formed  synthetically 
by  the  action  of  concentrated  H2SO4  upon  phenyl-acetyl-malonic  ester 
(A.  298,  383).     For  other  dioxy-naphthoic  acids,  see  B.  29,  39. 

D.   N aphthalene-di-  and  poly-carboxylic  Acids. — Six  of  these  acids 


680  ORGANIC   CHEMISTRY 

are  known.  It  is  remarkable  that  the  i,  8-  or  peri-acid,  so-called 
naphthalic  acid'  C10H6[i,  8](COOH)2,  is  produced  by  the  oxidation  of 
acenaphthene  and  also  from  its  semi-nitrile,  which  is  made  by  saponify- 
ing the  diazo-derivative  of  peri-amido-naphthoic  acid.  The  follow- 
ing diagram  represents  the  relations  of  a  series  of  peri-naphthalene 
derivatives  : 

NO,  NO,  N02  COOH 


Peri-dinitro  Peri-nitro-naph- 

naphthalene  thoic  acid 

NH2  COOH  OH  COOH         COOH  COOH  CH,— CH, 


vN/ 


Peri-amido-  Peri-naphthol-  Naphthalic  Acenaphthene. 

naphthoic  carboxylic  acid 

acid  acid 

Just  as  in  the  case  of  other  peri-derivatives,  so  here  naphthalic 
acid  when  heated  to  180°  breaks  down  without  melting  into  water  and 
its  anhydride  Ci0H6(CO)20,  melting  at  266°,  which  also  forms  easily  on 
treating  the  acid  with  alcoholic  HC1,  and  in  many  other  processes.  Like 
phthalic  anhydride,  it  condenses  with  phenol  to  phenol-naphthale'in 

°H)2   (B-    28»    R-    621)  ;    with    malonic*  acid   ester    and 


ZnCl2  to  peri-naphtho-indandione  C10H6/W^CH2  (C.  ion,  I.   1633). 

L  [8]CO 

Naphthal-imide  C10H6(CO)2NH,  m.p.  300°,  when  treated  with  sodium 
hypochlorite  gives  naphtho-styrile  (B.  43  440).  Cp.  B.  28,  360;  32, 
3283  ;  C.  1902,  II.  898  ;  A.  327,  77  for  naphthal-imide,  -anile,  and 
-phenyl-hydrazile.  1,  2-Naphthalene-dicarboxylic  acid,  obtained  by  the 
saponification  of  its  nitrile,  melts  at  175°  and  passes  into  its  anhydride, 
melting  at  105°  (B.  25,  2475).  1,  5-Naphthalene-dicarboxylic  acid,  B. 
29,  R.  516. 


l-Phenyl-naphthalene-2,  3-diearboxylie  acid  ceH4<~"—   =£;:;:„ 

\C(CgH.g)  :  GCOOH 

is  formed  as  an  anhydride,  m.p.  255°,  in  a  reaction  recalling  the  forma- 
tion of  benzene  rings  from  acetylenes,  on  heating  phenyl-propiolic  acid 
C6H5C  :  CCOOH  with  acetic  anhydride  and  on  illuminating  a  benzene 
solution  of  dibenzal-succinic  anhydride.  By  the  action  of  concentrated 
H2SO4  the  colourless  anhydride  passes  into  allo-chryso-keto-carboxylic 
acid,  m.p.  288°,  in  claret-coloured  needles,  which,  on  fusing  with  alkali, 
yields  an  isomeric  1-phenyl-naphthalene-diearboxylic  acid,  m.p.  288° 
(B.  40,  3372,  3839  ;  C.  1908,  II.  1357)  : 

>  C10H5\-COOH  >  C10H6COOH 

*  C6H4  /CO  *  C6H4COOH 

Naphthalene-tetraearboxylic  acid  C10H4[i,  4,  5,  8](CO2H)4,  with  the 


NAPHTHALENE  GROUP  681 

carboxyl  groups  in  the  two  peri-positions  of  naphthalene,  results  when 
pyrenic  acid  is  oxidised  (B.  20,  365). 

Naphtho-nitriles,  Cyano-naphthalenes. — Naphtho-nitriles  may  be 
obtained  by  the  distillation  of  the  alkali  salts  of  the  naphthalene- 
disulphonic  acids,  or  the  phosphoric  esters  of  the  naphthols  with 
potassium  cyanide  or  yellow  prussiate  of  potash  (B.  21,  E.  834),  or  from 
the  naphthylamines  by  means  of  the  diazo-compounds. 

a-Naphtho-nitrile,  a-cyano-naphthalene  C10H7.CN,  melting  at  37° 
and  boiling  at  298°,  has  also  been  prepared  from  formo-naphthalide 
C10H7.NH.COH. 

j8-Cyano-naphthalene  melts  at  66°  and  boils  at  304°.  1,  2-Dieyano- 
naphthalene  C10H6[i,  2](CN)2,  melting  at  190°,  is  produced  when  i,  2- 
chloro-naphthalene-sulphonic  acid  is  distilled  with  potassium  ferro- 
cyanide  (B.  25,  2475).  For  additional  isomeric  dicyano-naphthalenes, 
see  A.  152,  289  ;  J.  1869,  483,  etc. 

/C(CN)  :  COH 

1,  4-Dicyano-2,  3-dioxy-naphthalene  C6H4  <  |      t  m.p.  291°, 

is  formed  by  nuclear  synthesis  in  the  condensation  of  oxalic  ester  with 
o-xylylene  cyanide. 

12.  Dinaphthyl-,  Dinaphthyl-methane,  and  Trinaphthyl-me thane 
Derivatives. — Different  isomeric  dinaphthyls  have  been  made  by  con- 
ducting the  vapours  of  naphthylene  through  bronze  tubes  heated 
to  redness,  by  heating  naphthalene  with  A12C16,  or  from  bromo-naph- 
thalene  and  iodo-naphthalene  with  sodium,  and  by  heating  mercury 
dinaphthyl  Hg(C10H7)2,  etc.  (B.  28,  R.  184). 

The  aa-dinaphthyl,  on  heating  with  A1C13  to  140°,  joins  the  two 
naphthalene  residues  in  the  peri-position  and  yields  a  hydrocarbon 
consisting  of  five  condensed  benzene-rings,  and  called  perylene 
C10H8/^Hc10H6,  bronze-coloured  flakes,  b.p.  262°-265°,  the  con- 

H°J  J 

stitution  of  which  is  determined  by  its  formation  from  i,  8-di-iodo- 
naphthalene  on  heating  with  copper  bronze  (B.  43,  2202).  The  4,  4- 
diamido-i,  i-dinaphthyl  or  naphthidins,  corresponding  to  the  benzidins 
or  4,  4-diamido-diphenylenes,  are  formed  besides  the  1,  l-diamido-2,  2- 
dinaphthylene  or  dinaphthylinene,  by  transformation  of  hydrazo- 
naphthalenes,  or  direct  from  the  naphthylamines  by  the  action  of  80 
per  cent,  sulphuric  acid,  in  the  presence  of  oxidising  agents  such  as 
ferric  oxide  (B.  25,  R.  949).  In  the  same  way  the  naphthols  give 
dinaphthols  with  ferric  chloride.  On  binuclear  quinones  of  the  di- 
naphthyl series,  see  /.  pr.  Ch.  2,  62,  31  ;  B.  42,  1058. 

Dinaphthyl-methanes  and  their  derivatives  are  formed  by  methods 
used  in  forming  the  diphenyl-methane  series  :  a2-  and  /?2-dinaphthyl- 
methane  CH2(C10H7)2,  m.p.  109°  and  92° ;  a,  /3-dinaphthyl-methane,  m.p. 
96°,  see  B.  44,  449  ;  a3-trinaphthyl-methane  (C10H7)3CH,  m.p.  101°,  from 
its  carbinol  by  reduction  with  HI  in  glacial  acetic  acid  (B.  44,  1105). 
Trichloro-ethylidene-aa-dinaphthyl  CC13CH(C10H7)2,  m.p.  156°,  on  heat- 
ing with  alcohol  and  zinc  dust,  is  converted  into  aa-naphtho-stilbene 
C10H7CH  :  CHC10H7,  m.p.  161°.  The  latter  is  closely  related  to  picene, 
into  which  it  is  converted  on  superheating.  j8/?-Naphtho-stilbene,  m.p. 
255°  (B.  38,  509).  From  naphthylamine,  and  from  naphtholene  with 
aldehydes,  we  obtain,  with  particular  ease,  alkylidene-dinaphthyl- 


682  ORGANIC   CHEMISTRY 

amines  (C.  1900,  II.  481)  and  alkylidene-dinaphthols.  The  products 
formed  from  jS-naphthol  with  aldehydes  part  with  water  and  become 
xanthenes,  hence  they  in  all  probability  contain  the  alkylidene  groups 
in  the  o-position  with  reference  to  the  hydroxyls  :  /?-dinaphthol- 
methane,  melting  at  190°,  yields,  with  POC13,  dinaphtho-xanthene 
C10H.6<(^  .  \C10He,  while  benzaldehyde  and  j8-naphthol  at  once  form 

\Cri2/ 

ms-phenyl-naphtho-xanthene  C6H5CH(C10H6)O  (B.  25,  3477  ;  26,  83), 
together  with  an  acetal.  Sodium-/3-naphthol  and  chloroform  at  150° 
produce  an  anhydride  of  trioxy-trinaphthyl-methane  HOC10H6CH 
[C10H6J2O,  m.p.  273°,  which  is  also  formed  by  the  condensation  of 
J8-naphthol  and  jS-naphthol-aldehyde  (C.  1901,  I.  945,  1010). 

act-  and  ^-Dinaphthyl-carbinol  (C10H7)2CHOH,  from  a-  and  0- 
naphthyl-magnesium  bromide  and  formic  ester  ;  aaa-  and  aajS-tri- 
naphthyl-earbinol  (C10H7)3COH,  m.p.  169°  and  264°.  The  dinaphthyl- 
carbinols,  but,  strangely  enough,  not  the  trinaphthyl-carbinols,  show 
the  same  mobility  of  the  hydroxyl  group  as  the  diphenyl-  and  triphenyl- 
carbinol.  HC1  easily  produces  the  corresponding  chlorides  (C10H7)2 
CHC1,  from  which  aa-  and  jSj8-dinaphthyl-acetie  acid  (C10H7)2CHCOOH, 
m.p.  228°  and  179°  respectively,  are  obtained,  with  Mg  and  CO2.  On 
treatment  with  zinc  and  HC1,  the  dinaphthyl-carbinols  easily  split  off 
water  and  pass  into  aa-  and  Pfi-dinaphtho-fluorene  (B.42, 2377;  43, 2824). 

Numerous  dyes  of  the  naphthyl-diphenyl,  dinaphthyl-phenyl,  and 
trinaphthyl  series  have  been  prepared  by  known  methods,  but  are  of 
no  practical  interest,  on  account  of  their  slight  solubility  and  high 
price  (B.  37,  1899). 

13.  Acenaphthene. — Acenaphthene,    or    peri  -  efhylene  -  naphthylene 

( [i]CH2 
C10H6-{       |      ,  melting  at  95°  and  boiling  at  277°,  is  a  peculiar  deriva- 

l  [8]CH2 

tive  of  naphthalene,  which  is  obtained  by  conducting  a-ethyl-naphtha- 
lene  through  a  red-hot  tube,  or  by  the  action  of  alcoholic  potash  upon 
a-bromo-ethyl-naphthalene  C10H7.C2H4Br.  It  also  occurs  in  coal-tar. 
Inasmuch  as  acenaphthene  is  oxidised  by  sodium  bichromate  and 
sulphuric  acid  to  naphthalic  acid,  the  side  chain  C2H4  must  be  arranged 
in  the  two  peri-positions  (i  and  8)  of  naphthalene.  Acenaphthene- 
quinone  C10H6(CO)2,  melting  at  261°,  is  a  by-product  in  this  oxidation. 

Zinc  dust  and  acetic  acid  reduce  it  to  acenaphthenone  C10H6.CH2.CO, 
melting  at  121°,  while  hydriodic  acid  and  phosphorus  change  it  to 

bis-acenaphthylidene  (C10H6.CO.C  :  )2,  melting  at  294°,  and  alkalies 
decompose  it  into  naphthaldehydic  acid  (B.  26,  R.  710  ;  A.  290,  195  ; 

c.  1899,  ii.  378 ;  1909,  n.  775) : 


C10H6< 

i  /CO    Hn  /CHO  CH(OH) 

Bis-acenaphthylidene    ;.C10H6<  |     -^ — ^C10H6<  or  C10H8<     >O 

XCO  XCOOH  XCO 

Acenaphthene-  Naphthaldehydic  acid, 

quinone 

Acenaphthenone 

The  monoxime  of  acenaphthene-quinone  C12H6O(NOH),  m.p.  230°, 


NAPHTHALENE   GROUP  683 

is  converted  into  naphthalimide  by  Beckmann's  transposition  (C.  1903, 
I.  881). 

By  bromination,  nitration,  or  acidulation,  acenaphthene  is  substi- 
tuted in  the  4-position,  as  shown  by  the  conversion  of  the  corresponding 
derivatives  into  derivatives  of  naphthalic  acid  (A.  327,  77  ;  B.  43, 

2473). 

Acenaphthene-quinone  easily  unites  in  the  presence  of  condensing 
agents  like  A1C13,  ZnCl2,  with  aromatic  hydrocarbons,  amines,  and 

/CO 
phenols  to  form   diaryl-acenaphthenones  cioH6\c/R)    (B.  43,  2915). 

9, 9-Diphenyl-acenaphthenone  C10H6<^°  H    ,    m.p.    174°,  results 

/CfOH^C  H 
also  from   the  9,   lo-diphenyl-acenaphthene-glycol  cioH6\£/QHJc6H5' 

m.p.  156°,  the  product  of  the  action  of  C6H5MgBr  upon  acenaphthene- 
quinone  on  heating  with  concentrated  HC1  (pinacolin  transposition). 
Withindoxyl  andthio-indoxyl  (j8-oxy-thio-naphthene)  acenaphthene- 

quinone  condenses  to  a  violet  or  red  vat  dye  C«H4\NH/     :  C\  C  H  anc^ 

C«J«<Cs°>C :  C<C°H,  <B-  41>  3331  :  C.  1909,  II.  775). 

When  the  vapour  of  acenaphthene  is  conducted  over  lead  oxide 
heated  to  redness,  two  atoms  of  hydrogen  split  off  and  aeenaphthylene 
CH 

results.     This  forms  yellow  plates  (B.  26,  2354),  melts  at 
CH 

92°,  and  boils  at  270°  with  decomposition.  Chromic  acid  also  oxidises 
it  to  naphthalic  acid. 

On  a  synthesis  of  substituted  acenaphthylenes,  see  A.  369,  157. 
On  heating  acenaphthene  with  sulphur  to  about  290°,  we  obtain 

dinaphthylene-thiophene  C10H6 {  £_s_£  }  C10H8,  red  needles,  m.p.  278°, 
beside  the  yellow  hydrocarbon  [~C10H6<^1  :  trinaphthylene-benzol, 

m-P-  387°  (B.  36,  962).  By  reduction  with  hydrogen  and  finely 
divided  nickel  we  obtain  from  acenaphthene  tetrahydro-acenaphthene, 
b.p.  254°  (C.  1901,  II.  202)  and  decahydro-acenaphthene,  b.p.  230°- 
234°  (B.  42,  2094). 

14.  HYDRO-NAPHTHALENE  DERIVATIVES. 

Hydro-naphthalene  compounds  attach  themselves  to  naphthalene 
just  as  the  hydro-aromatic  benzene  derivatives  do  to  benzene. 
Naphthalene  and  its  derivatives  take  up  hydrogen  and  the  halogens 
more  readily  than  the  compounds  of  benzene.  Those  naphthalene 
derivatives  which  have  added  hydrogen  to  one  nucleus  alone  are 
remarkable  and  interesting,  because  they  manifest  in  one  substance 
the  differences  which  prevail  between  an  aromatic  and  a  hydro-aromatic 
or  alicyclic  nucleus.  While  the  non-hydrogenised  nucleus  of  the 
respective  naphthalene  compounds  retains  the  aromatic  properties,  the 
hydrogenised  alicyclic  nucleus  assumes,  on  the  contrary,  the  nature  of 
a  fatty  radicle,  and  as  a  consequence  the  whole  system  acquires  the 
character  of  an  homologous  benzene  derivative  (Bamberger,  A.  257,  i). 

A.  Dihydro-naphthalene  Derivatives.— Dihydro-naphthalene  C10H10, 
melting  at  15°  and  boiling  at  212°,  is  formed  when  naphthalene  is 


684  ORGANIC  CHEMISTRY 

reduced  with  sodium  in  a  boiling  ethyl-alcohol  solution.  The  entering 
hydrogen  atoms  assume  the  i,  4-position,  because  the  hydride  yields 
o-phenylene  diacetic  acid  when  it  is  oxidised.  It  can  be  viewed  as 
the  hydrocarbon  of  a-naphtho-quinone.  Dihydro-naphthalene  re- 
sembles the  olefins — e.g.  ethylene — in  that  it  readily  takes  up  two 
univalent  atoms  or  radicles.  Thus  with  bromine  it  forms  a  dibromide, 
with  hypochlorous  acid  a  glycol-chloro-hydrin.  Tetrahydro-naphthylene 
oxide  can  be  easily  obtained  from  the  latter,  and  is  capable  of  rearranging 
itself  to  1,  2-dihydro-j3-naphthol  C10H10O,  boiling  at  i62°-i68°  (28  mm.), 
which  may  be  oxidised  to  dihydro-iso-cumarin-carboxylic  acid,  and 
when  it  splits  off  water  naphthalene  is  produced  (A.  288,  74)  : 

/CH=CH  /CH,— CH  /CH,— CH\  /CH,— CHOH  /CH  =  CH 

C6H4<  I     ->C,H/  ||    ->QH/  |      >0->C8H/  |          ->C6H/ 

XCH=CH  \CH,— CH  XCH2— CH/  \CH  =  CH  XCH=CH 

Naphthalene      Dihydro-naphthalene  Tetrahydro-  Dihydro-0-naphthol       Naphthalene. 

naphthalene  oxide 

XH^eHjJ.CH 

Phenyl-hydro-naphthalene  C6H4<^  II    ,  m.p.  50°,  results  from 

phenyl-bromo-tetrahydro-naphthoic  acid  on  boiling  with  soda  solution, 
or,  better,  with  diethyl-aniline  (A.  306,  235). 

Naphthalene  dichloride  C10H8C12  is  a  yellow  oil  formed  when 
naphthalene  is  treated  with  potassium  chlorate  and  hydrochloric  acid. 
It  changes  to  a-chloro-naphthalene  at  4O°-50°,  arid  by  the  elimination 
of  hydrogen  chloride. 

Dihydro-naphthoic  Acids. — Sodiiim  amalgam  reduces  the  a-  and 
j8-naphthoic  acids,  two  hydrogen  atoms  being  added  to  the  nucleus 
already  carrying  the  carboxyl  group,  and  in  the  cold  there  result 
unstable,  and  when  heat  is  applied  stable,  dihydro-naphthoie  acids 
C10H9.CO2H.  The  former  are  unsaturated  at  /?  and  y,  the  latter  at 
a  and  j8 : 

a-Stable  melting  at  125°  ;  /3-stable  melting  at  161°. 
a-Unstable         ,,        91°  ;  6-unstable       ,,        104°. 

The  unstable  modifications  pass  into  the  stable  modifications  on 
boiling  them  with  caustic  soda.  Potassium  permanganate  oxidises 
the  stable  a-acid  to  hydro-cinnamic  acid,  while  the  unstable  acid 
yields  oxalic  acid  and  phthalic  acid.  The  dibromide  of  the  unstable 
.j8-acid,  in  contrast  with  the  stable  modification,  readily  changes  to  a 
brominated  lactone.  All  these  facts  point  to  the  following  formulae 
for  the  stable  a-  and  the  unstable  j8-acid  (A.  266,  169)  : 

/CH, CH2  /CH,— CH,  /CH=CH  /CH—  CHBr 


C,HA  I      ->CeHX  C6H4<  *C,HX 

\C(COOH)=CH  VOOH  COOH  \CH,.CH.COOH  \CH,— CH.CO— O 

Stable  dihydro-a-  Unstable  dihydro-/?- 

naphthoic  acid  naphthoic  acid. 

The  dihydro-j8-acids,  when  oxidised  with  potassium  ferricyanide, 
revert  again  to  jS-naphthoic  acid. 

The  stable  a-dihydro-naphthoic  acid,  like  other  a,  jS-unsaturated 
carboxylic  acids,  adds  sodium-aceto-acetic  ester  with  formation  of  a 
8-ketonic  acid  ester,  which,  however,  immediately  discards  alcohol,  and 
condenses  to  a  phenanthrene  (B.  31,  1896). 

a-Phenyl-dihydro-jS-naphthoic  acid  C10H8(C6H5)COOH,  m.p.  191°, 


NAPHTHALENE   GROUP  685 

is  obtained  by  condensation  of  dibenzyl-propionic  acid  by  means  of 
glacial  acetic  sulphuric  acid  (A.  306,  156). 

B.  Tetrahydro  -  naphthalene  Derivatives.—  Tetrahydro  -  naphthalene 
C10H12,  boiling  at  206°,  is  formed  in  the  reduction  of  naphthalene  with 
sodium  in  amyl  alcohol  solution  ;  also  from  ar-tetrahydro-naphthyl- 
amine  by  the  elimination  of  the  NH2  group  ;  hence  the  H  atoms  are 
only  present  in  the  one  nucleus.  Naphthalene  tetrachloride  C10H8C14, 
melting  at  182°,  is  produced  when  chlorine  is  conducted  into  a  chloro- 
form solution  of  naphthalene.  Boiling  alcoholic  potash  changes  it  to 
dichloro-naphthalene.  See  B.  28,  R.  392,  for  the  oxidation  of  naphtha- 
lene tetrachloride.  Consult  B.  24,  R.  713,  for  the  chlorine  addition 
products  of  chlorinated  and  sulphur-containing  naphthalenes.  Naphtha- 
lene tetrabromide  melts  at  m°  (C.  1897,  I.  984). 

The  naphthylamine  and  naphthol  hydrides  are  particularly  interest- 
ing. Sodium  acting  upon  the  boiling  amyl  alcohol  solution  of  the 
naphthols  and  naphthylamines  causes  these  bodies  to  add  four  hydrogen 
atoms  each  to  one  nucleus.  If  the  latter  carries  the  NH2  or  OH  group, 
the  body  formed  no  longer  possesses  the  character  of  a  naphthylamine 
or  a  naphthol,  but  has  that  of  a  benzene  homologue,  amidated  or 
bearing  the  OH  group  in  the  side  chain.  Should,  however,  the  non- 
substituted  nucleus  be  hydrogenised,  then  the  products  acquire  the 
nature  of  homologous  anilines  or  phenols.  E.  Bamberger,  who  first 
observed  these  relations  and  explained  them,  designated  the  second 
class  of  tetrahydro-derivatives  as  aromatic  (ar-),  and  the  first  class  as 
aliphatic-cyclic  or  alicyclic  (ac-)  : 
H. 


H(NH.)  H,  NH,  N(NH,) 

ac-Tetrahydro-  ar-Tetrahydro-  ar-,  ac-Tetrahydro- 

a-naphthylamine  ^-naphthol  i,  5-naphthylene-diamine. 

a-Naphthylamine  and  a-naphthol  upon  reduction  yield  ar-tetra- 
hydro-a-naphthylamine  and  naphthol,  while  the  jS-compounds  form 
both  the  ar-  and  the  ac-tetrahydro-derivative  ;  the  latter  predominates. 
i,  5-Naphthylene-diamine  yields  ac-,  ar-tetrahydro-naphthylene-dia- 
mine,  which,  by  elimination  of  the  aromatic  NH2  group,  forms  ac-tetra- 
hydro-a-naphthylamine. 

ar-Tetrahydro-naphthylamines  NH2.C6H3  :  (C4H8).  The  a-body 
boils  at  275°  and  the  j3-form  at  276°.  They  are  feeble  bases  and  form 
diazo-  and  azo-compounds.  They  exercise  a  reducing  power  with  salts 
of  the  noble  metals.  By  oxidation  with  potassium  permanganate  all 
yield  adipic  acid  and  oxalic  acid. 

Chromic  acid  oxidises  the  a-compound  to  ar-tetrahydro-a-naphtho- 
quinone  C6H2O2  :  (C4H8),  melting  at  55°,  which  in  every  respect  re- 
sembles benzo-quinone  and  possesses  much  greater  oxidising  power 
than  a  -  naphtho  -  quinone.  ac  -  Tetrahydro  -  naphthylamines  C6H4  : 
(C4H7.NH2)  ;  the  a-body  boils  at  246°  and  the  £-  at  249°.  They  are 
strong  bases,  which  absorb  carbon  dioxide  from  the  air.  They  do  not 
form  diazo-derivatives.  Potassium  permanganate  ruptures  the  hydro 
genised  ring  and  produces  o-cinnamo-carboxylic  acid. 

From  the  /?-,  ac-tetrahydro-naphthylamine,  by  means  of  d-bromo- 


686  ORGANIC   CHEMISTRY 

camphorosulphonic  acid,  an  optically  active  dextro-rotatory  modifica- 
tion has  been  obtained  (C.  1899,  II.  255  ;  1900,  I.  862). 

ac-,  ar-Tetrahydro-1,  5-naphthylene-diamine  NH2.C6H3  :(C4H7NH2), 
melting  at  77°  and  boiling  at  261°,  combines  in  itself  both  the  properties 
of  an  aromatic  and  of  an  alicyclic  amine.  It  contains  an  asymmetric 
carbon  atom,  and  has  been  resolved  into  a  dextro-  and  a  laevo- 
modification. 

ar-Tetrahydro-a-naphthol  OH.C6H3  :  (C4H8),  melting  at  69°  and 
boiling  at  265°,  is  also  derived  from  ar-tetrahydro-a-naphthylamine  by 
means  of  the  diazo-derivative. 

ae-Tetrahydro-/?-naphthol  C6H4  :  (C4H4OH)  is  an  oil,  boiling  at 
264°.  It  exhibits  the  character  of  a  fatty  alcohol  and  resembles 
similarly  constituted  camphor  alcohols,  like  menthol  and  borneol. 

A  series  of  tetrahydro-naphthalene  derivatives  has  been  obtained, 
starting  with  dihydro-naphthalene  :  Thus,  phenol  and  the  latter  form 
tetrahydro-naphthyl-phenol  C6H4  :  (C4H7.C6H4OH),  boiling  at  130°  (B. 
24,  179),  while  bromine  changes  it  to  dihydro-naphthalene  dibromide 
C6H4  :  (C4H6Br2).  Boiling  potassium  carbonate,  or  transformation 
with  silver  acetate  and  subsequent  saponification,  converts  the  latter 


into    tetrahydro-naphthylene    glycol   c6H4'-  melting    at 

\LJdL  2  —  CrlUri 

I35°  (cis-form)  and  118°  (trans-form),  which  by  oxidation  is  broken 
down  into  o-phenylene-diacetic  acid.  It  is  an  analogue  of  ethylene- 
glycol.  The  chloro-hydrin  (above)  C10H10C1(OH),  melting  at  117°,  with 
caustic  potash  yields  tetrahydro-naphthylene  oxide  C10H100,  melting  at 
43°  and  boiling  at  258°,  which  manifests  all  the  chemical  properties  of 
ethylene  oxide  (I.  298).  Bases  have  converted  the  chloro-hydrin  into 
a  series  of  "  alkines,"  of  which  mention  may  be  made  of— 

Trimethyl  -  oxy  -  tetrahydro  -  naphthylene  -  ammonium      hydroxide 

yCH2.CHOH 

\CH  CHN(CH    OH'    Because    of    its    intimate    connection    with 

choline   (I.   309).     The  feebler   alkalies   convert  this  oxide  into  the 

f*T-T  /"*  TT 

isomeric    fi-keto-tetrahydro-naphthalene   C6H4/          i     2,   melting   at 

\CH2  —  CO 

18°  and  boiling  at  138°  (16  mm.),  which  can  also  be  prepared  by 
the  distillation  of  o-phenylene-propion-acetic  acid  (B.  28,  745).  It 
behaves  like  a  fatty  ketone  (B.  27,  1547)  wi*n  sodium  bisulphite, 
phenyl-hydrazin,  and  hydroxylamine.  a-Keto-tetrahydro-naphthalene 

<QTT    _  QTT 
CQ^  _  £H2     is     obtained    by    intramolecular    condensation    of 

y-phenyl-butyric  acid  chloride  by  means  of  A1C13  (C.  1899,  I.  792). 

The  chlorine  addition  products  of  the  naphtho-quinones  are  diketo- 
tetmhydro-naphthalene  derivatives.  They  result  from  the  action  of  Cl 
upon  the  corresponding  dioxy-naphthalenes  or  naphtho-quinones  (A. 
300,  180  ;  334,  342)  : 

r  M  /CO  -  CO       r  TT  /CO—  -CCla     r  TT  /CO  -  CCL     r  TT  /CC12—  CO 

c'H4\cci2-cci2'  c'H4\co-cci2'  c«H4\cci2-co  '  C6H<cci2-co' 

Diketo-tetrahydro-naphthylene  oxide  c«H*<^o-CH/>O  '  meltinS 
at  136°,  is  produced  by  the  action  of  bleaching-lime  upon  a-naphtho- 
quinone  (p.  671  and  A.  286,  71). 


NAPHTHALENE  GROUP  687 

The  tetrahydro-naphthoic  acids  are  also  classified  into  aromatic  and 
alicyclic.  ar-Tetrahydro-a-naphthoic  acid  COOH.C6H3  :  (C4H8),  with 
an  amide  melting  at  182°,  is  derived  from  its  nitrile,  a  rearrangement 
product  from  ar-tetrahydro-a-naphthalene-diazo-chloride  and  potassio- 
copper  cyanide. 

ac-Tetrahydro-naphthoie  acids,  the  a-  melting  at  85°  and  the  j8-  at 
96°,  are  formed  when  naphthoic  and  dihydro-naphthoic  acids  are 
reduced  with  sodium  amalgam.  They  resist  the  action  of  potassium 
permanganate  more  strongly  than  the  dihydro-acids.  In  comparison 
with  the  latter  they  thus  prove  themselves  to  be  saturated  acids.  The 
long-continued  action  of  the  oxidant  finally  changes  them  to  phthalic 
and  oxalic  acids  (A.  266,  202). 

For  the  splitting  up  of  the  tetrahydro-naphthoic  acids  into  their 
optically  active  components,  see  C.  1906,  II.  962. 

ac-Phenyl-tetrahydro-jS-naphthoic  acid  C6H4[C4H6(C6H5)COOH] , 
m.p.  177°,  results  from  the  reduction  of  phenyl-bromo-tetrahydro- 
naphthoic  acid,  m.p.  205°,  obtained  synthetically  by  the  action  of  Br  at 
o°  upon  the  chloroform  solution  of  benzyl-phenyl-iso-crotonic  acid 
(A.  306,  231). 

ac-Tetrahydro-naphthalene-diearboxylie  acid  C6H4[C4H6(CO2H)2], 
melts  at  199°,  with  the  production  of  its  anhydride,  melting  at  184°. 
The  latter  is  also  formed  on  heating  potassium  tetrahydro-naphthalene 
tetracarboxylate,  the  ester  of  which  has  been  synthesised  from  o-xyly- 
lene  bromide  and  the  sodium  derivative  of  the  dimalonic  acid  ester 
(B.  17,  448).  Tetrahydro-1,  5-naphthalene-diearboxylic  acid  melts  at 
238°  (B.  29,  R.  517). 

C.  Hexa,-  octo-,  deca-,  and  dodecahydro-naphthalenes  C10H14, 
C10H16,  C10H18,  and  C10H20,  boil  at  200°,  i85°-i9O°,  i73°-i8o°,  and  153°- 
158°  respectively.  They  have  been  obtained  by  the  action  of  hydriodic 
acid  and  phosphorus  upon  naphthalene  (B.  16, 796, 3032  ;  A.  187,  164). 

Decahydro-naphthalene  has  also  been  obtained  by  reduction  with 
H  and  Ni  at  160°.  Deca-hydro-a-  and  -j8-naphthol  C10H17OH,  m.p.  62° 
and  75°,  b.p.14  109°  and  112°,  are  easily  formed  by  the  reduction  of 
a-  and  /3-naphthol  with  H  and  Ni  ;  by  rejection  of  water  they  yield 
two  isomeric  oetohydro-naphthalenes,  b.p.  190°  and  191°,  by  oxidation 
with  CrO3  the  corresponding  ketones  C10H16O,  m.p.  32°  and  b.p.  240°, 
the  oximes  of  which  are  reduced  by  Na  and  alcohol  to  a-  and  /?-deea- 
hydro-naphthylamine  C10H17NH2,  b.p.14  97°  and  112°  (C.  1911,  I.  318). 

III.  PHENANTHRENE  GROUP. 

Phenanthrene  occurs,  together  with  anthracene,  in  coal-tar  and 
in  the  so-called  "  stubb,"  a  substance  obtained  (together  with 
fluoranthene  and  pyrene)  in  the  distillation  of  mercury  ores  in  Idria. 
It  is  prepared  synthetically  (i)  (with  diphenyl,  anthracene,  and  other 
hydrocarbons)  from  various  benzene  compounds,  by  conducting  their 
vapours  through  a  red-hot  tube — e.g.  from  toluene,  stilbene,  diphenyl, 
and  ethylene,  and  particularly  from  dibenzyl  and  o-ditolyl  : 

UjHg.CHj  CgH^.CH  CgH4. 

I        *    I         ||        < | 

CaH5.CH2  CaH4.CH  C8H4.CH3 

Dibenzyl  Phenanthrene  o-Ditolyl. 


688  ORGANIC  CHEMISTRY 


(2)  Sodium  acting  on  o-bromo-benzyl  bromide  also  produces  it, 
together  v/ith  anthracene. 

C6H4— CH  ^  ^Br[i]C6H4[2]CH2Br         Br[i]C6H4[2]CH2Br  ^  ^cn/C,H4\cil 

C6H4— CH  Br[i]C6H4[2]CH2Br         BrCH2[2]C6H4[i]Br  \csH4/ 

Phenanthrene.  Anthracene. 

(3)  It  also  appears  in  the  condensation  of  cumarone  with  benzene 
(B.  23,  85)  : 

L— CH  C6H4— CH 

J     +C6H6  >    I  || 

II  v>gl"j.£ — \_/Jrl 

Cumarone  Phenanthrene. 

Chrysene  is  similarly  formed  from  cumarone  and  naphthalene,  and 
amido-naphthalene  (p.  694)  from  furfurane  and  aniline. 

(4)  When  the  diazo-derivative  of  o-amido-a-phenyl-acetic  acid  is 
acted  upon  with  copper  powder,  phenanthrene-carboxylic  acids  (B.  29, 
496)  result  : 

CH— C6H4.N2OH  CH— C6H4 

II *  II          I        • 

COOH.C— C6H5  COOHC  —  C6H4 

This  reaction  recalls  the  formation  of  diphenyl  from  benzene  and 
diazo-benzene,  as  well  as  that  of  diphenyl-ketone  from  the  diazo- 
derivative  of  o-amido-benzo-phenone. 

(5)  Quite  analogous  to  the  synthesis  of  a-naphthol  from  phenyl- 
iso-crotonic  acid  is  the  formation  of  4-oxy-phenanthrene  by  heating 

£-naphthyl-iso-erotonie  acid  c"u'^^^tH  ~   ~^Cl°HKc(OHTcH- 

(6)  The  following  synthesis  of  phenanthrene,  starting  from  a  naphtha- 
lene derivative,  is  of  interest  :    Dihydro-j3-naphthoic  acid  ester  (i) 
condenses  with  aceto-acetic  ester  to  a  diketo-octohydro-phenanthrene- 
carboxylic  ester,  which,  on  saponification  and  rejection  of  CO2,  yields 
octohydro-diketo-phenanthrene  (2),  which  in  turn  gives  phenanthrene 
by  zinc-dust  distillation. 

(i)  (2)  (3) 

CH2— CH2— CC02R  _^  CH2— CH2— CH— CO CH2  __^  CH=CH— C— CH=CH 

^6-^-'-4  CJbd  CgH4 CH — CH2 — CO  C6H4 C — CH=CH 

Phenanthrene  in  accordance  with  these  methods  of  production  must 
be  viewed  as  a  derivative  of  diphenyl,  in  which  two  ortho-positions  of 
the  two  benzene  rings  are  joined  by  the  group  CH=CH,  which  there- 
fore constitutes,  with  the  four  carbon  atoms  of  the  two  benzene  rings, 
a  third  normal  benzene  ring  : 

6    _5  43 

7  CH/  ^c c/          SCH  2. 

^CH—C^  V  — 

8 


•The  oxidation  01  phenanthrene  leads  to  a  similar  conclusion. 
Phenanthraquinone  is  the  first  product,  and  by  continued  oxidation  it 
yields  diphenic  acid  or  diphenyl-o2-dicarboxylic  acid  : 

C6H4.CH  C6H4.CO  C6H4.CO2H 

C6H4.CH  C6H4.CO  C6H4.CO2H 

Phenanthrene          Phenanthraquinone         Diphenic  acid. 


PHENANTHRENE  GROUP  689 

Since  phenanthrene  and  its  derivatives  have  been  obtained  as  dis- 
integration products  of  the  important  alkaloids  morphia,  codein,  and 
thebain,  the  chemistry  of  the  phenanthrenes  has,  of  late,  been  carefully 
studied. 

Phenanthrene  C14H10  crystallises  in  colourless  plates,  melting  at 
99°  and  boiling  at  340°.  It  dissolves  readily  in  ether  and  benzene, 
but  with  more  difficulty  in  alcohol  and  water.  The  solutions  exhibit  a 
blue  fluorescence. 

The  picrate  C14H10.C6H2(NO2)3.OH  separates  in  yellow  needles, 
melting  at  144°.  Consult  A.  196,  34  ;  B.  19,  761,  for  a  method  of 
isolating  phenanthrene  from  crude  anthracene. 

Alkylated  Phenanthrenes.  —  1-  and  3-methyl-phenanthrene  C14H9.CH3, 
m.p.  123°  and  65°,  result  from  the  synthetic  i-  and  3-methyl-phen- 
anthrene-9-carboxylic  acids  by  rejection  of  CO2.  9,  10-Dimethyl- 
phenanthrene  C14H8(CH3)2,  m.p.  139°,  by  reduction  of  9,  lo-dimethyl- 
9,  lo-dioxy-dihydro-phenanthrene  with  HI  and  phosphorus  (B.  39, 
3110  ;  A.  362,  250).  9,  10-Diphenyl-phenanthrene  C14HS(C6H5)2,  m.p. 
235°,  has  been  obtained  by  nuclear  synthesis  by  the  action  of  A1C13  upon 
tetraphenyl-ethylene  (B.  38,  203).  It  is  also  produced  by  a  remarkable 
atomic  displacement  in  the  reduction  of  benzoyl-phenyl-fluorene  with 
HI  and  phosphorus,  a  reaction  corresponding  to  the  formation  of 
tetraphenyl-ethylene  from  jS-benzo-pinacolin  (B.  37,  2887)  : 

C6H4\     /COC6H5  rC6H4\     /CH(OH)C6H5n  _    C6H4.C.C.H6 

C6H4/  \C6H5  "  LC6H4/   \C6H5  *  C6H4.C.C6H5 

Halogen  Phenanthrenes.  —  By  the  action  of  chlorine  upon  phen- 
anthrene substitution  products  are  formed  :  9,  10-dichloro-  and  2,  9, 
10-triehloro-phenanthrene  C14H8C12  and  C14H7C13,  m.p.  161°  and  124° 
(B.  39,  3891)  ;  octochloro-phenanthrene  C14H2C18,  m.p.  27o°-28o°,  is 
split  up  on  further  chlorination  into  C6C16  and  CC14.  Bromine  in 
CS2  solution  forms  an  addition  product,  phenanthrene  dibromide 
C14H1(}Br2,  which  splits  off  HBr  and  passes  into  9-bromo-phenanthrene 
C14H9Br,  m.p.  63°.  The  latter  is  oxidised  by  chromic  acid  to  phen- 
anthrene-quinone,  and  on  further  bromination  to  4,  9-(4,  10-)  dibromo- 
phenanthrene  C14H8Br2,  m.p.  •ii20-ii3°,  which  on  oxidation  yields 
4-bromo-phenanthrene-quinone  (A.  321,  330  ;  B.  37,  3553). 

Nitro-phenanthrenes.  —  The  nitration  of  phenanthrenes  produces 
three  nitro-phenanthrenes,  one  of  which  has  been  found  to  be  3-nitro- 
phenanthrene  C]4H9[3]NO2,  m.p.  I7o°-i7i°  (B.  34,  3532).  If  a  mixture 
of  acetic  anhydride  and  nitric  acid  is  nitrified  in  glacial  acetic  acid  we 
obtain  9-nitro-phenanthrene,  m.p.  Ii6°-ii7°,  which  is  also  obtained 
from  the  product  of  the  action  of  gaseous  nitrous  acid  upon  phenan- 
threne by  treatment  with  sodium  ethylate  solution  (B.  36,  2508).  By 
boiling  with  methyl-alcoholic  potash  the  9-nitro-phenanthrene  takes 
up  two  molecules  CH3OK  and  transposes  into  the  isomeric  phenan- 
threne-quinone-monoxime  by  way  of  phenanthrene-quinone-oxime- 
dimethyl-acetal  (A.  355,  307)  : 


H  }  2  _  ^  ir  H  \  /C  :  NOK  tc  U\/C:  NOH 

«H«)2\CH  (C6H4)2\C(OCH3)2    -        ^  (C6H*)2\CO 

Compare  the  similar  transposition  of  7-nitro-stilbene,  of  i-  and  2-nitro- 
naphthalene,  and  of  9-nitro-anthracene. 

VOL.  II.  2  Y 


690  ORGANIC  CHEMISTRY 

Amido-phenanthrenes,  phenanthrylamines,  have  been  obtained 
partly  by  the  reduction  of  the  nitro-phenanthrenes,  partly  from  the 
phenanthrols  by  heating  with  ammonia  salts  :  2-amido-phenanthrene 
C14H9(NH2),  m.p.  85°,  3-amido-phenanthrene,  m.p.  87° ;  9-amido- 
phenanthrene,  m.p.  I35°-I36°,  have  also  been  obtained  from  the  azide 
of  9-phenanthrene-carboxylic  acid  (A.  321,  312  ;  B.  34,  1461  ;  35, 

2726).  9, 10-Diamido-phenanthrene  £6H4IIcNH2>  from  phenanthrene- 
quinone-dioxime  by  reduction,  gives  by  atmospheric  oxidation  diphen- 
anthryl-azin  C14H8  :  N2  :  C14H8  (B.  35,  2738). 

Phenanthrene-sulphonic  Acids.— On  sulphurising  phenanthrene 
we  obtain  3-,  2-,  and  9-phenanthrene-sulphonie  acids,  C14H9.SO3H 
(3-sulpho-chloride,  m.p.  108°,  2-sulpho-chloride,  m.p.  156°,  Q-sulpho- 
chloride,  m.p.  125°),  whose  constitution  has  been  determined  by  con- 
verting them  into  oxy-  and  cyano-phenanthrenes  (A.  321,  251  ;  369, 
104  ;  379,  79  ;  B.  34,  4004). 

0 xy-phenanthrenes ,  phenanthrols,  have  been  obtained  by  fusion 
with  potash  from  the  sulphonic  acids  and  from  the  phenanthryl- 
amines, while  their  ethers  have  also  been  obtained  by  the  synthetic 
methylated  phenanthrene-g-carboxylic  acids  by  rejection  of  CO2, 
which  has  fixed  the  constitution  of  the  five  possible  and  known  iso- 
merides  :  1-methoxy-phenanthrene  C14H9-[i-](OCH3),  m.p.  106°, 
2-phenanthrol  C14H9[2]OH,  m.p.  168°  (methyl  ether,  m.p.  99°),  3- 
phenanthrol,  m.p.  124°  (methyl  ether,  m.p.  63°),  4-phenanthrol,  m.p. 
108°  (methyl  ether,  m.p.  68°),  formed  by  nuclear  synthesis  on  heating 
/3-naphthyl  iso-crotonic  acid. 

C*     TT  /"*TT  /"*     TT  f*T-T 

9-Phenanthrol,  phenanthrone  c^HcoH  or  tl\  —Co2'  m'P'  I53°> 
is  also  formed  by  the  reduction  of  phenanthraquinone  with  HI,  or  from 
phenanthrene-quinone  dichloride  C14HSOC12 ;  it  gives,  with  diazo- 
benzol  salts,  the  10-benzol-azo-9-phenanthrol,  m.p.  165°,  which  is  identi- 
cal with  the  product  of  the  action  of  phenyl-hydrazin  upon  phenanthra- 
quinone ;  2-,  3-,  and  9-phenanthrol  resemble  j8-naphthol  (A.  321,  276  ; 
B.  34,  1461,  3998  ;  41,  4215).  Of  the  amido-phenanthrols  (A.  321, 
286,  295)  and  the  dioxy-phenanthrenes,  the  9,  lo-derivatives  should 

be  separately  mentioned.  9, 10-Amido-oxy-phenanthrene  Ci2H8\(4NH , 
from  phenanthrene-quinone-oxime,  -imine  or  phenyl-hydrazone,  by 
reduction  easily  passes  into  phenanthrene-hydroquinone,  9,  lo-dioxy- 
phenanthrene  C14Hg(OH)2,  m.p.  147°- 148°,  which  is  best  formed  by 
reduction  with  zinc  and  glacial  acetic  acid,  or  with  H2S  in  alcoholic 
solution.  Nitro-phenanthrene-hydroquinones  have  been  obtained 
similarly  (B.  35,  3117). 

3, 4-Dimethoxy-phenanthrene,  dimethyl-morphol  C14H8(OCH3)2, 
m.p.  44°,  from  9-carboxylic  acid,  or  by  methylating  the  corresponding 
monomethyl-ether,  methyl-morphol  C14H8(OH)(OCH3),  which  is  a 
product  of  the  decomposition  of  the  alkaloid  codein  (q.v.)  (B.  33,  1816). 
3, 4, 5-Trioxy-phenanthrene  C14H7(OH)3,  m.p.  148°,  is  formed  by 
fusing  morphinol  with  caustic  potash  (B.  39,  1718). 

Phenanthrene-carboxylic  Acids. — Their  nitriles  have  been  obtained 
from  the  salts  of  the  sulphonic  acids  by  distillation  with  potassium  ferro- 
cyanide.  9-Phenanthrene-carboxylic  acid  and  its  substitution  pro- 


PHENANTHRENE  GROUP  691 

ducts  have  also  been  obtained  synthetically  by  method  4  (above). 
2-,  3-,  and  9-Cyano-phenanthrene  C14H9.CN,  m.p.  105°,  102°,  and  103°  ; 
2-,  3-,  and  9-phenanthrene-carboxylic  acids,  m.p.  254°,  269°,  and  250° 
(A.  321,  322).  8,  9-Phenanthrene-dicarboxylie  acid,  anhydride,  m.p. 
284°,  synthetically  by  method  4  (B.  39,  3115). 

1-,  2-,  3-,  and  4-Methoxy-phenanthrene-9-carboxylic  acid  C14H8 
(OCH3)CO2H,  m.p.  215°,  228°,  239°,  and  224°,  and  3,  4-dimethoxy- 
phenanthrene-g-carboxylic  acid  C14H7(OCH3)2COOH,  m.p.  228°,  from 
the  corresponding  methoxy-amido-a-phenyl-cinnamic  acids,  split  off 
CO  2  on  distillation  and  form  methoxy-phenanthrenes  (B.  34,  3998). 
2,3-  and  3,  2-Phenanthrol-carboxylic  acid  C14H8(OH).CO2H,  m.p.  227° 
with  decomposition  and  303°  with  decomposition,  have  been  obtained  by 
a  salicylic  acid  synthesis  by  2-  and  3-sodium-phenanthrol  by  heating 
with  CO  2  under  pressure.  They  are  coloured  yellow  and  resemble 
2,  3-oxy-naphthoic  acid  (B.  35,  4419).  3,  4-Dimethoxy-phenanthrene- 
8-carboxylic  acid,  m.p.  196°,  has  been  obtained  from  apo-morphin,  a 
transformation  product  of  morphin  (q.v.),  by  methylation  and  decom- 
position (B.  40,  1998). 

Hydro-phenanthrenes.  —  By  reduction  of  phenanthrene  with  sodium 
and  amyl  alcohol,  or  by  hydrogen  in  the  presence  of  finely  divided 
nickel,  colloidal  platinum,  or  palladium,  as  well  as  heating  with  HI  and 
phosphorus,  we  obtain  9,  10-dihydro-phenanthrene  C14H12,  m.p.  94°, 
b-P-  313°.  Tetra-,  hexa-,  octo-,  deca-,  dodeca-,  and  per-hydro-phenan- 
threne  C14H14,C14H16,  C14H18>  C14H20,  C14H22,  and  C14H24,  b.p.  310°,  306°, 
28o°-285°,  275°,  269°,  and  27o°-275°  (B.  41,  1000,  4225  ;  C.  1905,  I. 
1396  ;  1911,  I.  651). 

Derivatives  of  the  9,  lo-dihydro-phenanthrene  are  found  in  the  di- 
tertiary  glycols  obtained  by  the  action  of  alkyl-  and  aryl-magnesium 
haloids  upon  phenanthraquinone  ditertiary  glycol  :  9,  10-dimethyl-, 

diethyl-,  and  diphenyl-9,10-dioxy-dihydro-phenanthrene  (C« 


m.p.  164°,  122°,  and  179°.     By  HI  and  phosphorus  they  are  reduced 
to  9,  lo-dialkyl-phenanthrenes,  and  by  chromic  acid  they  are  oxidised 


to  o,  o'-diacyl-diphenylene  (C«H«)»<Q3R>  from  which,  by  reduction, 
the  original  glycols,  or  other  stereo-isomeric  forms,  are  regenerated. 
On  heating  with  dehydrating  agents  they  undergo  pinacolin  transposi- 
tion and  form  10,  10-dialkyl-phenanthrones  (C6H4)a<^^  ,  (?)  10,  10- 

dimethyl-,  diethyl-,  and  diphenyl-phenanthrone,  m.p.  75°,  65°,  and  198°, 
(cp.  also  10,  lo-Diphenylene-phenanthrone)  (A.  362,  242  ;  B.  37,  2887  ; 
C.  1905,  I.  878). 

Phenanthraquinone  (C6H4)2(CO)2  is  formed  in  the  action  of  chromic 
acid  upon  phenanthrene  in  glacial  acetic  acid  solution  ;  most  readily 
by  heating  it  with  a  chromic  acid  mixture  (A.  196,  38).  It  crystallises 
in  long,  orange-yellow  needles,  melts  at  198°,  and  distils  without  decom- 
position. It  dissolves  readily  in  hot  alcohol,  ether,  and  benzene,  but 
sparingly  in  water.  It  dissolves  in  concentrated  sulphuric  acid  with  a 
dark-green  colour,  and  is  reprecipitated  by  water.  By  adding  toluene 
containing  thiotolene  and  sulphuric  acid  to  the  acetic  acid  solution 
of  phenanthraquinone  a  bluish-green  coloration  is  produced  (see 
Thiophenc). 

In  behaviour  it  recalls  /3-naphtho-quinone.     It  is  odourless,  not 


692  ORGANIC  CHEMISTRY 

volatile  in  steam,  unites  with  one  and  two  molecules  of  hydroxylamine, 
and  is  not  reduced  by  sulphuric  acid. 

Phenanthraquinone-monoxime  C14H8O(N.OH)  consists  of  golden- 
yellow  needles,  melting  at  158°.  If  it  is  heated  together  with  glacial 
acetic  acid  and  hydrochloric  acid  to  130°  it  sustains  the  transposition 
of  ketoximes,  and  forms  diphenimide  (B.  21,  2356)  : 

C6H4— C  :  NOH  C6H4— CO 

I         I  >  I 

C6H4— CO  C6H4— CO 

^N. 

The  dioxime  forms  an  anhydride  C14H8^    No,  melting  at   181°. 

This  is  a  furazane  derivative. 

The  monophenyl-hydrazone  of  phenanthraquinone  is  identical  with 

/C.OH 
the  9,  lo-benzol-azo-phenanthrol  (C6H4)2<(  j|  .     Also,  the  acyl- 

XC.N  :  NC6H5 

phenyl-hydrazones  obtained  by  the  transformation  of  as-acetyl- 
and  benzoyl-phenyl-hydrazin  with  phenanthraquinones  pass  spontane- 
ously into  the  isomeric  O-acyl-compounds  of  9,  lo-benzol-azo-phen- 
anthrol  (A.  378,  211). 

Phenanthraquinone,  being  an  o-diketone,  forms  phenazin  deriva- 
tives with  o-diamines.  See  B.  24,  R.  630,  631,  for  the  condensations  of 
aceto-acetic  ester  and  acetone.  By  oxidation  with  chromic  acid,  or 
by  boiling  with  alcoholic  potash,  phenanthraquinone  is  oxidised  to 
diphenic  acid  ;  ignition  with  soda-lime  produces  diphenylene-ketone, 
fluorene,  and  diphenyl.  Diphenylene-gly collie  acid,  fluorene  alcohol, 
and  diphenylene-ketone  are  obtained  on  boiling  with  aqueous  soda-lye. 
Ignition  with  zinc  dust  produces  phenanthrene. 

By  sulphurous  acid,  or  hydrogen  sulphide,  it  is  reduced  to  phen- 
anthrene-hydroquinone,  by  HI  to  phenanthrone.  With  HI  and  phos- 
phorus in  glacial  acetic  acid  we  obtain  aceto-phenanthrene-hydro- 
quinones  C14H8(OH)(OCOCH3),  m.p.  78°  (B.  26,  R.  585  ;  C.  1897,  II. 
1072).  Mixtures  of  phenanthrene  and  quinone  in  sunlight  give  acidyl- 
phenanthrene-hydroquinones  (A.  249,  137).  With  phenol  it  can  be 
condensed  to  phenoxy-phenanthrene-hydroquinone  (C.  1900,  II.  360). 

Bromine  acts  upon  phenanthrene-quinone  at  low  temperatures  with 
formation  of  an  addition  product  C14H8O2Br2  (B.  37,  3556).  At  100° 
substitution  products  are  formed  :  2-bromo-  and  2,  7-dibromo-phen- 
anthrene-quinone,  m.p.  234°  and  323°.  3-  and  4-bromo-phenanthrene- 
quinone,  m.p.  286°  and  126°,  have  been  obtained  from  3,  9-  and  4,  9- 
dibromo-phenanthrene ;  2-chloro-phenanthrene-quinone,  m.p.  236°, 
from  2,  9,  lo-trichloro-phenanthrene  by  oxidation  with  CrO3  (B.  37, 
355i;  39,3893). 

By  heating  with  nitric  acid,  phenanthrene-quinone  is  converted  into 
2-  and  4-nitro-phenanthrene-quinone  C14H7(NO2)O2,  m.p.  257°  and 
180°,  and  after  prolonged  action  into  2, 7-  and  4, 5-dinitro-phen- 
anthrene-quinone  C14H6(NO2)2O2,  m.p.  3oo°-3O3°  and  228°.  3-Nitro- 
phenanthrene-quinone,  m.p.  275°,  is  formed  from  g-bromo-phenan- 
threne,  as  well  as  from  9,  lo-diacetamido-phenanthrene  with  nitric  acid 
(B.  41,  3679).  By  oxidation  with  chromic  acid  mixture  nitro-phen- 
anthrene-qui nones  yield  nitro-diphenic  acids  ;  by  means  of  reduction, 
amido-phenanthrene-quinones  have  been  obtained,  and  from  tnese  oxy- 


PHENANTHRENE  GROUP  693 

phenanthrene-quinones  (B.  36,  3726  ;  A.  322,  135).  The  latter  also 
result  from  acidulated  phenanthrols  by  oxidation  with  CrO3  :  3-oxy- 
phenanthrene-quinone  C14H7(OH)O2,  in  needles  resembling  alizarin  and 
capable  of  sublimation  ;  2-oxy-phenanthrene-quinone,  dark  violet 
needles,  m.p.  28o°-283  ;  4-oxy-phenanthrene-quinone,  red  powder, 
m.p.  285°  (B.  44,  740).  3,  4-Dioxy-phenanthrene-quinone,  morphol- 
quinone  C14H6(OH)2O2  (diaceto-compound,  m.p.  196°)  has  been  ob- 
tained from  3-oxy-phenanthrene-quinone  by  way  of  the  nitro-  and 
amido-compounds  (B.  41,  3696). 

3-Phenanthrene-quinone-sulphonie  acid  C14H7O2(SO3H)  from  3- 
phenanthrene-sulphonic  acids  with  CrO3  (A.  321,  339). 

Retene     or     l-methyl-7-iso-propyl-phenanthrene 

:H3[l]CeH3\CHTcEpC'H3[73C3H7'  melting  at  98°  and  boiling  at  394°,  is 
a  homologue  of  phenanthrene. 

Retene  occurs  in  the  tar  of  highly  resinous  pines,  and  in  some 
mineral  resins.  It  is  isolated  from  those  portions  that  boil  at  elevated 
temperatures. 

It  results  from  the  distillation  of  abietic  acid  (probably  a  deka- 
hydro-retene-carboxylic  acid)  with  sulphur  (B.  36,  4200).  Its  picrate 
forms  orange-yellow  needles,  melting  at  123°.  Chromic  acid  in  glacial 
acetic  acid  solution  oxidises  retene  to  retene-quinone  C18H16O2  (methyl- 
iso-propyl-phenanthraquinone),  melting  at  197°.  It  resembles  phen- 
anthraquinone  in  its  entire  behaviour.  Sodium  hydrate  converts 
retene-quinone  into  : 

Retene-diphenic  acid  C^I^CQ'H  and  retene-glycollic  acid  C16H16. 
C(OH).CO2H.  Potassium  permanganate  oxidises  retene-quinone  to 
retene  -ketone  C 


lene-ketone-i-carboxylic    acid    CO2H[i3C<H3^--7C6H3[7]C(OH)(CH3)2 

diphenylene-ketone-i,  y-dicarboxylic  acid  co 

the  latter,  in  turn,  passing  into  a  mixture  of  1,2,  3-  and  i,  2,  4-benzol- 
tricarboxylic  acid.  The  7-oxy-iso-propyl-diphenylene-ketone-i-car- 
boxylic  acid  can  be  broken  down  to  p-iso-propyl-diphenyl  C6H5.C6H4 
[4]C3H7  by  means  of  KOH,  reduction  with  HI,  and  rejection  of  the 
carboxyls,  which  proves  the  position  of  the  side-chains  in  retene  (C. 
1910,  I.  1530). 

Retene  dodeca-hydride,  dehydro-fichtelite  C18H30  is  an  oil,  boiling  at 
336°.  It  is  formed  when  retene  is  heated  with  hydriodic  acid  and  phos- 
phorus to  250°,  and  also  in  the  action  of  iodine  upon  fichtelite  C18H32, 
melting  at  46°,  which  occurs,  together  with  retene,  in  the  peat  of  fossil 
plants  (B.  22,  498,  635,  780,  3369). 

Chrysene  and  picene  possess  a  structure  similar  to  that  of  phenan- 
threne. They  can  be  derived  from  phenyl-naphthalene  and  dinaphthyl 
the  same  as  phenanthrene  from  diphenyl  : 

C6H4—  CH  C6H4—  CH  C10H8—  CH 

C6H4—  CH  C10H6—  CH  C10H6—  CH 

I       Phenanthrene  Chrysene  Picene. 

The  constitution  of  these  bodies  is  deduced  mainly  from  the  pro- 


694  ORGANIC   CHEMISTRY 

ducts  of  their  oxidation.  Chromic  acid  first  changes  them  to  chryso- 
quinone  and  piceno-quinone,  which  can  be  further  transposed  into 
chrysene-  and  picene-ketones,  chrysenic  acid  and  picenic  acid,  j3-phenyl- 
naphthalene  and  jS-dinaphthyl  : 

C6H4  .  CO  C6H4X  C6H5  C6H5 

C10H6—  CO  Ci0H6/  C10H6.COOH  C10H7 

Chryso-quinone    Chrysene-  ketone       Chrysenic  acid    /5-Phenyl-naphthalene. 

cioHe  —  CO  C10H6,  C10H7  C10H7 

C10H6—  CO  C10H/  C10H6.COOH  C10H7 

Piceno-quinone       Picene-ketone  Picenic  acid  /S-Dinaphthyl. 

Chrysene  C18H12,  m.p.  250°  and  b.p.  448°,  consists,  in  a  pure  con- 
dition, of  silver-white  flakes  with  a  violet  fluorescence.  When  impure 
it  has  a  yellow  colour  (hence  the  name  from  ^pucreo?,  gold-yellow). 
It  occurs  in  those  portions  of  coal-tar  which  have  high  boiling-points. 
It  can  be  synthesised  from  phenyl-naphthyl-ethane  C6H5.CH2.CH2. 
C10H7,  just  as  phenanthrene  is  produced  from  dibenzyl  ;  also  by  heat- 
ing naphthalene  with  cumarone.  It  is  formed  in  large  quantities  by 
heating  indene  2C9H8—  C1QH12+4H  (B.  26,  1544).  See  B.  24,  949,  for 
substituted  chrysenes.  The  hydrides,  C18H28,  b.p.  360°,  and  C18H30, 
m.p.  115°  and  b.p.  353°  (B.  22,  135),  result  upon  heating  chrysene  with 
hydriodic  acid  and  phosphorus. 

When  digested  with  chromic  acid  and  glacial  acetic  acid  chrysene 
oxidises  to  so-called  chryso-quinone  C18H10O2  (a  diketone),  which  cry- 
stallises in  red  needles,  melting  at  235°. 

Chryso-ketone  C17H10O  results  when  chryso-quinone  is  distilled  with 
lead  oxide.  Hydriodic  acid  and  phosphorus  reduce  it  to  chryso-fluorene 
C17H12. 

On  boiling  with  permanganate,  chrysene-qumone,  and  chrysene- 
ketone  even  more  readily,  give  diphthalic  acid  COOHC6H4CO.COC6H4 
COOH.  On  heating  with  soda-lime  or  potash  and  PbO2,  chrysene- 
quinone  yields  chrysenic  acid  or  jS-phenyl-a-naphthoic  acid,  which  by 
rejection  of  CO,  yields  fi-phenyl-phthalin  (B.  26,  1745).  A  transposi- 

7C  :  NOH 

tion  of   chrysene-quinone-oxime  C16H10/  |  ,  m.p.  161°,  produces 

CO 

at    100°    two    isomeric    amido-acids    C16H10<^  ,   m.p.   220°   and 


C6H4COOH 

275°,  which  on  saponification  give  chryso-diphenic  acid    I 

C10H6COOH 
m.p.  199°,  and,  in  the  manner  of  diphenaminic  acid,  are  converted  by 

sodium  hypochlorite  into  a-  and  jS-naphthanthridone  ^^  6CO  ,   m.p. 

332°,  and  ^6NCH  >  m.p.  338°  (A.  311,  257  ',  335,  124  ;  B.  35,  2744). 

Picene  C22H14  is  the  hydrocarbon  with  the  highest  melting-point 
(364°)  .  It  is  formed  by  the  distillation  of  lignite,  coal-tar,  and  petroleum 
residues.  It  can  be  synthesised  from  naphthalene  and  ethylene 
bromide  by  means  of  A1C13  (B.  24,  R.  963  ;  32,  3341  ;  C.  1910,  II.  471). 
It  is  very  sparingly  soluble  in  most  solvents,  but  most  readily  in  crude 
cymol.  When  heated  to  250°  with  hydro-iodic  acid  and  phosphorus, 


FLUORENE   GROUP  695 

picene-perhydride  C22H36  is  produced.  It  melts  at  175°.  Picene  is 
oxidised  by  chromic  acid  to  an  orange-red  quinone  C22H12O2,  which, 
like  chrysene,  is  changed  on  the  one  hand  to  picene-ketone,  picene- 
fluorene  alcohol,  and  picene-fluorene  (C10H6)2CH2,  and  on  the  other  to 
picenic  acid  or  dinaphthyl-carboxylic  acid  and  j3-dinaphthyl  (B.  26, 


Pyrene  C16H10,  lemon-yellow  plates,  m.p.  149°,  b.p.60  260°  ;  picrate, 
m.p.  222°  ;  it  is  converted,  by  chromic  acid  in  glacial  acetic  acid,  into 
pyrene-quinone  C16HSO2,  and  on  further  oxidation  to  pyrenic  acid 
C12H6(CO)(COOH)2  (M.  31,  861),  a  ketone-dicarboxylic  acid  which 
easily  shows  anhydride  and  imide  formations  (B.  19,  1997),  and,  on 
distillation,  produces  pyrene-ketone  C12HS(CO),  m.p.  141°.  On  oxidis- 
ing pyrenic  acid  with  MnO4K,  we  obtain  i,  4,  5,  8-naphthalene-tetra- 
carboxylic  acid,  and  from  pyrene-ketone  naphthalic  acid.  On  the 
constitutions  of  pyrene,  as  one  of  the  ring  systems  consisting  of  four 
condensed  benzene  nuclei,  see  B.  20,  365  ;  A.  351,  218. 

Triphenylene  ^624'^~  S=£2,  white  needles,  m.p.  198°,  is  formed 

L,6rl4.C  —  Crl  =  Crl 

on  conducting  benzene  vapours  through  incandescent  tubes.  Fuming 
nitric  acid  oxidises  it  to  mellithic  acid.  A  dodeca-hydro-triphenylene 
Ci8H24,  m.p.  233°,  is  formed  by  the  condensation  of  cyclo-hexanone 
with  alcoholic  H2SO4,  as  mesitylene  from  acetone  (B.  40,  153).  See 
also  tricyclo-trimethylene  benzol  C15H1S,  m.p.  96°  (B.  30,  1094). 

IV.  FLUORENE  GROUP. 

Just  as  phenanthrene,  chrysene,  and  picene  were  regarded  as  sym- 
metrical o2-ethylene  derivatives  of  diphenyl,  phenyl-naphthyl,  and 
dinaphthyl,  so  fluorene,  chrysene-fluorene,  and  picene-fluorene  may  be 
viewed  as  o2-methylene  derivatives  of  the  last-mentioned  hydrocarbons, 
and  accordingly  may  be  designated  diphenylene-methane,  phenylene- 
naphthylene,  and  dinaphthylene-methanes.  On  the  other  hand,  they  can, 
like  indene,  be  regarded  as  condensed  cyclo-pentadiene  derivatives  :  di- 
benzo-,  benzo-naphtho-,  and  dinaphtho-cyclo-pentadiene.  Fluorene 
is  also  closely  allied  to  diphenylene  oxide,  diphenylene  sulphide,  and 
diphenylene-imide  or  carbazol  (q.v.),  dibenzo-derivatives  of  furfurane, 
thiophene,  and  pyrrol  : 


CH2 
t,H/ 
Fluorene 


?'H> 

C.H/ 
Diphenylene 
oxide 

1  '    *\S 

Diphenylene 
sulphide 

1  '    4\NH 
C.H/ 

Diphenylene- 
imide. 

General  Methods  of  Formation.  —  I.  Fluorene  is  formed  by  con- 
ducting vapours  of  diphenyl-methane  through  tubes  heated  to  redness  ; 
chryso-fluorene  is  similarly  obtained  from  j8-naphthyl-phenyl-methane  : 


\CH,X 


2.  o-Diphenyl-carboxylic  acid,  phenyl-naphthyl-carboxylic  acid  or 
chrysenic  acid,  and  dinaphthyl-carboxylic  or  picenic  acid,  when  heated 
alone  or  in  the  form  of  salts,  yield  fluorene-,  chrysene-,  and  picene- 


696  ORGANIC   CHEMISTRY 

ketones,  which  can  be  readily  reduced  to  fluorene,  chryso-fluorene,  and 
picene-fluorene  ;  conversely,  the  acids  are  reformed  when  the  ketones 
are  fused  with  caustic  potash  : 

C6H4.COOH  -  >  C6H4x 

|  \CO. 

C6H5  «  ---  C6H/ 

3.  Fluorene-ketone  is  also  obtained  from  the  diazo-derivative  of 
o-amido-benzo-phenone  by  the  elimination  of  nitrogen  ;  similarly, 
chrysene-ketone  is  formed  from  o-amido-phenyl-a-naphthyl-ketone 
(B.  29,  826)  : 

C6H4—  N2OHC6H5  -  >  C6H4  ___  C6H4. 


4.  Phenanthraquinone,  chryso-quinone,  and  piceno-quinone,  when 
oxidised,  also  yield  the  ketones  of  the  corresponding  fluorenes  : 

C6H4—  CO  C6H4 

C6H4—  CO          ^C6H/ 

Fluorene,  diphenylene-methane  C13H10,  m.p.  113°  and  b.p.  295°, 
crystallises  in  colourless  leaflets  with  a  violet  fluorescence.  It  forms 
a  compound  with  picric  acid,  melting  at  81°. 

It  is  found  in  coal-tar  (fraction  27O°-3OO°)  ;  on  heating  with  sodium 
or  sodium  amide  to  I2o°-I5o°,  it  forms  a  sodium  salt  (C6H4)2  :  CHNa, 
by  means  of  which  it  can  be  detached  from  the  accompanying  hydro- 
carbons (B.  41,  2913). 

It  results  upon  exposing  diphenyl-methane  to  a  high  temperature 
(above),  and  in  the  reduction  of  diphenylene-ketone  with  zinc  dust  or 
upon  heating  it  to  160°  with  HI  and  phosphorus.  The  chromic  acid 
mixture  oxidises  it  to  diphenylene-ketone. 

In  fluorene  the  hydrogen  atoms  of  the  CH2  group  are  mobile  as  in 
cyclo-pentadiene  and  indene,  but  to  a  less  extent.  Heating  with  caustic 
potash  and  benzyl  chloride  forms  dibenzyl-fluorene  (C6H4)2C(CH2C6H5)2, 
m.p.  148°  ;  with  benzaldehyde,  cinnamic  aldehyde,  etc.,  it  condenses  to 
colourless  or  faintly  coloured  benzylidene-fluorene  (C6H4)2C  :  CHC6H5, 
m.p.  76°,  and  cinnamylidene-fluorene  (C6H4)2C  :  CH.CH  :  CHC6H5, 
m.p.  154°  ;  with  oxalic  ester  to  fluorene-oxalic  ester  (C6H4)2CHCOCO2 
C2H5,  m.p.  75°  ;  with  formic  ester  to  formyl-fluorene  or  diphenyl- 
acetaldehyde  (C6H4)2CH.CHO,  m.p.  about  70°  (B.  43,  2719)  ;  with 
amyl  nitrite  and  ethyl  nitrate  under  the  influence  of  potassium  ethylate 
free  from  alcohol,  it  yields  fluorenone-oxime  (C6H4)2C  :  NOH  and 
9-nitro-fluorene  (C6H4)2CHNO2  respectively,  which,  like  phenyl-nitro- 
methane,  occurs  in  an  acid  form  soluble  in  alkalies,  m.p.  135°,  and  a 
neutral  form,  insoluble  in  alkalies,  m.p.  182°  (A.  347,  290  ;  B.  33,  852  ; 

41,  3334). 

By  reduction  of  fluorene  with  HI  and  phosphorus,  or  hydrogen  and 
nickel,  we  obtain  perhydro-fluorene  C13H22,  b.p.  256°-258°,  D22  0-9203 
(B.  42,  920,  2093).  The  isolation  of  a  hexahydro-fluorene  C13H16, 
from  coal,  by  extraction  with  benzene,  or  distillation  in  a  vacuum,  is 
noteworthy  (B.  44,  2486). 

By  bromination  of  fluorene  in  boiling  chloroform  we  obtain  2,  7- 
dibromo-fluorene  C13H,Br2,  m.p.  164°,  and  2,  6(?),  7-tribromo-fluorene 


FLUORENE  GROUP  697 

C13H7Br3,  m.p.  200°  (B.  38,  3764).  g-Chloro-fluorene  C13H9C1,  m.p.  90° 
from  fluorene  alcohol  with  PC15  (B.  37,  2896). 

Nitration  of  fluorene  in  glacial  acetic  acid  produces  2-nitro-fluorene 
NO2  —  C13H9,  m.p.  153°,  which,  by  known  methods,  can  be  converted 
into  2-amidb-diazo-  and  oxy-fluorene  and  2-fluoryl-hydrazin.  Nitration 
of  the  2-acetamido-fluorene  produces  2,  7-  and  2,  1-amido-nitro- 
fluorene,  m.p.  232°  and  206°,  which  produce  2,  7-  and  2,  1-diamido- 
fluorene,  m.p.  164°  and  193°  (B.  34,  1758  ;  35,  3284)  ;  9-amido- 
fluorene,  two  modifications,  m.p.  54°  and  123°,  by  reduction  of  fluorenone 
oxime  (B.  41,  1243). 

Retene  -  fluorene,      i  -  methyl  -  7  -  iso  -  propyl  -  diphenyl  -  methane 

,H3)C«jH3  NcH2,  melting  at  97°,  is  derived  from  its  ketone  upon  dis- 
(C3H7)C6H3/ 

tillation  with  zinc  dust  .  Chry  so-fluorene  ,  naphthylene-phenylene-methane 
CIOH6  —  CH2  —  C6H4,  melting  at  180°,  is  erived  from  j3-benzyl-naphtha- 
lene  or  from  chryso-ketone.  An  iso-naphtho-fluorene  ff^pH«ffi^>cH2> 

m.p.  208°,  has  been  obtained  from  iso-naphtho-fluorenone  (A.  376,  276  ; 
B.  27,  953).  Picene-fluorene,  picylene-methane  (C10H6)2CH2,  melting 
at  306°,  is  produced  on  heating  its  ketone  to  i6o°-i75°  with  hydriodic 
acid  (A.  284,  70). 

This  is  isomeric  with  the  aa-  and  j8j3-dinaphtho-fluorene,  m.p.  236° 
and  186°,  obtained  from  aa-  and  j3j3-dinaphthyl  carbinol  (B.  43,  2832). 

Methyl-hexahydro-fluorene,  boiling  at  128°  (14  mm.),  results  from 
the  action  of  P2O5  upon  methyl-benzyl-cyclo-hexanol,  the  reduction 
product  of  benzylidene-methyl-cyclo-hexanone  (CH3)(OH)C6H9  :  CH2. 

C6H5  --  >  (CH3)C6H9.CH2.C6H4  (B.  29,  2962  ;   A.  305,  264). 

Diphenylene-phenyl-methane,  phenyl-  fluorene  (C6H4)  2CHC6H5,  melt- 
ing at  146°,  results  (i)  on  heating  triphenyl-methane  chloride  (C6H5)3CC1, 
or  potassium-triphenyl-methane  ;  (2)  from  triphenyl-carbinol  by  dis- 
tillation with  crystallised  phosphoric  acid  ;  (3)  from  fluorene  alcohol, 
benzene-sulphuric  acid  ;  (4)  from  9-chloro-fluorene,  benzene,  and  A1C13 
(5)  from  hydro-fluoranic  acid  by  distillation  over  soda-lime  ;  and  (6) 
by  reduction  of  diphenylene  -  phenyl  -  carbinol,  9  -  phenyl  -fluorenol 

C^  T-T  \.          /^~\TT 

,6    */C^         ,  m.p.  107°.     The  latter,  analogous  to  triphenyl-carbinol, 


is  obtained  from  diphenylene-ketone  with  phenyl-magnesium  bromide, 
or  by  oxidation  of  9-phenyl-fluorene  with  chromic  acid  ;  it  gives 
intensely  coloured  double  salts  and  perchlorate  ;  with  aniline  chloro- 
hydrate  it  condenses  to  diphenylene-p-amido-diphenyl-methane 
(C6H4)2C(C6H5)C6H4NH2,  m.p.  179°  ;  with  phenol  and  sulphuric  acid 
to  diphenylene-p-oxy-diphenyl-methane,  m.p.  191°  (B.  37,  73).  By 
the  action  of  PC15,  acetyl  chloride,  or  gaseous  HC1,  it  passes  into  9,  9- 
phenyl-chloro-fluorene  (C6H4)2CC1C6H5,  m.p.  79°,  which,  like  triphenyl- 
chloro-methane,  is  distinguished  by  the  mobility  of  its  chlorine  atom. 
By  heating  with  copper  powder  in  benzene  solution  it  passes  into 
di-biphenylene-diphenyl-ethane  (C6H4)  2(C6H5)C.C(C6H5)  (C6H4)  2,  m.p. 
254°.  This  forms  colourless  crystals  which  dissolve  colourless  in  the 
cold,  and  only  assume  a  dark-brown  colour  on  heating,  with  partial 
decomposition  into  two  molecules  biphenylene-phenyl-methyl  (^6^-4)2 
C(C6H5).  In  the  air  it  absorbs  oxygen,  and  accordingly  passes  into 


698  ORGANIC  CHEMISTRY 

the  corresponding  peroxide,  m.p.  193°.  Still  more  stable  is  the 
analogous  body  di-biphenylene-di-biphenyl-ethane  (C6H4)2(C6H5.C6H4)C. 
C(C6H4.C6H5)(C6H4)2,  m.p.  176°,  obtained  from  9,  9-biphenyl-chloro- 
fluorene  (C6H4)2CC1C6H4.C6H5,  m.p.  139°,  which  only  undergoes  a 
slight  dissociation  in  boiling  anisol  and  is  insensitive  to  oxygen,  both 
in  solution  and  in  the  solid  state  (A.  372,  21  ;  B.  43,  1753). 

Phenyl-chryso-fluorene  51^>ScHCtHi,  m.p.  195°,  from  diphenyl-a- 

t-/6"4   ' 

naphthyl-carbinol  with  concentrated  SO4H2  or  ZnCl2  (B.  38,  2215)  ; 
9,  9-diphenyl-fluorene  (C6H4)2C(C6H5)2,  m.p.  220°,  analogous  to 
diphenyl-monobiphenyl-carbinol  (B.  38,  4105). 

Diphenylene-diphenyl-ethane  (C6H4)  2CH.CH(C6H6)  2,  melting  at 
217°,  and  diphenylene-diphenyl-ethylene  (C6H4)2C  :  C(C6H5)2,  melting 
at  229°,  arise  in  the  breaking-down  of  diphenylene-diphenyl-succinic 

anhydride  ,  "    *  \  rr»^°'  mel:  :1&  at  256°»  one  °*  tne  reaction  products 


of  cold  concentrated  sulphuric  acid  upon  benzilic  acid.  Diphenylene- 
diphenyl-ethylene  is  produced  on  heating  benzo-phenone  chloride  with 
fluorene.  It  consists  of  colourless  crystals,  the  solutions  of  which  are 
coloured  intensely  yellow.  The  moderated  oxidation  of  this  body  with 
chromic  acid  gives  rise  to  9,  9-benzoyl-phenyl-fluorene  (C6H4)2C(C6H5) 
COC6H5,  m.p.  172°,  by  pinacolin  transformation  from  the  pinacone 
first  formed.  It  is  also  obtained  from  potassium-triphenyl-methane, 
or  potassium-9-phenyl-fluorene  with  benzoyl  chloride.  Alcoholic 
potash  breaks  it  up  into  9-phenyl-fluorene  and  benzoic  acid.  By 
reduction  with  HI  and  phosphorus,  benzoyl-phenyl-fluorene  is  converted 
into  9,  lo-diphenyl-phenanthrene,  with  reversal  of  the  pinacolin  trans- 
position and  expansion  of  the  ring  (B.  37,  2887). 

Bi-diphenylene-ethane  (C6H4)2CH.CH(C6H4)2,  colourless  needles, 
melting  at  246°,  is  produced,  together  with  bi-diphenylene-ethylene, 
bifluorene  (C6H4)2C  :  C(C6H4)2,  melting  at  188°,  on  heating  fluorene 
with  lead  oxide.  The  second  hydrocarbon  is  also  formed  on  heating 
fluorene  with  bromine,  chlorine,  or  sulphur,  and  by  the  action  of 
alcoholic  potash  upon  9-bromo-fluorene  (A.  376,  271)  ;  or  of  copper 
powder  upon  fluorene  dichloride  (B.  43,  1796). 

It  consists  of  beautiful  r^-coloured  needles.  Its  bromine  addition 
product  is  colourless,  and  when  heated  with  sodium  in  xylene  solution 
it  reverts  to  the  red  hydrocarbon  (B.  25,  3140  ;  A.  290,  238  ;  291,  i). 
The  following  diagram  is  interesting  from  the  point  of  view  of  the 
colour  of  highly  condensed  hydrocarbons  : 


C.H  C.H.  C.H  C.H,  C,H 

Tetraphenyl-ethylene.      Diphenylene-diphenyl-ethylene.      Bi-diphenylene-ethy- 
Colourless  Colourless  ;  yellow  in  solution          lene.     Red  needles. 

Compare  the  yellow  colour  of  acenaphthylene  and  the  red  colour  of 
diphenyl-fulvene.  On  oxidation  with  chromic  acid  the  di-biphenylene- 
ethylene  forms,  by  a  change  analogous  to  the  pinacolin  trans- 
position, besides  fluorenone,  a  10,  10  -  diphenylene  -  phenanthrone 

(C6H4)2  :  C—  C6H4 

I     I         (?),  m.p.    258°,    which    is    broken    up   by    alcoholic 
OC  —  C6H 


FLUORENE  GROUP  699 

potash  to  form  the  acid  (C6H4)  :  CH-C6H4.C6H4COOH.  The  same 
pinacolin  is  also  formed  in  the  reduction  of  fluorenone  with  zinc  dust 
and  acetyl  chloride.  It  is  probably  identical  with  the  so-called  di-bi- 
phenylene-ethylene  oxide  obtained  from  di-biphenylene-ethylene 
dibromide  by  heating  with  water.  By  reduction  with  HI  it  is  trans- 

f  TT    CT-T  f*  T-T 

formed    into    9, 10-diphenylene-phenanthrene    ^6H*  ^H'^'F  '    (?)    m-P- 

215°,  with  another  transposition  (B.  29,  2152  ;  37,  2894 ;  A.  291,  i). 

Fluorene  alcohol,  fluorenol  (C6H4)2CHOH,  m.p.  153°,  is  formed  from 
the  ketone  with  Na  amalgam  and  from  the  Na  salt  of  diphenyl-gly colic 
acid  by  heating  to  120°.  Like  fluorene  alcohol,  retene,  picene,  and 
chrysene-fluorene  alcohols,  m.p.  134°,  167°,  and  230°,  are  obtained. 
Fluorene  ether  [(C6H4)2CH]2O,  m.p.  228°,  from  9-chloro-fluorene  and 
Ag2O  (B.  43,  2490).  Methyl-,  ethyl-,  and  benzyl-fluorenol  (C6H4)2 
C(OH)R,  m.p.  174°,  101°,  and  139°,  are  formed  from  fluorenone  with 
the  corresponding  alkyl  Mg  haloids  (B.  38,  4105). 

Diphenylene-ketone,  fluorenone  \ 6 I*  >CO,  melting  at  84°  and  boiling 

C6H4/ 

at  341°  (B.  27,  R.  641),  is  obtained  from  diphenic  acid,  iso-diphenic  acid, 
and  o-diphenyl-carboxylic  acid  when  heated  with  lime  ;  by  oxidising 
fluorene  with  a  chromic  acid  mixture,  and  by  heating  phenanthra- 
quinone  with  caustic  lime  (A.  196,  45  ;  279,  257),  and  when  the  diazo- 
compound  of  o-amido-benzo-phenone  is  heated  with  water  (B.  28,  in). 
Potassium  permanganate  oxidises  it  to  phthalic  acid.  It  is  converted 
into  o-phenyl-benzoic  acid  on  fusion  with  potassium  hydroxide.  Its 
oxime  (C6H4)2C  :  NOH  melts  at  193° ;  the  phenyl-hydrazone  melts  at 
151°  (B.  29,  230,  R.  26).  

Retene-ketone    (C3H7)(CH3)(!:6H2.CO.C6H4  melts   at   90°.    Chryso- 

ketone,  naphtho-fluorenone  C6H4.CO.C10H6,  melts  at  130°.  On  the 
formation  of  the  latter  from  o-amido-phenyl-a-naphthyl-ketone,  see 
above.  An  iso-naphtho-fluorenone,  m.p.  152°,  has  been  obtained  by 
condensation  from  o-phthalaldehyde  with  a-hydrindone  by  means  of 
K  methylate  (A.  376,  269).  Picene-ketone  (C10H6)2CO,  m.p.  185°  ; 
aa-  and  /3/3-dinaphtho-fluorenone,  m.p.  225°  and  161°,  from  the  cor- 
responding dinaphtho-fluorenes  (B.  43,  2833). 

With  concentrated  HNO3  in  the  cold,  fluorenone  yields  a  loose 
addition  product  (C6H4)2CO.NO3H,  which  easily  separates  into  its 
components.  Energetic  nitration  gives  2, 7-dinitro-  and  2,  6,  7-trinitro- 
fluorenone,  m.p.  290°  and  181°  respectively  (B.  38,  3758). 

o-Oxy-diphenylene-ketone,  oxy-fluorenone  C6H3(OH).CO.C6H4,  melt- 
ing at  115°,  is  obtained  from  sym.  o-diamido-benzo-phenone  on  boil- 
ing its  diazo-salts  with  water,  together  with  xanthone  (B.  31,  3034)  ; 
and  from  1-amido-diphenylene-ketone,  m.p.  110°,  obtained  from  di- 
phenylene-ketone-i-carboxylic  amide  with  KOBr  (C.  1902,  II.  1472). 
The  i -oxy-fluorenone  forms  yellowish-red  or  dark-red  alkali  salts, 
showing  feeble  drying  properties. 

When  fused  with  caustic  potash  it  decomposes  into  o-phenyl- 
salicylic  acid  C6H5.C6H3(OH)COOH,  which  is  recondensed  by  concen- 
trated sulphuric  acid  to  oxy-diphenylene-ketone  (B.  23,  112).  4~Oxy- 
diphenylene-ketone  is  also  prepared  from  4-amido-diphenylene-ketone, 


700  ORGANIC  CHEMISTRY 

melting  at  138°,  which  is  obtained  from  diphenylene-ketone-carboxyl- 
amide  with  bromine  and  caustic  potash. 

By  fusing  with  potash  the  4-amido-fluorenone  is  transformed  into 
phenanthridone  (B.  28,  R.  455),  which  also  results  by  Beckmann's 
transposition  on  heating  the  oxime  of  fluorenone  with  zinc  chloride 
(B.  29,  230)  : 


C6H3(NH2)— CO— CGH4 >  C6H4— NH— CO— C0H4  < C6H4— C(NOH)— C6H4 

4-Amido-fluorenone  Phenanthridone  Fluorenone-oxime. 

2-Amido-fluorenone,  m.p.  163°,  from  2-nitro-fluorenone,  m.p.  222°- 
223°,  the  oxidation  product  of  2-nitro-fluorene,  by  reduction  with 
Am2S,  gives  with  the  diazo-salts  2-oxy-fluorenone,  m.p.  2io°-2ii° 
(B.  34,  1764).  3-Oxy-fluorenone,  m.p.  229°,  is  formed  from  synthetic 
3-oxy-fluorenone-4-carboxylic  acid  by  splitting  off  CO2. 

Carboxylic  Acids. — Diphenylene-acetic  acid,  fluorene-carboxylic  acid 
(C6H4)2CH.CO2H,  melting  at  221°,  results  on  reducing  diphenylene- 
glycollic  acid  with  hydriodic  acid  and  phosphorus.  Also  from  trichlor- 
acetic  ester  with  benzene  and  A1C13  (C.  1902,  II.  991).  Its  nitrile, 
m.p.  152°,  is  formed  from  diphenylene-acetaldoxime  with  acetyl 
chloride. 

Diphenylene-glycollie  acid,  ms-oxy-fluorene-carboxylic  acid  (C6H4)2 
C(OH).CO2H,  melting  at  162°,  is  produced  when  phenanthraquinone 
is  boiled  with  sodium  hydroxide.  In  this  instance  an  atomic  rearrange- 
ment occurs,  similar  to  that  observed  in  the  transition  of  benzile  to 
benzilic  acid,  or  of  j8-naphtho-quinone  to  oxy-indene-carboxylic  acids  : 

CgHgCO      H.O      C6H5V  C6H4 — CO      HO      C6H4x 

I       — *—+  \C(OH).COOH         |  I        — --*    I        \C(OH)COOH. 

C6H5CO  C6H/  C6H4— CO  C6H/ 

Chromic  acid  oxidises  it  to  diphenylene-ketone.  Analogues  of 
diphenylene-glycollic  acid  have  been  obtained  from  retene-  and 
chrysene-quinone  (above),  and  from  other  substituted  phenanthrene- 
quinones  (B.  38,  3737).  With  phenols  and  phenol  ethers  diphenylene- 
glycollic  acid  condenses  in  the  manner  of  benzilic  acid,  under  the  in- 
fluence of  tin  tetrachloride,  to  form  substituted  diphenylene-phenyl- 
acetic  acids  (B.  43,  2496).  With  PC15  it  forms  diphenylene-chloro- 
acetic-acid  chloride,  m.p.  112°,  which,  on  treatment  with  zinc  chips  in 
ether  solution,  passes  into  diphenylene-ketene  (C6H4)2C  :  CO,  golden- 
yellow  spears,  m.p.  90°,  an  analogue  of  diphenyl-ketene  (B.  39,  3062). 

Fluorene-oxalic  acid  (C6H4)2CH.COCOOH+H2O,  m.p.  I5o°-i5i°, 
decomposes  on  heating  into  CO,  CO2,  and  fluorene  ;  its  esters,  formed 
from  fluorene,  oxalic  ester,  and  sodium,  give,  with  Na  alcoholate  and 
ICH3  or  IC2H5,  methyl-  and  ethyl-fluorene-oxalic  esters,  and,  by  splitting 
up  the  latter,  9-methyl-fluorene  (C6H4)2CHCH3,  m.p.  46°-47°,  and 
9-ethyl-fluorene  (C6H4)2CHC2H5,  m.p.  108°,  b.p.ls  166°  (B.  35,  759). 

_co      COOH 

Diphenylene-ketone-carboxylic  acids,  or  i-acid    I    I    ~l     i 

The  a-acid,  melting  at  191°,  is  produced  by  the  oxidation  of  fluoranthene 
with   a   chromic   acid   mixture.     Sodium   amalgam   converts   it   into 

a-fluorenic  acid  C6H4.CH2.C6H3.CO2H,  melting  at  245°,  which  yields 
fluorene  if  it  be  distilled  with  zinc  dust.     Iso-diphenic  acid  results 


FLUORENE  GROUP  701 

when  it  is  fused  with  potassium  hydroxide,  while  heating  with  lime 
breaks  it  down  into  carbon  dioxide  and  diphenylene-ketone. 

C0_ 
The  y-,  ortho-,  or  4-acid  J  —  p  —  J  —  !—  is  formed  when  diphenic 

HOCO 

acid  is  heated.  It  melts  at  227°.  Fusion  with  caustic  potash  changes 
it  to  diphenic  acid  (B.  20,  846  ;  22,  R.  727).  Also  from  diphenic 
anhydride  with  A1C13  in  benzene,  besides  o-benzoyl-fluorenone,  m.p.  95° 
(C.  1902,  I.  875). 

HOCO     CO 
Diphenylene-ketone-1,  7-dicarboxylic    acid       Jj  _  n  _  ^j  _  I  COOH 

is  formed  from  retene-quinone  (above)  with  MnO4K.  It  is  a  yellow 
powder,  decomposing  at  270°  into  CO2  and  diphenylene-ketone-2-ear- 
boxylic  acid,  m.p.  275°.  Distilled  with  lime  it  forms  diphenyl.  On 
heating  its  silver  salt  it  forms  diphenylene-ketone,  and,  on  further 
oxidation  with  MnO4K,  a  mixture  of  I,  2,  3-  and  I,  2,  4-benzol-tricar- 
boxylic  acid  (A.  229,  158  ;  C.  1904,  II.  449  ;  1910,  I.  1530). 

co_ 
3-Oxy-diphenylene-ketone-2-carboxylie    acid     |    I    -  _  j  _  LCOOH, 

OH 

m.p.  278°,  is  formed  by  nuclear  synthesis  in  the  action  of  concentrated 
potash  upon  indane-dione-methenyl-aceto-acetic  ester  (C.  1906,  1.  849). 

C10H5-COOH 
Chryso-ketone-carboxylic  acid   I       \co      ,  m.p.  283°,  is  formed, 

C6  H4/ 

besides  small  quantities  of  an  isomeric  acid,  by  the  action  of 
concentrated  SO4H2  upon  chryso-diphenic  acid  (A.  335,  119).  A 
third  isomeric  allo-chryso-ketone-earboxylie  acid,  m.p.  288°,  has  been 
obtained  by  heating  i-phenyl-naphthalene-2,  3-dicarboxylic  acid  with 
concentrated  H2SO4  (C.  1908,  II.  1360). 

Fluor  anthene  and  pyrene,  occurring  in  the  "  stubb  fat  "  of  Idria, 
are  also  found  with  the  condensed  hydrocarbons  just  mentioned  in  the 
high  boiling  fractions  of  coal-tar. 

Fluoranthene  C15H10,  idryl,  melts  at  110°.  Its  picric  acid  compound 
melts  at  182°.  Fluoranthoquinone  C15H8O2  is  obtained  by  oxidising 
idryl  with  chromic  acid.  It  melts  at  188°,  and  may  be  further  oxidised 
(with  the  elimination  of  CO2)  to  obtain  a-diphenylene-ketone-car- 
boxylic  acid. 

The  constitution  of  fluoranthene  and  of  fluoranthoquinone  probably 
corresponds  to  the  formulae  (A.  200,  i)  : 


C8H4-  C6H4V  .4X 

>CH  >CHX  *\CO 

C6H3<^  C«H3\        >co  C.H3/ 

XCH=CH  \co/  \CO,H 

Fluoranthene  Fluoranthoquinone        ct-Diphenylene-ketone- 

carboxylic  acid. 

Cp.  also  phthalacene  C20H16  (B.    17,  1389  ;    C.   1908,  I.  644  ;    1909, 
I-  535). 

V.  ANTHRACENE  GROUP. 

Anthracene  (from  avdpa£,  carbon),  occurring  together  with  the  iso- 
meric phenanthrene  in  the  high-boiling  portions  of  coal-tar,  is  the 
parent  substance  of  a  large  group  of  bodies  to  which  a  series  of  vegetable 


702  ORGANIC  CHEMISTRY 

compounds,  and  in  particular  the  very  important  dye  (alizarin  ,purpurin, 
etc.)  of  madder  root  belong. 

Synthetic  Methods  for  the  Production  of  Anthracene  Derivatives. 

1.  Anthracene   may   be   formed   from   benzene,    acetylene   tetra- 
bromide,  and  A1C13  (B.  16,  623). 

2.  It  is  also  produced  from  methylene  bromide,  benzene,  and  A12C16. 
Dihydro-anthracene  is  the  primary  product,  but  it  loses  two  atoms  of 
hydrogen,  and  anthracene  results. 

3.  Further,  dihydro-anthracene,  and  subsequently  anthracene,  is 
obtained  (together  with  toluene)  from  two  molecules  of  benzyl  chloride 
on  heating  it  with  aluminium  chloride  or  with  water  to  200°  (Limpricht, 
1866),  when  dibenzyl  will  also  be  produced. 

Anthracene  may  also  be  derived  from  diphenyl-methane  with 
A1C13.  It  is  very  probable  that  the  diphenyl-methane  is  first  resolved 
into  benzyl  chloride  and  benzene.  Unsym.  diphenyl-ethane  in  an 
analogous  manner  yields  ms-dimethyl-anthracene  (B.  27,  3238). 

4.  Finally,  dihydro-anthracene  is  obtained  from  two  molecules  of 
o-bromo-benzyl  bromide  by  the  action  of  metallic  sodium  (B.  12,  1965) 
(cp.  p.  689)  : 

BrCHBr  /CHS 

(1)  C6H6+       I  +C6H6  -'->    C6H4<J      SC.Ht 

BrCHBr  XCH/ 

BrCH2Br  _  HB].  yCH. 

(2)  C6H6+       I  +C6H6  --  >    C.H4<    I     >C6H4 

BrCH2Br  XCH/ 

C1CH2  _  9Hn  /       \ 

(3)  C6H5X  +  \C6H6  -->    C6H/  |      >C6H4 

\CH2C1  XCH/ 

<CH2Br  Br 

Br         +BrCH 

Anthraquinones  are  obtained  (5^)  by  the  action  of  zinc  dust  upon 
the  chloride  of  phthalic  acid  and  benzene.  (56)  Similarly,  oxy-anthra- 
quinones  are  produced  on  heating  phthalic  anhydride  with  one  molecule 
of  a  mono-  or  polyhydric  phenol  and  sulphuric  acid  to  150°.  If  there 
is  an  excess  of  phenol  present,  phthaleins  result.  (6)  o-Benzoyl- 
benzoic  acid  and  P2O5  yield  anthraquinone  on  the  application  of  heat. 
The  substituted  benzoyl-benzoic  acids  form  the  substituted  anthra- 
quinones,  and  benzyl-benzoic  acid  forms  anthrone.  (7)  Di-  and  tetra- 
oxy-anthraquinones  are  formed  when  metaoxy-  and  dimeta-dioxy- 
benzoic  acids  are  heated  with  sulphuric  acid  : 


(ja)        C6H,  +CSH6 

(5b)        C.H 


C6H4<£°>C6H4 
(7)    OH.C,H4/  +  HOOC/C«H'°H  -  ->OH.C6H3<^>C6H3.OH 


The  methods  just  given  and  a  series  of  others  —  e.g.  the  production  of 
anthraquinone  from  o-tolyl-phenyl-ketone  and  lead  oxide,  and  that  of 


ANTHRACENE  GROUP  703 

anthracene  and  methyl-anthracene  from  otolyl-phenyl-ketone  and 
o-ditolyl-ketone  by  means  of  zinc  dust  (B.  23,  R.  198)  —  demonstrate 
the  accepted  symmetry  of  the  derivatives  of  anthracene,  which  is 
further  proved  by  the  following  fact  :  brominated  o-benzoyl-benzoic 
acid  from  o-phthalic  acid  yields  bromo-anthroquinone  ;  the  oxy-anthra- 
quinone  obtained  from  the  latter,  however,  can  be  oxidised  to  o-phthalic 
acid  ;  so  that  both  in  the  synthesis  and  decomposition  of  the  molecule 
o-phthalic  acid  appears,  which,  in  the  first  instance,  is  connected  with 
the  one  and  in  the  second  case  with  the  second  half  of  the  molecule 
(cp.  constitution  of  naphthalene)  (B.  12,  2124)  : 

r[i]CO.c6H5  _  VOHCH  /[I]CO[I]VH  _  >HOOC[I] 

Br.C6H3  ^  [2]COQH  -C6H3  ^  [2]CO[2]  j>C6H4  -       ->  HOOCj>] 

Therefore  anthraquinone  and  anthracene,  which  are  genetically  con- 
nected, have  a  symmetrical  constitution  corresponding  to  the  symbols  : 

CH  CO 


Anthracene  Anthraquinone. 

Anthracene  is  a  nucleus  resulting  from  the  condensation  of  three 
benzene  nuclei,  of  which  the  intermediate  or  middle  member  shows  a 
para-union.  The  positions  i,  4,  5,  8  (a-)  are  alike  ;  also  2,  3,  6,  7  (j3-). 
By  the  replacement  of  the  middle  hydrogen  atoms  of  anthracene 
y-derivatives  or  w^so-derivatives  are  obtained.  In  contrast  with  this 
the  substituents  of  the  two  outer  benzene  nuclei  are  designated  by  the 
prefix  benz.  In  most  of  the  anthracene  transpositions  the  intermediate 
C  atoms  are  first  attacked. 

Anthracene  C14H10,  melting  at  213°  and  boiling  at  351°,  is  isomeric 
with  phenanthrene,  and  is  produced  according  to  the  methods  indicated 
above.  (See  also  B.  28,  R.  148.)  It  is  found  in  large  quantities  in 
coal-tar. 

Crude  anthracene,  boiling  at  34O°-36o°  and  beyond,  is  best  purified 
by  treating  it  with  liquid  sulphurous  acid,  which  chiefly  takes  up  the 
admixtures  (B.  26,  R.  634).  For  additional  methods  of  purification,  see 
B.  18,  3034  ;  21,  R.  75  ;  A.  191,  288.  Chemically  pure  anthracene  is 
prepared  by  heating  anthraquinone  with  zinc  dust. 

Anthracene  crystallises  in  colourless  monoclinic  tables,  showing  a 
beautiful  blue  fluorescence.  It  dissolves  with  difficulty  in  alcohol  and 
ether,  but  easily  in  hot  benzene.  Picric  acid  unites  with  it,  yielding 
C14H10.C6H2(NO2)3OH,  crystallising  in  red  needles,  and  melting  at  138°. 

When  the  cold  saturated  solution  of  anthracene  in  benzene,  or, 
better,  in  xylene  (B.  26,  R.  547),  is  exposed  to  sunlight,  a  dimolecular 
modification  of  anthracene,  para-anthracene  (C14Hi0)2,  separates  out 
in  plates.  It  dissolves  with  difficulty  in  benzene,  is  not  attacked  by 
nitric  acid  or  bromine,  melts  at  244°,  and,  in  so  doing,  reverts  to 
common  anthracene. 

/CHV  /CRV 

Alkylic   Anthracenes.  —  (a)  c,H4</|    ^>C6H3R;  (b)  c6H4<(j    p>c6H4 

Benzalkyl  derivatives          meso-  or  y-Alkyl 

derivatives. 


704  ORGANIC  CHEMISTRY 

(a)  The  benzo-mono-alkylic  anthracenes  can  exist  in  two  isomerides 
(a-  and  )S-). 

a-Methyl-anthracene  C6H4(CH2)C6H3[i]CH3,  m.p.  86°,  is  formed  by 
zinc  dust  distillation  from  I,  4-chloro-methyl-anthraquinone  (/.  pr.  Ch. 
2,  83,  201). 

^-Methyl-anthracene  C6H4(CH2)C6H3[2]CH3,  m.p.  207°,  closely 
resembles  anthracene,  and  is  found  in  the  crude  anthracene  of  coal-tar. 

At  high  temperatures  it  is  formed  out  of  ditolyl-methane  and  ethane 
(/.  pr.  Ch.  2,  79,  555)  ;  also  by  boiling  benzoyl-xylol  C6H5CO.C6H3 
(CH3)2 ;  by  reduction  of  j8-methyl-anthraquinone  with  zinc  dust 
(A.  311,  181)  ;  and  from  vegetable  chrysophanic  acid  and  emodin, 
which  are  hydroxylated  methyl-anthraquinones.  By  oxidation  with 
nitric  acid,  methyl-anthracene  forms  methyl-anthraquinone,  and  with 
chromic  acid  mixture  and  oxidation  of  the  methyl  group  it  forms 
anthraquinone-carboxylic  acid.  In  sunlight  it  polymerises  like 
anthracene  to  dimethyl-dianthracene,  m.p.  229°  (C.  1899,  II.  623). 

1,  6-  and  2,  6-Dimethyl-anthraeene  C14H8(CH3)2,  m.p.  240°  and  244°, 
are  formed  together  from  toluol  and  methylene  chloride  or  acetylene 
tetrabromide  with  A1C13  (method  2).  The  second  body  has  also  been 
obtained  by  boiling  m-xylyl-tolyl-ketone  (C.  1910,  II.  1386  ;  1911,  I. 
1294).  From  the  aniline  oils  of  high  boiling-point  also  a  dimethyl- 
anthracene  has  been  obtained. 

(b)  Meso-  or    y-alkyl- anthracenes  are    obtained  from  the  alkylic 

/T^T?  /f>kTT\\ 

hydranthranols    C6H4\CH        /C6H4    by    the    elimination    of    water. 

This  happens  on  boiling  them  with  alcohol,  hydrochloric  acid,  or  picric 
acid  (A.  212,  100).  Alkylic  oxanthranols  are  formed  upon  oxidation  : 
y-ethyl-,  iso-butyl-,  and  amyl-anthracenes,  melting  at  60°,  57°,  and  59°. 
y-Phenyl-anthraeene  C14H9(C6H5),  melting  at  152°,  is  obtained  from 
phenyl-anthrone. 

y-  or  9, 10-Diphenyl-anthraeene  C6H4(C.C6H5)2C6H4,  m.p.  240°, 
from  diphenyl-dioxy-anthracene  hydride  with  zinc  dust  and  glacial 
acetic  acid  (C.  1904,  II.  117  ;  1906,  I.  44). 

y-  or  9, 10-Diriiethyl-anthraceneC6H4(C.CH3)2C6H4,  melting  at  179°, 
is  derived  from  its  dihydride,  the  condensation  product  obtained  from 
ethidene  chloride  and  benzene  by  means  of  A12C16  (see'  B.  21,  1176). 

9, 10-Dibenzyl-anthracene  C6H4(C.CH2C6H5)2C6H4,  m.p.  240°,  is 
formed  by  prolonged  boiling  of  anthracene  with  benzyl  chloride  and  a 
little  zinc  dust  in  CS2  solution  (C.  1902,  II.  745  ;  1904,  II.  1136). 

Substituted  Anthracenes. — Chlorine  and  bromine  acting  upon  the 
CS2  solution  of  anthracene  first  substitute  the  middle  CH  groups  with 
the  production  of  y-mono-  and  dihalogen-anthraeenes.  y-Dibromo- 
anthracene  is  also  formed  by  the  action  of  bromine  upon  anthracene 
hydride. 

The  action  of  nitric  acid  upon  anthracene  easily  produces  anthra- 
quinone  and  nitrified  anthraquinones.  But  on  nitrifying  with  acetic 
anhydride  and  sulphuric  acid  in  glacial  acetic  acid  at  i5°-2O°,  we  obtain 
9-nitro-anthracene  C14H9.NO2,  yellow  needles,  m.p.  i45°-i46°,  which 
may  be  distilled  under  reduced  pressure,  and  9, 10-dinitro-anthracene 
C10H8(NO2)2,  m.p.  294°.  These  compounds  are  easily  obtained  in- 
directly. On  digesting  anthracene  in  glacial  acetic  acid  with  one 
molecule  nitric  acid  at  30°-35°,  we  obtain  the  acetate  of  nitro-hydran- 


ANTHRACENE  GROUP  705 


thranol  cc<rtf  which,  with  HC1,  yields  the  corre- 

\C8H4/ 

spending  chloride,  with  N2O3  the  nitrite,  and  with  alcohol  the  ethers, 
also  produced  direct  on  nitrifying  with  HNO3  and  the  alcohols.  On 
treatment  with  alkali,  the  chloride  forms  g-nitro-anthracene,  and 
this,  treated  with  NO2  in  chloroform,  gives  trinitro-hydranthranol 

(NO2)2C<f^6^4\CH(NO2),  which,  with  alkali,  yields  9,  lo-dinitro-anthra- 

\C6H4/ 

cene.  In  a  similar  manner,  9-ethyl-10-nitro-anthraeene  C14H1S(C2H5) 
(NO  2),  m.p.  135°,  has  been  obtained  from  ethyl-anthracene.  By  boiling 
with  alcoholic  potash,  g-nitro-anthracene  has  been  transposed,  by  way 
of  several  intermediaries  due  to  the  addition  of  potassium  alcoholate, 

etc.,   into   anthraquinone  -  oxime   CH^ffi^c.NO^co^ffiNc  :  NOH 

\C6hL4/  \C,±i4/ 

(cp.  g-nitro-phenanthrene).  When  nitric  acid  acts  upon  anthracene 
in  iso-butyl  alcohol,  we  obtain  nitro-anthrone  CO(C6H4)2CH.NO2, 
which  is  converted  by  alkali  into  a  red  isomer  CO(C6H4)2C  :  NOOH  (?) 
(A.  330,  133  ;  B.  42,  1216). 

9-  or  meso-Amido-anthraeene,  anthramine,  m.p.  i45°-i5o°,  from 
g-nitro-anthracene  with  SnCl2  and  HC1  ;  dinitro-anthracene  cannot 
be  reduced  to  diamido-anthracene.  The  9-anthramine,  like  the  a-  or 
1  -anthramine,  m.p.  130°,  and  the  jS-  or  2-anthramine,  m.p.  237°,  has 
also  been  obtained  from  the  corresponding  oxy-anthracenes  by  heating 
with  NH3.  With  diazo-benzol  chloride,  the  9-amido-anthracene  unites 
to  form  benzol-azo-meso-anthramine  C6H5N  :  N.C14H8.NH2,  m.p.  183°, 
which  is  split  up  by  acids  into  anthraquinone,  phenyl-hydrazin,  and 
ammonia  (B.  40,  518),  and  passes  on  reduction  into  the  easily  oxidised 
1,  4-anthra-diamine  (B.  41,  1434)  ;  meso-phenyl-anthramine,  m.p. 
203°  (C.  1909,  II.  1249). 

Anthracene  -  sulphonic  acids  are  formed  from  anthracene  with 
sulphuric  acid,  and  by  reduction  of  anthraquinone-sulphonic  acids. 
1-Anthracene-sulphonie  acid,  see  B.  37,  70.  On  moderate  treatment 
with  dilute  sulphuric  acid,  anthracene  yields  2-anthracene-monosul- 
phonic  acid  C14H9.SO3H,  chloride,  m.p.  122°  (B.  28,  2258).  Concen- 
trated H2SO4  produces  i,  5-  and  i,  8-anthracene-disulphonic  acids 
(chlorides,  m.p.  249°  and  225°),  which,  on  fusion  with  potash,  form  the 
corresponding  dioxy-anthracenes  mfol  and  chrysazol  (B.  42,  1413). 

/CHX  /COHX 

Oxy-anthracenes:    (i)  C6H4/|     V6H3OH.    (2)  C6H/|       )>C6H4. 

x3H  CH    ' 

(i)  a-  and  jS-Monoxy-anthracene,  a-  and  j3-anthrol,  behave  like 
phenols  or  naphthols.  a-Anthrol,  from  i-anthracene-monosulphonic 
acid  by  fusion  with  potash,  forms  yellowish  flakes,  melting  at  152° 
(B.  37,  71).  /?-Anthrol,  from  jS-anthracene-sulphonic  acid  and  j8-oxy- 
anthraquinone,  is  changed  by  nitrous  acid  to  a-nitroso-/2-anthrol 
C6H4(CH)2C6H2(OH)(NO),  which,  upon  reduction,  yields  a-amido-jS- 
anthrol.  The  latter  may  be  oxidised  to  1,  4  -  anthraquinone 

CH—  C—  CO—  CH 
C6H4<(  J  melting  with  decomposition  at  208°,  and  isomeric 

\CH—  C—  CH—  CH 

with  a-naphtho-quinone  (B.  39,  926  ;    41,  1434  ;    A.  344,  78).     i,  2- 
Anthraquinone,  similarly  formed  from  the  a-anthrol,  gives  on  reduc- 
VOL.  II.  2  z 


706  ORGANIC  CHEMISTRY 

tion  with  zinc  dust  and  glacial  acetic  acid  1,  2-anthra-hydroquinone 
C6H4(CH)2C6H2(OH)2,  m.p.  131°  with  decomposition  (A.  342,  59). 
The  anthrols  can  only  be  oxidised  by  CrO3  to  oxy-anthraquinones 
after  acetylating  the  OH  group  (cp.  oxidation  of  phenols).  The  i,  2- 
anthra-hydroquinones  in  this  manner  yields  alizarin. 

Benzo-dioxy-anthraeenes.—  Two  isomerides  —  ehrysazol  and  rufol, 
m.p.  225°  and  265°—  having  the  formula  OH.C6H3  :  (CH)2  :  C6H3OH, 
are  obtained  from  a-  and  j8-anthracene-disulphonic  acids.  When  their 
acetyl  derivatives  are  oxidised  and  saponified,  chrysazine  and  anthra- 
rufin  result.  These  are  the  corresponding  dioxy-anthraquinones. 

2,  3-Dioxy-anthracene,  decomposing  at  180°  by  reduction  of 
hystazarin-dimethyl  ether  with  zinc  dust  and  NH3,  and  saponification 
with  HI  (A.  342,  90). 

(2)  meso  -  Oxy  -  anthracene,  anthranol  C6H4<^°H^>C6H4,  yellowish- 
brown  needles,  m.p.  120°  when  quickly  heated,  desmotropic  with 
anthrone  C6H4<^°  ^>C6H4,  colourless  brilliant  needles,  m.p.  155°  (A. 

379,  37).     The  latter  is  formed  synthetically  from  b-benzyl-benzoic 

/CH  r  TT 
acid  C6H4\QOOH      with  concentratecl  sulphuric  acid  at  90°  (B.  27, 

2789),  also  from  phthalide  chloride,  benzene,  and  A1C13,  and  is 
obtained  by  reduction  of  anthraquinone  with  tin  or  zinc  and  glacial 
acetic  acid  besides  dianthryl  (C14H9)2  (A.  379,  55  ;  C.  1908,  II.  1218). 
Anthranol  acetate,  m.p.  134°,  is  also  formed  by  the  oxidation  of 
anthracene  and  PbO2  in  glacial  acetic  acid  (A.  379,  75).  The  anthrone 
is  insoluble  in  cold  alkali,  but  dissolves  on  heating  with  formation  of 
salts  of  anthranol,  which  can  be  precipitated  from  this  solution  by  a 
careful  addition  of  dilute  H2SO4.  The  isomers  capable  of  independent 
existence  in  the  solid  state,  form,  on  solution  or  melting,  an  allelotropic 
mixture  of  both  forms,  in  which  the  more  stable  anthrone  is  predomi- 
nant. The  solutions  therefore  show  reactions  characteristic  of  both 
forms  :  on  heating  with  acetic  anhydride  we  obtain  anthranol  acetate, 
but  on  alkylating  with  C2H5I  and  potash  we  obtain,  simultaneously, 

anthranol  -  ethyl    ether    cH^^5i\coc2H5,    liquid,    ethyl  -  anthranol- 


/rir\ 
ethyl    ether    c2H5cx  r*"4  )coc2H5,    m.p.    77°,    and    diethyl  -  anthrone 

/r  w  \  \U*M4/ 

(C2H5)2C<^6£4>CO,   m.p.    136°    (B.    21,   2505).      With   benzaldehyde, 

\L/(j.rI4/ 

anthrone  condenses,  under  the  influence  of  piperidin,  to  benzylidene- 
anthrone  C6H5CH  :  C(C6H4)2CO,  yellow  needles,  m.p.  127°  (C.  1906,  I. 
138)  ;  with  benzo  -  phenone  chloride  to  diphenyl  -  anthraquinone- 
methane  (C6H5)2C  :  C(C6H4)2CO,  m.p.  196°  (C.  1910,  I.  1722).  With 
benzol  -  diazonium  chloride  it  forms  benzol  -  azo  -  anthranol 

C6H5N  :  NC^54^>COH,  m.p.  183°,  identical  with  the  anthraquinone- 

\C6ri4/ 

monophenyl-hydrazone  formed  from  dibromanthrone  CBr2(C6H4)2CO, 
m.p.  157°,  and  phenyl-hydrazin  (B.  40,  518).  By  the  action  of  atmo- 
spheric oxygen,  or  mild  oxidisers  like  FeCl3,  HgO,  etc.,  anthrone  and 
anthranol  are  oxidised  to  meso  -  dihydro  -  dianthrone  CO(C6H4)2CH. 
CH(C6H4)2CO,  m.p.  245°,  which  is  also  obtained  from  mono-brom- 
anthrone,  m.p.  148°,  by  heating  with  copper  powder.  It  is  insoluble 
in  alkalies,  but,  on  heating  with  alcoholic  alkali,  it  forms  the  alkali 


ANTHRACENE  GROUP  707 


salt  of  dianthranol  HOCcoH,  yeUowish  crystals,  m.p. 

\^6-"-4/  \£»**4/ 

230°,  easily  obtained  by  reduction  of  anthraquinone,  with  zinc  dust  and 
soda  under  pressure  at  160°,  and  transposed  by  alcoholic  HC1  into  meso- 
dihydro-dianthrone.  By  oxidation  with  FeQ3  it  passes  into  the 
dianthrone  CO(C6H4)2C  :  C(C6H4)2CO,  analogous  to  dipheno-quinone, 
in  the  shape  of  a  lemon-yellow  powder  from  which  zinc  dust  and  glacial 
acetic  acid  regenerate  dianthranol  (M.  30,  165). 

/S-Methyl-anthrone,  m.p.   87°  (C.   1910,   I.   1722).     Oxy-anthrone 

C6H4^  'Nc6H3(OH),    m.p.    221°,    is    prepared   from    oxy  -  dimethyl- 

methane-o-carboxylic  acid  (B.  31,  2793).  Dimethyl-amido-anthrone 
C14H10O[N(CH3)2],  m.p.  8o°-85°,  is  obtained  from  o-dimethyl-amido- 
benzyl-benzoic  acid,  with  H2SO4  (A.  307,  313). 

/C(OH)X 
Dioxy-anthrone  C6H4/  |         ^>C6H2(OH)2,  so-called  anthrarobin,  results 

when  alizarin  is  reduced  with  zinc  dust  and  ammonia.  It  has  been 
applied  therapeutically  in  certain  skin  diseases. 

A  few  isomeric  dioxy-anthranols  have  been  obtained  by  reduction 
of  quinizarin,  anthra-rufin-hystazarin,  and  chrysazin  with  HI  (B.  35, 
2923,  2930  ;  36,  2938). 

meso-Phenyl-anthrone  C6H5CH(C6H4)2CO,  m.p.  I4i°-i44°,  is  formed 
when  sulphuric  acid  acts  upon  triphenyl-methane-o-carboxylic  acid. 
Its  oxidation  product  is  phenyl-oxanthrone.  It  yields  phenyl-anthra- 
cene  by  reduction.  Substituted  triphenyl-methane-carboxylic  acids 
form  substituted  phenyl-anthrones.  In  accordance  with  their  source, 
the  hydroxyl  -  phenyl  -  anthrones,  like  dioxy  -  phenyl  -anthrone, 

c6H3OH,  have  been  designated  phthalidins  because 


they  are  formed  from  the  phthalins,  the  reduction  products  of  the 
phthaleins  or  diphenol-phthalides.  When  oxidised,  the  phthalidins 
become  phthalide'ins,  hydroxyl-phenyl-oxanthranols. 

Diphenyl-anthrone  CeH^^^a^H,,  m.p.  192°,  is  a  derivative 

of  anthrone.  It  is  obtained  by  condensing  unsym.  phthalylene 
tetrachloride  with  benzene,  as  well  as  from  phenyl-oxanthrone  by 
means  of  benzene  and  sulphuric  acid  (B.  28,  R.  772). 

On  reduction  with  zinc  dust  and  glacial  acetic  acid  it  yields  9,  9- 
diphenyl-dihydro-anthraeene.  Mixed  diaryl-anthrones  are  obtained, 
either  from  phenyl-oxanthrone,  benzene  homologues,  and  H2SO4,  or, 
with  benzene  derivatives  and  A1C13,  from  phenyl-oxanthranyl  chloride 
co</c(1H4\>c</CeH5^  mp  ^o.  the  latter  is  forme(i  from  diphenyl- 

phthalide  on  heating  with  PC15  to  140°  (C.  1898,  I.  209  ;  1899,  II. 
204).  With  phenols  it  condenses  on  simply  heating  the  components 
to  form  oxy-diphenyl-anthrones  (B.  38,  3802).  meso-Dichloranthrone 
CO(C6H4)2CC12,  m.p.  133°,  from  o-tolyl-phenyl-ketone  by  heating 
with  chlorine  to  120°,  or  by  heating  anthrone  with  Cl,  gives,  with 
dimethyl-aniline  and  A1C13,  tetramethyl  -  diamido  -  diphenyl  -  anthrone 
[(CH3)2NC6H4]2C(C6H4)2CO,  yellow  needles,  m.p.  278°  (C.  1903; 
I-  837). 

From  anthrone,  also,  the  group  of  anthro-cumarins  can  be  derived, 
These  are  produced  by  condensing  cinnamic  acids  and  oxy-benzoic 


7o8  ORGANIC  CHEMISTRY 

acids  by  means  of  sulphuric  acid.     Anthra-eumarin  §^4 

m.p.  260°,  from  m-oxy-benzoic  acid  and  cinnamic  acid  ;  dioxy-anthra- 
cumarin,  styro-gallol,  from  gallic  and  cinnamic  acids  (B.  20,  2588,  3143  ; 

C.  1899,  II.  967).  Cp.  also  the  benzoin  yellow  ^^^^^^  (?) 
produced  from  benzoin  and  gallic  acid  (B.  31,  2975). 

meso  -  Dioxy  -  anthracene,  anthra  -  hydroquinone  C6H4\£/O]  [\^C«H4' 
brown  needles,  with  a  diaceto-compound  melting  at  260°,  desmotropic 
with  oxanthrone  C6H4<^^  \c6H4,  white  needles  with  a  yellow 

tinge,  m.p.  167°,  are  related  to  each  other  like  anthranol  and  anthrone, 
except  that  mutual  transformation  in  solutions  is  exceedingly  slow, 
and  that  the  enol-form,  anthra-hydroquinone,  is  the  more  stable. 
Anthra-hydroquinone  is  formed  by  reducing  anthraquinone  with 
zinc  dust  and  potash ;  it  oxidises  back  to  anthraquinone  in  the  air. 
In  alkalies  it  easily  dissolves  with  a  red  colour.  Treatment  with 
alcoholic  HC1  converts  it,  to  a  slight  extent,  into  oxanthrone,  which  is 
easily  obtained  by  heating  bromanthrone  with  aqueous  acetone,  or 
direct,  by  the  action  of  bromine  upon  anthracene  in  aqueous  acetone 
solution.  Reduction  with  zinc  dust  and  glacial  acetic  acid  produces 
anthranol  and  anthrone  respectively.  Heating  with  alkali  or  alcoholic 
HC1  converts  oxanthrone  into  anthro-hydroquinone.  On  alkylating 
anthra-hydroquinone  with  alkyl  iodide  or  dialkyl  sulphate  and  alkali, 
the  mono-  and  dialkyl  ether  of  anthra-hydroquinone  and  alkyl- 

oxanthrone  are  obtained  together  CflH4/c(o^?Alk\c6H4  (A.  379,  43). 

Anthracene -carboxylic  Acids. — The  a-  and  j8-acids  C6H4(CH)2 
C6H3COOH  are  formed  from  the  anthracene-monosulphonic  acids  by 
means  of  the  cyanides,  and  from  the  anthraquinone-carboxylic  acids 
by  reduction  with  ammonia  and  zinc  dust ;  the  a-acid  melts  at  245°, 
the  j8-acid  at  281°. 

meso-Anthracene-carboxylic  acid  is  formed  from  its  chloride,  which 
is  produced  when  anthracene  is  heated  with  phosgene  or,  better,  oxalyl 
chloride,  to  160°  (B.  44,  205).  It  melts  at  217°  with  decomposition. 
Chromic  acid  oxidises  it  to  anthraquinone. 

meso-Benzoyl-anthracene,  anthra-phenone  C14H9.COC6H5,  m.p.  148°, 
is  obtained  from  anthracene,  benzoyl  chloride,  and  zinc  dust  or  A1C13. 
In  the  latter  case  two  isomers,  melting  at  75°  and  203°  respectively,  are 
also  obtained  (B.  33,  816  ;  34,  2766). 

Hydro-anthracenes. — Anthracene  dihydride  C14H12  results  from  the 
action  of  sodium  amalgam  upon  the  alcoholic  solution  of  anthracene. 
It  can  also  be  obtained  by  many  other  synthetic  methods.  On  heating 
with  hydriodic  acid  or  with  hydrogen  and  nickel  at  200°-25o°,  we 
obtain  tetra-,  -hexa-,  -octo-,  and  -perhydride  C14H14,  C14H16,  C14H18, 
and  C14H24,  m.p.  89°,  63°,  7*°>  and  88°,  b.p.  310°,  290°,  293°,  and  270° 
(B.  21,  2510  ;  41,  996  ;  A.  Chim.  Phys.  8,  12,  468). 

meso-Alkylic  derivatives  of  anthracene  dihydride  are  produced  in  the 
reduction  of  the  alkyl-oxanthrones,  and  meso-dialkyl  derivatives  syn- 
thetically from  alkylidene  chlorides,  benzene,  and  A1C13. 

meso-Dimethyl-anthracene  hydride  C6H4(CH.CH3)2C6H4,  m.p.  181°, 
yields  anthraquinone  by  oxidation  (A.  235,  305),  just  as  benzo-phenone 


ANTHRACENE   GROUP  709 

is  obtained  from  unsym.  diphenyl-ethane.  It  is  obtained  from  ethy- 
lidene  chloride,  benzene,  and  A1C13.  meso-Diphenyl-anthracene  hydride, 
m.p.  153°,  from  benzal  chloride,  benzene,  and  A1C13,  besides  triphenyl- 
methane  (Am.  Ch.  J.  13,  556). 

9, 9-Diphenyl-dihydro-anthracene  (C6H5)2C(C6H4)2CH2,  m.p.  196°, 
by  reduction  of  diphenyl-anthrone  with  zinc  dust  in  glacial  acetic  acid 
(B.  38,  1800). 

Anthraquinone  or  diketo-dihydro-anthracene  must  be  included  with 
the  derivatives  of  dihydro-anthracene.  Thereto  belong  also  : 

Anthrone  and  oxanthrone,  which  have  already  been  discussed  in 
connection  with  anthranol  and  dioxy-anthraquinone.  We  must  also 

include    dihydro- anthranol    C6H4<^°^>C6H4,  m.p.  76°,  obtained 

by  reducing  anthraquinone  with  zinc  dust  and  ammonia.  It  easily 
decomposes  into  water  and  anthracene  on  standing  in  air.  The 

alkyl     derivatives    of    dihydro-anthranol      C,H4/£^  ^/C6H4    are 

obtained  by  reduction  of  the  alkyl-oxanth rones,  or,  direct,  by  the 
reduction  of  anthraquinone  with  zinc  dust  and  soda  in  the  presence  of 
halogen-alkyls.  Like  dihydro-anthranol,  they  easily  split  off  water  on 
boiling  with  HC1  and  pass  into  y-alkyl-anthracenes  (B.  18,  2150  ;  24, 
R.  768  ;  A.  212,  67). 

meso  -  Triphenyl  -  hydranthranol  (C6H5) 2C(C6H4) 2C(OH)C6H5,  m.p. 
200°,  from  diphenyl-anthrone  with  C6H5MgBr,  gives  on  reduction 
triphenyl  -  hydranthracene  (C6H5)2C(C6H4)2CHC6H5,  m.p.  220°.  The 
latter  also  results  from  the  condensation  product  of  triphenyl-methane- 
carboxylic  ester  with  C6H5MgBr  by  treatment  with  H2SO4  (C.  1904, 

II.  530). 

Phenyl-oxanthrone  is  formed  by  the  oxidation  of  phenyl-anthrone, 
and  the  action  of  C6H5MgBr  upon  anthraquinone.  In  a  similar  manner, 
several  further  meso-aryl-  and  meso-alkyl-anthracenes  have  been 
converted  into  the  corresponding  oxanthranones.  Thus  we  get  the  tetra- 

methyl  -  diamido  -  phenyl  -  oxanthrone  y^^C^^te^CO, 

m.p.  213°,  from  the  condensation  product  of  tetramethyl-diamido- 
diphenyl-methane-o-carboxylic  acid.  It  combines  with  dimethyl-aniline 
and  POC13  to  form  the  dyestuff  Phal  green,  the  chloride  of  the  base 

c=H<c!oH![c:H;N|cH:i:]>c«H3N(cH3)2  <c.  1903,  n.  nso),  which  » 

based  upon  diphenyl  -  dioxy-anthracene  hydride  C6H4[C(OH)C6H5]2 
C6H4,  m.p.  242°.  The  latter,  from  anthraquinone  with  phenyl-mag- 
nesium  bromide,  condenses  easily,  like  meso-triphenyl-hydranthranol, 
with  phenols  and  aromatic  amines  to  tetra-aryl-dihydro-anthracenes 
(C.  1904,  I.  814  ;  1905,  I.  744). 

Dimethyl-  and  diethyl-dioxy-anthracene  hydride  C6H4[CR(OH)]2 
C6H4,  m.p.  181°  and  175°,  from  anthraquinone,  with  methyl-  and  ethyl- 
magnesium  iodide  respectively  (C.  1906,  I.  47). 

Anthraquinone,  diphenylene-diketone  C6H4(CO)2C6H4,  melting  at 
285°  and  boiling  at  382°,  sublimes  in  yellow  needles.  It  is  not  only 
produced  by  synthetic  methods,  but  also  quite  easily  by  the  oxidation 
of  anthracene  with  a  chromic  acid  mixture  (technical  preparation,  A. 
Suppl.  7,  285),  as  well  as  from  anthra-hydride,  meso-dichloro-,  dibromo-, 
and  dinitro-anthracene.  It  is,  compared  with  the  isomeric'phenanthra- 


710  ORGANIC  CHEMISTRY 

quinone,  very  stable  toward  oxidants.  It  combines  with  hydroxyl- 
amine  to  anthraquinone-oxime,  subliming  above  200°.  Sulphurous 
acid  does  not  reduce  it  (unlike  the  true  quinones). 

It  reverts  to  anthracene  if  heated  to  150°  with  hydriodic  acid,  or 
with  zinc  dust  and  ammonia.  A  variety  of  intermediate  products  are 
obtained  in  this  reaction  by  simply  applying  different  reducing  agents  : 


.H.  _»  C.H<C,OH,>C>H. 
Anthraquinone         Anthra-hydroquinone 
~H*°  CH 


or  C  H 
OT  C«H 

Anthranol  Anthrone  Dihydro-anthranol  Anthracene. 

On  digesting  with  zinc  dust  and  soda,  anthra-hydroquinone  is  formed, 
and  its  red  alkaline  solution,  shaken  in  air,  regenerates  anthraquinone 
(qualitative  test  for  anthraquinone). 

When  fused  with  potassium  hydroxide  (at  250°),  it  decomposes  into 
two  molecules  of  benzoic  acid  ;  heated  with  soda-lime,  it  yields  benzene 
and  a  little  diphenyl. 

Homologous  anthraquinones  are  obtained  partly  in  the  synthetic  way 
and  in  part  by  the  oxidation  of  benz-alkylic  anthracenes. 

Methyl-anthraquinone  C6H4(CO)2C6H3.CH3,  melting  at  177°,  from 
nitric  acid  and  methyl-anthracene,  is  also  present  in  crude  anthra- 
quinone. 

Substituted  Anthraquinones.  —  Halogen-anthraquinones  are  formed 
(i)  by  the  action  of  chlorine  or  bromine  upon  anthraquinone  ;  (2)  from 
chlorine-  and  bromine-anthracenes  by  oxidation  ;  (3)  from  amido- 
anthraquinones  by  means  of  their  diazonium  salts  (B.  37,  59)  ;  (4)  by 
the  action  of  chlorine  and  bromine  upon  anthraquinone  or  anthracene- 
sulphonic  acids  in  aqueous  solution,  the  sulpho-groups  being  easily 
replaced  by  halogen  (C.  1909,  I.  414  ;  1911,  I.  102)  ;  (5)  by  synthesis 
from  halogen-benzo-phenone-o-carboxylic  acids  :  1-chloro-,  bromo-,  and 
iodo-anthraquinone,  m.p.  209°,  205°,  and  176°  ;  from  2-bromo-anthra- 
quinone  and  from  dibromo-anthraquinone,  alizarin  is  obtained  by 
fusing  with  potash.  The  halogen  atoms  in  the  a-position  can  easily 
be  replaced  by  the  groups  OH,  OR,  OC6H5,  NH2,  and  NHR  on  heating 
with  lime-water,  sodium  alcoholate  or  phenolate,  ammonia  or  amines, 
if  necessary  with  an  addition  of  copper  salts. 

Nitro-  anthraquinones.  —  From  anthracene  or  anthraquinone,  by 
heating  with  nitric  acid,  we  obtain  besides  1-nitro-anthraquinone, 
m.p.  230°,  chiefly  1,  5-dinitro-anthraquinone  (C.  1906,  I.  1070).  2- 
Nitro-anthraquinone,  m.p.  185°,  has  been  obtained  from  2-amido- 
anthraquinone  by  transposition  of  the  diazonium  salt  with  sodium- 
copper  nitrite  ;  also  from  3-amido-2-nitro-anthraquinone,  by  elimin- 
ating the  amido-group  ;  and  synthetically  from  o-benzoyl-p-nitro- 
benzoic  acid  (B.  37,  4435  ;  38,  295).  By  moderate  alkaline  reduction 
of  the  nitro-anthraquinones  we  obtain  comparatively  stable  /?- 
hydroxyl-amino-anthraquinones  C14H7O2(NHOH),  C14H6O2(NHOH)2, 
which,  by  transposition  with  acids,  yield  amino-oxy-anthraquinones 
(B.  35,  666). 

Amido-anthraquinones  and  their  derivatives  have  lately  acquired 
great  technical  importance,  since  some  of  them,  like  the  benzoyl-amido- 
anthraquinones  and  tri-anthraquinone-di-imides,  have  the  character 


ANTHRACENE  GROUP  711 

of  vat  dyes,  and  some  of  them,  like  2-amido-anthraquinone,  can  be 
easily  converted  into  these  by  simple  operations.  Vat  dyes  are  dyes 
insoluble  in  water  and  alkalies,  which  can  be  converted  by  alkaline 
reduction  into  hydro-compounds  soluble  in  alkali,  and  then  have  the 
faculty  of  combining  with  the  fibre,  and  of  regenerating  the  original 
dye  on  the  fibre  by  subsequent  oxidation  in  air.  All  vat  dyes  contain 
one  or  more  CO  groups,  and  their  character  depends  upon  the  possibility 
of  converting  these  groups  into  OH  groups  capable  of  forming  salts. 
The  vat  dyes  are  mostly  distinguished  by  their  great  permanence 
(B.  43,  987  ;  Ch.  Ztg.  34,  731). 

Amino-anthraquinones  are  formed  (i)  by  the  reduction  of  nitro- 
anthraquinones ;  (2)  synthetically  from  amino-benzoyl-o-benzoic 
acid  by  condensation  (C.  1909, 1.  475)  ;  (3)  by  replacing  nitro-,  halogen-, 
sulpho-,  and  hydroxyl-groups  in  the  a-  or  i-position  in  anthraquinone 
by  NH2  or  NHR  groups,  on  heating  with  ammonia,  amines,  and 
particularly  anilines,  with  the  possible  addition  of  copper  powder 
(C.  1901,  II.  1379  >  I902'  II-  368,  etc.).  1-  and  2-Amino-anthra- 
quinone,  red  needles,  m.p.  242°  and  302°.  The  2-amino-anthra- 
quinone  is  converted,  by  fusion  with  potash  at  250°,  into  the  interesting 
and  valuable  vat  dye  indanthrene  (q.v.),  and  under  different  conditions, 
such  as  heating  with  aluminium  chloride  or,  better,  by  boiling  with 
antimony  pentachloride  in  nitro-benzene  solution,  into  the  similar  but 
yellow-coloured  flavanthrene  (q.v.)  : 


Flavanthrene. 

Di-  and  poly-amido-anthraquinones  have  been  obtained  by  the 
reduction  of  poly-nitro-  or  nitro-amido-anthraquinones,  usually  with 
sodium  sulphide  :  1,  4-,  1,  5-,  and  1,  8-diamido-anthraquinones  melt 
at  268°,  319°,  and  262°  (C.  1902,  II.  1232  ;  B.  38,  637).  I,  2-  and  2,  3- 
Diamido-anthraquinones  condense  like  o-phenylene  -  diamines  with 
o-diketones  to  azins  (B.  37,  4531  ;  C.  1906,  II.  80). 

As  already  mentioned,  numerous  acyl-derivatives  of  amido-anthra- 
quinones,  especially  benzoyl  -  amido  -  anthraquinones,  are  directly 
useful  as  vat  dyes.  The  latter  are  either  obtained  from  amido-anthra- 
quinones  with  benzoyl  chloride  or  from  halogen-anthraquinones  with 
benzamide  and  copper  powder.  Benzoyl-a-amido-anthraquinone  and 
dibenzoyl-i,  5-  and  I,  8-diamido-anthraquinone  give  yellow  colora- 
tions, which  are  slightly  displaced  towards  red  by  the  substitution. 
The  amido-anthraquinone  derivatives  of  dicarboxylic  acid,  malonic 
acid,  succinic  acid,  phthalic  acid,  etc.,  possess  to  some  extent  the 
character  of  vat  dyes.  To  these  belong  the  dyes  known  as  algol- 
yellow  W.G.,  algol-pink  R,  and  algol-scarlet  G. 


712  ORGANIC   CHEMISTRY 

Dianthra-quinonimides,  dianthrimides 


and    trianthraquinone-di-imides,    trianthrimides   A—  NH  —  A—  NH—  A 

are  formed  by  the  condensation  of  mono-  and  diamido-anthra- 
quinones  with  halogen-anthraquinones  by  boiling  the  components 
with  sodium  acetate  in  nitro-benzol  with  perhaps  some  copper 
powder  (C.  1905,  II.  1206).  They  possess  an  immediate  dyestuff 
character,  though  some  of  them  require  further  transformations  to 
produce  vat  dyes.  Some  of  their  names  are  :  indanthrene-claret  B, 
indanthrene-red  G,  algol-orange  R,  algol-claret  3B,  and  algol-red  B. 

Like  o-amido-benzaldehyde  and  o-amido-acetophenone,  a-amido- 
anthraquinone  is  capable  of  forming  heterocyclic  ring-systems,  the 
linkage  being  in  the  I,  g-position  with  respect  to  the  anthraquinone 
nucleus.  Thus,  by  condensation  with  acetone  and  soda,  analogous  to 
the  formation  of  quinaldin  from  o-amido-benzaldehyde,  we  obtain  a 

c-methyl-anthra-pyridin  a^^'ft™**  (C-  I9°7'  IL  863)'  With 
methane,  a-amido-anthraquinone  combines  to  form  anthra-pyrimidone 

CO—  C  H  IsTH  (^"  I9°9'  I-  327)>  with  formamide  to  anthra-pyrimidin 

/~>  TT     p  •  TSJ  PfT 

Co_lc  *H  '-^  (C.  1910,  I.  1305).  Other  hetero-ring  formations,  see 
C.  i902,3II.  368  ;  1906,  II.  386  ;  1908,  II.  1658. 

The  action  of  NO3H  upon  the  free  amido-anthraquinones  leads  to 
the  very  stable  nitro-nitramino-anthraquinones  (B.  37,  4227).  The 
simplest  1-nitramino-anthraquinone  C14H7O2.NHNO2,  yellow  needles, 
m.p.  193°  with  decomposition,  is  formed  by  the  oxidation  of  i-anthra- 
quinone-diazonium  sulphate  with  sodium  hypochlorite  (C.  1905,  1.  313). 
Somewhat  easier  is  the  nitrification  of  the  acetyl  compounds  and  the 
urethanes  of  the  amido-anthraquinones,  the  former  yielding  chiefly 
p-nitro-,  and  the  latter  o-nitro-  and  o,  p-dinitro-amido-anthraquinones 
(C.  1906,  II.  468). 

On  bromination  i-amido-anthraquinone  gives  2-bromo-  and 
2,  4-dibromo-anthraquinone,  m.p.  181°  and  222°,  whereas  2-amido- 
anthraquinone  gives  the  1,  3-dibromo-2-amido-anthraquinone  (B.  40, 
1701  ;  C.  1905,  I.  1447).  The  2-bromo-compound  is  of  especial 
interest,  since,  by  heating  with  sodium  acetate  in  nitro-benzol  solution 
and  addition  of  copper  chloride,  it  can  be  transformed  into  indanthrene 
(C.  1905,  I.  843). 

Anthraquinone  -  sulphonic  Acids.  —  Heating  anthraquinone  with 
fuming  sulphuric  acid  produces  a  little  i-anthraquinone-sulphonic  acid, 
but  chiefly  2-anthraquinone-sulphonic  acid,  and  on  further  sulphuration 
2,  6-  and  2,  7-acids  are  formed.  On  adding  some  finely  divided 
mercury  salt  to  this  sulphurated  mixture,  the  i-acid  is  mostly  produced, 
with  some  i,  5-  and  i,  8-acid.  i-Monosulphonic  acid,  sulphurated  with 
mercury  salt,  yields  i,  6-  and  i,  7-disulphonic  acid.  Sulpho-groups  in 
the  i-position,  on  being  heated  with  NH3,  or  amines,  are  easily  replaced 
by  NH2  or  NHR  groups  ;  with  methyl-alcoholic  potash  or  potassium 
phenolate  they  are  replaced  by  CH3O  or  C6H5O  groups  ;  and  on 
heating  with  lime-water  under  pressure  by  HO  groups  (B.  36,  4194  ;  37, 
66,  331,  646).  On  fusing  with  potash  these  acids,  which  contain  the 


ANTHRACENE  GROUP  713 

sulpho-groups  in  the  2-position,  yield  both  normal  and  higher  hydroxyl- 
ated  products  : 

/ — >  2-Oxy-anthraquinone 
2-Anthraquinone-monosulphomc  acid — ^ ^  Alizarin  (i  2  OH) 

f — >  Anthra-flavinic  acid  (2,  6  OH) 
2,  6-Anthraqninone-disulphonic  acid         -^  Flavo.purpurin  (l>  2§  6  OH) 

/ — >  Iso-anthra-flavinic  acid  (2,  7  OH) 
2,  7-Anthraqumone-disulphomc  acid         -  ^  Anthra.purpurin  (l ,  2,  7  OH)  etc. 

The  sulpho-acids  of  the  amido-alkyl-amido-  and  aryl-amido-anthra- 
quinones  are  to  a  great  extent  valuable  wool-dyes,  e.g.  alizarin 

saphirol  NHa[8]SO3H[6]OH[5]C6H<^^^>c6H[i]OH[2]SO3H[4]NH2,  obtained 
by  reduction  of  dmitro-anthrarufin-disulphonic  acid  ;  alizarin  pure 
blue  c6H4<^°^CcH[i]NH2[2]Br[4]NHC7H6S03H,  alizarin-cyanin  green, 

anthraquinone  green,  and  many  others.  They  are  formed  mostly 
by  transformation  of  a-halogen,  or  a-nitro-  or  a-oxy-anthraquinones, 
with  ammonia,  or  aliphatic  or  aromatic  amines,  and  subsequent 
sulphuration  (B.  34,  2344  ;  C.  1904,  II.  339). 

A  summary  of  the  literature  of  the  anthraquinone-sulphonic  acids 
and  their  derivatives  is  found  in  Chemische  Industrie,  32,  477. 

The  oxy-anthraquinones  are  derived  (i)  from  the  bromo-  and  chloro- 
anthraquinones  and  from  the  sulphonic  acids  on  fusion  with  alkalies, 
when  the  substituting  groups  are  replaced  by  hydroxyls. 

By  stronger  fusion  there  generally  ensues  an  additional  entrance  of 
hydroxyl  (oxy-  and  dioxy-anthraquinones  result  from  the  mono- 
sulphonic  acids)  ;  the  same  is  true  in  the  fusion  of  the  oxy-anthra- 
quinones (B.  11,  1613). 

(2)  The  oxy-anthraquinones  may  be  synthetically  prepared  on 
heating  phthalic  anhydride  with  phenols  (mono-  and  poly-valent)  and 
sulphuric  acid  to  150°.  The  m-oxy-benzoic  acids  and  oxy-benzoyl-o- 
benzoic  acids  also  yield  them  when  similarly  treated  (C.  1908,  I.  1697). 

The  introduction  of  hydroxyl  into  anthraquinone  and  the  oxy- 
anthraquinones  can  be  effected  practically  by  persulphates  in  sulphuric 
acid  solution.  One  or  several  hydroxyl  groups  will  then  enter  the 
anthraquinone  molecule,  depending  upon  the  conditions  which 
prevail  (B.  29,  R.  988). 

Continued  fusion  with  alkalies  causes  the  oxy-anthraquinones  to 
separate  into  their  component  oxy-benzoic  acids  (in  the  same  way  as  an- 
thraquinone decomposes  into  benzoic  acid),  and  this  reaction  aids  in  the 
determination  of  the  position  of  the  isomerides  (B.  12, 1293  ;  A.  280,  i). 

Oxy-anthraquinones  are  reduced  to  anthracene  when  heated  with 
zinc  dust. 

Individual  hydroxyls  in  the  oxy-anthraquinones  are  reduced  by 
heating  the  latter  with  stannous  chloride  and  sodium  hydroxide  (A.  183, 
216).  Heated  to  I5o°-2oo°  with  ammonia  water,  single  OH  groups 
are  replaced  by  amide  groups. 

During  the  etherification  of  the  oxy-anthraquinones  a  striking  rule 
is  observed,  recalling  the  etherification  of  the  benzoic  acids.  Only  the 
hydroxyls  in  the  j8-position,  but  not  those  in  the  a-position,  are  etherified 
on  treatment  with  halogen  alkyls  or  dialkyl  sulphate  and  alkali.  This 
behaviour  has  been  used  successfully  for  determinations  of  constitution. 


714  ORGANIC  CHEMISTRY 

The  oxy-anthrones  and  oxy-anthracenes  show  no  such  impediment  to 
reaction  (A.  349,  201). 

(a)  Monoxy-anthraquinones  C14H7O2(OH)   the   a-  or  erythro-oxy- 
anthraquinone,  melting   at    190°,  and   the    /3-   at  323°,   are  formed 
simultaneously  on  heating  together  phenol  and  phthalic  anhydride. 
The  jS-body  is  also  prepared  from  jS-bromo-  or  sulpho-anthraquinone. 

Both  oxy-anthraquinones  yield  alizarin  when  fused  with  caustic 
potash. 

(b)  Dioxy-anthraquinones. — The  members  of  this  group  containing 
two  OH  groups  in  the  I,  2-position  are  especially  interesting,  because 
they  unite  with  metallic  oxides  to  form  insoluble,  very  stable  lakes, 
which  adhere  closely  to  the  fibre.     Their  colour  varies  with  the  char- 
acter of  the  metal.     They  are,  therefore,  very  valuable  mordant  dyes 
(B.  21,  435,  1164)  (compare  the  similar  behaviour  of  the  dioxy-benzo- 
phenones,  and  naphthazarin,  etc.      For  the  theoretical  side,  consult 
B.  26,  1574).     Alizarin,   i,  2-dioxy-anthraquinone,  is  the  most  im- 
portant of  these  dyes. 

Nine  of  the  ten  possible  isomeric  dioxy-anthraquinones  are  known. 

Alizarin,  i,  2-dioxy-anthraquinone,  melting  at  290°  and  subliming  at 
higher  temperatures  in  orange-red  needles,  is  the  chief  constituent  of 
the  dye  of  the  madder  root  (Rubia  tinctorium),  in  which  it  is  contained 
as  ruberythric  acid  (identical  with  morindin,  from  Morinda  citrifolia). 

Through  the  action  of  a  ferment  in  the  madder  root,  or  when  it  is 
boiled  with  dilute  acids  or  alkalies,  ruberythric  acid  decomposes  into 
glucose  and  alizarin  : 

Ruberythric  acid     C26H28O14+2H2O=2C6H12O6+CUH6O2(OH)2     Alizarin. 

The  alizarin  products  (garancin,  etc.)  obtained  by  such  decomposi- 
tions of  madder  root  were  formerly  used  in  dyeing.  At  present  they 
have  been  almost  entirely  supplanted  by  pure  synthetic  alizarin. 

Artificial  alizarin  was  first  obtained  by  Graebe  and  Liebermann,  in 
1868,  by  heating  dibromo-anthraquinone  with  potassium  hydroxide. 
They  had  previously  observed  that  the  natural  alizarin  yielded  anthra- 
cene when  it  was  heated  with  zinc  dust.  Alizarin  is  also  produced  from 
dichloro-  and  monobromo-anthraquinone,  from  the  two  oxy-anthraquin- 
ones and  anthraquinone-sulphonic  acid,  by  fusion  with  caustic  potash. 

Technically,  it  is  made  from  anthraquinone  prepared  from  purified 
(50  per  cent.)  anthracene.  The  latter  is  converted  by  fuming  sulphuric 
acid  into  anthraquinone-monosulphonic  acid,  which  is  then  fused  under 
pressure  for  several  days  with  caustic  soda  at  a  temperature  ranging 
from  i8o°-20O°.  Potassium  chlorate  is  added  as  an  oxidising  agent. 
The  product  of  the  reaction  is  sodium-alizarin,  which  is  then  decom- 
posed with  hydrochloric  acid  and  brought  into  the  market  in  the  form 
of  a  paste  (10-20  per  cent.). 

Alizarin  also  results,  together  with  isomeric  hystazarin,  on  heating 
phthalic  anhydride  with  pyro-catechin  and  sulphuric  acid. 

Alizarin  dissolves  readily  in  alcohol  and  ether,  and  sparingly  in  hot 
water.  It  dissolves  with  a  purple-red  colour  in  the  alkalies  ;  lime  and 
barium  salts  throw  out  the  corresponding  salts  as  blue  precipitates. 
Alums  and  tin  salts  produce  red-coloured  precipitates  (madder  lakes)  ; 
while  ferric  salts  form  blackish-violet,  and  chromium  salts  violet-brown 
precipitates. 


ANTHRACENE  GROUP  715 

In  cotton  dyeing  and  printing  the  beautiful  red  lake  and  the  almost 
black  iron  lake  are  generally  employed.  The  goods  are  mordanted  with 
alumina  (by  immersing  them  in  aluminium  acetate  and  then  heating, 
whereby  aluminium  hydroxide  is  deposited  on  the  fibres)  and  then 
dipped  into  the  solution  of  alizarin  ;  the  resulting  alizarin  aluminate 
is  fixed  by  the  fibres.  In  dyeing  with  turkey-red  it  is  customary  to 
mordant  the  cloth  with  oil  and  alum,  when  the  alumina  then  unites 
both  with  the  oleic  acid  and  with  the  alizarin. 

Alizarin  is  decomposed  by  protracted  fusion  with  caustic  potash  into 
benzoic  and  proto-catechuic  acids. 

Alizarin-dimethyl  ether  C14H6O2(OCH3)2,  m.p.  215°,  results  from 
i,  2-dimethoxy-anthrone  on  oxidation,  and  from  i-nitro-2-methoxy- 
anthraquinone  by  heating  with  methyl-alcoholic  potash.  On  saponi- 
fication  with  concentrated  H2SO4  it  yields  the  alizarin-2-monomethyl 
ether,  m.p.  230°,  also  obtained  by  direct  methylation  of  alizarin  (A.  349, 
201).  The  isomeric  alizarin-1-monomethyl  ether,  m.p.  179°,  hitherto 
unobtainable  by  synthesis,  is  found,  besides  hystazarin-monomethyl 
ether  and  anthragallol-i,  2-,  and  -i,  3-dimethyl  ether,  in  the  root  of 
Oldenlandia  umbellata  ("  chaz  root  ")  (C.  1908,  I.  646). 

jS-Nitro-alizarin,  alizarin  orange  C6H4(CO)2C6H(OH)2(3)NO2,  consists 
of  orange-red  leaflets,  melting  at  244°.  It  is  produced  by  nitrating 
alizarin  in  glacial  acetic  acid  or  by  the  action  of  NO2  vapours.  It  is 
prepared  technically.  Its  alumina  lake  is  orange  in  colour. 

The  jS-amido-alizarin  obtained  by  the  reduction  of  /2-amido-alizarin 
forms  with  acetic  anhydride  an  anhydro-base,  and  therefore  contains 
the  NH2  group  in  the  o-position  with  respect  to  an  OH  group  (B.  18, 
1666;  35,906). 

Alizarin  blue,  a  derivative  of  anthraquinolin  (B.  18,  447),  results 
upon  heating  it  with  glycerol  and  sulphuric  acid.  (See  Skraup's  quino- 
lin  synthesis)  (B.  18,  447).  The  isomeric  a-nitro-alizarin  C6H4(CO)2 
C6H(OH)2[4]NO2,  m.p.  195°,  is  formed  by  nitrifying  diacetyl-alizarin 
(cp.  B.  24,  1610).  The  a-amido-alizarin  obtained  by  reduction  gives, 
with  glycerin,  nitre-benzol,  and  sulphuric  acid,  a  green  dye,  alizarin 
green,  isomeric  with  alizarin  blue. 

l-Oxy-2-amido-anthraquinone,  alizarin  amide  C14H6O2(OH)NH2, 
m.p.  225°,  is  obtained  by  heating  alizarin  with  ammonia  water  to  200° 
(B.  39,  1201). 

Amido-oxy-anthraquinones  can  also  be  prepared  from  the  hydroxyl- 
amido  -  anthraquinones  obtained  by  the  -reduction  of  nitro-anthra- 
quinones,  by  transposing  them  with  sulphuric  acid  (B.  29,  2934  ;  35, 
666)  ;  also  by  the  action  of  fuming  sulphuric  acid  upon  amino-  and 
alkyl-amino-anthraquinones  (C.  1904,  II.  1013).  Bromo-alizarin,  see 
B.  33,  1664.  Alizarin-sulphonie  acid,  see  C.  1909,  II.  244. 

Three  of  the  dioxy-anthraquinones  isomeric  with  alizarin  contain 
the  OH  groups  in  one  benzene  nucleus.  They  are  : 

(1,  3)-Purpuro-xanthin,  from  phthalic  anhydride  and  resorcinol  ; 
(1, 4)-quinizarin,  from  hydroquinone ;  and  (2, 3)-hystazarin,  from 
pyro-catechin  (B.  28,  116).  They  are  prepared  more  advantageously 
from  their  ethers,  which  result  by  the  condensation  of  the  corresponding 
dioxy-benzene  ethers  with  phthalic  anhydride  and  A12C16  (A.  342,  99). 
Quinizarin  is  also  formed  in  the  action  of  concentrated  sulphuric  acid 
and  nitrous  acid  upon  anthraquinone  and  i-oxy-anthraquinone,  a 


716  ORGANIC  CHEMISTRY 

process  in  which  the  sulphate  of  i-oxy-4-diazo-anthraquinone  could 
be  isolated,  which,  on  further  heating  with  sulphuric  acid,  splits  up  into 
quinizarin  and  nitrogen  (C.  1905,  II.  184).  On  prolonged  heating  with 
concentrated  H2SO4,  hystazarin  is  partly  transposed  into  alizarin 
(B.  35, 1778).  For  derivatives  of  hystazarin,  see  B.  30,  2936. 

The  following  dioxy-anthraquinones  containing  their  OH  groups 
in  different  benzene  nuclei  (hetero-nuclear)  have  been  mostly  obtained 
from  the  corresponding  disulpho-acids  by  heating  with  lime-water  : — 

1,  5-Anthrarufin,  1,  6-  and  1,  7-dioxy-anthraquinone,  1,  8-ehrysazin, 
2, 6-anthraflavie  acid.  Iso-anthraflavie  acid  is  obtained  from  j8- 
anthraquinone-sulphonic  acid.  Chrysazin  is  another  isomeride.  It  is 
obtained  from  its  tetranitro-compound  C14H2(NO2)4(O2)(OH)2,  the  so- 
called  chrysammic  acid,  by  reduction  and  the  replacement  of  the  amido- 
groups.  This  latter  acid  is  obtained  when  aloes  are  digested  with  con- 
centrated nitric  acid.  Consult  B.  19,  2327,  upon  the  spectra  of  the 
dioxy-anthraquinones. 

Homologous  Dioxy-anthraquinones.  —  Dioxy-methyl-anthraquinone 
C14H5(CH3)O2(OH)2,  is  ehrysophanic  or  rheinie  acid,  melting  at  178° 
(A.  284,  193).  It  exists  in  senna  leaves  (of  the  Cassia  varieties)  and  in 
the  root  of  rhubarb  (from  the  Rheum  variety),  together  with  methyl- 
chrysophanic  acid  (A.  309,  32).  Zinc  dust  reduces  it  to  methyl-an- 
thracene. 

Chrysarobin  C30H36O7,  a  reduction  product  of  ehrysophanic  acid, 
occurs  in  goa-  and  arroroba-powder,  a  secretion  of  coloured  Brazilian 
woods.  Air  oxidises  its  alkaline  solution  to  ehrysophanic  acid.  The 
same  occurs  in  the  animal  organism  (B.  21,  447). 

Methyl-alizarin,  melting  at  25o°-252°,  is  isomeric  with  dioxy- 
methyl-anthraquinone.  It  is  obtained  from  methyl-anthraquinone- 
sulphonic  acid.  It  is  very  similar  to  alizarin. 

Various  methyl-purpuro-xanthins  have  been  prepared  by  the  con- 
densation of  i,  3,  5-dioxy-benzoic  acid  with  o-  and  m-toluic  acids 
(B.  29,  R.  141). 

By  the  condensation  of  5-methyl-phthalic  acid  with  pyro-catechin, 
besides  a  methyl-alizarin,  m.p.  216°,  a  methyl-hystazarin  (OH)2[6,  7] 
C6H2(CO)2C6H3[2]CH3,  has  been  obtained  (B.  33,  1629). 

Dimethyl-anthrarufln  (CH3)(OH)C6H2(CO)2C6H2(CH3)(OH)  can  also 
be  obtained  by  the  action  of  sulphuric  acid  upon  sym.  oxy-toluic  acid 
(B.  22,  3273). 

(c)  Trio%y-anthraquinones. — These  are  produced  on  oxidising  an- 
thraquinone-disulphonic  acids  and  dioxy-anthraquinones,  or  by  fusing 
them  with  alkalies. 

Purpurin  C6H4^^c8H[i,2,4](OH)3+H2o,  melting  at  253°  (an- 
hydrous) and  sublimable,  is  present  with  alizarin  in  the  madder  root. 
It  is  prepared  artificially  by  heating  alizarin  and  quinizarin  with 
manganese  dioxide  and  sulphuric  acid  to  150°.  It  is  also  obtained 
from  tribromo-anthraquinone.  It  dissolves  with  a  pure  red  colour 
in  hot  water,  alcohol,  ether,  and  the  alkalies.  Lime  and  baryta  water 
yield  purple  red  precipitates.  It  yields  a  beautiful  scarlet  red  with 
alumina  mordants. 

Purpurin-amide  C14H5O2(OH)2NH2  is  obtained  on  digesting  pur- 
purin  with  aqueous  ammonia  at  150°. 


ANTHRACENE   GROUP  717 

The  following  are  isomerides  of  purpurin  :  anthragallol  (i,  2,  3),  a 
constituent  of  alizarin  brown,  anthra-  or  iso-purpurin  (i,  2,  7),  and 
flavo-purpurin  (i,  2,  6),  applied  technically  in  dyeing  and  printing,  and 
also  oxy-ehrysazin  (1,2,5?),  oxy-anthrarufln  (1,2,5)  (A-  349,  215) 
and  1, 4, 8-trioxy-anthraquinone  (C.  1905,  II.  1142).  Consult  A.  280,  i, 
for  the  determination  of  the  constitution  of  these  bodies  from  the 
decompositions  of  the  disulphonic  acids  genetically  connected  with 
them. 

Homologous  Trioxy-anthraquinones. — Emodin,  and  a  trioxy-methyl- 
anthraquinone,  melting  at  203°  and  isomeric  with  it,  are  formed,  together 
with  rhamnose,  by  the  decomposition  of  frangulin,  from  the  bark  of 
Rhamnus  frangula,  by  means  of  alcoholic  hydrochloric  acid  (B.  25,  R; 
371).  Emodin  also  results  from  the  decomposition  of  polygonine. 

An  isomeric  emodin  is  aloe  emodin,  m.p.  224°,  which  is  found  in 
company  with  barbalo'in  in  many  aloe  species  (C.  1898,  II.  211)  as  well 
as  in  senna  leaves  (C.  1900,  II.  871).  On  oxidation  with  chromic  acid 
it  passes  into  a  dioxy-anthraquinone-carboxylic  acid,  the  so-called 
rhe'in,  which  has  also  been  extracted  from  Chinese  rhubarb  (C.  1909, 
II.  622).  A  trioxy-methyl-anthraquinone  isomeric  with  emodin  is 
probably  the  mormdone,  m.p.  272°,  obtained  by  splitting  up  morindin, 
a  glycoside  from  Morinda  citrifolia. 

(d)  Tetra-  and  Poly-oxy-anthraquinones. — When  oxy-anthraquinones 
are  heated  with  fuming  sulphuric  acid,  new  hydroxyls  enter  these 
bodies,  para-hydrogen  atoms  of  the  non-substituted  nucleus  being  re- 
placed (/.  pr.  Ch.  2,  43,  231  ;  44,  103).  Thus  alizarin  yields  quin- 
alizarin,  alizarin-bordeaux  Cj4H402-i,  2,  5,  8-  (OH)4. 

Two  tetraoxy-anthraquinones,  anthra-ehrysone  and  rufiopin,  are 
obtained  by  heating  symmetrical  dioxy-benzoic  acid  and  opianic  acid 
or  proto-catechuic  acid  with  sulphuric  acid. 

Rufigallic  acid  is  a  hexaoxy-anthraquinone  C14H202-i,  2,  3,  5,  6,  7- 
(OH)6,  which  is  formed  when  gallic  acid  is  heated  with  sulphuric  acid. 
It  dissolves  with  an  indigo-blue  colour  in  alkalies. 

It  dyes  chrome-mordanted  material  brown.  It  appears  in  trade 
in  conjunction  with  anthra-purpurin  as  alizarin  or  anthracene  brown. 
Anthracene  blue,  formed  by  the  action  of  fuming  sulphuric  acid  upon 
di-nitro-anthraquinone,  is  an  isomeric  hexaoxy-anthraquinone. 

Anthraquinone-carboxylic  acids.— a-  andjS-Anthraquinone-carboxylic 
acids  are  produced  in  the  oxidation  of  anthracene-carboxylic  acids. 
The  a-acid  (m.p.  285°)  is  also  formed  in  the  condensation  of  benzoyl- 
phthalic  acid  and  iso-phthalic  acid  (B.  29,  R.  284),  and  the  j8-acid 
when  chromic  acid  acts  upon  methyl-anthracene.  The  amide  of  the 
a-acid,  treated  with  bromine  and  alkali,  yields  i-amido-anthraquinone 
(B.  30,  1115).  Trioxy  -  anthraquinone  -  earboxylie  acid,  purpurin- 
carboxylic  acid  C14H4O2(OH)3CO2H,  is  pseudo-purpurin,  which  occurs 
in  crude  purpurin  (from  madder).  On  heating  it  decomposes  into 
carbon  dioxide  and  purpurin. 

See  C.  1894,  II.  784,  for  the  synthetic  purpurin-carboxylic  acids. 

Dianthraquinoyls.— This  term  is  used  to  designate  those  compounds 
in  which  two  anthraquinone  residues  are  directly  joined  in  the  a-  or 
jS-position.  They  are  formed  either  on  the  analogy  of  diphenyl  (i)  from 
the  iodo-anthraquinones  by  heating  with  powdered  copper ;  (2)  from 
anthraquinone-diazonium  sulphates  with  acetic  anhydride  and  powdered 


7i8  ORGANIC  CHEMISTRY 

copper  (B.  40,  1697  ;  C.  1909,  II.  1906)  ;  or  (3)  on  the  analogy  of  an- 
thraquinone  synthesis  by  dehydrating  the  diphenyl-diphthaloyl  acids, 
obtained  by  heating  diphenyl  and  phthalic  anhydride  in  the  presence 
of  A1C18  (B.  44,  1075)  : 


1,  l'-Dianthraquinoyl,  yellowish-brown  needles,  by  methods  i  and 
2  ;  2,  2'-dianthraquinoyl,  m.p.  388°,  by  i,  2,  and  3  ;  2,  2'-dimethyl- 
1,  I'-dianthraquinoyl,  m.p.  367°  ;  2,  4,  2'  4'-tetramethyl-l,  I'-dian- 
thraquinoyl, m.p.  297°  (B.  43,  512). 

The  dianthraquinoyls  are  distinguished  by  the  fact  that  they  can 
be  easily  converted  by  a  further  fusion  of  the  anthraquinone  nuclei  into 
quinonoid  compounds  with  highly  condensed  ring  systems.  Thus  the 
i,  i-dianthraquinoyl,  reduced  with  Cu  or  Ni  powder  and  concentrated 
H2SO4,  yields  meso-benzo-dianthrone  (similar  to  meso-dianthrone), 
steel-blue  aggregates  resembling  haematite,  and  passing  on  heating  with 
A1C13  to  I4o°-i45°  into  meso-naphtho-dianthrone  (see  below),  blue 
needles,  with  rejection  of  2H  and  further  linking  of  two  benzene  nuclei 
(B.  43,  1734).  The  2,  2/-dimethyl-i,  I'-dianthraquinoyl  condenses, 
on  heating  alone,  to  35o°-38o°,  or,  better,  by  boiling  with  concentrated 
alcoholic  potash  and  rejection  of  2H2O  to  pyranthrone,  reddish-brown 
needles,  which  resembles  flavanthrene  in  its  structure  and  is  related 
to  it,  as  is  anthraflavone  to  indanthrene  (B.  43,  346)  : 

CO 


X/VV 


\/s 

co  •  Co  co 

Meso-benzo-dianthrone      Meso-naphtho-dianthrone  Pyranthrone. 

The  three  compounds  all  possess  the  character  of  vat  dyes.  Pyran- 
throne more  particularly  is  known  as  a  specially  permanent  orange  dye 
under  the  name  of  "  indanthrene  gold-orange." 

Benzanthrones.  —  On  heating  anthraquinone  or,  better,  anthrone 
with  glycerin  and  concentrated  sulphuric  acid  to  ioo°-no°,  we  obtain 
the  so-called  benzanthrone  with  attachment  of  a  new  benzene  ring  in  the 
i,  9-position  (B.  38,  170)  : 

C6H4.CH2      HOCH2\ 
C 


2\ 
2/ 


_ 
CO—  C6H/  HOCH2/  I^H  -     CO—  C6H3.CH 

From  the  amido-anthraquinone  we  obtain,  with  simultaneous 
formation  of  a  ring  containing  nitrogen,  benzanthrone-quinolins. 

Benzanthrone  (formula  above),  light-yellow  needles,  m.p.  170°  ; 
2-methyl-  and  2,  4-dimethyl-benzanthrone,  m.p.  199°  and  165°. 

On  fusing  with  caustic  potash  the  benzanthrones,  except  the  oxy-, 
nitro-,  and  amido-benzanthrones,  close  up  two  molecules  and  form  ex- 


ANTHRACENE  GROUP  719 

cellent  vat  dyes  with  a  structure  resembling  pyranthrone  and  of  a  blue 
or  violet  colour.  They  are  called  violanthrenes  and  iso-violanthrenes. 
To  these  belong  indanthrene  dark  blue,  and  its  isomers  and  substitution 
products  indanthrene  violet  and  indanthrene  green. 

yCHL 

Naphthanthracene  C6H4<^  j    ^>C10H8,  melting  at  141°,  is  isomeric  with 

chrysene.  It  is  formed  when  its  quinone  is  digested  with  zinc  dust  and 
ammonia. 

Naphthanthraquinone  C6H4(CO)2C10H6,  melting  at  168°,  is  obtained 

/{^(~*\(~\\  T 

from  naphthoyl-o-benzoic  acid  C6H«\CO  c  H  ,  the  same  as  anthra- 

quinone  from  benzoyl-benzoic  acid  (B.  19,  2209  ;  29,  827). 

Naphthanthraquinone  is  split  up  by  melting  with  potash  into  j8- 
naphthoic  acid  and  benzoic  acid  (B.  19,  2209  ;  29,  827  ;  33,  446).  Phen- 
anthro-anthraquinone  C14H3(CO)2C6H4,  m.p.  234°,  see  C.  1908,  1.  1223. 


or 


is  isomeric  with  naphth  anthracene  ;  it  is  formed  from  its  oxygen  deriva- 
tives oxy-  and  dk  xy-naphthacene-quinone  by  distillation  with  zinc  dust. 

to 


m 


,co.     HC  -  c-v 
.p.  347°,  red  flakes,  from  ethindiphtalyl  C9uS      \O    \     o/     ^>C6H4 

^C  —          CH    \CCr 
by  transposition  with  sodium  methylate,  or  by  the  oxidation  of  diketo- 
hydrindene  with  potassium  persulphate;  by  oxidation  with   HNO3 

we  obtain  naphthacene-di-quinone  c«H*<(£o'£'ro)>c«H«>  m-P-  333°»  which 

reverts  very  easily  into  the  dioxy-naphthacene-quinone  ;  by  reduction 
of  the  latter  with  phosphorus  and  HI  we  obtain  dihydro-naphthaeene 
C18H14,  m.p.  207°,  which  with  chromic  acid  yields  naphthacene-quinone 
C10H6(CO)2C6H4,  m.p.  294°,  an  isomer  of  naphthanthraquinone  (B.  31, 
1272  ;  33,  446).  By  condensation  of  phthalic  anhydride  and  a-naph- 
thol,  or  of  a-oxy-naphthoyl-o-benzoic  acid  with  boric  acid  and  sulphuric 

acids,  we  obtain  monoxy-naphthacene-quinone  C6H4/J:      ']  fC10H5[i]OH, 

\L/UL3J  J 

m.p.  303°,  which,  on  oxidation,  easily  passes  into  the  above  dioxy- 
naphthacene-quinone,  and  can  be  converted  by  reduction  into 
naphthacene  and  dihydro-naphthacene  (B.  36,  547,  719,  2326). 


VI.  GLYCOSIDES  OR  GLUCOSIDES  AND  PENTOSIDES. 

Glycosides  or  glucosides  are  those  vegetable  substances  which  break 
down  into  sugars,  chiefly  grape  sugar  or  glucose,  and  other  bodies,  when 
they  are  exposed  to  the  action  of  unorganised  ferments  or  enzymes (1-587) . 
Some  of  them  decompose  into  iso-dulcite  or  rhamnose,  a  pentose,  hence 
they  are  designated  as  pentosides.  In  many  glycosides  the  exact  nature 
of  the  sugar  is  not  known.  The  glycosides  and  pentosides  are  therefore 
to  be  regarded  as  ethereal  sugar  derivatives.  Some  of  them  were  de- 
scribed under  their  decomposition  products,  while  many  have  been 
synthesised. 

E.  Fischer  demonstrated  that  the  simplest  glucosides  could  be  pre- 


720  ORGANIC  CHEMISTRY 

pared  by  the  action  of  hydrochloric  acid  upon  alcoholic  sugar  solutions  ; 
they  have  been  described  in  Vol.  I. 

A  second  method  of  forming  artificial  glucosides,  due  to  Michael, 
is  based  upon  the  mutual  action  of  phenols  and  aceto-chloro-  or  bromo- 
glucose  (Vol.  I.)  in  alkaline-alcoholic  solution. 

la.  Sinigrin,  potassium  myronate  C10H18NS2O10K=C3HBN :  C 

.6u5 

+H2O,  m.p.  127°  (anhydrous,  132°),  is  found  in  black  mustard-seed  and 
in  the  root  of  Cochlearia  armoracia.  It  crystallises  from  water  in  brilliant 
needles.  On  boiling  with  baryta  water,  or  by  the  action  of  the  ferment 
myrosin,  contained  in  mustard-seed,  it  is  split  up  into  d-glucose,  allyl- 
mustard  oil,  and  primary  potassium  sulphate  (B.  30.  2322). 

OS02.O.C16H24N05 
ib.  Sinalbin   C30H44N2s2o16=c^sc6Hno6  +H2o  (?)    is    found 

^N.CH2C6H4OH 

in  white  mustard  -  seed.  Myrosin  decomposes  it  into  glucose, 
sinalbin-mustard  oil,  and  p-oxy-benzyl-mustard  oil  SC  :  NCH2C6H4 
[4] OH  and  sinapin  sulphate  Ci6H24NO5.HSO4.  Sinapin  easily  splits 
up  into  cholin  (Vol.  I.)  and  sinapic  or  oxy-dimethoxy-cinnamic  acid 
(CH30)2[3,  5](OH)[4]C6H2CH  :  CH.COOH  (B.  30,  2327). 

A  constitution  resembling  that  of  sinalbin  may  also  be  possessed  by 
the  glucosides  of  various  cresses,  such  as  Tropceolwm  majus,  Lepidium 
sativum,  and  Nasturtium  officinale,  which,  on  splitting  up,  give  benzyl- 
ethyl  and  phenyl-ethyl-mustard  oil,  instead  of  allyl-mustard  oil  (B.  32, 

2335). 

2.  Arbutin  C12H1607  and  methyl  arbutin  C13H18O7  are  found  in  the 
leaves  of  Arbutus  uva  ursi.     Arbutin  crystallises  in  fine  needles,  with 
J-i  molecule  of  water,  and  melts  at  187°  (B.  16,  800)  in  the  anhydrous 
state.     Methyl  arbutin  melts  at  176°.     It  is  formed  artificially  from 
arbutin  by  the  action  of  methyl  iodide  and  potash. 

By  their  decomposition  we  get,  besides  grape  sugar,  hydroquinone 
or  methyl-hydroquinone  : 

C12H1607+H20=C6H1206+C6H4(OH)2. 

3.  Salicin   C6HnO6.O.C6H4CH2OH,   m.p.    201°,    saligenin  glucose, 
occurs  in  the  bark  and  leaves  of  willows — e.g.,  Salix  helix — and  some 
poplars,  from  which  it  may  be  extracted  with  water.     It  can  be  artifici- 
ally prepared  by  reducing  helicin  with  sodium  amalgam.     It  forms 
shining  crystals,  which  dissolve  easily  in  hot  water  and  alcohol.     Its 
taste  is  bitter. 

Oxidants  convert  it  into  helicin,  hence  the  saligenin  in  salicin  is 
linked  by  means  of  the  phenol-oxygen  atom  with  the  glucose.  The 
enzymes  ptyalin  and  emulsin  (Vol.  I.)  decompose  salicin  into  glucose 
and  saligenin  : 

C6HnO5-O.C6H4.CH2.OH+H2O=C6H12O6+HO.C6H4.CH2.OH. 

Boiling  dilute  acids  decompose  it  in  a  similar  manner,  but  in  so 
doing  the  saligenin  is  changed  to  saliretin. 

Salicin  was  discovered  almost  simultaneously  by  Leroux  (1830) 
and  Buchner,  and  its  composition  was  cleared  up  by  Piria  in  1845 
(A.  56,  35). 

Populin,  the  benzoyl  derivative  of  salicin  C13H17(C7H5O)O7+2H2O, 


GLYCOSIDES  OR  GLUCOSIDES  721 

occurs  in  the  bark  and  leaves  of  Populus  tremula.  It  can  also  be  arti- 
ficially made  by  the  action  of  benzoic  anhydride  or  benzoyl  chloride 
upon  salicin. 

Helicin,  salicyl-aldehyde-glucose  C6H4(O.C6HnO5).CHO,  is  pro- 
duced by  oxidising  salicin  with  nitric  acid.  It  reverts  to  salicin  upon 
reduction.  It  can  be  artificially  prepared  from  salicylic  aldehyde  and 
aceto-chloro-hydrose.  It  is  broken  down  just  like  salicin  by  ferments 
or  dilute  acids. 

Glucose-cumaraldehyde  C6HnO5.O.C6H4.CH=CH.CHO  and 
Methyl-gluco-o-cumar-ketone  result  from  the  condensation  of  helicin 
with  acetaldehyde  and  acetone  (B.  24,  3180). 

4.  Gem  C6H22O7  is  found  in  the  root  of  Geum  urbanum.     It  splits 
up  into  glucose  and  eugenol  (C.  1905,  I.  1329). 

5.  Gaultherin  C6HnO5O.C6H4COOCH3-f-H2O  is  found  in  numerous 
species   of   Gaultheria   and   Spircea,   also   in  Betula  lenta,  besides  an 
enzyme  "  gaultherase,"  by  which  it  is  split  up  into  glucose  and  salicylic 
methyl  ester. 

6.  Coniferin  C16H22O84-2H2O  is  found  in  the  cambium  of  coniferous 
woods,  in  asparagus,  and  in  the  black  root  of  Scorzonera  hispanica 
(B.  25,  3221).     It  effloresces  in  the  air,  and  melts  at  185°.     It  acquires 
a  dark-blue  colour  when  moistened  with  phenol  and  hydrochloric  acid. 
Boiling  acids  or  emulsin  decompose  it  into  glucoses  and  coniferyl 

alcohol  C6H3(°^H3Yc3H4.OH,  which  is  oxidised  by  chromic  acid  to  : 

Glyco-vanillin  C6H3(O.CH3)(O.C6HnO5).CHO,  the  glucoside  of 
vanillin,  melting  at  192°.  Acids  or  emulsin  split  it  up  into  glucoses  and 
vanillin  (B.  18,  1595,  1657). 

Syringin,  methoxyl  -  coniferin  C17H24O9+H2O=C6Hn05.O.C6H2 
(OCH3)2C3H4OH,  occurs  in  the  bark  of  Syringia  vulgaris  and  Ligustrum 
vulgare.  It  melts  at  191°  and  shows  changes  similar  to  those  of 
coniferin. 

7.  Phlorizin  C21H24O10,  melting  at  108°,  occurs  in  the  root-bark  of 
various  fruit  trees ;  hence  the  name,  from  ^Aotos-,  bark,  and  pi^a,  root. 
It  is  intimately  related  to  the  pentosides  :  naringin  and  hesperidin. 
It  breaks  down  into  grape  sugar  and  phloretin,  the  phloro-glucin  ester 
of   p-oxy-hydratropic    acid,   and   the   latter   into   phloro-glucin    and 
phloretic  acid  : 

C21H24O10+H2O=C6H12O6(Glucose)  +C15H14O2  (Phloretin) 

ci5H14O5  +H2O=C6H6O3  (Phloro-glucin) +C9H10O3  (Phloretic  acid). 

Administered  internally,  it  produces  strong  glucosuria. 

8.  £lseulin   C15H16O9+iH2O    melts   at    about    205°   when    it    is 
anhydrous.     It  is  found  in  the  horse-chestnut,  Jisculus  hippocastanum, 
and  in  the  root  of  the  wild  jasmine,  Gelsemium  sempervirens.     Acids  or 
ferments  resolve  it  into  glucose  and  aesculetine  or  4,  5-dioxy-cumarin. 

9.  Daphnin  C15H16O9+2H2O,  melting  at  200°,  is  isomeric  with  the 
preceding.     It  is  obtained  from  the  bark  of  Daphne  alpina.     It  breaks 
down  into  glucose  and  daphnetin  or  3,  5-dioxy-cumarin. 

10.  Fraxin  C16H18O10  occurs  in  the  bark  of  Fraxinus  excelsior,  and, 
like  sesculin,  in  the  bark  of  the  horse-chestnut.     It  decomposes  into 
glucose  and  fraxetin,  the  monomethyl  ether  of  a  trioxy-cumarin  (B. 
27,  R.  130). 

VOL.  II.  3  A 


722  ORGANIC  CHEMISTRY 

11.  Iridin  C24H26013,  melting  at  208°,  occurs  in  the  root  of  the 
violet,  Iris  florentina,  etc.     Dilute  sulphuric  acid  resolves  it  into  grape 
sugar  and  irigenin  C18H16O8.     The  latter  is  probably  a  poly oxy-ket one. 
Concentrated  caustic  alkali  decomposes  it  into  formic  acid,  an  aromatic 
oxy-acid — iridic  acid  C10H12O6,  melting  at  118°,  which,  by  loss  of  CO2, 
becomes  iridol  or  3-oxy-4,  5-dimethoxy-i-methyl-benzene,  melting  at 
57° — and  iretol  C7H8O4,   or  methoxy-phloroglucin,   melting   at   186° 
(B.  26,  2010  ;  27,  R.  514). 

12.  Ruberythrie     acid     C26H28O14=HO.C14H6O2.O;C12H14O3(OH)7, 
melting  at  258°-26o°,  is  the  glucoside  of  alizarin.     It  is  formed  in  the 
madder  root  of  Rubia  tinctorum,  and  breaks  down  under  the  influence 
of  hydrochloric  acid  into  alizarin  and  glucose  (B.  20,  2244).     Purpurin 
is  also  contained  in  the  madder  root  as  a  glucoside. 

13.  Saponarin  C21H24O12  is  found  in  Saponaria  officinalis.     Boiling 
witrTdilute  mineral  acids  splits  it  up  into  glucose  and  vitexin  C15H14O7. 
The  latter,  probably  a  flavone  derivative,  gives,  on  boiling  with  potash, 
phloro-glucin  and  p-oxy-aceto-phenone  (C.  1906,  II.  1062). 

14.  Digitalin    (Digitalinum    verum,    Kiliani)    C35H56O14  (?)    is    an 
amorphous  glucoside.     It  is  the  active  principle  of  the  digitalis  gluco- 
sides,  which  occur  in  the  leaves  of  Digitalis  purpurea  and  lutea.     Con- 
centrated hydrochloric  acid  breaks  it  down  into  digitaligenin  C16H22O2, 
grape  sugar  C6Hi2O6,  and  digitalose  C7H14O5. 

Its  therapeutic  action  consists  in  its  occasioning  "  less  frequent  but 
more  satisfactory  heart  contractions."  * 

The  chief  ingredient  of  the  digitalis  glycosides  is  without  thera- 
peutic action.  It  is  crystalline  digitonin  C27H44O13,  which  is  resolved 
by  aqueous  alcoholic  hydrochloric  acid  into  digitogenin  C15H24O4, 
glucose,  and  galactose.  The  decomposition  of  the  latter  has  led  to  a 
series  of  acids,  the  constitution  of  which  is  as  yet  undetermined  (B.  27, 
R.  881  ;  28,  R.  1056  ;  31,  2454  ;  32,  2201 ;  37,  1215  ;  and  43,  3562). 

From  the  leaves  of  Digitalis  purpurea  another  pharmaceutically 
effective  glucoside  is  obtained,  called  digitoxin  C34H54On  m.p.  145°, 
which  is  split  up  by  HC1  into  digitoxose  C6H12O4  (two  molecules) 
and  digitoxigenin  C22H32O4  (?).  Besides  digitoxin  we  find  a  small 
quantity  of  a  yellow  pigment,  the  so-called  digito-flavone  C15H10O6, 
which  belongs  to  the  group  of  the  flavones  (q.v.),  and  is  identical  with 
luteolin  (B.  32,  2196,  1184  ;  34,  3577). 

15.  Saponin  C32H54O18,  from  the  root  of  Saponaria  officinalis,  is  a 
white  amorphous  powder,   which   provokes  sneezing   and   foams  in 
aqueous  solutions.     Its  decomposition  yields  glucose  and  sapogenin 
C14H2202  (B.  42,  238). 

16.  Convolvulin  C31H50O16,  from  the  jalapa  root  of  Convolvulus  purgay 
is  a  gummy  mass,  which  is  a  powerful  purgative.     Among  its  decom- 
position products  are,  in  addition  to  a  sugar,  d-methyl-ethyl-acetic 
acid  and  an  oxy-pentadecylic  acid  C2H5CH(CH3).CH(OH)C9H18.CO2H, 
melting  at  50°.     Nitric  acid  oxidises  the  latter  to  methyl-ethyl-acetic 
acid  and  an  acid  C10H18O4  (B.  27,  R.  885),  melting  at  116°,  isomeric 
with  sebacic  acid  (B.  27,  R.  885  ;  C.  1901,  I.  1042  ;   II.  425,  426). 

17.  Jalapin,  scammonin  C34H58O16,  from  Convolvulus  orizabensis,  and 
from  scammonium  resin,  yields  acetic  acid,  tiglic  acid,  and  palmitic 
acid  upon  distillation  (B.  26,  R.  591 ;  27,  R.  736). 

*  Binz,  Gvundzuge  der  Arzneimittellehre,  p.  52. 


PENTOSIDES  723 

18.  Polygonin  C21H20O5,  melting  at  203°,  is  a  glycoside,  and  has 
been  obtained  from  the  root  bark  of  Polygonum  cuspidatum.     It  yields 
emodin  when  it  is  decomposed  with  alcoholic  hydrochloric  acid  (B. 
29,  R.  86). 

19.  Amygdalin,        mandelo-nitrile        di glucose 
C20H27NOn  +  3H20  :  C.H.CH.CN 

occurs  in  bitter  almonds  and  in  the 
O.C12H21010 

kernels  of  Pomaceae  and  Amygdalaceae,  as  well  as  in  cherries,  peaches, 
apricots,  and  the  leaves  of  the  cherry  tree.  Amygdalin  crystallises 
from  alcohol  in  white  shining  leaflets,  and  dissolves  readily  in  water 
and  hot  alcohol. 

History, — Amygdalin  was  discovered  in  1830  by  Robiquet  and 
Boutron-Chalard  (^4.  Chim.  Phys.  2,  44,  351).  The  composition  and 
nature  of  amygdalin  were  cleared  up  by  Liebig  and  Kohler  (A.  22,  i). 

On  boiling  with  dilute  acids,  or  upon  standing  with  water  and 
emulsin,  an  enzyme  present  in  bitter  almonds,  amygdalin,  is  decom- 
posed into  oil  of  bitter  almonds,  dextrose,  and  hydrocyanic  acid. 

Yeast  splits  off  only  one  molecule  of  glucose  from  amygdalin,  and 
we  thus  obtain  1-mandelic  nitrile  glucoside  C6H5CH(CN).O.C6HnO5, 
m.p.  148°,  which  is  decomposed  by  emulsion  with  intermediate  forma- 
tion of  d-mandelic  nitrile  into  benzaldehyde,  prussic  acid,  and  d-glucose, 
and,  on  saponification  with  concentrated  HC1,  yields  l-mandelic  acid, 
together  with  glucose  and  ammonia  (B.  28,  1508).  For  lauro-cerasin, 
see  C.  1885,  570.  Other  glucosides  are  prulaurasin  (C.  1907,  II.  1340), 
sambunigrin  (C.  1907,  II.  69),  durrhin,  linamarin,  and  virianin. 

Pentosides,  Rhamnosides. — The  following  pentosides  are  to  be 
regarded  as  ethereal  compounds  of  rhamnose  C6H14O6=C6H12O5+H2O 
(I.  536),  or  of  iso-dulcite  : 

1.  Naringin  C21H26On+4H2O,  melts  when  anhydrous  at  170°.     It 
is  found  chiefly  in  the  blossoms  and  also  in  other  parts  of  the  tree 
Citrus  decumana  of  Java.     The  name  of  the  pentoside  is  derived  from 
"  naringi,"  a  Sanscrit  word  meaning  orange.     Dilute  acids  decompose 
it  into  rhamnose  and  naringenin,  melting  at  230°.     The  latter  is  the 
phloro  -  glucin    ether  of  p  -  oxy  -  cinnamic   acid,  which   concentrated 
caustic  potash  breaks  down  into  phloro-glucin  and  p-cumaric  acid 
(B.  20,  296)  : 

C21H26On    =C6H1406  (Rhamnose)     +C15H12O5  (Naringenin) 
C15H12O5-fH2O=C6H6O3  (Phloro-glucin) +C9H8O3  (p-Cumaricacid). 

2.  Hesperidin  C50H60O22  (?),  melting  at  251°,  is  present  in  unripe 
oranges,   lemons,    etc.     It   decomposes,    when   heated,   into   glucose, 
rhamnose,  and  hesperetin,  melting  at  226°.     Caustic  potash  resolves 
the  latter  into  phloro-glucin  and  iso-ferulic  acid  (B.  14,  948)  : 

C50H60O27+3H2O=2C6H12O6+C6H14O6  (Rhamnose)  +2C16H14O6  (Hesperetin). 
C16H14O6  +  H2O=C6H6O3  (Phloro-glucin)  +C10H10O4  (Iso-ferulic  acid). 

3.  Quercitrin  C21H22O12  is  present  in  the  bark  of  Quercus  tinctoria, 
and  is  applied  under  the  name  quercitrone  as  a  yellow  dye.     It  breaks 
down  into  rhamnose  and  quercetrin  (see  this),  a  phenyl-benzo-pyrene 
derivative  (B.  26,  R.  234  ;  28,  2303)  : 

C21H22012+H20=C6H1406  (Rhamnose) +C15H6007  (Quercetrin). 


724  ORGANIC   CHEMISTRY 

4.  Frangulin  C21H20O9,  melting  at  286°,  occurs  in  the  bark  of 
Rhamnus  frangula.     When  it  is  saponified  with  alcoholic  hydrochloric 
acid  rhamnose,  emodin  and  a  trioxy-methyl-anthraquinone,  isomeric 
with  the  latter,  are  produced  (B.  25,  R.  370)  : 

C21H20O9+2H2O=C6H14O6  (Rhamnose) +C15H10O5  (Emodin). 

5.  Aloin. — Several  apparently  different   aloins  :    aloin,  barbaloin, 
nataloin,  are  found  in  aloes,  the  dried  juice  of  various  species  of  aloe. 
The  best  known  is  barbaloin,  isolated  from  Barbadoes  aloes,  occurring 
in  yellowish  needles,  C14H5O2(OH)2CH2.O.C6HnO4  (?)  (C.  1909,  II.  622). 
On  heating  with  aqueous  alcoholic  HC1  it  is  split  up  into  an  aldo- 
pentose   (osazone,  m.p.   209°)   and  aloe-emodin,  and  therefore  shows 
the  same  transformations  as  the  latter  (C.   1910,  I.   104).     Chromic 
acid  oxidises  it  to  rhein,  a  dioxy-anthraquinone-carboxylic  acid  (above)  ; 
with  HNO3  chrysamic  acid  is  obtained,  and  the  so-called  aloetic  acid, 
probably  a  mixture  of  several  highly  nitrated  aloe-emodins. 

VII. — BITTER  PRINCIPLES. 

Under  the  head  of  "  bitter  principles,"  or  indifferent  substances,  is 
embraced  a  class  of  vegetable  bodies  many  of  which  have  already 
found  their  place  in  the  chemical  system.  Those  yet  uninvesti- 
gated  are  : 

Cantharidin  C10H12O4,  melts  at  218°  and  sublimes  readily.  It  is 
contained  in  Spanish  flies  and  other  insects.  It  tastes  very  bitter,  and 
produces  blisters  on  the  skin.  It  dissolves  when  heated  with  alkalies 
and  forms  salts  of  cantharinic  acid  C10H14O5.  It  combines  with  phenyl- 
hydrazin  to  an  addition  product  C16H20N2OH,  melting  at  194°,  and  a 
phenyl-hydrazone,  melting  at  238°  (B.  26,  140).  Cantharidin  is  pro- 
bably a  lactone-carboxylic  acid.  Hydriodic  acid  converts  Cantharidin 
into  cantharic  acid  C10H12O4=C8HnO.CO.CO2H,  isomeric  with  it. 
When  this  acid  is  distilled  with  lime,  cantharene  or  dihydro-o-xylene 
results. 

Anemonin  C10H8O4,  m.p.  150°,  appears  to  be  closely  related  to 
Cantharidin.  It  is  a  crystalline  constituent  of  the  extracts  of  nearly 
all  Anemones  and  Ranunculacece  (M.  20,  634). 

Pier o- toxin  C15H16O6+H2O  is  found  in  the  grains  of  cockle,  and 
crystallises  in  fine  needles,  melting  at  201°.  It  has  an  extremely 
bitter  taste,  and  is  very  poisonous. 

It  is  a  mixture  of  two  bodies  :  picro-toxinin  C15H16O6+H2O,  m.p. 
201°,  and  picrotin  C15H18O7,  m.p.  249°,  which  are  best  separated  by 
bromination  in  aqueous  solution.  In  this  case  only  the  picro-toxinin 
is  brominated  to  sparingly  soluble  bromo-picro-toxinin,  which  can 
then  be  reduced  to  picro-toxinin  ;  the  latter  is  a  strong  reducing  agent, 
contains  two  hydroxyl  groups,  and  seems  to  be  a  lactone  (B.  31,  2958). 

Santonin  C15H18O3,  melting  at  170°,  [a]D=— 171-37°,  is  the  active 
principle  of  artemisia  cina.  It  dissolves  in  alkalies  to  salts  of  santonic 
acid  C15H20O4,  which  breaks  down  at  120°  into  water  and  santonin. 
On  boiling  with  baryta  water  we  obtain  salts  of  isomeric  santoic  acid 
C15H20O4,  which  melts  at  171°. 

This  acid,  upon  further  oxidation,  yields  a  tetracarboxylic  acid. 
For  its  constitution,  see  B.  29,  R.  1119.  Santonin  is  a  lactone.  It 


BITTER  PRINCIPLES  725 

bears  the  same  relation  to  santonic  and  santoic  acids  as  cumarin  to 
cumarinic  and  cumaric  acids.  Again,  it  contains  the  ketone  group  ; 
its  phenyl-hydrazone  melts  at  220°.  When  santonin  is  reduced  with 
hydriodic  acid  or  with  stannous  chloride  and  hydrochloric  acid,  santous 
acid  C15H20O3  results.  This  is  dextro-rotatory  and  melts  at  179°.  The 
corresponding  laevo-rotatory  modification  and  the  (d-j-l)-acid  are  known. 
When  these  three  acids  are  fused  with  caustic  potash,  propionic  acid, 
dimethyl-j3-naphthol,  and  hydrogen  are  produced.  Hence  it  would 
seem  that  santonin  is  a  derivative  of  a  hexahydro-dimeihyl-naphthalene 
(B.  27,  530  ;  28,  R.  392  ;  29,  R.  291,  296).  When  santonin  is  reduced 
with  tin  and  hyolrochloric  acid,  not  only  santous  acid  is  formed,  but  also 
a  hydrocarbon  C10H13(CH3)2(C2H5),  boiling  at  248°,  which  probably  is 
dimethyl-ethyl-octohydro-naphthalene  (B.  28,  R.  622). 

By  heating  with  mineral  acids  under  various  conditions  santonin 
is  converted  into  diverse  so-called  desmo-tropo-santonins  C15H18O3, 
distinguished  by  then-  optical  rotatory  power,  and  from  santonin  by 
the  absence  of  the  ketone  reaction  and  the  presence  of  phenol  reactions. 
It  is  therefore  assumed  that  there  is  a  transformation  of  a  ketone 
form  into  a  phenol  form,  as  in  the  case  of  carvone  and  carvacrol  (B.  31, 
3131  ;  36,  1386,  2667).  Other  transformations  are  produced  by  sun- 
light. In  an  acetic  acid  solution  the  two-basic  so-called  photo-santonic 
acid  C15H22O5  is  formed  together  with  iso-photo-santonie  acid,  a 
dioxaldehyde-carboxylic  acid  ;  the  former  passes  into  dehydro-photo- 
santonic  acid  C15H20O4,  with  loss  of  water,  which  on  oxidation  yields 

dimethyl  -  phthalide  -  earboxylie  acid  CK^C(CI*?^r[2]  }c8H3[5]COOH,    and 

N GOL2J  J 

on  distillation  of  its  Ba-salt  i,  5,  2-diethyl-iso-propyl-benzol  (C.  1902, 
I.  1402).  From  these  data  the  following  formulae  have  been  deduced  : 

CH,— C(CHS)=C— CH,-CH— O \^Q  >  CH=C(CH,)-C— CH,— CH— O~ 

CO— C(CH,)=C— CH,— CH— CH(CH,)/     ^          C(OH)  :  C(CH,)-C— CH,— CH— CH(CHJ/ 
Santonin  \  Desmo-tropo-santonin 

CH,.CH(CH,).C=CH— CHOH  *  HOCHJ.CH(CH,).C=CH— CHOH 

HOCO.CH(CH,).C=CH— CHCH(CH,)COOH  HOC.CH(CH,).C=CH— CHCH(CH,)COOH 

Photo-santonic  acid  Iso-photo-santonic  acid. 

Artemisin  C15H18O4,  from  the  seeds  of  Artemisia  maritima,  is  a 
lactone  closely  related  to  santonin  (cp.  B.  34,  3717  ;  C.  1905,  I.  98). 

VIII. — NATURAL  DYES. 

The  important  natural  dyes,  indigo,  alizarin,  and  its  allies,  euxanthic 
acid,  gentisin,  etc.,  have  found  their  place  in  the  system  of  organic 
chemistry.  The  following  are  some  of  the  natural  dyes  which  have  not 
yet  been  investigated  : 

Brasilin  C16HUO5  is  found  in  Brazil-wood  and  red-wood  ;  crystallises 
with  iJH2O  in  white,  shining  needles,  and  dissolves  in  alkalies  with  a 
carmine-red  colour  on  exposure  to  the  air.  Acids  then  precipitate 
brasilein  C16H12O5+H2O  from  the  solution.  The  action  of  iodine 
upon  brasilin  also  produces  this  compound.  It  can  be  reconverted 
into  brasilin  by  reduction,  best  by  way  of  its  acetyl  compound  (B.  36, 
3951  ;  M.  25,  871).  Brasilein  is,  therefore,  related  to  brasilin  as  dyes 
are  related  to  leuco-bodies.  Brasilin  forms  mono-,  di-,  tri-,  and 
tetra-alkyl  ethers  (B.  27,  524 ;  R.  304 ;  29,  R.  219)  ;  while  brasilein 


726  ORGANIC  CHEMISTRY 

forms,  besides  the  normal  -di-  and  trialkyl  ethers,  tri-  and  tetra-alkyl 
brasileinols,  with  attachment  of  one  molecule  H2O  (C.  1908,  II.  609). 
On  distillation,  brasilin  yields  much  resorcin.  On  conducting  air 
for  some  time  through  a  strongly  alkaline  solution  of  brasilin,  we 
obtain  a  compound  C9H6O4  which  probably  has  the  constitution 
C6H3(OH)^£|£~£^  since  its  dimethyl  ether  is  split  up  by 
sodium  alcoholate  into  formic  acid  and  flsetol-dimethyl  ether 
C6H3[5](OCH3){[[^]^CH2(OCH3),  a  decomposition  product  of  fisetin  (B. 

32,  1024).  Oxidation  of  trimethyl-brasilin  C16H10O(OH)(OCH3)3,  m.p. 
140°,  with  MnO4K,  on  the  other  hand,  produces  various  acids,  among 
which  may  be  mentioned  5-methoxy-phenoxy-aeeto-2-carboxylic  aeid 
(CH30)C6H3<(£™.£0  >H,  4,  5-dimethoxy-phenyl-aeeto-2-earboxylie  acid 

(CH3o)2c6H2<^2£°2H,  and  m-hemipinic  acid  (CH3O)2C6H2(COOH)2, 
also  brasilic  acid  (CH3O)C6H3<^~£|^H)  CH2COOH  and  brasilinie  acid 

(CH30)C6H3<(CO  ^/H^H.J.CO.H- 

This  last  acid  is  also  formed  by  the  condensation  of  m-hemipinic 
anhydride  with  m-methoxy-phenoxy-acetic  ester  by  means  of  A1C13. 
In  a  similar  manner,  the  anhydro-brasilic  acid  C12H10O5  obtained  from 
brasilic  acid  by  dehydration  has  been  prepared  synthetically  (C.  1908, 
I.  1698).  On  oxidising  trimethyl-brasilin  with  chromic  acid,  we  obtain 
a  ketone,  trimethyl-brasilone  C19H18O6,  which  is  converted  by  HNO3 
into  nitro-hydroxy-dihydro-trimethyl-brasilone  C19H19O7(NO2).  This 
can  be  split  up  by  alkalies  into  methoxy-salicylic  acid  (CH3O)C6H3 
(OH)COOH  and  nitro-homo-veratrol  NO2C6H2(CH3)(OCH3)2.  The 
trimethyl-brasilone  easily  passes  into  trimethyl-dehydro-brasilone 
C19H16O5,  with  loss  of  H2O,  and  this  behaves  precisely  like  a  derivative 
of  j8-naphthol.  With  diazonium  solutions  it  couples  up  to  azo-dyes ; 
with  HNO3  it  forms  a  nitro-compound,  from  which,  by  successive 
reduction  and  oxidation,  an  o-quinone  corresponding  to  j8-naphtho- 
quinone  is  obtained,  known  as  trimethoxy-a-brasane-quinone  C19H14O6 
(C.  1909,  I.  1569).  By  treatment  with  HI  and  with  concentrated 
H2SO4,  trimethyl-brasilone  is  isomerised,  and  appears  to  pass  into 
derivatives  of  j3j3-phenylene-naphthylene  oxide  (brasane)  (C.  1902,  II. 
746  ;  35,  1609  ;  36,  2193  ;  37,  631  ;  M.  23,  165). 

Hsematoxylin  C16H14O6+3H2O  is*  the  colouring-matter  of  logwood 
(Hcemato%ylon  campechianum) ,  is  very  soluble  in  water  and  alcohol, 
and  crystallises  in  yellowish  prisms  having  a  sweet  taste.  It  dissolves 
in  alkalies  with  a  violet-blue  colour.  The  importance  of  logwood  lies 
in  the  production  of  bluish-black  shades  by  means  of  iron  and  chrom- 
ium. Distillation,  or  fusion  with  potash,  produces  pyrogallic  acid  from 
haematoxylin  (B.  36,  1561).  When  distilled  or  fused  with  potassium 
hydroxide,  pyrogallic  acid  and  resorcinol  result  from  it.  If  the  am- 
monium hydroxide  solution  be  allowed  to  stand  exposed  to  the  air, 
there  results  haematem-ammonia  C16HU(NH4)O6,  from  which  acetic 
acid  precipitates  the  free  haematin  C16H12O6  (at  120°),  a  reddish-brown 
body,  which  has  metallic  lustre  after  drying  (A.  216,  236).  It  yields 
penta-ethyl-  and  penta-acetyl  ethers.  In  the  oxidation  of  tetra- 


NATURAL  DYES  727 

methyl-haematoxylin  with  MnO4K,  acids  are  obtained  analogous  to 
those  from  the  oxidation  of  trimethyl-brasilin,  e.g.  dimethoxy-phenoxy- 

acetic-o-earboxylic    acid    (CH3O)AH2(W°^fOOH,   meta-hemipinic 

It. !  2Jx^vJvJlrL 

acid,  and  the haematoxylinicacid  corresponding  to  brasilinic  acid  (above). 
Similarly,  tetramethyl-haematoxylin  on  oxidation  with  CrO3  yields 
tetramethyl  -  haematoxylone,  corresponding  to  trimethyl  -  brasilone, 
and  giving  quite  similar  decomposition  products  (C.  1902,  II.  750  ; 
B.  36,  2202).  Haematoxylin  is  therefore  only  distinguished  from 
brasilin  by  the  entry  of  an  HO  group  into  the  benzene  nucleus.  From 
the  data  hitherto  obtained,  Perkin  has  deduced  the  following  formulae 
for  brasilin  and  haematoxylin  : 

HO[5]C.H,  {  [IJOCIITO.]  }c.Hl[4,5](OH) 

(H0),[5, 

Haematoxylin . 

Carthamin  C14H16O7  occurs  in  safflower,  the  blossoms  of  Carthamus 
tinctorium,  and  is  precipitated  from  its  soda  solution  by  acetic  acid  as  a 
dark-red  powder,  which,  on  drying,  acquires  a  metallic  lustre.  It 
dissolves  with  a  beautiful  red  colour  in  alcohol  and  the  alkalies. 
It  yields  para-oxy-benzoic  acid  with  caustic  potash  (A.  136,  117). 
On  boiling  with  dilute  potash  it  forms  p-cumaric  acid  and  p-oxy- 
benzaldehyde  (C.  1910,  II.  805). 

CurcuminC21H20O6=[CH3O[3]OH[4]C6H3CH  :  CH.CO]2CH?(?),  m.p. 
183°,  the  dyestuff  of  the  curcuma  root  of  Curcuma  longa  and  viridiflora, 
crystallises  in  orange  prisms  and  dissolves  in  alkalies  to  form  reddish- 
brown  salts.  It  yields  a  dimethyl  ether  C21H18O4(OCH3)  2,  m.p.  137°,  and 
a  diacetyl  compound  C21H18O6(C2H3O)  2  (C.  1911, 1.  652) .  With  hydroxyl- 
amine  we  obtain,  according  to  conditions,  an  oxime  C21H21O6N,  m.p. 
162°,  or  an  isoxazol  derivative  C21H19O5N,  m.p.  173°.  On  heating 
with  potash  it  forms  ferulic  acid  (B.  43,  2163). 

Lichen  dyes  (/.  pr.  Ch.  2,  58,  465  ;  A.  306, 282  ;  310,  230),  compare 
orseille,  litmus,  vulpinic  acid.  Of  the  numerous  substances  contained 
in  lichens,usnie  acid  C18H16O7,  occurring  in  usnea  and  many  other  species, 
has  been  studied  in  detail.  The  acid  is  optically  active,  and  is  found 
naturally  in  the  antipodic  forms  [a]D=;±;49*50,  m.p.  203°,  and  in  the 
racemic  form,  m.p.  192°.  It  forms  an  oxime,  an  oxime  anhydride,  and 
a  semi-carbazone,  and  is  therefore  probably  a  ketonic  acid. 

On  oxidation  it  is  completely  burnt  to  CO2,  oxalic  acid,  and  acetic 
acid  ;  it  therefore  contains  no  aromatic  nucleus  ;  by  gentle  oxidation 
with  Mn04K  the  di-basic  usnonic  acid  is  obtained,  C18H16O3.  On 
heating  with  alcohols  to  150°,  usnic  acid  splits  off  CO2,  takes  up  H2O, 
and  forms  dibasic  decarbo-usnic  acid  C17H18O6.  For  its  constitutional 
formula,  see  A.  310,  281  ;  324,  139. 

Carminic  acid  C11H12O7  is  found  in  cochineal,  from  Coccus  cacti 
coccinelliferi,  an  insect  peculiar  to  different  cactus  varieties.  It  is  a 
purple-red  mass,  dissolving  readily  in  water  and  alcohol,  which  forms 
red  salts  with  the  alkalies.  Cochineal  is  applied  in  wool-dyeing  for  the 
production  of  scarlet-red  colours.  This  application  has  diminished 


728  ORGANIC  CHEMISTRY 

very  greatly  since  the  discovery  of  the  red  azo-dyes,  like  Bieberich 
scarlet  and  others.  The  constitution  of  carminic  acid  is  not  yet  fully 
elucidated  (B.  42,  1611).  Potassium  permanganate  oxidises  it  to  a 
methyl-trioxy-a-naphtho-quinone-carboxylie  acid  C12H17O7,  which,  in  its 
behaviour,  closely  resembles  iso-naphthazarin,  and  is  therefore  called 
carminazarin.  On  oxidation  with  HNO3  it  yields  a  tetraketone, 
carminazarin-quinone  C12H6O7+2H2O,  and  in  alkaline  solution  it  is 
converted  by  atmospheric  oxygen  into  a  cresotin-glyoxyl-dicar- 
boxylic  acid  CnH8O8+2H2O,  which,  on  heating  with  concentrated 
H2SO4,  decomposes  into  CO  and  the  so-called  eoehinelic  acid  C;0H807. 
This  acid,  first  obtained  by  the  direct  oxidation  of  carminic  acid  with 
potassium  persulphate,  is  probably  an  m-cresol-4,  5,  6-tricarboxylic 
acid,  since,  on  heating  with  water,  it  yields  oxy-uvitinic  acid  (a-coccinic 
acid),  and  I,  3,  5-cresotinic  acid,  and  on  heating  alone,  oxy-methyl-o- 
phthalic  acid  (B.  30,  1731).  By  boiling  with  HNO3,  carminic  acid  is 
converted  into  nitro-coceie  acid  or  symmetrical  trinitro-cresotinic 
acid.  The  following  formulae  illustrate  this  demolition  of  carminic 
acid  : 


NO2  HOjC        O  HO,C       O  HO2C       CO2H  CO2H 


2  j  ,  2  2  2 

Nitro-coccic  acid      Carminic  acid  Carminazarin  Cresotin-glyoxyl-       Cochenelic  acid. 

dicarboxyHc  acid 

The  action  of  bromine  upon  carminic  acid  takes  place  in  several 
stages.  A  dibromo-hydro-bromide  C22H20Br2O13.HBr  is  first  formed. 
This,  on  heating,  easily  splits  off  HBr  and  CO2,  and  passes  into 
decarboxy-dibromo-carminic  acid  C21H20Br2O11.  By  strong  action  of 
bromine,  several  so-called  bromo-carmines  are  formed  :  a-bromo- 

carmine,  a  derivative  of  diketo-hydrindene   HO(CH3)C6Br2/co\CBr2, 

which,  on  heating  with  soda  solution,  decomposes  into  bromoform  and 
dibromoxy-methyl-phthalic  acid,  and  /3-bromo-carmine  C11H6Br3O4, 
probably  a  naphtho-quinone  derivative  (B.  43,  1363).  On  methylating 
carminic  acid  we  obtain,  according  to  the  conditions,  various  methyl 
derivatives,  including  carminic  acid  hexamethyl  ether  C22H16(CH3)6O13 
(B.  42,  1922).  Closely  related  to  carminic  acid  is  : 

Kermessic  acid  C18H12O9,  red  needles,  m.p.  250°  with  decomposition, 
from  the  insect  Lecanium  Ilicis.  Oxidation  with  HNO3  gives  nitro- 
coccic  acid  in  this  case  also.  Its  dimethyl  ether  yields,  with  MnO4K, 
methyl-cochenilic  methyl  ester,  as  well  as  the  dimethyl  ether  of 
cresotin-glyoxyl-dicarboxylic  acid  (B.  43,  1387).  Compare  also  the 
similarly  constituted  laccainic  acid  C16H12O8  (B.  29,  1285). 


INDEX 


SUBSTANCES  should  also  be  sought  in  the  more  general  paragraphs  of  the 
various  sections  and  derivatives,  also  under  the  various  compounds. 


ABIETIC  Acid,  548 
Acenaphthene,  50,  682 
Acenaphthene-quinone,  682 
Acenaphthenone,  682 
Acetamido-azo-benzol,  144 
Acetamido-cinnamic  Acid,  422 

Anhydride,  422 

Acetanilide,  95 

AcetanthranUido-acetic  Acid,  308 
Acetenyl-benzene,  407 
Acetiodoso-benzoic  Acid,  298 
Aceto-acetic  Anilide,  98 
Aceto-acetic-ester  phenyl-hydrazone,  159 
Aceto-benzoic  Acid,  353 

Anhydride,  279 

Aceto-benzoyl-benzoic  Acid,  575 
Aceto-chloramide,  100 
Aceto-isatinic  Acid,  389 
Aceto-naphthone,  677 
Aceto-oxindol,  310 
Aceto-phenone,  266 
Aceto-phenone-acetone,  375 
Aceto-phenone  Alcohol,  371 

Ammonia,  267 

Aceto-phenone-anilide,  372 
Aceto-phenone-carboxylic  Acid,  353 
Aceto-phenone  Oxime,  267 
Aceto-phenyl-hydrazide,  157 
Aceto-phenyl-imido-methyl-ether,  95 
Aceto-phthal-aldehydic  Acid,  351 
Aceto-piperone,  326 
Aceto-pyro-catechol,  326 
Aceto-vanillon,  326 
Aceto-veratron,  326 
Acetone,  42 

Acetone-diphthalide,  640 
Acetone-oxalic  Ester,  43 
Acetonyl-phthalide,  401 
Acetoxy-phenyl-pyro-racemic  Nitrile,  394 
Acetoxy-phthalide,  351 
Acetyl-aceto-phenone,  375 
Acetyl-amidrazone,  164 
Acetyl-anisol,  326 
Acetyl-anthranile,  303 
Acetyl-anthranilic  Acid,  302 
Acetyl-aurins,  593 
Acetyl-benzenyl-amidoxime,  296 
Acetyl-benzisoxazolone,  301 
Acetyl-benzol,  266 
Acetyl-benzoyl  Oxime,  257 
Acetyl-carbanilide,  100 
Acetyl-cumarin,  438 

Acetyl-cyclo-hexane-carboxylic  Ester,  476 
Acetyl-cyclo-hexanone,  468 
Acetyl-cyclopentanone,  19 
Acetyl-Ax-cyclopentene,  19 
Acetyl-dioxindol,  378 
Acetyl-diphenyl-thio-urea,  107 
Acetyl-diphenyl-urea,  107 
Acetyl-hexanitro-diphenyl-amine,  112 
Acetyl-isatin,  389 

Acetyl-methyl-phenyl-triazene,  136 
Acetyl-opianic  Acid,  352 
Acetyl-phenyl-acetylene,  417 


Acetyl-phenyl-hydroxylamine,  78 
Acetyl-phenyl-isindazol,  571 
Acetyl-phenyl-urea,  100 
Acetyl-propionyl,  43 
Acetyl-salicylic  Acid,  330 
Acetyl-salicyl  Chloride,  331 
Acetyl-thio-phenol,  327 
Acetyl-trimethylene,  8 
Acetyl-trimethylene-carboxylic  Ester,  9 
Acetylene,  42 
Acetylene-anisol,  413 
Acetylene  Benzenes,  407 
Acetylene-benzol,  30 
Acetylene-bis-thio-salicylic  Acid,  332 
Acetylene-phenetol,  413 
Acid  Fuchsine,  587 
Acid  Green,  584 
—  Yellow,  179 
Acidum  cinnamylicum,  419 
Acidyl  Anthraniles,  308 
Acidyl-phenyl-hydrazides,  164 
Acridone,  308,  332,  571 
Adipin-ketone,  17 
Adipinic  Acid,  457 
Adrenah'n,  370 
/Esculetin,  431 
/Esculin,  721 

jEsculus  hippocastanum,  721 
Alcohol-carboxylic  Acids,  347 
Alcoholic  Hydroxyls,  105 
Aldehyde  Acids,  350 

Alcohols,  345 

Green,  588 

Aldehydins,  116 
Aldehydo-benzoic  Acid,  353 
Aldehydo-dicarboxylic  Acids,  364 
Aldehydrazones,  152 
Aldonaniline,  91 
Aldoximes,  254 
Ah'phatic  Compounds,  2 

Diazo-compounds,  6 

AJizarin,  702,  714,  725 

Blue,  715 

Alizarin-bordeaux,  717 
Alizarin-dimethyl  Ether,  715 
Alizarin  Saphirol,  713 
Alizarin-sulphonic  Acid,  715 
Alizarine,  212 
Alkali  Blue,  589 
Alkaline  Diazotates,  124 
Alkyl-aryl-sulphones,  182 
Alkyl-benzoic  Acids,  274 
Alkyl-benzols,  51 

Halogen  Derivatives  of,  64 

Nitro-halogen  Derivatives  of,  74 

Nitro-products  of,  73 

Alkyl-cumarins,  428 
Alkyl-phenyl-hydrazin,  152 
Alkyl-phenyl-ureas,  99 
Alkyl-terephthalic  Acids,  362 
Alkylamines,  156 
Alkylated  diphenyls,  550 

•  Phenanthrenes,  689 

Phenyl-hydrazins,  152 


729 


730 


INDEX 


Alkylated  Rosanilins,  588 
Alkylic  Anthracenes,  703 

Para-rosanilins,  587 

Rhodamins,  601 

Alkylidene-dianilines,  90 
Alkylidene-monoanilines,  90 
Allo-chryso-keto-carboxylic  Acid,  680 
Allo-chryso-ketone-carboxylic  Acid,  701 
AUo-cinnamic  Acid,  420 

Dibromide,  386 

Bichloride,  385 

Allophanic  Acid,  100 
Allyl-aceto-phenone,4i  7 
Allyl-benzol,  406 

Allyl-benzoyl-acetic  Ester,  393,  438 
Allyl-cyclo-hexane,  449 
AUyl-phenol,  409 
Allylene,  42,  51 
Almond  Acid,  376 
Aloetic  Acid,  724 
Aloin,  724 

Alphyl-cyanides,  286 
Alphyl-Hydroxylamines,  77 
Alphyl-nitroso-hydroxylamines,  79 
Aluminium  phenate,  186 
Alyl-naphthalin,  658 
Amaric  Acid,  639 
Amarine,  257 
Amber,  549 
Amide  Iodides,  286 
Amido-aceto-phenones,  269,  372 
Amido-alizarin,  715 
Amido-anilic  Acid,  230 
Amido-azo-benzol,  144 
Amido-azo-benzol-sulphonic  Acids,  178 
Amido-azo-compounds,  142 
Amido-azo-naphthalene,  662,  663 
Amido-azo-toluol,  144 
Amido-benzal-acetone,  416 
Amido-benzaldehydes,  263 
Amido-benzene,  29 
Amido-benzo-hydrol,  566 
Amido-benzo-phenones,  570,  571 
Amido-benzoic  Acid,  309 
Amido-benzol,  79 
Amido-benzol-sulphonic  Acids,  177 
Amido-benzoyl-carbinol,  372 
Amido-benzyl  Alcohol,  250 
Amido-benzyl-amine,  250,  252 
Amido-benzyl-aniline,  250 
Amido-benzyl  Chloride,  251 
Amido-benzyl-phenols,  564 
Amido-butyro-phenone,  373 
Amido-campholene,  538 
Amido-camphor,  534 
Amido-camphor-chlorohydrate,  534 
Amido-chloro-styrol,  406 
Amido-cinnarnic  Acids,  422,  423 
Amido-cyclo-hexane,  455 
Amido-diazo-benzol-imide,  138 
Amido-dimethyl-aniline,  115 
Amido-diphenyls,  552 
Amido-diphenyl-amine,  116,  147 
Amido-diphenyl-aniline:  114 
Amido-diphenyl-guanidin,  104 
Amido-diphenylene-ketone,  699 
Amido-diphenyl-methanes,  564 
Amido-diphenyl  Sulphide,  180 
Amido-ditolyls,  552 
Amido-ethyl-benzol,  87 
Amido-fluorene,  697,  700 
Amido-guanidone,  235 
Amido-hemi-pinic  Acid,  359 
Amido-hydrindene,  648 
Amido-hydro-carbo-styrile,  311 
Amido-hydro-cinnamic  Acid,  383 
Amido-iso-propyl-benzol,  87 
Amido-mandelic  Acid,  378 
Amido-methyl-benzols,  85 
Amido-naphthoic  Acid,  678 
Amido-naphthols,  667 
Amido-naphthol-sulphonic  Acids,  670 
Amido-nitro-fluorene,  697 
Amido-octyl-benzol,  87 
Amido-oxindol,  310 
Amido-oxy-anthraquinones,  715 


Amido-oxy-biphenyls,  557 
Amido-oxy-diphenyl,  557 
Amido-oxy-naphthoic  Acid,  679 
Amido-oxy-phenanthrene,  690 
Amido-oxy-triphenyl-carbinols,  592 
Amido-pentamethyl-benzol,  37 
Amido-phenanthrene,  690 
Amido-phenanthrene-quinones,  692 
Amido-phenols,  117,  199 
Amido-phenyl-acetylene,  407 
Amido-phenyl-arsinic  Acid,  170 

Oxide,  170 

Amido-phenyl-fatty  Acids,  310 
Amido-phenyl-glyceric  Acid,  385 
Amido-phenyl-guanidin,  162 
Amido-phenyl-methyl-hydrazin,  152 
Amido-phenyl-propiolic  Acid,  433 
Amido-phenyl  Sulphides,  210 
Amido-phenyl-urethane,  114 
Amido-phthalic  Acids,  359 
Amido-phthalide,  351 
Amido-polymethyl-benzols,  86 
Amido-propio-phenone,  372,  373 
Amido-propyl -benzol,  87 
Amido-quinone  Imine,  234 
Amido-quinones,  229 
Amido-sah'cylic  Acid,  333 
Amido-saligenin,  316 
Amido-styrol,  406 

Amido-suberane-carboxylic  Acid,  25 
Amido-terebentene,  519 
Amido-tert. -butyl-benzol,  82,  87 
Amido-tetramethylene,  n 
Amido-thio-pbenols,  96,  117,  209 
Amido-triphenyl-amine,  116 
Amido-triphenyl-carbinols,  582 
Amido-valero-phenone,  373 
Amidol,  202 
Amidoximes,  286,  392 

Hetero-ring  Formations  of,  296 

Amidrazones,  142,  157,  163,  291 
Amino-anthraquinone,  711 
Amino-aurin,  594 
Amino-cyclo-heptene,  24 
Amino-trimethylene,  7 
Amino-triphenyl-carbinol,  582 
Amino-triphenyl-methane,  578 
Amygdalin,  225,  255,  723 
Amyl-anthracenes,  704 
Andropogon  nardus,  522 
Anemones,  724 
Anemonin,  724 
Anethol,  334,  363,  410 

Dibromide,  369 

Nitrite,  410 

Anethol-nitroso-chloride,  410 
Anethol-pseudo-nitrosite,  410 
Anethum  fceniculum,  410 

graveolens,  412 

Angra.cum  fragrans,  427 
Anhydro-acetonebenzile,  17 
Anhydro-bases,  667 
Anhydro-benzile-laevulinic  Acid,  17 
Anhydro-brasilic  Acid,  726 
Anhydro-geraniol,  487 
Anile-aceto-acetic  Ester,  98 
Anile-pyro-racemic  Acid,  98 
Anile-uvitoninic  Acid,  98 
Anilic  Acid,  356 
Anilido-acetic  Acid,  97 
Anilido-azo-benzol,  144 
Anilido-butylidene-aniline,  91 
Anilido-butyric  Acid,  98 
Anilido-crotonic  Ester,  99 
Anilido-malonic  Acid,  108 
Anilido-phenyl,  100    • 
Anilido-phenyl-acetic  nitrile,  379 
Anilido-phosphoric  Dichloride,  93 
Anih'do-propionic  Acid,  98 

Ester,  98 

Anilido-pyrrols,  155 
Aniline,  69,  79,  83 

Black,  237 

Blue,  91,  92,  589 

Chlorohydrate,  82 

Salts,  84 


INDEX 


Aiiilino-cyclo-pentene,  16 
Anilino-diacetic  Acid,  98 
Anilino-guanidin,  162 
Anilino-methylene-acetic  Ester,  96 
Anilino-methylene-malonic  Ester,  96 
Anilo-biguanide,  162 
Anilo-succimide,  163 
Anis-acetone,  327 
Anisal  Chloride,  323 
Anisaldoxime,  322 
Anisic  Acid,  334 

Aldehyde,  322 

Anisile,  618 
Anisilic  Acid,  607 
Anisol,  190 

Anisol-diazonium  Cyanide,  125 
Anisolines,  602 
Anisyl  Alcohol,  316 
Annidalin,  188 
Anol,  410 

Anthra-chrysone,  717 
Anthra-cumarin,  707,  708 
Anthra-diamine,  705 
Anthra-hydroquinone,  706,  708 
Anthra-phenone,  708 
Anthra-purpurin,  717 
Anthra-pyrimidin,  712 
Anthra-pyrimidone,  712 
Anthracene,  27,  50,  703 

Group,  701 

Anthracene-carboxylic  Acids,  708 
Anthracene  Dihydride,  708 
Anthracene-monosulphonic  Acid,  705 
Anthracene-sulphonic  Acid,  705 
Anthraflavic  Acid,  716 
Anthragallol,  717 
Anthramine,  705 
Anthranile,  73,  302 

Sulpho-acid,  73 

AnthranUic  Acid,  72,  301 

Dimolecular  Anhydrides  of,  304 

Betain,  306 

Formalide,  307 

Nitrile,  302 

Anthranilido-acetic  Acid,  307 

Anthranilido-diacetic  Acid,  307 

Anthranilido-diaceto-nitrile,  307 

Anthranol-ethyl  Ether,  706 

Anthranoyl-anthranilic  Acid,  304 

Anthraquinone,  705,  709 

Anthraquinone-carboxylic  Acids,  717 

Anthraquinone-oxime,  705 

Anthraquinone-sulphonic  Acids,  712 

Anthrarobin,  707 

Anthrarufin,  706,  716 

Anthrol,  705 

Anthrone,  706,  709 

Anthroxan-aldehyde,  374 

Anthroxanic  Acid,  303,  389 

Antifebrin,  95 

Antipyrin,  149 

Apinol,  412 

Apiol,  412 

Apionol,  223 

Apo-camphoric  Acid,  525,  544 

Arbutin,  720 

Arbutus  uva  ursi,  720 

Archil,  217 

Aristol,  188 

Armstrong,  41 

Arnica  montana,  219 

Aromatic  Acid  Haloids,  278 

Acids,  Imido-ethers  of  the   288 

Thiamides  of  the,  288 

Amido-monocarboxylic  Acids,  301 

Carboxylic  Acids,  Imido-thio-ethers    of    the, 

289 

Compounds,  27 

Di-aldehydes,  346 

Dicarboxylic  Acids,  363 

Di-halogen  Toluols,  66 

Hexacarboxylic  Acid,  366 

Monaldehydes,  252 

Monocarboxylic  Acids,  269 

Formazyl  Derivatives  of  the,  292 

Substituted,  297 


Aromatic  Monoketones,  264 

o-Amido-ketones,  269 

Oxymono-aldehydes,  321 

Pentacarboxylic  Acid,  366 

Polyalcohols,  367 

Substances,  2 

Tetracarboxylic  Acids,  365 

Thionylamines,  92 

Arsanilic  Acid,  170 
Arsen-anilido-dibromide,  93 
Arsen-anilido-dichloride,  93 
Arsen-anih' do-dimethyl-ether,  93 
Arsen-dianilido-monochloride,  93 
Arseno-benzol,  170 
Artemisia  Barrelieri,  510 

etna,  499 

mantima,  725 

Artemisin,  725 
Aryl-acetaldoximes,  405 
Aryl-hydroxylamines,  77 
Aryl-magnesium  Haloids,  171 
Asarone,  325,  412 
Asarum  ari folium,  411 

europ&um,  411 

Asaryl-aldehyde,  325 
Aseptol,  207 
Asperula,  428 

Essence,  428 

Asperula  odorata,  428 

Aspidium  filix-mas,  222 

Atro-glyceric  Acid,  384 

Atro-lactinic  Acid,  379 

Atropic  Acid,  425 

Atroxindpl,  311 

a-Truxillic  Acid,  13 

Auramin,  572 

Aurins,  1 86,  590,  593 

Azelaol,  26 

Azelaone,  26 

Azi-benzile,  616 

Azimides,  116 

Azimido-benzoic  Acid,  310 

Azo-benzide,  141 

Azo-benzoic  Acids,  311 

Azo-benzol,  69,  140,  141 

Azo-benzol-m-monocarboxylic  Acid,  312 

Azo-benzol-phenyl-hydrazin-sulphonic  Acid,  157 

Azo-camphenone,  533 

Azo-camphor,  534 

Azo-cpmpounds,  140 

Azo-dibenzoyl,  283 

Azo-di-carbon-anUide,  101 

Azo-naphthols,  668 

Azo-opianic  Acid,  359 

Azo-phenols,  204 

Azo-toluols,  142 

Azo-trimethyl-benzols,  142 

Azo- violet,  457 

Azoxy-aniline,  140 

Azoxy-benzaldehydes,  262 

Azoxy-benzide,  139 

Azoxy-benzoic  Acids,  311 

Azoxy-benzol,  69,  139 

Azoxy-benzyl  Alcohol,  250 

Azoxy-compounds,  139 

Azoxy-phenols,  203 

Azoxy-toluol,  140 

Azoxylenes,  142 

Azurin,  237 

BAEYER,  VON,  3,  41,  418,  443.  477,  485,  486,  495, 
5i6,  599 

Tension  theory  of,  3 

Barbaloin,  717,  724 
Benckiser,  231,  232 
Benzal-aceto-acetic  Ester,  438 
Benzal-acetone,  416 
Benzal-acetone-phenyl-hydrazone,  416 
Benzal-amidp-sulphonic  Acid,  260 
Benzal-angelic  lactone,  439 
Benzal-anfline,  257 
Benzal-azin,  258 
Benzal-barbituric  Acid,  439 
Benzal-benzamidine,  290 
Benzal-benzoyl-hydrazin,  284 
Benzal-benzyl-acetone,  638 


732 


INDEX 


Benzal-bis-acetyl-acetone,  376 
Benzal  Bromide,  257 
Benzal  Chloride,  30,  64,  257 
Benzal-diphenyl-dihydro-tetrazone,  167 
Benzal-diphenyl-maleide,  623 
Benzal-divanillin,  594 
Benzal-ethyl-amine,  257 
Benzal-glutaric  Acid,  441 
Benzal-hydrazin,  258 
Benzal-la?voxime,  438 
Benzal-laevulinic  Acid,  438,  439 
Benzal-malonic  Acid,  439 
Benzal-mesityl  Oxide,  418 
Benzal-nitro-aceto-phenone,  628 
Benzal-phenyl-croto-lactone,  635 
Benzal-phenyl-glyceric  Ester,  384 
Benzal-phenyl-hydrazone,  258 
Benzal-phthalide,  620 
Benzal-pinacolin,  417 
Benzaldehyde,  30,  64,  255 

Derivatives  of,  256 

Benzaldehydes,  Haloid,  260 

Substituted,  260 

Benzaldehyde,  Sulphur  Derivatives  of,  257 
Benzaldehyde-potassium  Bisulphite,  257 
Benzaldoximes,  253,  258 
Benzaldoxime  Peroxide,  260 
Benzamarone,  639 
Benzamide,  281          • 

Bromide,  287 

Chloride,  287 

Haloids,  297 

Iodide,  287 

Benzamidine,  289 
Benzamidine-diazo-benzol,  290 
Benzamidine-urethane,  290 
Benzanilide,  281 

Chloro-iodide,  287 

Benzanilide-imido-chloride,  287 
Benzanthrones,  718 
Benzantialdoxime,  259 

Acetate,  260 

Benzaurin,  591 
Benzazimide,  311 
Benzazurin,  557 
Benze'ins,  590,  591 
Benzene,  46,  49 

Azo-sulphonic  Acid,  127 

Carbohydrates,  49 

Derivatives,  27 

General  Survey  of,  29 

Isomerism  of,  31 

Benzene-diazo-acetanilide,  135 
Benzene-diazo-carboxyl-amide,  128 
Benzene-diazo-sulphones,  127 
Benzene,  Halogen  Substitution  Products  of,  60 

Hexabromide,  447 

Hexachloride,  447 

Hydrocarbons,  Nitrogen  Derivatives  of,  67 

Nitroso-Derivatives  of,  75 

Nucleus,  Constitution  of,  40 

Oxy-quinones,  230 

Poly-substitution  Products,  Isomerism  of,  39 

Ring  Formations,  42 

Ring  Splittings,  45 

Substitution  Produc 

for,  34 

Benzenyl-amidine,  289 
Benzenyl-amidoxime,  296 
Benzenyl  Compounds,  287 
Benzenyl-diphenyl-diureide,  290 
Benzenyl-ethoxime  Bromide,  294 
Benzenyl-ethyl  Ether,  297 
Benzenyl -hydrazidin,  291 
Benzenyl-hydrazidoxime,  296 
Benzenyl-hydroxylamine-acetic  Acid,  294 
Benzenyl-methoxime  Chloride,  294 
Benzenyl-nitrazone,  291 
Benzenyl-nitrosazone,  291 
Benzenyl-oxy-tetrazotic  Acid,  290 
Benzenyl-tetrazotic  Acid,  291 
Benzenyl  Trichloride,  297 
Benzidin,  147,  553 

Dyes,  178,  555 

Homologues,  554 

Sulphate,  554 


lucts,  Principles  of  Location 


Benzidin-sulphonic  Acids,  556 
Benzidin  Transposition,  147 
Benzile,  616 

Benzile-carbpxylic  Acid,  620 
Benzile-dioxime  Diacetates,  617 
Benzile-dioximes,  617 
Benzile-osazone,  617 
Benzile-semi-carbazone,  616 
Benzilic  Acid,  607 
Benzimido-ethyl  Ether,  288 
Benzimido-methyl  Ether,  288 
Benzimido-thio-ethyl  Ether,  289 
Benzimido-thio-phenyl  Ether,  289 
Benzisoxazolone,  301 
Benzol-azo-meso-anthramine,  705 
Benzo-cyclo-heptadienone,  642 
Benzo-cyclo-heptadione,  642 
Benzo-cyclo-heptane,  642 
Benzo-cyclo-heptanone,  642 
Benzo-cyclo-heptene,  642 
Benzo-diazo-thin,  161 
Benzo-dioxy-anthracenes,  706 
Benzo-hydrols,  565 
Benzo-hydrol-carboxylic  Acids,  574 
Benzo-hydroxamic  Acid,  293 

Haloids  of,  294 

Benzo-hydroxamoxime,  297 
Benzo-hydroximic  Acid  Alkyl  Ethers,  293 

Chloride,  294 

Benzo-hydryl-amine,  565 
Benzo-hydryl-hydrazin,  566 
Benzo-nitrile,  97,  259,  286 

Oxide,  295 

Benzo-nitrolic  Acid,  294 
Benzo-nitrosolic  Acid,  295 
Benzo-norcaradiene-carboxylic  Ester,  641 
Benzo-phenol,  185 
Benzo-phenones,  567,  603 
Benzo-phenone  Bromide,  568 

Chloride,  568 

Benzo-phenone-dicarboxylic  dilactone,  575 
Benzo-phenone  Hexachloride,  570 

Homologues,  568 

Benzo-phenone-hydrazone,  569 
Benzo-phenonoxime,  569 
Benzo-phenyl-amido-ethyl  Xanthide,  289 
Benzo-pinacolin,  625 

Alcohol,  625 

Benzo-pinacone,  625 
Benzo-quinone,  225,  226 
Benzo-quinone-bis-diphenyl-methane,  602 
Benzo-sulpho-hydroxamic  Acid,  175 
Benzo-sulphone-anthranilic  Acid,  302 
Benzo-tetronic  Acid,  437 
Benzo-thiazols,  209 
Benzo-trichloride,  64,  297 
Benzo-trifluoride,  297 
Benzoic  Acid,  31,  64,  273 

Trichloride,  297 

Anhydride,  279 

Benzoic-arsenic  Anhydride,  279 
Benzoic-boric  Anhydride,  279 
Benzoic-carbonic  Anhydride,  280 
Benzoic  Sulphinide,  314 
Benzoic-thionyl-hydrazone,  312 
Benzoin,  615 

Benzoln-anile-anilide,  616 
Benzoin-anilide,  616 
Benzoin  Hydrazone,  616 

Yellow,  708 

Benzol,  49 

Benzol-azo-aceto-acetic  Ester,  154 
Benzol-azo-aldoximes,  142 
Benzol-azo-anthranol,  706 
Benzol-azo-benzyl  Alcohol,  251 
Benzol-azo-cyanamide,  136 
Benzol-azo-diphenyl-amine,  144 
Benzol-azo-ethane,  142 
Benzol-azo-methane,  140,  142,  152 
Benzol-azo-naphthalene,  662 
Benzol-azo-nitronic  Acids,  142 
Benzol-azo-phenyl-cyanamide,  144 
Benzol-azo-phenyl-glycin,  144 
Benzol-azo-sah'cylic  Acid,  333 
Benzol-carboxylic  Acid,  31 
Benzol-diazo-anilide,  135 


INDEX 


733 


Benzol-diazo-carboxylic  Acids,  142 

Benzol-diazo-oxy-amido-methane,  137 

Benzol-diazonium-chloride,  125 

Benzol-diazonium  fluorides,  125 

Benzol-dicarboxylic  Acid,  31 

Benzol-disulphinic  Acid,  181 

Benzol-disulphonic  Acids,  176 

Benzol -disulphoxide,  181 

Benzol-hexacarboxylic  Acid,  43 

Benzol -iodp-fluoride,  61 

Benzol-o-dicarboxylic  Acid,  37 

Benzol-phenol-phthalide,  596 

Benzol-phthalin,  594 

Benzol-seleninic  Acid,  181 

Anhydride,  181 

Benzol-seleno-acid,  176 

Benzol-sulphamide,  174 

Benzol-sulphinic  Acid,  180 

Anhydride,  180 

Chloride,  180 

Benzol-sulpho-acid,  29 

Benzol-sulpho-diazo-benzol-amide,  1 75 

Benzol-sulpho-dichlor-amide,  174 

Benzol-sulpho-isocyanate,  175 

Benzol-sulpho-nitramide,  174 

Benzol-sulphone,  182 

Benzol -sulphone-anilide,  174 

Benzol-sulphone-azode,  175 

Benzol-sulphone-phenyl-hydrazide,  175 

Benzol-sulphonic  Acid,  174,  178 

Benzol -sulphono-hydrazide,  174 

Benzol-sulphono-phenyl-hydroxylamine,  78 

Benzol-thio-sulphonic  Acid,  181 

Benzol-tricarboxylic  Acid,  31 

Benzol-trisulphonic  Acid,  176 

Benzoleinic  Acid,  471 

Benzolene,  30 

Benzoxazoles,  201 

Benzoyl-acetaldehyde,  374 

Benzoyl-acetic  Acid,  391 

Ester,  392 

Benzoyl-aceto-nitrile,  392 

Benzoyl-acetone,  375 

Benzoyl-acetyl,  374 

Benzoyl-acrylic  Acid,  438 

Benzoyl-alanin,  283 

Benzoyl-amido-cinnamic  Anhydride,  422 

Benzoyl-amyl-acetylene,  417 

Benzoyl-anthracene,  708 

Benzoyl-anthranile,  303 

Benzoyl-anthranilic  Acid,  302 

Benzoyl-asparaginic  Acid,  283 

Benzoyl-azide,  284 

Benzoyl  Azimide,  279 

Benzoyl-benzo-hydroxamic  Ester,  293 

Benzoyl-benzoic  Acid,  575 
Benzoyl-benzylamine,  281 

Benzoyl  bromide,  279 
Benzoyl-bromimide,  281 
Benzoyl-butane-diol,  400 
Benzoyl-butyl-carbinol,  373 
Benzoyl-camphor,  536 
Benzoyl-carbinol,  371 

Acetate,  371 

Chloride,  371 

Benzoyl  Chloride,  278 
Benzoyl-chlorimide,  281 
Benzoyl-crotonic  Acid,  438 
Benzoyl-cumarone,  629 
Benzoyl  Cyanide,  388 

Anile,  388 

Benzoyl-cyano-acetic  Methyl  Ester,  399 
Benzoyl-diazo-benzol,  142 
Benzoyl-diazo-methane,  372 
Benzoyl-dibenzyl-methane,  630 
Benzoyl  Disulphide,  280 

Fluoride,  279 

Benzoyl-formaldehyde,  373 
Benzoyl-formic  Acid,  367,  387 
Benzoyl-formoin,  635 
Benzoyl-formoxime,  374 
Benzoyl-glutaric  Acid,  399 

Ester,  399 

Benzoyl-glycocoll,  282 
Benzoyl-glycollic  Acid,  278,  394 
Benzoyl-glyoxylic  Acid,  395 


Benzoyl-hydrazin,  283 

Benzoyl-hydrogen  Peroxide,  255 

Benzoyl  Iodide,  279 

Benzoyl-isatin,  389 

Benzoyl-iso-cyanate,  282 

Benzoyl-iso-succinic  Ester,  399 

Benzoyl-malonic  Ester,  399 

Benzoyl-mesitylene,  568 

Benzoyl  Nitrate,  279 

Nitride,  279,  284 

Nitrite,  279 

Peroxide,  280 

Benzoyl-phenyl-acetylene,  630 

Benzoyl-phenyl-alanin,  381 

Benzoyl-phenyl-carbinol,  615 

Benzoyl-phenyl-fluorene,  698 

Benzoyl-phthalic  Acid,  575 

Benzoyl-propio-aldehyde,  374 

Benzoyl-pyro-racemic  Acid,  395 

Benzoyl  Sulphide,  280 

Benzoyl-tetramethylene,  268 

Benzoyl-tricarballylic  Acids,  400 

Benzoyl-trimethylene,  268,  393 

Benzoyl-tri-methylene-carboxylic  Acid,  393 

Benzoyl-xylol,  568 

Benzoylated  Paraflins,  267 

Benzoylene-urea,  308 

Benzyl  Acetamide,  247 

Acetate,  243 

Benzyl-aceto-acetic  Ester,  393 

Benzyl-aceto-phenone,  628 

Benzyl-aceto-succinic  Ester,  399 

Benzyl-alcohol,  30,  64,  241 

Benzyl-amido-acetone,  373 

Benzyl-amines,  245 

Benzyl-aniline,  247 

Benzyl-arabinoside,  243 

Benzyl-azides,  248,  249 

Benzyl-benzol,  563 

Benzyl  Bromide,  243 

Carbinol,  242 

Carbonimide,  247 

Chloride,  30,  64,  243 

Benzyl-cinnamic  Acid,  631 

Benzyl-crotonic  Acid,  425 

Aldehyde,  415 

Benzyl-cyanurate,  247 

Benzyl-desoxy-benzoin,  629 

Benzyl-diazo-compounds,  248 

Benzyl  Disulphide,  244 
Disulphoxide,  244 

Benzyl-durols,  563 

Benzyl-ethyl-amine,  246 
Benzyl-glutaconic  Ester,  441 
Benzyl-hydrazins,  248 

Benzyl  Hydride,  255 
Benzyl  hydroxylamines,  249 
Benzyl-hyposulphurous  Acid,  244 
Benzyl-indene,  645 
Benzyl  Iodide,  243 
Benzyl  Iso-cyanate,  247 
Benzyl-iso-nitroso-aceto-phenone,  628 
Benzyl-malic  Acid,  398 
Benzyl-malpnic  Acid,  396 
Benzyl-mesitylene,  563 
Benzyl-methyl-ethyl  Ketone,  268 
Benzyl-methyl-ketone,  376 
Benzyl-methyl-triazene,  248 
Benzyl-mustard  Oil,  248 
Benzyl-nitramine,  248 
Benzyl  Nitrite,  243 
Benzyl-oxalacetic  Ester,  399 
Benzyl-oxethyl-amine,  247 
Benzyl -phenyl-acetic  Acid,  621 
Benzyl-phenyl-iso-crotonic  Acid,  636 
Benzyl-phenyl-carbinol,  613 
Benzyl-phenyl-triazene,  249 
Benzyl  Phosphates,  243 
Benzyl-phthalazone,  620 
Benzyl-phthah'midine,  620 
Benzyl-propyl  Ketone,  268 
Benzyl-pyro-racemic  Acid,  391 
Benzyl-succinic  Acid,  397 
Benzyl  Sulphide,  244 
Benzyl-sulphinic  Acid,  244 
Benzyl  Sulphone,  244 


734 


INDEX 


Benzyl-sulphonic  Acid,  244 

Benzyl  Sulphoxide,  244 

Benzyl-sulphuric  Acid,  243 

Benzyl  Sulphydrate,  244 

Benzyl-tartronic  Acid,  398 

Benzyl-toluenes,  563 

Benzyl-triazenes,  248 

Benzyl-urea,  247 

Benzyl-urethane,  247 

Benzylidene-aceto-phenone,  628 

Benzylidene-acetone,  416 

Benzylidene-acetyl-phenyl-triazane,  10 

Benzylidene-aniline,  257 

Benzylidene-anthrone,  706 

Benzylidene-benzoyl-acetic  Ester,  631 

Benzylidene-bis-benzoyl-acetic  Ester,  640 

Benzylidene-bis-desoxy-benzofn,  639 

Benzylidene-campholic  Acid,  537 

Benzylidene-camphor,  536 

Benzylidene-desoxy-benzoin,  629 

Benzylidene-diaceto-phenone,  639 

Benzylidene-fluorene,  696 

Benzylidene-formyl-phenyl-triazane,  167 

Benzylidene-hydrazin,  258 

Benzylidene  Imide,  257 

Benzylidene-menthone,  506 

Benzylidene-methyl-ethyl-ketone,  416 

Benzylidene-phenoxy-acetone,  417 

Benzylidene-phthalide,  620 

Benzylidene-pulegone,  508 

Benzylidene-thujone,  510 

Bergaptene,  435 

Bernthsen,  599] 

Berthelot,  49 

Berzelius,  226 

Be  tula  lenta,  721 

Bidesyl,  634 

Bi-diphenylene-e thane,  698 
Bi-diphenylene-ethylene,  698 
Bieberich  Scarlet,  179,  668 
Bifluorene,  698 
Biguanide,  162 
Bihydroquinone,  557 
Biphenol,  557 
Biphenyl,  550 

Biphenyl-carboxylic  Acids,  559 
Biphenyl-dicarboxylic  Acids,  560,  561 
Biphenyl-monocarboxylic  Acids,  559 
Biphenyl-sulphonic  Acids,  556 
Biphenylene-biphenyl-chloro-methane,  62  7 
Biphenylene-phenyl-methyl,  697 
Biphenylene  sultame,  556 
Bipyro-catechin,  557 
Bis-acenaphthylidene,  682 
Bis-amido-benzyl-resorcin,  576 
Bischoff,  418 

Bis-cyclopentadiene-carboxylic  Acid,  20 
Bis-diazo-benzol-diphenyl-tetrazone,  1 68 
Bis-triazo-benzol,  138 
Bismarck  Brown,  114,  145 
Bismuth  Gallate,  341 

Oxy-iodide  Gallate,  341 

Bismuth-triphenyl,  170 
Bi-thio  Acids,  280 
Bi-thio-phenyl-phthalide,  355 
Bitter-almond  Oil,  255 
Blomstrand,  123 
Borneo  Camphor,  526 
Borneol,  526,  529 
Bornyl-iso-valerianate,  527 
Bornyl-xanthogenic  Methyl  Esters,  527 
Bornylamine,  528 
Bornylene,  524 

Bornylene-carboxylic  Acid,  535 
Bornylone,  533 
Bornyval,  527 
Boutron-Chalard,  723 
Brasanes,  672 
Brasilic  Acid,  726 
Brasilin,  725 
Brasilinic  Acid,  726 
Briganum  hirtum,  188 
Brom-acetanilide,  95 
Bromaceto-phenone,  268 
Bromanilic  Acid,  230 
Bromethenyl-phenyl  Ether,  190 


Bromethyl-phenyl  Ether,  190 

Bromindone,  647 

Bromine  Tribromo-phenol,  194 

Bromo-aceto-phenone,  371 

Bromo-alizarin,  715 

Bromo-anthraquinone,  710 

Bromo-benzo-phenone,  569 

Bromo-benzols,  31,  61 

Bromo-camphor,  532 

Bromo-carmine,  728 

Bromo-cinnamic  Acids,  421,  422 

Bromo-cumarin,  428 

Bromo-diazo-benzol-imide,  138 

Bromo-diazonium  Silver  Cyanide,  125 

Bromo-diketo-hydrindene,  649 

Bromo-diphenacyl,  634 

Bromo-hydrin,  369 

Bromo-iodo-benzols,  61 

Bromo-methylene-phthah'de,  434 

Bromo-naphthalenes,  659 

Bromo-nitro-benzols,  35,  76 

Bromo-nitro-camphane,  532 

Bromo-nitro-camphor,  532 

Bromo-nitroso-acetanilide,  120 

Bromo-pentamethyl-benzol,  66 

Bromo-phenanthrene,  689 

Bromo-phenyl-hydrazin,  150 

Bromo-phthalide,  351 
Bromo-piperonal,  325 
Bromo-salicylic  Acid,  333 
Bromo-styrol,  404,  405 
Bromo-suberane-carboxylic  Acid,  24 
Bromo-toluol,  65 
Bromo-xylol,  66 
Bromyl-phthalimide,  357 
Brown,  Crum,  74 
Briihl,  40 

Bucco-camphor,  508 
Butane-tetracarboxylic  Ester  9 
Butea,  212 
Butea  frondosa,  628 
Butein,  628 
Butenyl-benzol,  406 
Butryl-phenyl-acetylene,  417 
Butyl-benzol,  59 
Buzylene,  168 

CADINENE,  547 

Cczsalpina  coriaria,  340 

Caffeic  Acid,  429 

Calcium  phenate,  186 

Sah'cylate,  329 

Camphane,  513,  525 

Camphane-diamine,  529 

Camphanic  Acid,  541 

Camphanonazine,  533 

Camphel  Alcohol,  527 

Camphelamine,  537 

Camphenamine,  529 

Camphene,  522 

Camphene  Dibromide,  522 

Camphene-glycol,  522 

Camphene  Hydrate,  527 

Hydrochloride,  522 

Camphenilane-aldehyde,  523 

Camphenilanic  Acids,  523 

Camphenile  Nitrite,  522 

Camphenilol,  528 

Camphenilone,  523 

Camphenone,  534 

Camphenylamine,  529 

Campherol,  534 

3amphidin,  540 

3amphidonene,  540 

"ampho-acid,  544 
Campho-carboxyUc  Acid,  534 

-.ampho-ceanic  Ring,  14 

3ampho-pyro-acid,  544 
Camphol,  526 
Alcohol,  527 

^ampholamine,  529,  537 
Camphplene,  539 
Dibromide,  539 

"ampholenic  Acid,  14,  538 
Campholic  Acid,  537 
Campholide,  544 


INDEX 


735 


Campholytic  Acid,  14,  543 
Camphor,  14,  443,  529 

Dichlorides,532 

Camphor-dioxime,  533 
Camphor-glycol,  534 

Camphor-methylene-carboxylic  Acid,  536 
Camphor-nitrilic  Acid,  541 
Camphor-oxalic  Acid,  537 
Camphor-oxime,  532 
Camphor-phenyl-hydrazone,  533 
Camphor-quinone,  533 
Camphor-quinone-phenyl-hydrazone,  533 
Camphor-sulphonic  Acids,  532 
Camphoranic  Acid,  545 
Camphoric  Acid,  14,  21.  539,  541 
Camphorimine,  532,  533 
Camphorone,  540 
Camphoronic  Acid,  545 
Camphorphorone,  14 
Camphoryl-carbamide,  534 
Camphoryl-dimethyl-carbinol,  537 
Camphoryl-glycocoll  Ester,  534 
Camphoryl-hydroxylamine,  541 
Camphoryl-iso-cyanate,  534 
Camphoryl-malonic  Acid  Ester,  544 
Camphoryl-methyl-carbinol,  536 
Camphoryl-mustard  Oil,  534 
Camphyl-glycols,  536 
Camphylamine,  528,  538 
Cantharene,  450 
Cantharic  Acid,  724 
Cantharidin,  724 
Cantharinic  Acid,  724 
Caoutchouc,  549 
Carane,  513 

Carbamic  Acid  Derivatives,  161 
Carbaminic  a-phenyl-hydrazide,  160 

Ethyl  Ether,  100 

Carbanile,  99,  104 

Carbanilic  Acid  99 

Carbanilide,  99 

Carbinol-benzoic  Acids,  347 

Carbinols,  579 

Carbo-benzoyl-propionic  Acid,  402 

Carbo-diazone,  142 

Carbo-diphenyl-imide,  106 

Carbo-mandeh'c  Acid,  401 

Carbo-methoxy-salicylic  Acid,  330 

Carbo-phenyl-glyoxylic  Acid,  402 

Carbodi-p-tolyl-imide,  107 

Carbolic  Acid,  185 

Carbonate,  125 

Carbonyl-benzamide,  282 

Carbonyl-salicyl-amide,  332 

Carbostvrilic  Acid,  305 

Carboxy-phenyl-trimethylene-dicarboxyh'c  Acid, 

642 

Carboxyl-anthranilic  Dimethyl  Ester,  304 
Carboxyl-apo-camphoric  Acid,  524,  544 
Carboxylic  Acids,  631 
Carminazarin,  728 
Carminic  Acid,  727 
Carnation  Acid,  41 1 
Caro,  586 
Carone,  514 
Caronic  Acid,  80 
Carro-menthene,  449 
Carthamin,  727 
Carthamus  tinctorium,  727 
Carva-crotinic  Acids,  335 
Carvacrol,  188 
Carvene,  491 
Carvenolidene,  509 
Carvenone,  507 
Carvenylamine,  504 
Carveol.  507 

Carveol-methyl  Ether,  503 
Carvestrene,  496 
Carvo-menthene,  496 
Carvo-menthol,  498 
Carvo-menthylamine,  504 
Carvo-pinone,  521 
Carvone,  25 
Carvotan-acetone,  507 
Carvoxime,  510 
Carvum  carvi,  188 


Caryo-phyllene,  547 
Castoreum,  186 
Catechin,  338 
Catechinic  Acid,  343 
Catechu-tannin,  343 
Caucasian  Petroleum,  14 
Cedriret,  558 
Cedrol,  548 
Centric  Scheme,  41 
Cetyl-benzol,  60 
Chamterops  humilis,  453 
Chavibetol,  411 
Chavica  Betle,  409 
Chavicol,  409 
Chloraceto-phenone,  268 
Chloraceto-pyro-catechin,  373 
Chloranilamic  Acid,  230 
Chloranile,  229 
Chloranile-amide,  229 
Chloranilic  Acid,  230 
Chloraniline-o-siilphomc  Acid,  93 
Chloranilino-triphenyl-amine,  116 
Chlorindazol,  312 
Chloro-aceto-phenone,  371 
Chloro-anthraquinone,  710 
Chloro-benzene,  29 
Chloro-benzile,  618 
Chloro-benzol  Hexachloride,  447 
Chloro-benzols,  61 
Chloro-benzyl-aceto-phenone,  628 
Chloro-benzyl  Chloride,  30 
Chloro-bromo-benzols,  62 
Chloro-bromo-stilbene,  620 
Chloro-camphor,  532 
Chloro-cinnamic  Acids,  421,  422 
Chloro-diazo-benzol  Anhydride,  126 

Sulphocyanide,  125 

Chloro-i,  2-diketo-pentamethylene,  18 
Chloro-diphenacyl,  634 
Chloroform,  48 
Chloro-hydrin,  369 
Chloro-methyl-benzamide,  348 
Chloro-methyl-benzanilide,  348 
Chloro-methyl-benzo-nitrile,  348 
Chloro-methyl-benzoic  Acid,  348 
Chloro-methylene  camphor,  536 
Chloro-naphthalenes,  658 
Chloro-naphthalene-sulphonic  Acids,  664 
Chloro-nitro-benzol,  76 
Chloro-2-nitro-toluol,  74 
Chloro-4-nitro-toluol,  74 
Chloro-5-nitro-toluol,  74 
Chloro-p-oxy-benzyl  Alcohol,  316 
Chloro-phenyl-hydrazin,  150 
Chloro-phenyl-hydrazo-aldoximes,  165 
Chloro-phenyl-hydroxylamine,  78 
Chloro-sah'cyl  Chloride,  331 
Chloro-salicylic  Acid,  333 
Chloro-stilbene  Dichloride,  619 
Chloro-styrol,  405 
Chloro-toluol,  30,  65 
Chloryl-phthalimide,  357 
Cholesterin,  548 
Chrysamic  Acid,  724 
Chrysamine,  555 
Chrysammic  Acid,  716 
Chrysanisic  Acid,  309 
Chrysarobin,  716 
Chrysazin,  716 
Chrysazine,  706 
Chrysazol,  705,  706 
Chrysene,  693,  694 
Chrysene-fluorene,  695 
Chryso-diphenic  Acid,  694 
Chryso-fluorene,  697 
Chryso-ketone,  694,  699 
Chryso-ketone-carboxyh'c  Acid,  701 
Chryso-quinone,  694 
Chrysopham'c  Acid,  716 
Cicuta  virosa,  58,  429 
Cinene,  491 
Cinenic  Acid,  500 
Cineol,  499,  500 
Cineolic  Acid,  500 
Cinnamal-lasvulinic  Acid,  439 
Cinnamenyl-acrylic  Acid,  433 


736 

Cinnamenyl-dihydro-resorcin,  459 
Cinnamenyl-glutaric  Acid,  441 
Cinnamenyl-itaconic  Acid,  441 
Cinnamenyl-paraconic  Acid,  441 
Cinnamenyl-succinic  Acid,  441 
Cinnamic  Acid,  419 

Dibromide,  385 

Bichloride,  385 

Aldehyde,  415 

Cinnamomum  camphor  a,  529 

ceylanicum,  415 

Cinnamyl-acetone,  417 
Cinnamyl  Alcohol,  413 
Cinnamyl-carboxylic  Acid,  436 
Cinnamyl  Cyanide,  437 
Cinnamyl-formic  Acid,  437 
Cinnamylene-benzylidene-acetone,  640 
Cinnamylidene-acetic  Acid,  433 
Cinnamylidene-aceto-phenone,  639 
Cinnamylidene-fluorene,  696 
Cinnamylidene-indene,  643 
Cinnamylidene-malonic  Acid  440 
Cinnamylidene-propionic  Acid,  433 
Cinnamylidene-succinic  Acid,  441 
Cis-cyclopentane-i,  3-dicarboxylic  Acid,  20 
Citral,  42,  490 

Citralidene-malonic  Ester,  43 
Citrene,  491 
Citronellal,  489 
Citronellic  Acid,  490 
Citronellol,  488 
Citrus  aurantium,  491 

—  Bergamia,  435 

decumana.  723 

Claus,  41 
Coal-tar,  50 
Coccoloba  uvifera,  343 
Cochinelic  Acid,  728 
Cocos  nucifera,  454 

—  plumosa,  454 
Cocosate,  454 
Codem,  689 
Coerulignone,  558 
Colophony,  548 
Congo  Red,  664 

Yellow,  555 

Coniferin.  721 
Coniferyl  Alcohol,  414,  721 
Conrad,  418 
Convolvulin,  722 
Convolvulus  orizabensis,  722 

purga,  722 

Copper-methyl-phenyl-triazene,  136 
Coriander  Oil,  488 
Cornicularic  Acid,  635 
Cotarnic  Acid,  359 
Coto,  573 

Bark,  437 

Co  torn,  573 
Couper,  28 
Crafts,  52 
Creosol,  214 
Cresols,  187 
Cresol  Benzein,  591 
Cresotinic  Acids,  334 

Chloride,  331 

Croconic  Acid,  14,  222,  224,  232 

Hydride,  232 

Croton-aldehyde,  255 
Crotonylene,  42 
Crystal  Violet,  587 
Cubebin,  414 
Cudbear,  217 
Cumarandione,  390 
Cumaric  Acid,  427,  429 

—  Aldehyde,  415 

—  Dimethyl  Ether,  427 
Cumarilic  Acid,  428 
Cumarin,  328,  427 

Bromide,  428 

Cumarin-carboxylic  Amide,  440 
Cumarin  Homologues,  428 
Cumarin-monomethyl-ester  Acid,  428 
Cumarin-propionic  Acid,  441 
Cumarines,  185 
Cumarinic  Dimethyl  Ester,  428 


INDEX 


Cumaro-ketone,  417 

Cumarone,  414 

Cumaroxime,  428 

Cumic  Acid,  256 

Cumic  Aldehyde,  256 

Cuminal-acetone,  417 

Cuminic  Acid,  275 

Cuminile,  619 

Cuminilic  Acid,  607 

Cuminoin,  615 

Cuminol,  256 

Cuminum  cymimim,  58 

Cumol,  55,  57 

Cumyl  Alcohol,  256 

Cumyl-ethyl-amine,  246 

Cuprous  Bromide,  124 

Curcuma  tonga,  727 

Curcumin,  727 

Cyan-amidrazone,  168 

Cyan-anilide;  106 

Cyan-o-toluic  Acid,  363 

Cyanated  Carbinol,  583 

Cyano-benzo-hydrol,  574 

Cyano-benzoic  Acid,  358,  360,  362 

Cyano-benzoic  Acid  Ester,  358 

Cyano-benzol-sulphonic  Acid,  313 

Cyano-benzyl  Chloride,  348 

Cyano-benzyl  Cyanide,  363 

Cyano-benzyl-rhodanide,  349 

Cyano-camphor,  535 

Cyano-carone,  514 

Cyano-cinnamic  Acid,  435,  439 

Cyano-cumarin,  439 

Cyano-cyclopentanone,  22 

Cyano-diphenyl-methane,  574 

Cyano-formanilide,  107 

Cyano-2-keto-pentamethylene-carboxylic  Ester,  22 

Cyano-lauronic  Acid,  541 

Cyano-methylene-camphor,  536 

Cyano-naphthalenes,  68 1 

Cyano-phenanthrene,  691 

Cyano-phenin,  290 

Cyano-phenyl-hydrazin,  160,  312 

Cyano-trimethylene-carboxylic  Acid,  9 

Cyano-triphenyl-methane,  595 

Cyclic  Amidines,  116 
—  Diazides,  178 

Guanidin  Derivatives,  116 

Ketone  Formation,  5 

Syntheses  with  Malonic  Acid  Esters,  Acetic 

Acid  Esters,  etc.,  5 

with    the    aid    of    Metallorganic    com- 
pounds, 4 

Ureas,  116,  161 

Cyclo-butane,  i,  6 

Cyclo-butanol,  7,  n 

Cyclo-butene,  10 

Cyclo-citral,  467 

Cyclo-formazyl-carboxylic  Ester,  556 

Cyclo-geranic  Acid,  472,  490 

Cyclo-geraniolene,  449 

Cyclo-heptadiene,  23 

Cyclo-heptadiene-carboxylic  Acid,  24 

Cyclo-heptane,  i,  6,  23 

Cyclo-heptane-carboxylic  Acid,  24 

Cyclo-heptanol,  23 

Cyclo-heptanol-acetic  Acid,  25 

Cyclo-heptanone,  24 

Cyclo-heptatriene,  23 

Cyclo-heptatriene-carboxylic  Acids,  24 

Cyclo-heptene,  23 

Cyclo-heptene-carboxylic  Acid,  24 

Cyclo-heptenol-ethyl  Ether,  23 

Cyclo-hexadienes,  449,  450 

Cyclo-hexanes,  i,  6,  444,  445 

Cyclo-hexane-diones,  459,  460 

Cyclo-hexane-triones,  460 

Cyclo-hexanol,  452,  454 

Cyclo-hexanol-acetic  Acid,  474 

Cyclo-hexanolone,  458 

Cyclo-hexanone-carboxylic  Acid,  475 

Cyclo-hexanone-pimelin-ketone,  457 

Cyclo-hexenes,  447  448 

Cyclo-hexene-acetic  Acid,  473 

Cyclo-hexenone,  461 

Cyclo-hexenone-carboxylic  Acid,  476 


INDEX 


737 


Cyclo-hexyl-aceto-acetic  Ester,  476 
Cyclo-hexyl-acetone,  468 
Cyclo-hexyl-acetylenes,  45 1 
Cyclo-hexyl-allylene,  451 
Cyclo-hexyl-amine,  455 
Cyclo-hexyl-aniline,  455 
Cyclo-hexyl  Ether,  452 
Cyclo-hexyl-glycidic  Esters,  475 
Cyclo-hexyl-malonic  Acid,  477 
Cyclo-hexyl  Mercaptan,  455 
Cyclo-hexyl-methyl-amine,  456 
Cyclo-nonane,  i,  6,  26 
Cyclo-nonanol,  26 
Cyclo-nonanone,  26 
Cyclo-octadiene,  25 
Cyclo-octane,  i,  6,  25 
Cyclo-octanone,  26 
Cyclo-paraffins,  i,  4 
Cyclo-pentadiene,  13,  15 
Cyclo-pentane,  i,  6 
Cyclo-pentane-aldehyde,  19 
Cyclo-pentane-carboxylic  Acid,  19 
Cyclo-pentane- 1,  2-dicarboxylic  Acid,  13,  20 

—  i,  2,  4-tricarboxylic  Acid,  20 
Cyclo-pentanol,  n,  16 
Cyclo-pentanol  Acid  Ester,  21 
Cyclo-pentanol-isobutyric  Ester,  21 
Cyclo-pentanol-propionic  Ester,  2 1 
Cyclo-pentanone,  17 
Cyclo-pentenaldehyde,  19 
Cyclo-pentene,  14 
Cyclo-pentene-acetic  Acid,  20 
Cyclo-pentene-carboxylic  Acid,  20 
Cyclo-pentene- 1,  2-dicarboxylic  Acid,  20 
Cyclo-pentene-propionic  Acid,  20 
Cyclo-pentenol  Acetate,  17 
Cyclo-pentenolone,  18 
Cyclo-propane,  i,  6,  7 
Cymo-phenol,  188 
Cymol,  55,  58 
CysteTn,  283 
Cystin,  283 


D&monorops  Draco,  273 
Dale,  586 
Dambonite,  454 
Daphne  alpina,  721 

mezereum,  430 

Daphnetin,  431 
Daphnin,  721 

Deca-hydro-acenaphthene,  683 
Deca-hydro-naphthylamine,  687 
Decarboxy-dibromo-carminic  Acid,  728 
Dehydracetic  Acid,  43 
Dehydro-benzal-phenyl-hydrazone,  167 
Dehydro-camphoric  Acid,  542 
Dehydro-nchtelite,  693 
Desmo-tropo-santonins,  725 
Desoxy-anisoln.  614 
Desoxy-benzoin,  613 
Desoxy-toluom,  613 
Dessaignes,  282 
Desyl-acetic  Acid,  622 
Desyl-aceto-phenone,  634 
Desyl-anilide,  616 
Desyl-bromide,  616 
Desylene-acetic  Acid,  622 
Diacetanilide,  95 
Diaceto-benzidin,  554 
Diaceto-caffeic  Acid,  430 
Diaceto-phenol-phthalem,  598 
Diaceto-phenyl-hydrazide,  157 
Diaceto-resorcin,  347 
Diacetonyl-dibenzyl,  623 
Diacetyl,  43 
Diacetyl-benzol,  347 
Diacetyl  Compound,  727 
Diacetyl-dioxy-stilbene,  619 
Diacetyl-mesitylene,  347 
Diacetyl-phenetidin,  202 

Diacetyl-tetramethylene-dicarboxylic  Ester,  12 
Diacid  Alcohols,  499 
Diacyl-diphenylene,  691 
Diagonal  Scheme,  41 
Dialk-oxy-quinone,  227 

VOL.  II. 


Dialkyl-2, 3-dicyano-trimethylene-2,  3-dicarboxylic 

Acids,  10 

Dialkyl-phenanthrones,  691 
Diamido-anthraquinones,  711 
Diamido-azo-benzol,  144,  145 
Diamido-azoxy-benzol,  140 
Diamido-benzo-phenones,  571 
Diamido-benzoic  Acids,  310 
Diamido-benzols,  35,  79,  114 
Diamido-dibenzyl,  610 
Diamido-diphenyl,  553,  554 
Diamido-diphenyl-acetic  Acid,  607 
Diamido-diphenyl-amine,  116 
Diamido-diphenyl-arsinic  Acid,  170 
Diamido-diphenyl  Disulphide,  209 
Diamido-diphenyl-methane,  564 
Diamido-ditolyls,  147 
Diamido-dixenylamine,  554 
Diamido-fluorene,  697 
Diamido-hydrazo-benzol,  146 
Diamido-menthane,  504 
Diamido-mesitylene,  115 
Diamido-naphthalenes,  661 
Diamido-phenanthrene,  690 
Diamido-phenazin,  116 
Diamido-phenols,  202 
Diamido-pseudo-cumol,  115 
Diamido-quinone  Imine,  235 
Diamido-stilbene,  612 
Diamido-tolane,  613 
Diamido-toluols,  115 
Diamido-triphenyl-methane,  578 
Diamines,  113 
Diamine  Black,  557 
Dianilido-acetic  Acid,  98 
Dianilido-quinone  Anile,  238 
Dianilido-quinone  Dianile,  227,  238 
Dianilido-tolu-quinone,  231 
Dianilino-fuchsone-anile,  589 
Dianilino-guanidin,  162 
Dianthra-quinonimides,  712 
Dianthra-qiiinoyls,  717,  718 
Dianthranilide,  304 
Dianthranol,  707 
Dianthrimides,  712 
Diatropic  Acids,  425 
Diazo-aceto-phenone,  372 
Diazo-alkali  Salts,  124 
Diazo-amido-benzoic  Acids,  311 
Diazo-amido-benzol,  135 
Diazo-amido-compounds,  132 
Diazo-amido-derivatives,  Formation  of,  132 
Diazo-benzaldoxime  Anhydride,  263 
Diazo-benzoic  Acids,  311 
Diazo-benzol-amide,  134 
Diazo-benzol  Anhydride,  126 
Diazo-benzol-anilide,  1 35 
Diazo-benzol  Bromide,  124 

Chloride,  124,  156 

Cyanide,  128 

Diazo-benzol-dimethyl-amine,  136 
Diazo-benzol-ethyl-amide,  136 
Diazo-benzol-imide,  138 
Diazo-benzol-imido-compounds,  Transformations 

of,  138 

Diazo-benzol-methyl-amide,  135 
Diazo-benzol  Methyl  Ether,  126 

Nitrate,  125 

Diazo-benzol-p-amido-bromo-benzol,  135 
Diazo-benzol-p-amido-toluol,  135 
Diazo-benzol  perbromide,  125 

Perchlorate,  125 

Diazo-benzol-phenyl-hydrazide,  1 68 
Diazo-benzol-piperidin,  136 
Diazo-benzol  Potassium,  126 

Salts,  123 

Sulphate,  125 

Sulphocyanide,  125 

Sulphonic  Acid.  127 

Diazo-benzol-sulphonic-acid  Anhydrides,  178 
Diazo-benzol  Sulphoxide,  156 
Diazo-benzol-thio-phenyl  Ether,  208 
Diazo-benzolic  Acid,  120 

Methyl  Ester,  120 

Diazo-compounds,  121 
Diazo-cyanides,  142 


738 


INDEX 


Diazo-derivatives,  Reactions  of,  132 
Diazo-group,  Replacement  of,  by  Halogens,  129 

of,  by  Hydrogen,  129 

of,  by  Hydroxyl,  130 

of,  by  the  Cyanogen  Group,  131 

of,  by  the  Nitro-group,  131 

of,  by  the  Sulphinic  Acid  Residue,  131 

of,  by  the  Sulphydrate  Group,  130 

Diazo-hydrazo-compounds   168 
Diazo-imido-benzoic  Acids,  311 
Diazo-imido-compounds,  137 
Diazo-naphthalene  Acid,  662 
Diazo-naphthalin-imide,  662 
Diazo-naphthalene-sulphonic  Acid,  665 
Diazo-oxy-amido-benzol,  137 
Diazo-oxy-amido-compounds,  137 
Diazo-per-halides,  125 
Diazo -phenols,  203 
Diazo-phenol  Cyanide,  203 
Diazo-pseudo-cumolic  Acid,  120 
Diazo- toluolic  Acid,  120 
Diazonium  Salts,  124 
Dibenzal-acetone,  638 
Dibenzal-acetone  Dichloride,  638 
Dibenzal-diethyl-ketone,  638 
Dibenzal-propio-phenone,  633 
Dibenzamide,  281 
Dibenzamidin-urea,  290 
Dibenzenyl-azo-selenime,  289 
Dibenzenyl-azoxime,  260,  295,  617 
Dibenzo-hydrazide  Chloride,  287 
Dibenzo-hydryl-benzol,  576 
Dibenzo-hydrylamine,  565 
Dibenzol-sulphimide,  174 
Dibenzol-sulphon-hydroxylamine,  1 75 
Dibenzol-sulphone-dianthranilide,  304 
Dibenzol-sulphone-hydrazin,  175 
Dibenzoyl,  616 
Dibenzoyl-acetic  Acid,  631 
Dibenzoyl-acetone,  630 
Dibenzoyl-acetyl-methane,  630 
Dibenzoyl-benzols,  576 
Dibenzoyl-dibenzyl,  634 
Dibenzoyl-diphenyl-butadiene,  640 
Dibenzoyl-diphenyl-propane,  639 
Dibenzoyl-ethane,  633 
Dibenzoyl-fumaric  Acid,  637 
Dibenzoyl-maleic  Acid  Ester,  637 
Dibenzoyl-malic  Acid,  637 
Dibenzoyl-malo-nitrile,  631 
Dibenzoyl-methane,  630 
Dibenzoyl-phenol-phthalein,  598 
Dibenzoyl-propane,  639 
Dibenzoyl-stilbene,  634 
Dibenzoyl-styrol,  634 
Dibenzoyl-succinic  Acid,  636 
Dibenzoylene-pyridin,  649 
Dibenzyl,  27,  244,  609 
Dibenzyl-acetic  Acid,  631 
Dibenzyl-aceto-phenone,  630 
Dibenzyl-acetone-dicarboxylic  Ester,  640 
Dibenzyl,  Alcohol  and  Ketone  Derivatives  of,  613 
Dibenzyl-amine,  246 
Dibenzyl-aniline,  247 
Dibenzyl-anthracene,  704 
Dibenzyl-benzenes,  576 
Dibenzyl-carbinol,  628 
Dibenzyl-carboxylic  Acid,  621 
Dibenzyl-dicarboxylic  Acid,  622 
Dibenzyl-ethane,  632 
Dibenzyl-ethylamine,  631 
Dibenzyl-fluorene,  696 
Dibenzyl-glycolic  Acid,  631 
Dibenzyl  Group,  Carboxylic  Acids  of,  620 
Dibenzyl-guanidin,  247 
Dibenzyl,  Homologues  of,  610 
Dibenzenyl-hydrazidin,  291 
Dibenzyl-hydrazin,  248 
Dibenzyl-ketone,  627 
Dibenzyl-malonic  Acid,  631 
Dibenzyl-methane,  627 
Dibenzyl-oxalate,  244 
Dibenzyl-phenyl-carbinol,  628 
Dibenzylidene-acetpne,  638 
Dibenzylidene-succinic  Acid,  636 
Dibenzylindene,  645 


Dibiphenylene-dibiphenyl-ethane,  627 
Dibiphenylene-diphenyl-ethane,  697 
Dibromaniline,  no 
Dibromo-anthranilic  Acid,  73,  308 
Dibromo-anthraquinone,  710,  712 
Dibromo-butane,  7 
Dibromo-camphor,  532 
Dibromo-cinnamic  Acids,  422 
Dibromo-cyclo-butane,  10 
Dibromo-cyclo-butene,  1 1 
Dibromo-diazo-phenol,  203 
Dibromo-diketo-R-pentene,  18 
Dibromo-durol,  66 
Dibromo-fluorene,  696 
Dibromo-gallic  Acid.  341 
Dibromo-glyoxime  Peroxide,  108 
Dibromo-hydratropic  Acid.  384 
Dibromo-hydrindene,  648 
Dibromo-hydro-bromide,  728 
Dibromo-isodurol,  66 
Dibromo-menthone,  505 
Dibromo-mesitylene,  66 
Dibromo-phenanthrene,  689 
Dibromo-phenol-diazo-sulphonic  Acid,  203 
Dibromo-phthalic  Acid,  358 
Dibromo-prehnitol,  66 
Dibromo-pseudocumol,  66 
Dibromo-quinone  Chlorimine,  235 
Dibromo-quinone  Phenol-imine,  236 
Dibromo-stilbenes,  620 
Dibromo-styrol,  405 

Dibromo-tetramethylene-dicarboxylic  Acid,  12 
Dicarboxy-valero-lactonic  Acid,  518 
Dicarboxylic  Acids,  354 
Dichloracetamide,  48 
Dichloracetic  Acid,  221 
Dichloraniline,  no 
Dichloranthrone,  707 
Dichloro-anthranilic  Acids,  308 
Dichloro-acetyl-trichloro-crotonic  Acid,  48 
Dichloro-benzylidene-aceto-phenone,  628 
Dichlorocamphanes,  532 
Dichloro-camphor,  532 
Dichloro-cinnamic  Acid,  422 
Dichloro-diketo-hydrindene,  649 
Dichloro-dinitro-benzol,  72 
Dichloro-hydrindene,  648 
Dichloro-hydroquinone-disulphonic  Acid,  219 
Dichloro-maleic  Acid,  47,  48 
Dichloro-malonic  Ester,  48 
Dichloro-methyl-chloro-vinyl-o-diketone,  48 
Dichloro-naphthalenes,  659 
Dichloro-phenanthrene,  689 
Dichloro-piperonal  Chloride,  324 
Dichloro-salicyl-chloride,  331 
Dichloro-stilbene,  612,  619 
Dichloro-styrol,  405 
Dichloro-tolane,  613 
Dichloro-toluol,  30 
Dichloro-trimethylene,  7 
Dichloro-vinyl-phenyl-iodonium  Chloride,  64 
Dichroins,  185 

Dicinnamenyl-chloro-carbinol,  638 
Dicinnamenyl-dichloro-methane,  638 
Dicinnamylidene-succinic  Anhydride,  640 
Dicumarketone,  638 
Dicyanamino-benzoyl,  305 
Dicyano-benzol,  360,  362 
Dicyano-phenyl-hydrazin,  163 
Dicyano-hydroquinone,  227 
Dicyano-stilbene,  623 
Dicyclic  Terpenes,  510 
Dicyclo-hexyl,  550 
Dicyclopentadiene,  15 
Dicyclopentyl,  14 
Diduro-quinone,  229 
Diethyl-aniline,  89 
Diethyl-aniline-sulphinic  Acid,  181 
Diethyl-anthranilic  Acid,  306 
Diethyl-anthrone,  706 
Diethyl-carbinol,  n 
Diethyl-cyclo-hexane,  446 
Diethyl-diketo-hydrindone,  649 
Diethyl-diketo-tetramethylene-dicarboxylic   Ester, 

!3 

Diethyl-diphenyl-tetrazone,  167 


INDEX 


739 


Diethyl  Ester,  304 

Diethyl-methyl-benzol,  59 

Diethyl-phenols,  189 

Diethyl-phenyl-hydrazin,  152 

Diethyl-phenyl-hydrazonium  Bromide,  151 

Diethyl-proto-catechuic  Acid,  338 

Diethyl-terephthalyl  347 

Diethyl-tetramethylene-ketone,  1 1 

Difluoro-benzol,  61 

Difluoro-chloro-toluol,  297 

Diformazyl,  166 

Digallic  Acid,  343 

Digitaligenin,  722 

Digitalin,  722 

Digitalinum  verum,  722 

Digitalis  purpurea,  722 

Digitalose,  722 

Digito-flavone,  722 

Digitogenin,  722 

Digitonin,  722 

Digitoxigenin,  722 

Digitoxin,  722 

Digitoxose,  722 

Diglycol-anilic  Acid,  98 

Diglycol-phenyl-amidlc  Acid,  98 

Diglycol-phenyl-amidic  Anhydride,  98 

Diglycolic  Anile,  98 

Dihalogen-anthracenes,  704 

Dihaloids,  369 

Dihippenyl-urea,  284 

Dihydrazone,  649 

Dihydro-anthranol,  709 

Dihydro-benzaldehyde,  467 

Dihydro-benzoic  Acids,  472 

Dihydro-benzols,  449,  450 

Dihydro-camphene-pyrazin,  534 

Dihydro-campholene-lactone,  538 

Dihydro-campholenic  Acid,  539 

Dihydro-carvone,  506 

Dihydro-cumin  Alcohol,  454 

Dihydro-cumin-aldehyde,  467 

Dihydro-dicarboxylic  Acids,  479 

Dihydro-diphenyl,  550 

Dihydro-diphthalyl-di-imide,  621 

Dihydro-eucarveol,  514 

Dihydro-eucarvone,  514 

Dihydro-fencholene,  526 

Dihydro-iso-phorol,  462 

Dihydro-m-xylol,  450 

Dihydro-methyl-trimesinic  Acid,  483 

Dihydro-myrcene,  487 

Dihydro-naphthacene,  719 

Dihydro-naphthalene,  683 

Dihydro-naphthalene  Derivatives,  683 

Dihydro-naphthalene  Dibromide,  686 

Dihydro-naphthoic  Acids,  684 

Dihydro-o-xylol,  450 

Dihydro-phenanthrene,  691 

Dihydro-pheno-triazin,  144 

Dihydric  Phenols,  211 

Dihydro-pinylamine,  521 

Dihydro-quinazolin,  251 

Dihydro-resorcin,  215   459 

Dihydro-salicylic  Acid,  476 

Dihydro-shikimic  Acid,  474 

Dihydro-terephthalic  Acids,  480 

Dihydro-terpinolene,  497 

Dihydro-toluol,  450 

Dihydro-umbellulone,  513 

Dihydro-uvitinic  Acid,  483 

Di-iodanih"ne,  no 

Di-iodo-camphor,  532 

Di-iodo-cinnamic  Acid,  422 

Di-iodo-di-thymol,  188 

Di-iodo-styrol,  405 

Diketo-hexamethylenes,  459 

Diketo-hydrindene,  649 

Diketo-hydrindene-carboxylic  Ester,  650 

Diketo-pentamethylene,  18 

Diketo-pentamethylene-3,  5-dicarboxylic  Ester,  22 

Diketo-pentamethylene-3,  4,  5-tricarboxylic  Ester, 

22 

Diketo-tetrahydro-naphthylene  Oxide,  672,  686 
Diketone-carboxylic  Acids,  395 
Diketones,  Intramolecular  formation  of,  5 
Dilliso-apiol,  412 


Dimethoxy-phenanthrene,  690 
Dimethoxy-phthalazone,  352 
Dimethoxy-tolane,  613 
Dimethyl-amido-anthrone,  707 
Dimethyl-amido-azo-benzol-[4]-sulphonic  Acid,  179 
Dimethyl-amido-triphenyl-me thane,  578 
Dimethyl-amino-cycloheptene,  24 
Dimethyl-amino-triphenyl-carbinol,  583 
Dimethyl-aniline,  89,  169 

Oxide,  90 

Dimethyl-aniline-sulphinic  Acid,  181 
Dimethyl-anthracene,  704 
Dimethyl-anthranih'c  Acid,  306 
Dimethyl-anthrarufin,  716 
Dimethyl-apionol,  223 
Dimethyl-aurin,  593 
Dimethyl-beozamide  Chloride,  287 
Dimethyl-benzidin,  554 
Dimethyl-benzoic  Acids,  275 
Dimethyl-benzols,  30,  35 
Dimethyl-caff eic  Acid,  430 
Dimethyl-camphor,  536 
Dimethyl-cyclo-hexadiene,  450 
Dimethyl-cyclo-hexane,  446 
Dimethyl-cyclo-hexene,  449 
Dimethyl-cyclopentane-carboxylic  Acid,  19 
Dimethyl-cyclopentanone,  17 
Dimethyl-diamino-triphenyl-carbinol,  583 
Dimethyl-dibenzyl,  610 
Dunethyl-i,     2-diketo-pentamethylene-3,     5-     di- 

carboxylic  Acid,  22 

Dimethyl-2,  4-diketo-tetramethylene,  n 
Dimethyl-2,    4-diketo  -  tetramethylene  -  carboxylic 

Ester,  13 

Dimethyl-4,  5-diphenyl-cyclopentanone,  17 
Dimethyl-diphenyl-tetrazone,  167 
Dimethyl  Ether,  727 
Dimethyl-fulvene,  15 
Dimethyl-gentisin  Alcohol,  320 
Dimethyl-heptinol,  449 
Dimethyl-hydro-phthalide,  345 
Dimethyl-hydro-resorcin,  460 
Dimethyl-methylene-tetramethylene,  1 1 
Dimethyl-methylene-trimethylene,  7 
Dimethyl-morphol,  690 
Dimethyl-norcaradiene-carboxylic  Ester,  641 
Dimethyl-pen tamethylene,  n,  14 
Dimethyl-4 -keto-pentamethylene-carboxylic  Acid, 

22 

Dimethyl-phenanthrene,  689 
Dimethyl-phenyl-betain,  98 
Dimethyl-phenyl-hydrazin.  152 
Dimethyl-phenyl-oxy  -  ammonium  -  chlorohydrate , 

88 

Dimethyl-phenylene  Green,  239 
Dimethyl-phthaUde,  349 
Dimethyl-phthalide-carboxylic  Acid,  725 
Dimethyl-quinol,  320 
Dimethoxy-quinone  Oxime,  222 
Dimethyl-tert.-cyclopentanol,  16 
Dimethyl-tetramethylene-ketone,  1 1 
Dunethyl-tolane,  613 
Dimethyl- tricarballylic  Acid,  517 
Dimethyl-trimethylene,  7 
Dimethyl-trim  thylene-carboxylic  Acid,  8 
Dimethyl-trimethylene-2,  3-dicarboxylic  Acid,  10 
Dimethyl-umbelHferone,  430 
Dinaphtho-fluorene,  682 
Dinaphtho-fluorenone,  699 
Dinaphtho-xanthene,  682 
Dinaphthol-methane,  682 
Dinaphthyls,  681 
Dinaphthyl-acetic  Acid,  682 
Dinaphthyl-carbinoL  682 
Dinaphthyl  Ethers,  666 
Dinaphthyl-methane,  68 1 
Dinaphthyl  Sulphides,  671 
Dinaphthylamine,  660 
Dinaphthylene-methanes,  695 
Dinaphthylene-thiophene,  683 
Dinitraniline,  in 
Dinitro-aceto-phenone,  269 
Dinitro-anthracene,  704 
Dinitro-anthraquinone,  710 
Dinitro-azo-benzol,  142 
Dinitro-azoxy-benzol,  140 


740 


INDEX 


Dinitro-benzaldehyde,  262 
Dinitro-benzoic  Acid,  299 
Dinitro-benzols,  70,  77 
Dinitro-benzol-azo-benzol,  142 
Dinitro-benzyl-acetic  Acid,  631 
Dinitro-chloro-benzol,  72 
Dinitro-cinnamic  Acid,  423 
Dinitro-diazo-amido-benzol,  135 
Dinitro-dibenzyl,  610 
Dinitro-dibenzyl-acetone,  638 
Dinitro-dichloro-benzols,  72 
Dinitro-dinitroso-benzol,  77 
Dinitro-diphenic  Acid,  561 
Dinitro-diphenyl-amine,  112 
Dinitro-diphenyl-hydroxylamine,  78 
Dinitro-durol,  74 
Dinitro-ethyl-benzol,  73 
Dinitro-hydroquinone,  219 
Dinitro-isodurol,  74 
Dinitro-m-xylol,  73 
Dinitro-mesitylene,  73 
Dinitro-naphthalene,  659 
Dinitro-o-xylol,  73 
Dinitro-oxanilide,  108 
Dinitro-p-tolyl-methyl-nitramine,  120 
Dinitro-p-xylol,  73 
Dinitro-phenols,  196 
Dinitro-phenol  Ether,  191 
Dinitro-phenyl-hydroxylamine,  78 
Dinitro-phenyl-malonic  Ester,  396 
Dinitro-phenyl-nitramine,  121 
Dinitro-prehnitol,  74 
Dinitro-pseudocumol,  73 
Dinitro-stilbene,  612 
Dinitro- toluol,  72,  73 
Dinitro-trichloro-benzol,  72 
Dinitroso-benzol,  77 
Dinitroso-naphthalene,  659 
Dinitroso-toluol,  76 
Dios-phenol,  508 
Dioxindol,  378 
Dioxy-anthracene,  708 
Dioxy-anthra-cumarin,  708 
Dioxy-anthraquinones,  714,  716 
Dioxy-anthrone,  707 
Dioxy-azo-benzol,  206 
Dioxy-benzal-diketo-hydrindene,  649 
Dioxy-benzaldehydes,  323 
Dioxy-benzo-phenones,  226,  573 
Dioxy-benzoic  Acids,  336 
Dioxy-benzols,  30,  35,  117 
Dioxy-benzyl  Alcohols,  320 
Dioxy-benzyl-amine,  321 
Dioxy-biphenyls,  556 
Dioxy-cinnamic  Acid,  431 
Dioxy-dibenzal-acetone;  638 
Dioxy-dihydro-shikimic  Acid,  474 
Dioxy-dimethyl-triphenyl-methane,  590 
Dioxy-dinaphthyl  Sulphide,  671 
Dioxy-diphenyl,  557 
Dioxy-diphenyl-methane,  565 
Dioxy-diphenyl-sulphone,  180,  227 
Dioxy-diquinoyl,  231 
Dioxy-durylic  Acid,  339 
Dioxy-hexahydro-terephthalic  Acid,  481 
Dioxy-hydro-campholenic  Acid,  538 
Dioxy-iso-phthalic  Acid,  361 
Dioxy-m-xylo-quinone,  231 
Dioxy-methyl-anthraquinone,  716 
Dioxy-monocarboxylic  Acids,  336 
Dioxy-naphthacene-quinone,  719 
Dioxy-naphthalene,  670,  671 
Dioxy-naphthoic  Acid,  679 
Dioxy-phenanthrene-quinone,  693 
Dioxy-phenyl-acetic  Acid,  340 
Dioxy-phenyl-fatty  Acids,  339 
Dioxy-phenyl-olefin-carboxylic  Acids,  429 
Dioxy-phthalimide,  359 
Dioxy-quinone,  230 
Dioxy-quinone-dicarboxylic  Ester,  482 
Dioxy-stilbene,  612 
Dioxy-terephthalic  Acid,  362 
Dioxy-terephthalic  Ethyl  Ester,  362 
Dioxy-tetrazotic  Acids,  290 
Dioxy-thymo-quinone,  231 
Dioxy-toluic  Acids,  339 


Dioxy-triphenyl-carbinol,  591 
Dioxy-triphenyl-methane,  590 
Dipentamethenyl,  14 
Dipentene,  491 
Diphenacyl,  633 

Diphenacyl-aceto-acetic  Ester,  639 
Diphenacyl-amine,  372 
Diphenamino  Acid,  561 
Diphenanthryl-aziny  690 
Diphenic  Acid,  560 

Anhydride,  561 

Chloride,  561 

Diphenimide,  561,  692 

Diphenin,  146 

Diphenol-ethane,  604 

Diphenoxy-acetic  Acid,  191 

Diphenyl,  27,  550 

Diphenyl-acenaphthenone,  683 

Diphenyl-acet-amidin,  95 

Diphenyl-acetic  Acid,  606,  639 

Diphenyl-aceto-nitrile,  606 

Diphenyl-acetone,  605 

Diphenyl-acetylene,  613 

Diphenyl-aconic  Acid,  608 

Diphenyl-adipic  Acid,  623 

Diphenyl-anthracene,  704 

Diphenyl-anthranilic  Acid,  306 

Diphenyl-anthraquinone-methane,  706 

Diphenyl-anthrone,  707 

Diphenyl-arsenious  Chloride,  170 

Diphenyl-arsinic  Acid,  170 

Diphenyl-barbituric  Acid,  109 

Diphenyl-benzamide,  282 

Diphenyl-benzamidin,  290 

Diphenyl-benzols,  562 

Diphenyl-benzyl-sultame,  581 

Diphenyl-biguanide,  104 

Diphenyl-bismuth  Iodide,  170 

Diphenyl-biuret,  100 

Diphenyl-boron  Bromide.  170 

Diphenyl-boron  Chloride,  170 

Diphenyl-bromo-methane.  565 

Diphenyl-butadiene,  632,  640 

Diphenyl-butadiene-acetic  Acid,  636 

Diphenyl-butenin,  633 

Diphenyl-butenone,  633 

Diphenyl-butylene,  632 

Diphenyl-butyric  Acid,  608 

Diphenyl -butyro-lactone,  631 

Diphenyl-carbazide,  160 

Diphenyl -carbazide-dicarboxylic  Ester,  160 

Diphenyl-carbazone,  160 

Diphenyl-carbinol,  565 

Diphenyl-carbinol  Chloride,  565 

Diphenyl-carbo-diazone,  160 

Diphenyl -chloro-methane,  565 

Diphenyl-citraconic  Acid,  608 

Diphenyl  Compounds,  Formation  of,  from  Diazo- 

derivatives,  131 
Diphenyl-croto-lactone,  608 
Diphenyl  Cyanamide,  106 
Diphenyl-cyclopentane,  18 
Diphenyl-cyclopentenolone,  17,  638 
Diphenyl-cyclopentenolone-acetic  Acid,  17 
Diphenyl-diacetylene,  633 
Diphenyl-diacipiperazine,  97 
Diphenyl-dibromo-quino-methane,  591 
Diphenyl-diethylene,  632 
Diphenyl-dihydro-anthracene,  707,  709 
Diphenyl-dihydro-resorcin,  459 
Diphenyl-diketo-hexane,  640 
Diphenyl-diketo-nonane,  640 
Diphenyl-diketo-octane,  640 
Diphenyl-dimethyl-ethane,  610 
Diphenyl-dinitro-butylene,  632 
Diphenyl-dinitro-ethane,  611 
Diphenyl-dinitro-methane,  569 
Diphenyl-dioxy-anthracene  Hydride,  709 
Diphenyl-ethane,  603 
Diphenyl-ethenyl-amidin,  97 
Diphenyl-ethylene,  610 
Diphenyl-ethylene-chlorp-hydrin,  605 
Diphenyl-ethylene-diamine,  615 
Diphenyl-ethylene  Oxide,  615 
Diphenyl-fonnamidin,  96,  97 
Diphenyl-fulvene,  15 


INDEX 


741 


Diphenyl-furfurane,  633 
Diphenyl-glutaric  Acid,  623 
Diphenyl-glycin-anhydride,  97 
Diphenyl-glycolic  Acid.  607 
Diphenyl-glycolide,  377 
Diphenyl-glyoxal,  616 
Diphenyl -guanidin,  104 
Diphenyl-hexadiene,  640 
Diphenyl-hydantoin,  100 
Diphenyl-hydrazin,  145,  146,  150,  167 
Diphenyl-hydroxylamine,  78 
Diphenyl-indone,  646 
Diphenyl-iodonium  Hydroxide,  61 

—  Iodide,  64 
Diphenyl-iso-butane,  610 
Diphenyl-iso-dihydro-tetrazine,  158 
Diphenyl-itaconic  Acid,  608 
Diphenyl-ketene,  605 
Diphenyl-ketipic  Acid,  637 
Diphenyl-keto-tetrahydro-a-triazin,  158 
Diphenyl-ketone,  567 
Diphenyl-maleic  Acid,  623 
Diphenyl-malonyl-urea,  109 
Diphenyl-methane,  27,  563,  602 
Diphenyl-methane  Carboxylic  Acids,  574 
Diphenyl-methyl-benzaldehyde,  594 
Diphenyl-methyl-cyanidin,  290 
Diphenyl-methyl-quino-methane,  591 
Diphenyl-mono-biphenyl-carbinol,  580 
Diphenyl-nitrosamine,  119 
Diphenyl-nitroso-amine,  149 
Diphenyl-octa-tetrene,  640 
Diphenyl-oxalyl-diacetic  Acid,  637 
Diphenyl-oxethylamine,  615 
Diphenyl  Oxide,  191 
Diphenyl-oxy-biazole,  617 
Diphenyl-oxy-cyanidin,  290 
Diphenyl-oxy-formamidin,  96 
Diphenyl-oxyguanidin,  104 
Diphenyl-parabanic  Acid,  109 
Diphenyl-pentamethylene,  14 
Diphenyl-phenanthrene,  689 
Diphenyl-phenol,  636 
Diphenyl-phenylenes,  562 
Diphenyl-phosphine,  169 
Diphenyl-phosphine  Chloride,  169 
Diphenyl-phosphinic  Acid,  169 
Diphenyl-propane,  610 
Diphenyl-propio-phenone,  629 
Diphenyl-propionic  Acid,  607,  608 
Diphenyl-propylene,  627 
Diphenyl-phthalide,  595 
Diphenyl-pyridazin,  634 
Diphenyl-quino-methane,  591 
Dipheno-quinone,  558 
Diphenyl  Selenide,  183,  217 
Diphenyl-selenium  Oxide,  181 
Diphenyl-selenone,  183 
Diphenyl -semicarbazide,  160 
Diphenyl-silicol,  171 
Diphenyl  Substitution  Products,  551 
Diphenyl -succinic  Acid,  622 
Diphenyl-sulphide,  183 
Diphenyl-sulpho-carbazide,  162 
Diphenyl-sulpho-carbazone,  142,  162 
Diphenyl-sulpho-carbo-diazone,  162 
Diphenyl-sulpho-semicarbazide,  1 6 1 
Diphenyl-sulpho-urea,  102 
Diphenyl-sulphone,  181,  182 
Diphenyl-sulphone-phthalide,  355 
Diphenyl-sulphoxide,  181,  182 
Diphenyl  Telluride,  211 
Diphenyl-tetraketone,  635 
Diphenyl-tetraketoxime,  635 
Diphenyl-tetramethylene-dicarboxylic  Acid,  13 
Diphenyl-tetrazolium  Hydroxide,  166 
Diphenyl-tetrene-dicarboxylic  Acid,  13 
Diphenyl- tbio-carbonic  Ester,  193 
Diphenyl-trichloro-ethane.  604 
Diphenyl-triketo-pentamethylene,  1 8 
Diphenyl-triketone,  630 
Diphenyl-uramile,  109 
Diphenyl-urazin,  160,  161 
Diphenyl-urea,  99,  100 

Chloride,  99 

Diphenyl-uric  Acid,  109 


Diphenyl-</»-uric  Acid,  109 
Diphenyl- valeric  Acid,  621 
Diphenyl-violuric  Acid,  109 
Diphenylamine,  79,  91 

Blue,  589 

Diphenylene-acetic  Acid,  700 
Diphenylene-diketone,  709 
Diphenylene-diphenyl-ethane,  698 
Diphenylene-diphenyl-ethylene,  698 
Diphenylene  diselenide,  215 

Disulphide,  209,  214 

Diphenylene-glycollic  Acid,  692,  700  . 
Diphenylene-iodonium  Iodide,  552 
Diphenylene-ketene,  700 
Diphenylene-ketone,  692,  699 
Diphenylene-ketone-carboxylic  Acids,  700 
Diphenylene-methane,  695,  696 
Diphenylene  Oxide,  186 
Diphenylene-phenanthrene,  699 
Diphenylene-phenanthrone,  698 
Diphenylene-phenyl-carbinol,  697 
Diphenylene-phenyl-methane,  697 
Diphenylene  Sulphide,  210 
Diphenylin,  147 
Diphthalide  Ether,  351 
Diphthalyl,  621 
Diphthalylic  Acid,  620 
Diprotp-catechuic  Acid,  337 
Dipterix  odorata,  428 
Diquinoyl-dioxime,  216 
Disah'cylide,  331 

Dis-diazo-amido-compounds,  132 
Dis-diazo-benzol-amide,  135 
Dis-diazo-benzol-anilide,  135 
Dis-diazo-benzol-ethyl-amine,  136 
Dis-diazo-benzol-methyl-amine,  136 
Disodium  Salicylate,  192 
Disuberyl,  23 

Disulpho-benzoic  Acid,  314 
Disulphones,  181 
Disulphoxides,  180 
Ditetramethylene-ketone,  n 
Dithio-aniline,  209 
Dithio-benzoic  Acid,  280 
Dithio-diphenyl-phthaHde,  596 
Dithio-diphthalyl,  621 
Dithio-hydroquinone,  220 
Dithio-malon-anilide,  108 
Dithio-oxanih'de,  108 
Dithio-sah'cylic  Acid,  332 
Ditoluol-sulpho-hydroxamic  Acid,  175 
Ditolyl-amines,  91 
Ditolyl-disulphone,  181 
Ditolyl  Ketone,  568 
Divinyl-benzol,  408 
Dixylylene  Disulphide,  344 
Doebner,  584 

Dryobalanops  camphora,  526 
Duridin,  86 
Durol,  55,  58 
Durrhin,  723 
Dypnone,  629 
Dypnone-hydroxylamine,  629 


ELEMICIN,  412 
Ellagic  Acid,  341 
Emeraldin,  237 
Emodin,  724 
Emulsin,  720 
Eosin,  600 

Ephedra  vulgaris,  369 
Ephedrin,  369 
Eriodictyol,  629 
Erlenmeyer,  E.,  382 

Sen.,  123 

Erythrin;  339 
Erythrinic  Acid,  339 
Erythro-oxy-anthraquinone,  714 
Erythrol  Tetrabenzoate,  278 
Erythrosin,  600 
Estragol,  409 
Ethene-pyrocatechin,  213 
Ethenyl-phenyl-hydrazin,  163 
Ethine-diphthalyl,  637 
Ethoxy-benzaldoxime,  322 


742 


INDEX 


Ethoxy-benzo-thiazol,  101 
Ethoxy-cinnamic  Ester,  436 
Ethoxycumarin,  437 
Ethoxy-cyanamino-benzoyl,  305 
Ethoxy-methylene-aniline,  95,  253 
Ethoxy-mustard  Oil,  101 
Ethoxy-phthalide,  351 
Ethyl-acetanilide,  95 
Ethyl-amido-cinnamic  Acid,  423 
Ethyl-aniline,  89 
Ethyl-anthranilic  Acid,  306 
Ethyl-anthranol-ethyl  E'ther,  706 
Ethyl-benzoic  Acids,  274 
Ethyl-benzol,  30,  55,  57 
Ethyl-campho-carboxylic  Ethyl  Ester,  535 
Ethyl-camphor,  536 
Ethyl-chavicol,  409 
Ethyl  Chloride,  64 
Ethyl-diphenyl-iso-urea,  100 
Ethyl  Ester.  99 
Ethyl-fluorene,  700 
Ethyl-gallic  Ester,  341 
Ethyl  Iso-formanilide,  95 
Ethyl-iso-thio-acetanilide,  96 
Ethyl-ketpne,  n 
Ethyl-mesitylene,  59 
Ethyl-methyl  Ester,  101 
Ethyl  Ortho-benzpate,  297 
Ethyl-orthobenzoic  Ester,  297 
Ethyl-phenols,  188 
Ethyl-phenyl-dithio-urethane,  101 
Ethyl-phenyl  Ether,  190 
Ethyl-phenyl-hydrazin,  151 
Ethyl-phenyl-iso-urea,  100 
Ethyl-phenyl-methyl-iso-urea,  100 
Ethyl-phenyl-oxalic  Ester,  193 
Ethyl-phenyl  Urea,  99 
Ethyl-pseudo-cumol,  59 
Ethyl-phthalide,  349 
Ethyl-stilbene,  611 
Ethyl-suberane,  23 
Ethyl-toluol,  57 
Ethylene-carbanilide,  100 
Ethylene-diphenyl-diamine,  90 
Ethylene-diphenyl-disulphone,  182 
Ethylene-monophenyl-diamine,  90 
Ethylene-phenyl-hydrazin,  152 
Ethylene-phenyl-urea,  100 
Ethylene-succinic  Acid,  162 
Ethylidene-aniline,  91 
Ethylidene-camphor,  536 
Ethylidene  Chloride,  64 
Ethylidene-cyclopentane,  15 
Ethylidene-dibenzamide,  282 
Ethylidene-diphenyl-diamine,  90 
Ethylidene-phthalide,  434 
Ethylidene-propionic  Acid,  47 
Eucalyptol,  499 
Eucalyptus,  212 
Eucalyptus  amygdalina,  494 

globulus,  520 

maculata,  489 

Eucarvpne,  25,  514 
Euchroic  Acid,  367 
Eugenia  caryophyllata,  411 

pimenta,  411 

Eugenic  Acid,  411 
Eugenol,  368,  411 
Eugenol-methyl  Ether,  411 
Eupatorium  ayapana,  219 
Eupitton,  594 
Eupit tonic  Acid,  594 
Eurhodins,  144 
Euthio-chronate,  219 
Euxanthic  Acid,  725 
Evernia  prunastris,  339 
Everninic  Acid,  339 
Exalgin,  95 

FARADAY,  50 

Fatty  Acid  Derivatives,  157 

—  Aromatic  Sulphides,  210 
Fehling's  Solution,  149 
Fenchelylamine,  529 
Fenchene,  525,  520 
Fenchenol,  528 


Fencholenamine,  529 
Fenchone,  58,  545 
Fenchyl  Acetate,  528 

—  Alcohol,  528,  529 
•  Bromide,  528 

—  Chlorides,  528 
Fenchylamine,  529 
Ferulic  Acid,  430 
Fichtelite,  693 
Ficus  elastica,  549 
Fischer,  149,  584.  586,  719 
Fisetol-dimethyl  Ether,  726 
Fittig,  52,  418 
Flavanilin,  95 
Flavanthrene,  711 
Flaveanic  Hydride,  164 
Flavo-phenin,  555 
Flavo-purpurin,  717 
Fluo-nitro-benzoic  Acid,  299 
Fluorane,  598,  599 
Fluoranthene,  50,  701 
Fluoranthoquinone,  701 
Fluorene.  27,  50,  650,  695,  696 

Alcohol,  692,  699 

Fluorene-carboxylic  Acid,  700 
Fluorene  Group,  695 
Fluorene-oxalic  Acid,  700 

Ester,  696 

Fluorenol,  699 
Fluorenone,  699 
Fluorenone-oxime,  696 
Fluoresceins,  599 
Fluorescem-anilide,  600 
Fluoresce'in-carboxyl-methyl  Ester,  600 
Fluorescei'n-phenyl-hydrazide,  600 
Fluorescine,  595 

Fluoro-benzols,  60,  6 1 
Fluoro-naphthalenes,  658 
Fluoro-toluol,  65 
Formaldehyde-aniline,  89 
Formaldehyde-dianthranilic  Acid,  306 
Formamidine-benzo-hydryl,  565 
Formanilide,  94,  97 
Formazyl,  142 
Formazyl-acrylic  Acid,  166 
Formazyl-azo-benzol,  166 
Formazyl-benzol,  292 
Formazyl-carboxylic  Acid,  166 
Formazyl  Compounds,  163,  165 

Derivatives,  157 

Formazyl-glyoxalic  Acid,  166 
Formazyl  Hydride,  166 
Formazyl-methyl  Ketone,  166 
Formyl  Acetanilide,  95 
Formyl-acetic  Ester,  43 
Formyl-aceto-phenone,  374 
Formyl-acetone,  43 
Formyl-amido-phenol,  200 
Formyl-anthranilic  Acid,  302 
Formyl-benzamide,  281 
Formyl-camphpr,  536 
Formyl-hippuric  Ester,  283 
Formyl-phenyl-glycin,  98 
Formyl-phenyl-hydrazide,  157 
Formyl-phenyl-hydroxylamine,  78 
Formyl-propionic  Acid,  43 
Frangulin,  717,  724 
Fraxetin,  431 
Fraxin,  721 
Fraxinus  excelsior,  721 
Friedel,  52 
Fuchsine,  584 

Fuchsine-sulphurous  Acid,  585 
Fuchsone,  591 
Fulvenes,  15 
Furazane,  233 

Galipea  officinalis,  547 
Galipene,  547 
Gall-aceto-phenone,  327 
Gallanol,  341 
Gallem,  601 
Gallic  Acid.  340 
Gallic-acid  Anilide  341 
GaUic  Aldehyde,  325 
Gallo-bromol,  341 


INDEX 


743 


Gallo-carboxylic  Acid,  363 
Galloflavin,  341 
Gallo-tannic  Acid,  342 
Gallyl-galHc  Acid,  343 
Garancin,  714 
Garden,  650 
Garlic,  Oil  of,  408 
Gaultherase,  721 
Gaultheria,  721 

Gaultheria  procumbens,  328,  330 
Gaultherin,  721 
Gem,  721 

Gelsemium  sempervirens,  721 
Gentisin,  725 
Gentisin-aldehyde,  325 
Gentisinic  Acid,  339 
Geranic  Acid,  490 
Geranial,  490 
Geraniol,  42,  488 
Geraniolene,  449 
Gibson,  74 

Glucose-cumaraldehyde,  72 1 
Glucose  Pentabenzoate,  278 
Glucosides,  221,  719 
Glutaconic  Acid  Ester,  43 
Glycerine-monophenyl  Ether,  190 
Glycerol  Tribenzoate,  278 
Glyco-vanillin,  721 
Glycocoll,  177 
Glycol-chloro-hydrin,  684 
Glycol  Dibenzoate,  278 
Glycol-diphenyl  Ether,  190 
Glycol-monophenyl  Ether,  190 
Glycol-phenyl-urea,  100 
Glycosides,  719 
Glyoxal- dipyrocatechin,  213 
Glyoxalins,  116 
Glyoxime-N-phenyl-ether,  107 
Gorgonia  Carolinii,  382 
Graebe,  586,  714 
Griess,  123 
Guaiacol,  212 

Guaiacol-sulphonic  Acids,  213 
Gum  Lac,  548 

ILEMATEIN-AMMONIA,  726 

Haematin,  726 
Haematoxylin,  726 
Hcematoxylon  campeckianum,  726 
Halogen  Benzoic  Acids,  297 

Diphenyls,  551 

Hydrins,  368 

Phenanthrenes,  689 

Haloid  Anhydrides  of  the  Aromatic  Acids,  278 

Cinnamic  Acids,  421 

Nitro-phenols,  198 

Hantzsch,  124,  250 

Hedeoma  pulegioides,  505,  507 

Helianthin,  115 

Helicin,  322,  720,  721 

Heliotropine,  324 

Hemi-mellitic  Acid,  365 

Hemimellithol,  55,  57 

Heptacarbocyclic  Compounds,  22 

Heptachloro-resorcin,  48,  215,  460 

Heptamethylene,  i,  3,  23 

Heptamethylene-terpene,  23 

Heptanaphthene,  446 

Heptyl-benzol,  60 

Hesperetol,  410 

Hesperidene,  491 

Hesperidin,  221,  723 

Hesperitin,  628 

Hetero-ring  Formations  in  Formazyl  Compounds, 

166 

Hexa-bromo-cyclo-butane,  1 1 
Hexa-bromo-triketo-cyclo-hexane,  461 
Hexa-carbocyclic  Compounds,  27 
Hexa-chloro-a-oxy-cyclopentene-carboxylic     Acid, 

20 

Hexa-chloro-benzol,  61 
Hexa-chloro-cyclopentenones,  18 
Hexa-chloro-keto-R-pentene,  47 
Hexa-chloro-diketo-R-hexene,  47 
Hexa-chloro-p-diketo-R-hexene,  47 
Hexa-chloro-R-pentene-oxy-carboxylic  Acid,  47 


Hexa-chloro-  [i,  3,  5]-triketo-R-hexylene,  48 
Hexa-ethyl-benzol,  55,  57 
Hexa-hydro-aceto-phenone,  467 
Hexa-hydro-benzaldehyde,  466 
Hexa-hydro-benzoic  Acids,  470 
Hexa-hydro-benzols,  444.  445 
Hexa-hydro-benzyl-amine,  456 
Hexa-hydro-carvacrol,  452 
Hexa-hydro-cymol,  497 
Hexa-hydro-dicarboxylic  Acids,  477 
Hexa-hydro-dioxy-benzoic  Acid,  474 
Hexa-hydro-diphenyl,  550 
Hexa-hydro-fluorene,  696 
Hexa-hydro-iso-phthalic  Acids,  478 
Hexa-hydro-mandelic  Acid,  475 
Hexa-hydro-oxy-benzoic  Acids.  473 
Hexa-hydro-oxy-phenyl  Fatty  Acids,  474 
Hexa-hydro-phenol,  452 
Hexa-hydro-phenyl-acetic  Acid,  472 
Hexa-hydro-phenyl-propiolic  Acid,  473 
Hexa-hydro-phenyl-propionic  Acid,  472 
Hexa-hydro-phenyl-tetrolic  Acid,  473 
Hexa-hydro-phthalic  Acids,  477 
Hexa-hydro-propio-phenone,  468 
Hexa-hydro-pseudo-cumol,  446 
Hexa-hydro-salicylic  Acid,  473 
Hexa-hydro-terephthalic  Acids,  478 
Hexa-hydro-tetraoxy-benzoic  Acid,  474 
Hexa-hydro-thio-phenol,  455 
Hexa-hydro-thymol,  452 
Hexa-hydro-toluol,  446 
Hexa-iodo-benzol,  62 
Hexa-methoxy-aurin,  594 
Hexa-methoxy-benzile,  619 
Hexa-methoxy-benzilic  Acid,  607 
Hexa-methyl-benzol,  59 
Hexa-methyl-benzol,  55,  59 
Hexa-methyl-p-leukaniline,  90 
Hexa-methyl-para-rosanilin,  587 
Hexa-methyl-triamido-triphenyl-carbinol,  588 
Hexa-methyl-triamido-triphenyl-methane,  588 
Hexa-methylene,  i,  3,  13,  445 
Hexa-methylene-carboxylic  Acids,  470 
Hexa-methylene-tetracarboxylic  Acid,  484 
Hexa-nitro-diphenyl-amine,  112 
Hexa-m'tro-hydrazo-benzol,  146 
Hexa-oxy-benzene,  224 
Hexa-oxy-biphenyls,  557 
Hexa-phenyl-ethane,  626 
Hexa-phenyl-melamine,  107 
Hexyl  Iodide,  42 
Hipparaffin,  282 
Hippenyl-urethane,  284 
Hippurazide,  284 
Hippuric  Acid,  282 

Nitrile,  283 

Hippuryl-phenyl-buzylene,  168 
Hlasiwetz,  221 
Hoff,  Van,  477 
Hofmann,  50,  145,  585 
Homo-benzoylated  Paraffins,  268 
Homo-caffeic  Acid,  430 
Homo-camphoric  Acid,  544 
Homo-erio-dictyol,  628 
Homo-ferulic  Acid,  430 
Homo  Gentisinic  Acid,  340 
Homo-iso-phthalic  Acid,  364 
Homo-linaloof,  489 
Homo-phthaumide,  363 
Homo-piperonal,  325 
Homo-piperonyl  Alcohol,  321 
Homo-proto-catechuic  Acid,  339 
Homo-pyrocatechol,  214 
Homo-saligenin,  316 
Homo-tanacetone-dicarboxylic  Acid,  310 
Homo-terephthalic  Acid,  364 
Homo-terpenylic  Acid,  517 
Homo-veratric  Acid,  340 
Homologous  Anthraquinones,  710 
—  Cinnamic  Acids,  424 

Iso-phthalic  Acids,  360 

Monoxy-benzaldehydes,  323 

Olefin-benzols,  406 

Phenols,  186 

Phenyl-glyoxylic  Acids,  390 

Pyrocatechols,  214 


744 

Homologues  of  Benzoic  Acid,  274 
Hordenin,  316 
Hubner,  32 
Hydra-benzile,  616 
Hydracrylic  Acids,  383 
Hydrastic  Acid,  359 
Hydrate  de  Ph6nyle,  186 
Hydratropic  Acid,  276 

Hydratropic  Nitrile,  287 
Hydrazi-dicarbon-anilide,  101 

Hydrazidins,  163,  291 

Hydrazidoximes,  296 

Hydrazins,  123 

Hydrazin-benzoic  Acids,  312 

Lactazame,  312 

Hydrazin-cinnamic  Acid,  423,  424 

Hydrazin  Compounds,  145 

Hydrazin-salicylic  Acid,  333 

Hydrazino-diphenyl,  556 

Hydrazo-benzoic  Acid,  312 

Hydrazo-benzol,  69,  145,  146 

Hydrazo-benzol-m-disulphonic  Acid,  179 

Hydrazo-compounds,  145 

Hydrazo-naphthalene.  663 

Hydrazo-naphthalin,  663 

Hydrazo-phenols,  206 

Hydrazo-toluene,  147 

Hydrazo-toluols,  146 

Hydrazo-triphenyl-methane,  581 

Hydrazo-xylols,  146 

Hydrazoic  Acid,  284 

Hydrazones,  266 

Hydrazoximes,  153 

Hydrindamine,  647 

Hydrindene,  647 

Hydrindene  Derivatives,  647 

Hydrindic  Acid,  378 

Hydrindone,  647,  648 

Hydrindone-azine,  647 

Hydro-anthracenes,  708 

Hydro-aromatic  Aldehydes,  466 

Carboxylic  Acids,  469 

Dicarboxylic  Acids,  477 

Hydrocarbons,  443 

Ketones,  467 

Monocarboxylic  Acids,  469 

Substances,  2 

Hydro-benzamide,  257 
Hydro-benzoin,  254,  614 
Hydro-benzol  Derivatives,  443 
Hydro-benzol-tetracarboxylic  Acids,  484 
Hydro-benzol-tricarboxylic  Acids  483 
Hydro-caffeiic  Acid,  340 
Hydro-carbo-styrile,  311 
Hydro-cinnamic  Acid,  276 

Aldehyde,  256 

Azide,  284 

Hydrazide,  284 

Nitrile,  286 

Hydro-cinnamide,  415 
Hydro-cinnamoin,  640 
Hydro-cinnamyl  Alcohol,  242 
Hydro-coerulignone,  557 
Hydro-cornicularic  Acid,  637 
Hydro-cotom,  573 
Hydro-cumaric  Acids,  336 
Hydro-cumarilic  Acid  381 
Hydro-cumarin,  336 
Hydro-dicamphene.  525 
Hydro-diphthalyl-lactonic  Acid,  621 
Hydro-fluoranic  Acid  595 
Hydro- juglones,  671 
Hydrolytic  Condensation,  44 
Hydro-naphthalene  Derivatives,  683 
Hydro-naphtho-quinone,  670 
Hydro-p-xylo-quinone,  219 
Hydro-phenanthrenes,  691 
Hydro-phlorone,  219 
Hydro-phthalide,  345 
Hydro-pinene-carboxylic  Acid,  535 
Hydro-piperic  Acid,  430 
Hydro-quinone,  35 
Hydro-quinone-benzein,  592 
Hydro-quinone-carboxylic  Acid,  339 
Hydro-quinone  Diacetate,  218 
• —  Dibenzoate,  219 


INDEX 


Hydro-quinone  Disulphide,  223 

Lactic  Acid,  381 

Hydro-quinone-monomethyl  Ether,  218 
Hydro-quinone-phenyl-phthalide,  596 
Hydro-quinone-phthalem,  601 
Hydro-quinone-propionic  Acid,  340 
Hydro-quinone-succinein,  599 
Hydro-terpenes,  496 
Hydro-tetrazones,  167 
Hydro-tropilidene,  23 
Hydro-umbellic  Acid,  340 
Hydroxamic  Acids,  254 

Their  Ethers  and  Esters,  292 

Hydroxamoximes,  297 
Hydroxime-acid  Chlorides,  292 
Hydroxy-campho-carboxylic  Acid,  544 
Hydroxylamino-anthraquinones,  710 
Hydroxylamino-benzaldehyde,  262 
Hydroxylamino-benzaldoxime,  262 
Hydroxylamino-benzyl-alcohol,  250 
Hydroxylamino-carboxylic  Acids,  300 
Hydroxylamino-carvoxime,  510 
Hydroxylamino-hydro-cinnamic  Acid,  383 
Hyssopus  officinalis,  521 
Hystazarin,  715 
Hystazarine,  212 

Illicium  anisatum,  410 

— —  religiosum,  337,  4",  474 

Imidazols,  116 

Imide,  98 

Imido-benzoyl-cyano-methane,  392 

Imido-chlorides,  287 

Imido-dibenzyl,  610 

Imido-oxy-naphthalene-sulphonic  Acid,  670 

Imido-phenyl-carbaminic  Thio-methyl  Ester,  102 

Immo-benzo-phenone,  569 

Imino-2-cyano-cyclopentane,  22 

Imino-3-cyano-cyclopentane-i-carboxylic  Ester,  22 

Indacene,  650 

Indamines,  238 

Indanone.  647,  648 

Indanthrene,  711 

Indene,  27 

Indene-carboxylic  Acid,  646 

Indene  Derivatives,  645 

Indene-oxalic  Ethyl  Ester,  646 

Indiazonoxime,  263 

Indigo,  95,  98 

Indo-amine,  117 

Indo-anilines,  236 

Indo-phenols,  117,  236,  239,  676 

Indols,  155 

Indone-acetic  Acid,  441 

Indoxyl,  98,  308 

Indoxylic  Acid  Esters,  307 

Indulins,  144,  238 

Inosite,  453,  454 

Intramolecular  Aceto-acetic  Ester  Condensation,  4 

Pinacone  Formation,  4 

[odaceto-phenone,  268 

[odide  Chlorides,  61 

todo-aceto-phenone,  372 

lodo-anthraquinone,  710 

todo-benzoic  Acids,  298 

[odo-benzols,  61,  62 

todo-camphor,  532 

'odo-chloride-benzol  Sulpho-chloride,  177 

iodo-cinnamic  Acid.  422 

:odo-diphenacyl,  634 

'odogorgic  Acid,  382 

^odo-hydrin,  369 

iodo-naphthalene,  659 

:odo-o-phthalic  Acids,  358 

odo-oxy-naphtho-quinone,  673 

odo-phenyl-hydrazin,  150 

odo-propionic  Ester,  98 

odo-salicylic  Acid,  333 

odo-toluol,  65 

odoso,  298 

odoso-benzol,  61 

odoso-benzol-sulphonic  Acid,  177 

odoso-naphthalenes,  659 

onone,  468 

retol,  223,  722 

ridic  Acid,  342,  722 


INDEX 


745 


Iridin,  722 

Iridol,  722 

Irigenin,  223 

Iris  florentina,  468,  722 

germanica,  468 

pallida,  468 

Irodol,  221 

Irone,  468 

Isapiol,  223 

Isatin,  389 

Isatin-diphthalyl,  649 

Isatinic  Acid,  389 

Isatoic  Anhydride,  305,  308 

Dialkyl  Ester,  304 

Isatropic  Acids,  425 
Iso-allyl -benzol,  406 
Iso-amenyl-benzol,  407 
Iso-amino-camphor,  539 
Iso-amyl  Ether,  190 
Iso-anthraflavic  Acid,  716 
Iso-benzile,  619 
Iso-borneol,  527 
Iso-borneol  Acetate,  522 
Iso-butyl-alk.,  82 
Iso-butyl-benzol,  59 
Iso-butyl-mesitylene,  59 
Iso-campholic  Acid,  537 
Iso-camphoric  Acid,  541 
Iso-camphoronic  Acid,  517,  538 
Iso-capro-lactpne,  518 
Iso-carbo-styril,  435 
Iso-cumarin,  434,  435 
Iso-cumarin-carboxylic  Acid  442 
Iso-cyano-phenyl-chloride,  97,  105 
Iso-cyclic  Compounds,  i 
Iso-dihydro-lauro-lactone,  542 
Iso-dihydrp-phene-tetrazins.  144 
Iso-diphenic  Acid,  561 
Iso-duridin,  86 
Iso-durol,  55,  58 
Iso-elemicin,  412 
Iso-eugenol,  368,  411 
Iso-eugenpl-methyl  Ether,  411 
Iso-ethindiphtalyl,  719 
Iso-fencho-camphoric  Acid,  546 
Iso-fencholene  Alcohol,  528 
Iso-fencholic  Acid,  546 
Iso-fenchone,  546 
Iso-fenchyl  Alcohol,  528 
Iso-ferulic  Acid,  430 
Iso-homo-pyrocatechol,  214 
Iso-keto-camphoric  Acid,  538 
Iso-laurolene,  543 
Iso-lauronolic  Acid,  542 
Iso-naphthazarin,  673,  674 
Iso-naphtho-fluorene,  697 
Iso-naphtho-fluorenone,  648,  699 
Iso-nitroso-aceto-phenone,  374 
Iso-nitroso-camphor,  533 
Iso-nitroso-hydrindone,  647 
Iso-orcin,  217 

Iso-oxalyl-dibenzyl-ketone,  636 
Iso-phenyl-acetic  Acids,  24 
Iso-phorone,  462 
Iso-photo-santonic  Acid,  725 
Iso-phthalic  Acid,  36,  38,  56,  359 
Iso-prene,  487 
Iso-propenyl-benzol,  406 
Iso-propenyl-naphthalin,  658 
Iso-propyl-benzom,  616 
Iso-propyl-benzol,  55,  57 
Iso-propyl-cyclopentane-i,  6-diol,  16 
Iso-propyl-dihydro-resorcin,  459 
Iso-propyl-diphenyl.  693 
Iso-propyl-hexyl-benzol,  60 
Iso-propyl-idene-cyclopentane,  1 5 
Iso-propyl-phenol,  188 
Iso-propylidene-cyclo-hexanone,  462 
Iso-pulegol,  489 
Iso-pulegone,  508 
Iso-purpurin,  717 
Iso-safrol,  368,  412 

Dibromide.  369 

Iso-thio-cyanic  Phenyl  Ester,  106 
Iso-thujone,  513 
Iso-valerianic  Ester,  498 


Iso-vanillic  Acid,  338 
Iso-vanillin,  324 
Iso-violanthrenes,  719 
Iso-xylol,  36,  38,  55,  56 

JACKSON,  418 
Jalapin,  722 
Jayne,  418 
Juglpnic  Acid.  359 
Juniperus  virginiana,  548 

KEKULE,  2,  27,  29,  123,  443,  586 
Kermessic  Acid,  728 
Keto-dihydro-naphthoic  Acid,  679 
Keto-dihydro-quinazolins,  308 
Keto-hexamethylene,  457 
Keto-hydrazones,  152 
Keto-hydro-monocarboxylic  Acids,  475 
Keto-iso-camphoric  Acid.  517 
Keto-menthanes,  505 
Keto-menthenes,  506 
Keto-pentamethylene,  17 
Keto-pentamethylene-3-carboxylic  Acid,  21 
Keto-pentamethylene-carboxylic  Ester,  21 
Keto-pentamethylene-2,  3-dicarboxylic  Ester,  21 
Keto-pentamethylene-3,  4-dicarboxylic  Acid,  21 
Keto-phenyl-paraconic  Ester,  400 
Keto-tetramethylene-cyclo-butanone,  1 1 
Keto-tetramethylene-tricarbo-esters,  12 
Ketone-aldehydes,  373,  374 
Ketone-carboxylic  Acids,  353,  387.  393 
Ketone-tricarboxylic  Acids,  403 
Kino.  212 
Kino-tannin,  343 
Kohler,  723 
Kolbe,  334 
Korner,  31,  32 
Kynuric  Acid,  305 

LACCAINIC  Acid,  728 

Lactames,  159 

Ladenburg,  31,  33,  41,  334 

Laevuhnic  phenyl-hydrazone,  159 

Laurent,  186,  355 

Laurolene,  543 

Lauronoh'c  Acid,  542 

Lead-tetraphenyl,  172 

Lecanium  Ilicis,  728 

Lecanora,  217 

Lecanpric  Acid,  339 

Lepidium  sativum,  286,  720 

Leuco-benzaurin,  590 

Leuco-benzein,  590 

Leuco-malachite  Green,  578 

Leuco-rosolic  Acid,  590 

Leucaniline,  579 

Leucaurins,  590 

Leuconic  Acid,  14,  232 

Lichen  Dyes,  727 

Liebermann,  714 

Liebig,  255,  282,  382,  723 

Ligustrum  vulgar e,  721 

Limonene,  491 

Linaloolene,  487 

Linalool,  487,  488 

Linamarin,  723 

Lipp, 382 

Lippia  ctiriodora,  487 

Liauidambar  oriental  is,  413 

Litmus,  217 

Loschmidt,  28.  29 

Lupinus  luteus,  380 

Luteic  Acid,  341 

LuteoUn,  338 

MACI  Oil,  412 
Maclurin,  338,  343,  573 
Magnesium-diphenyl,  171 
Malachite  Green,  90,  583 
Maleic  Acid,  46 
Maleino-phenyl-hydrazil,  163 
Malon-anih'c  Acid,  108 
Malon-anilide,  108 
Malonic  Diphenyl  Ester,  193 

Ester  Phenyl-hydrazide,  162 

Methyl-anilide,'io8 


746 


INDEX 


Malono-phenyl-hydrazilic  Ester,  162 
Malonyl-diphenyl-hydrazide,  162 
Malonyl-phenyl-hydrazide,  162 
Manchester  Brown,  145 
Mandelic  Acid  Nitrile,  377 

Chloralide,  377 

Nitrile  Glucoside,  723 

Marignac,  355 

Matezite,  454 

Matricaria  Parthenium,  530 

Meconin,  349 

Meconin-acetic  Acid,  401 

Melanilin,  104 

Melilotic  Acid,  336 

Melilotus  officinalis,  336,  427,  428 

Mellimide,  366 

Mellithic  Acid,  43 

MeUitic  Acid,  366 

Mellophanic  Acid,  366 

Menaphthyl-amines,  677 

Mentha  pulegium,  507 

Menthadiene,  495 

Alcohols,  503 

Menthadiene-ketones,  509 
Menthane,  486,  497 
Menthene,  449,  496 

Alcohols,  502 

Menthene-glycol,  500 
Menthenol,  503 
Mentho-citronellal,  490 
Mentho-menthene,  496 
Mentho-naphthene,  497 
Mentho-nitrile,  506 
Menthone,  505 
Menthone-oxime,  506 
Menthonenic  Acid,  506 
Menthoximic  Acid,  505 
Menthyl  Chloride,  498 
Menthyl-xanthogenic  Methyl  Ester,  498 
Menthylamine,  504 
Mercaptans,  208 
Mercuri-nitro-phenols,  196 
Mercurio-acetanilide,  95 
Mercury-dialphyls,  172 
Mercury-diphenyl,  171 
Mercury  Phenate,  186 
Mercury-phenyl  Acetate,  172 

Bromide,  172 

Chloride,  172 

Hydroxide,  172 

Iodide,  172 

Mercury  Thio-phenate,  208 
Mesicerine,  345 
Mesidic  Acid,  360 
Mesidin,  86 

Mesidin-iodo-hydrate,  82 
Mesitol,  188 

Mesityl-hydroxylamine,  78 
Mesityl-iso-phthalic  Acid,  361 
Mesityl-quinol,  320 
Mesitylene,  33,  55>  56,  57 
Mesitylene-glycerin,  345 
Mesitylene-sulphonic  Acid,  175 
Mesitylene-trialdehyde,  346 
Mesitylenic  Acid,  31,  38.  56,  57 
Meso-amido-anthracene,  705 
Meso-benzo-dianthrone,  718 
Meso-dihydro-dianthrone,  706 
Meso-naphtho-dianthrone,  718 
Meso-phenyl-anthramine,  705 
Meso-phenyl-anthrone,  707 
Meso-xanil-amido-chloride,  97 
Mesorcin.  217 

Meta-bromo-benzoic  Acid.  32 
Meta-dinitro-benzol,  70 
Meta-hemi-pinic  Acid,  359 
Meta-oxy-benzoic  Acid,  31,  36 
Meta-phenol-sulphonic  Acid,  207 
Metanil  Yellow,  179 
Methane,  42 

Methene-cyclp-hexane,  449 
Methenyl-amido-thio-phenol,  105 
Methenyl-diphenyl-diamine,  96 
Metho-vinyl-benzol,  406 
Methoxy-benzyl  Alcohol,  316 
Methoxy-cinnamic  Acid,  427 


Methoxy  Aldehyde,  415 

Ester,  436 

Methoxy-hydratropa-aldehyde,  323 

Methoxy-phenanthrene,  690 

Methoxy-phenanthrene-g-carboxylic  Acid.  691 

Methoxy-phenyl-acetaldehyde,  323 

Methoxy-phthalide,  351 

Methoxy-salicylic  Acid,  726 

Methoxyl-coniferin,  721 

Methyl-acetanilide,  95 

Methyl-2  -acetyl- A1-cyclopentene,  1 9 

Methyl-2  -acetyl -pentamethylene,  1 9 

Methyl-i  -acetyl-pentamethylene-carboxylic     Acid, 

22 

Methyl-aesculetin,  431 

Methyl-alizarin,  716 

Methyl- a-amido-cyclopentane-carboxylic  Acid,  21 

Methyl-amido-phenol   200 

Methyl-aniline,  89 

Methyl-anthracene,  704 

Methyl-anthranile,  303 

Methyl-anthranilic  Acid,  306 

Methyl-anthranilido-acetic  Acid,  308 

Methyl-anthraquinone,  710 

Methyl-anthrone,  707 

Methyl  Arbutin,  720 

Methyl-atropic  Acid,  426 

Methyl-benzimido-chloride,  287 

Methyl-benzoic  Acids,  274 

Methyl-benzoic  Ester,  278 

Methyl-benzoin,  616 

Methyl-benzol,  30 

Methyl-benzoyl-acetic  Ester,  393 

Methyl-benzyl  Cyanides.  286 

Methyl-benzyl-malonic  Acid,  396 

Methyl-bromo-camphor,  535 

Methyl-camphenilol,  527 

Methyl-camphor,  535 

Methyl-carbostyrile,  98 

Methyl-cetyl-benzol,  60 

Methyl-chavicol,  409 

Methyl-chloro-stilbene,  619 

Methyl  Chloroform,  64 

Methyl-cinnamic  Acid,  424 

—  Aldehyde,  415 
Methyl-cumarilic  Ester,  191 
Methyl-cumarin,  429 
Methyl-cyclo-hexadiene-acetic  Acid,  473 
Methyl-cyclo-hexane,  446 
Methyl-cyclo-hexanol,  452 
Methyl-cyclo-hexanol-acetic  Acid,  474 
Methyl-cyclo-hexanone,  458 
Methyl-cyclo-hexenes,  448 
Methyl-cyclo-pentadiene-carboxyl-propionic    Acid, 

20 

Methyl-cyclo-pentane-carboxylic  Acid,  19,  20 
Methyl-cyclo-pentanol,  16 
Methyl- 1,  i  -cyclo-pentanol-acetic  Ester,  21 
Methyl-cyclo-pentanone,  17 
Methyl-cyclo-pentene,  14 
Methyl-cyclo-pentene-acetic  Acid,  20 
Methyl-cyclo-pentenone,  17 
Methyl-cyclo-propene-dicarboxylic  Acid,  10 
Methyl-diketo-hydrindene,  649 
Methyl-diphenylamine,  92 
Methyl-ditolyl-iso-urea,  100 
Methyl  Ester,  99 

Ether,  536 

Methyl-ethyl-aniline,  90 
Methyl-ethyl-aniline  Oxide,  90 
Methyl-ethyl-cyclopentane,  14 
Methyl-ethyl-fulvene,  15 
Methyl-ethyl-ketone,  42 
Methyl-fluorene,  700 
Methyl  Formanilide,  94 
Methyl-formazy],  166 
Methyl-gluco-o-cumar-ketouC;  721 
Methyl-glyoxal-phenyl-hydrazoxime.  153 
Methyl  Green,  588 
Methyl-heptenone,  489 
Methyl-hexahydro-fluorene,  697 
Methyl-hexanitro-diphenyl-amine,  112 
Methyl-hydrocotom.  573 
Methyl-hystazarin,  716 
Methyl-indene.  645 
Methyl-iridic  Acid,  342 


INDEX 


747 


Methyl-isatin,  390 
Methyl-iso-cumarin,  435 
Methyl  iso-formanilide,  95 
Methyl-iso-propyl-benzol.  58 
Methyl-iso-propyl-cyclo-hexane,  446 
Methyl-iso-propyl-phenanthraquinone,  693 
Methyl-iso-thio-acetanilide,  96 
Methyl-3-methylene-cyclopentane,  15 
Methyl-morphol,  690 
Methyl-n-propyl-ketone,  42 
Methyl-naphtho-quinitrol,  666 
Methyl-naphtho-quinol,  666 
Methyl-naphthol,  666 
Methyl-nopinol,  520 

Methyl-nor-caradiene-carboxylic  Ester,  641 
Methyl-nor-opianic  Acid,  352 
Methyl-opianic  Ester,  352 
Methyl-p-norm.-propyl-phenol,  189 
Methyl -pentamethylene,  14 
Methyl-phenanthrene,  689 
Methyl-phenyl-cyano-triazene,  136 
Methyl-phenyl  Ether,  190 
Methyl-phenyl-glycin,  98 
Methyl-phenyl-glycocoll-methyl  Ester,  98 
Methyl-phenyl-hydrazin,  119,  151 
Methyl-phenyl-iso-urea,  100 
Methyl  -phenyl-nitro-amine,  119 
Methyl-phenyl -nitrosamine,  119 
Methyl-phenyl-thio-carbamine  Chloride,  101 
Methyl-phenyl-triazene,  135 
Methyl-phenyl-urea  Chloride,    9 
Methyl-phthalazone,  353 
Methyl-purpuro-xanthins,  716 
Methyl-sabina-ketol,  511 
Methyl-salicyl  Chloride,  33^ 
Methyl-sinapinic  Acid,  431 
Methyl -stilbene,  611 
Methyl-suberene,  23 
Methyl-suberenone,  24 
Methyl-suberol,  23 
Methyl-sulphonic  Phenyl  Ester   191 
Methyl- tert. -butyl -benzol,  59 
Methyl-tetramethylene,  10 
Methyl-thio-acetanilide,  96 
Methyl-thio-benzamide,  289 
Methyl-thio-salicylic  Acid,  332 
Methyl-triketo-pentamethylene,  18 
Methyl-trimethylene,  7 
Methyl-triphenyl-methane,  577 
Methyl-umbelliferone,  430 
Methyl-vanillin,  324 
Methyl  Violet,  587,  588 
Methylene-anthranilic  Acid,  307 
Methylene-bis-hydro-resorcin,  565 
Methylene  Blue,  115 
Methylene-camphor,  535 
Methylene-cyclopentane,  14,  23 
Methylene-dianthranilic  Acid,  306 
Methylene-dibenzamide,  282 
Methylene  Dibenzoate,  278 
Methylene-diorcin,  565 
Methylene-diphenyl-diamine,  90 
Methylene-diphloro-glucin,  565 
Methylene-diresorcin,  565 
Methylene-phthah'de,  434 
Methylene-proto-catechuic  Acid,  338 
Methylene-quinones,  317,  318,  465,  564 
Meyer,  599 

Mimosa  catechu,  212,  343 
Mitscherlich,  50 

Monacid  Menthane  Alcohols,  497 
M  onarda  punctate,  188 
Mono-acetyl-hydrazo-benzol,  146 
Mono-bromo-acetylene,  42 
Mono-bromo-durol,  66 
Mono-bromo-isodurol,  66 
Mono-bromo-mesitylene,  66 
Mono-bromo-prehnitol,  66 
Mono-bromo-pseudocumol,  66 
Mono-bromo-stilbene,  619 
Mono-chloro-cyclopentene.  15 
Mono-chloro-quinone,  46 
Mono-chloro-stilbene,  619 
Mono-chloro-trimethylene,  7 
Mono-cyclic  Terpenes,  491 
Mono-haloid  Cinnamic  Acids,  422 


Mono-haloid  Phenols,  194 

Mono-hydric  Oxy-phenyl-paraffin  Alcohols,  314 

Phenols,  183 

Mono-methyl-aniline,  89 
Mono-nitro-phenols,  195 
Mono-nitro-terephthalic  Acid,  362 
Mono-nitroso-naphthalene,  659 
Mono-nuclear  Aromatic  Substances,  27 
Mono-sulphonic  Acids,  174 
Mono-thio-hydroquinone,  220 
Mono-thio-pyrocatechol,  214 
Monoxy-alcohol  Acids,  376 
Monoxy-anthracene,  705 
Monoxy-anthraquinones,  714 
Monoxy-benzaldehydes,  321 
Monoxy-benzoic  Acids,  328 
Monoxy-benzyl  Alcohols,  315 
Monoxy-biphenyls,  556 
Monoxy-monocarboxyh'c  Acids,  328 
Monoxy-naphthacene-quinone,  719 
Monoxy-phenyl-olefin-carboxylic  Acids,  4.26 
Monoxy-triphenyl-methanes,  589 
Morin,  343 

Morinda  citrifolia,  714,717 
Morindone,  717 
Moringa-tannin,  343 
Morphia,  689 
Morphol-quinone,  693 
Moms  tinctoria,  338,  343 
Mustard  Oil,  97,  408 
Myrcene,  487 
Myristicin,  412 
Myrtenol,  520 

NAPHTHACENE,  719 
Naphthacene-di-quinone,  719 
Naphthacene-quinone,  719 
Naphthaldehyde,  677 
Naphthaldehydic  Acid,  682 
Naphthalene,  657 

Naphthalene-dicarboxylic  Acid.  680 
Naphthalene  Bichloride  684 
Naphthalene-disulphonic  Acids  663 
Naphthalene  Disulphydrates,  671 

Group, 650 

Red,  662 

Ring,  Decompositions  of,  654 

Naphthalene-ring  Formations,  652 
Naphthalene-sulphinic  Acids,  665 
Naphthalene-sulphonic  Acids,  663 
Naphthalene  Tetrabromide,  685 
Naphthalene-tetracarboxylic  Acid,  680 
Naphthalene  Tetrachloride,  685 
Naphthalene-trisulphonic  Acids,  664 
Naphthalic  Acid,  673,  680 
Naphthalin,  37,  50 
NaphthaUn-azo-compounds,  178 
Naphthaline  Homologues,  657 
NaphthaUzarin,  673 
Naphthanthracene,  719 
Naphthanthraquinone,  719 
Naphthazarin,  673,  714 
Naphthenes,  444,  445,  470 
Naphthenic  Acid,  470 
Naphthidin,  663 
Naphtho-azimides,  661 
Naphtho-benzyl  Alcohols,  676 
Naphtho-benzyl-amines,  677 
Naphtho-benzyl  Chlorides,  676 
Naphtho-cumarin,  678 
Naphtho-fluorenone,  699 
Naphtho-furazane,  675 
Naphtho-methylene-quinone,  666 
Naphtho-nitriles,  68 1 
Naphtho-purpurin,  673 
Naphtho-pyrogallol,  671 
Naphtho-quinones,  668,  671,  672,  673,  674 
Naphtho-quinone-anile,  676 
Naphtho-quinone  Chlorimides,  675,  676 
Naphtho-quinone-dichlorimide,  676 
Naphtho-quinone-dipxime,  675 
Naphtho-quinone-imides,  676 
Naphtho-quinone-phenyl-hydrazones,  674 
Naphtho-quinoximes,  674 
Naphtho-resorcin-carboxylic  Acid,  679 
Ester,  399 


INDEX 


Naphtho-resorcinol,  670 
Naphtho-stilbene,  68 1 
Naphtho-styril,  678 
Naphtho-sultone,  670 
Naphtho-xanthones,  679 
Naphthoic  Acid,  678 
Naphthols,  81,  665 
Naphthol-aldehyde,  677 
Naphthol-alkyl  Ethers,  666 
Naphthol-azo-benzol,  668 
Naphthol  Blue,  239,  676 
Naphthol-carboxylic  Acids,  678,  679 
Naphthol-ethyl  Ether,  666 
Naphthol  Green,  675 

Homologues,  666 

Naphthol-methyl  Ether,  666 
Naphthol-methyl-ketone,  677 
Naphthol  Orange,  668 
Naphthol-sulphonic  Acids,  668 
Naphthoxazoles,  667 
Naphthyl-acetic  Acid,  678 
Naphthyl-acrylic  Acids,  678 
Naphthyl-azo-acetic  Ester,  662 
Naphthyl-benzene  Sulphamides,  661 
Naphthyl-carbinols,  676,  677 
Naphthyl-dimethylamine,  660 
Naphthyl-diphenyl-carbinol,  677 
Naphthyl-ethylamine,  660 
Naphthyl-hydrazins,  663 
Naphthyl-iodo-chlorides,  659 
Naphthyl-iso-crotonic  Acid,  688 
Naphthyl-mercaptan,  671 
Naphthyl-methyl-acetaldehyde,  677 
Naphthyl-methyl-ketone,  677 
Naphthyl-methylamine,  660 
Naphthyl-nitramine,  662 
Naphthyl-nitro-methane,  677 
Naphthyl-phenyl-carbinol,  677 
Naphthyl-phenyl  Ether,  666 
Naphthylamines,  81,  660 
Naphthylamine-sulphonic  Acids,  664 
Naphthylenes,  447 
Naphthylene-diamines,  66 1,  662 
Naphthylene-dihydrazin,  663 
Narcotin,  359 
Naringenin,  628,  723 
Naringin,  723 

Nasturtium  officinale,  286,  720 
Nerol,  488 
Neroli  Oil,  302 
Neville,  669 
Nietzki,  231,  232 
Nigritella  suaveolens,  324 
Nirvanin,  333 

Nitramino-anthraquinone,  712 
Nitranilic  Acid,  230 
Nitranilide,  120 
Nitranilines,  no 
Nitrazones,  163,  164 
Nitrile  Oxides,  295 
Nitrite,  125 

Nitro-acetaldehydrazone,  165 
Nitro-aceto-phenones,  268,  372 
Nitro-alizarin,  715 
Nitro-anthracene,  704 
Nitro-anthranilic  Acid,  308 
Nitro-anthraquinones,  710 
Nitro-anthrone,  705 
Nitro-azo-benzol,  142 
Nitro-azoxy-benzol,  140 
Nitro-benzal-acetone,  416 
Nitro-benzal-divanillin,  594 
Nitro-benzaldehydes,  261 
Nitro-benzene,  29 
Nitro-benzo-phenones,  570 
Nitro-benzoic  Acids,  298,  299 
Nitro-benzols,  69,  70 
Nitro-benzol-azo-p-amido-benzol,  144 
Nitro-benzoyl-acetic  acid,  393 
Nitro-benzoyl-formic  Acid,  388 
Nitro-benzyl-amine,  251 
Nitro-benzyl-malonic  Ester,  396 
Nitro-benzyl  Sulpho-cyanide,  251 
Nitro-bromo-durol,  74 
Nitro-camphane,  532 
Nitro-camphene.  522 


Nitro-camphor,  532 
Nitro-chloro-tolu-quinone,  319 
Nitro-cinnamic  Acids,  422,  423 
Nitro-cinnamic  Aldehydes,  415 
Nitro-cinnamyl-formic  Acid,  437 
Nitro-coccic  Acid,  728 
Nitro-cresols,  197 
Nitro-cumaric  Acid,  427 
Nitro-cumarinic  Acid,  426,  428 
Nitro-diazo-benzol-imide,  138 
Nitro-diazo-benzol  Methyl  Ether,  126 
Nitro-diazo-benzolic  Acid,  120 
Nitro-dimethyl-aniline,  89 
Nitro-dioxy-quinone-sulphonic  Acid,  231 
Nitro-diphenic  Acid,  561 
Nitro-diphenyls,  552 
Nitro-diphenyl-amines,  in,  112 
Nitro-diphenyl-methanes,  563 
Nitro-diphenyl-sulphone,  183 
Nitro-fluorene,  696,  697 
Nitro-fluorenone,  700 
Nitro-formaldehydrazone,  164 
Nitro-formazyl,  166 
Nitro-halogen-benzpls,  71 
Nitro-haloid  Benzoic  Acids,  299 
Nitro-homo-veratrol,  726 
Nitro-hydran-thranol,  704 
Nitro-hydratropic  Acids,  300 
Nitro-hydrazones,  157,  164 
Nitro-hydro-cinnamic  Acids,  300 
Nitro-hydroquinone,  219 

Nitro-hydroxy-dihydro-trimethyl-brasilone,  726 
Nitro-indene,  645 
Nitro-m-xylol,  73 
Nitro-malonic  Aldehyde,  43 
Nitro-mesitylene,  73 
Nitro-methylene-phthalide,  434 
Nitro-monocarboxylic  Acids,  298 
Nitro-naphthalenes,  659 
Nitro-naphthalene-sulphonic  Acids,  664 
Nitro-naphthoic  Acids,  678 
Nitro-naphthols,  666 
Nitro-naphthylamines,  661 
Nitro-nitroso-benzol,  76 
Nitro-o-phthalic  Acids,  358 
Nitro-o-xylol,  73 
Nitro-opianic  Acid,  352 
Nitro-oxanilic  Acid,  108 
Nitro-oxy-diphenyl,  557 
Nitro-p-phenylene-diamine,  115 
Nitro-p-xylol,  73 
Nitro-pentamethyl-benzol,  74 
Nitro-phenanthrenes,  689 
Nitro-phenanthrene-quinone,  692 
Nitro-phenols,  35,  195 
Nitro-phenyl-acetic  Acids,  300 
Nitro-phenyl-acetylene,  407 
Nitro-phenyl-amine,  112 
Nitro-phenyl-benzaldehyde,  559 
Nitro-phenyl-diazo-sulphide,  126 
Nitro-phenyl-diazo-disulphide,  127 
Nitro-phenyl-diazo-mercaptan  Hydrosulphide,  126 
Nitro-phenyl  Ether,  191 
Nitro-phenyl-glyceric  Acid,  385 
Nitro-phenyl-glycin,  98 
Nitro-phenyl-hydrazin,  150 
Nitro-phenyl-hydrazin-disulphonic  Acid,  156 
Nitro-phenyl-hydrazones,  142 
Nitro-phenyl-hydroxylamine,  78 
Nitro-phenyl-lactic  Acids,  381,  383 
Nitro-phenyl-propiolic  Acid,  432 
Nitro-phenyl-pyro-racemic  Acid,  391 
Nitro-phthalide,  349 
Nitro-phthalyl  Chloride,  358 
Nitro-piperonal,  325 
Nitro-prehnitol,  74 
Nitro-pseudocumol,  73 
Nitro-resprcin,  216 
Nitro-salicylic  Acid,  333 
Nitro-stilbene,  611 
Nitro-styrols,  405 
Nitro-terebentene,  519 
Nitro-thio-phenol,  208 
Nitro-toluols,  72,  73 


Nitro-triphenyl-carbinol,  582 
Nitro-xylenols,  198 


INDEX 


749 


Xitrolamines,  504 
Nitrosanilides,  119 
Nitrosazones,  165 
Nitroso-acetanilide,  113,  120 
Xitroso-acetyl-phenyl-hydrazin,  167 
Nitroso-aniline,  113 
Xitroso-benzaldehydes,  262 
Nitroso-benzoic  Acid,  261 

Esters,  261 

Nitroso-benzol,  69 
Nitroso-benzol-sulphonic  Acid,  177 
Nitroso-benzyl  Alcohol,  250 
Xitroso-benzyl-urethane,  248 
Nitroso-chloride,  15 
Xitroso-cresol,  199 
Xitroso-diethyl-aniline,  113 
Xitroso-dimethyl-aniJine,  89,  113 
Nitroso-diphenyl-amine,  113 
Xitroso-diphenyl-hydroxylamine,  79 
Xitroso-formanilide,  120 
Nitroso-formyl-phenyl-hydrazin,  167 
Xitroso-guaiacol,  213 
Xitroso-m-phenylene-diamine,  114 
Nitroso-mesitylene,  76 
Xitroso-methyl-anthranilic  Acid,  306 
Nitroso-monocarboxylic  Acids,  300 
Nitroso-monoethyl-aniline,  113 
Xitroso-monomethyl-aniline,  113,  119 
Nitroso-naphthalenes,  659 
Xitroso-naphthols,  674 
Xitroso-orcin,  217 
Xitroso-oxy-diphenyl,  557 
Nitroso-phenol,  198 
Nitroso-phenyl-hydrazones,  142 
Nitroso-phenyl-semicarbazide,  167 
Xitroso-phenyl-urea,  120 
Nitrosophthalimidin,  348 
Nitroso-pinene,  519 
Nitroso-salicylic  Acid,  333 
Nitroso-  thymol,  199 
Nitroso-toluol,  76 
Nitroso-xylol,  76 
Nonocarbbcych'c  Compounds,  26 
Nonomethylene,  i,  3 
Nononaphthene,  446 
Nopinene,  519 
Nopinic  Acid,  519 
Nopinol-acetic  Acid,  521 


Nopinone,  519,  521 
Xor-borneol,  ^ 


1,526 
Nor-camphane,  513 
Nor-caradiene-carboxylic  Acid,  25 
Nor-carane,  513,  641 
Nor-carane-dicarboxylic  Ester,  641 
Xor-hemi-pinic  Acid.  359 
Xor-opiamc  Acid,  352 
Xor-pinane,  513 
Xor-pinic  Acid,  13,  516 
Xuclear  Synthesis,  51 
Nutmeg  Oil,  412 

O-BENZO-BETA?N,  306 
o-Cyano-anilic  Acid,  305 
Oak -red,  343 
Ocimene,  487 
Octazones,  168 

Octo-carbocyclic  Compounds,  25 
Octo-chloro-acety-facetone,  48 
Octo-chloro-keto-tetrahydro-benzol,  463 
Octo-chloro-phenanthrene,  689 
Octo-decyl-benzol,  60 
Octo-hydro-carbostyril,  471 
Octo-hydro-naphthalenes,  687 
Octo-methylene,  i,  3 
Octo-naphthene,  446 
Octyl-benzol,  60 
Oglialoro,  418 
Oldenlandia  umbellata,  715 
Olefm-acetylene-benzols,  408 
Olefin-benzenes,  403 
Olefin-dioxy-benzols,  410 
Olefin-monoxy-benzols,  409 
Olefin-phenols,  408 
Olefin-tetraoxy-benzols,  412 
Olefin-trioxy -benzols,  412 
Olefinic  Terpene,  487 


Olefinic  Terpene  Acids,  490 

Terpene-aldehydes,  489 

Oleum  cadinum,  547 
Oleum  cina,  499 
Opianic  Acid,  350,  352 
Opianoximic  Acid,  352 
Orange-blossom  Oil,  302 
Orcin,  216,  217 
Orcin-aurin,  594 
Orcin-phthaleins,  601 
Orcyl-aldehyde,  325 
Orsellinic  Acid,  339 
Ortho-acetic -phenyl  Ester,  192 
Ortho-benzoic  Acid  Piperidide,  297 

Derivatives  of,  297 

Ortho-dinitro-benzol,  70 
Ortho-form,  334 
Ortho-oxy-benzoic  Acid,  31 
Ortho-phosphoric  Anilide,  93 
Ortho-quinones,  225 
Ortho-silico-benzoic  Acid  Ester,  170 
Ortho-xylol,  36 
Orthrin,  273 
Osazones,  152 
Oso-tetrazones,  155 
Oxal-phenyl-hydrazide,  162 
Oxal-phenyl-hydrazilic  Acid,  162 
Oxalate,  125 

Oxalo-acetic  Ester  Condensation,  4 
Oxalo-diamido-pxime,  164 
Oxalyl-anthranilic  Acid,  305 
Oxalyl-anthranilic  Acid  NitrUe,  305 
Oxalyl-diaceto-phenone,  640 
Oxalyl-dibenzyl-ketone,  18 
Oxanile  Dichloride  Acid  Ethyl  Ester,  108 
Oxanilic  Acid.  107 

Nitrile,  107 

Thio-amide,  107 

Oxanih'de,  107 

Dioxime,  108 

Oxanthrone,  708,  709 
Oxatolylic  Acid,  631 
Oxethyl-anisidin.  200 
Oximido-diphenyl-urea,  104 
Oximido-propio-phenone,  375 
Oxindol,  310 
Oxy-aceto-phenone,  326 
Oxy-acids,  376 
Oxy-anthracenes,  705 
Oxy-anthranile  301 
Oxy-anthraquinones,  713 
Oxy-anthrarufin,  717 
Oxy-anthrone,  707 
Oxy-azo-benzols,  204 
Oxy-azo-compounds,  178 
Oxy-benzal-acetone,  417 
Oxy-benzalazin,  322 
Oxy-benzo-hydrol.  566 
Oxy-benzo-phenones,  572 
Oxy-benzo-thiazol,  209 
Oxy-benzoic  Acids,  35,  334 
Oxy-benzyl-amine,  315 
Oxy-benzyl-benzols,  564 
Oxy-benzyl-benzyu'dene-indene,  643 
Oxy-benzlidene-aceto-phenone,  628 
Oxy-biazoline  Derivatives,  158 
Oxy-biphenyls;  556 
Oxy-biphenyl-carboxylic  Acids,  559 
Oxy-camphor,  533 
Oxy-carone,  574 
Oxy-cinnamic  Acid,  427 
Oxy-cinnamylidene-acetic  Acid.  437 
Oxy-cumarin,  431,  437 
Oxy-cyclopentane-carboxylic  Acid,  21 
Oxy-diazo-benzol-imide,  203 
Oxy-dibenzal-acetone,  638 
Oxy-dibromo-triphenyl-carbinol,  591 
Oxy-dihydro-cyclo-geranic  Acid,  474 
Oxy-diphenyl-acetic  Acid,  607 
Oxy-diphenyl-amine,  201,  202 
Oxy-diphenyl  Sulphide,  180 
Oxy-diphenylene-ketone,  699 
Oxy-fenchene  Acid,  525 
Oxy-fluorenone,  699,  700 
Oxy-glutaric  Acid,  7 
Oxy-hydrazo-benzol,  206 


750 


INDEX 


Oxy-hydro-carbo-styril,  381 
Oxo-hydro-cumarin,  391 
Oxy-hydroquinone,  223 
Oxy-hydroquinone-benzein,  592 
Oxy-hydroquinone-phthaleiin,  601 
Oxy-iso-phthalic  Acids,  361 
Oxy-juglone,  673 
Oxy-m-xylenols,  345 
Oxy-mandelic  Acid,  378 
Oxy-mesitylene-aldehyde,  323 
Oxy-mesitylenic  Acids,  335 
Oxy-methyl-benzoic  Acids,  347 
Oxy-raethyl-benzoic  Acid  Lactone,  347 
Oxy-methylene-acetic  Ester,  43 
Oxy-methylene-aceto-phenone,  436 
Oxy-methylene-acetone,  43 
Oxy-methylene-camphor,  536 
Oxy-methylene-menthone,  506 
Oxy-methylene-phenyl-acetic  Ester,  436 
Oxy-methylene-phthalide,  437 
Oxy-naphtho-quinones,  673 
Oxy-naphthoic  Acids,  678 
Oxy-o-phthalic  Acids,  359 
Oxy-pentadecylic  Acid,  722 
Oxy-phenanthrenes,  690 
Oxy-phenanthrene-quinone,  693 
Oxy-phenyl-acetic  Acids,  335 
Oxy-phenyl-arsinic  Acid,  170 
Oxy-phenyl-ethyl-Alcohol,  316 
Oxy-phenyl-ethyl-amine,  316 
Oxy-phenyl-ethyl-carbinol,  316 
Oxy-phenyl-fatty  Acids,  335 
Oxy-phenyl -lactic  Acid,  381 
Oxy-phenyl-olefin  Alcohols,  414 

Aldehydes,  415 

Oxy-phenyl-olefin-carboxylic  Acids,  426 
Oxy-phenyl-olefin  Ketones,  417 
Oxy-phenyl-propionic  Acids,  336 
Oxy-phenyl-pyro-racemic  Acid,  391 
Oxy-phenyl-phthalide,  349,  574 
Oxy-phenyl-urea,  201 
Oxy-phenyl-urethane,  200 
Oxy-phenyl-xanthydrol,  592 
Oxy-phosphazp-benzol-anilide,  92 
Oxy-pipitzahoic  Acid,  231 
Oxy-quinones,  230 
Oxy-stilbene,  612 
Oxy-styryl-benzyl-ketone,  633 
Oxy-styryl-diphenyl-carbinol,  629 
Oxy-suberane-acetic  Acid,  25 
Oxy-suberane-carboxylic  Acid,  25 
Oxy-sulphones,  180 
Oxy-terephthalic  Acids,  362 
Oxy-terpenylic  Acid,  509 
Oxy-tetramethylene,  n 
Oxy-thymoquinone,  231 
Oxy-toluic  Acids,  334 
Oxy-toluols,  187 
Oxy-tricarbpxylic  Acids,  365 
Oxy-trimellitic  Acid,  365 
Oxy-trimesic  Acid,  365 
Oxy-triphenyl-carbinol,  590 
Oxy-triphenyl-methane,  589 
Oxy-triphenyl-methane-carboxylic  Acids,  595 
Oxy-uvitinic  Acids,  361 
Aldehyde,  347 

PARA-ANTHRACENE,  703 
Para-dinitro-benzpl,  70 
Para-mandelic  Acid,  376 
Para-nitraniline,  32 
Para-nitro-benzaldehyde,  261 
Para-oxy-benzoic  Acid,  31,  32,  36 
Para-rosolic  Acid,  593 
Para-xylol,  36 
Paracoto,  573 
Paramide  366 
Patchouli' Alcohol,  548 
Penta-amido-benzol,  118 
Penta-amido-pentol,  233 
Penta-amido-toluene,  118 
Penta-bromaniline,  no 
Penta-bromo-cyclo-butane,  n 
Penta-bromo-diketo-oxy-cyclo-hexenol,  461 
Penta-bromo-toluol,  446 
Penta-carbocyclic  Compounds,  13 


Penta-chloraniline,  110 
Penta-chloro-glutaric  Acid,  48 
Penta-chloro-resorcin,  48 
Penta-chloro-naphthalene,  659 
Penta-ethyl-benzol,  55,  59 
Penta-keto-cyclo-pentane,  232 
Penta-keto-pentamethylene,  19 
Penta-methyl-acetyl-cyclopentene,  19 
Penta-methyl-benzoic  Acid,  275 
Penta-methyl-benzol,  55,  59 
Penta-methyl-phenol,  189 
Penta-methyl  Violet,  588 
Penta-methylene,  i,  3,  13,  14 
Penta-methylene-carbinol,  16 
Penta-methylene-glycol,  16 
Penta-methylene-methylamine,  16 
Penta-nitro-diphenyl-amine,  112 
Penta-phenyl-ethane,  625 
Penta-phenyl-ethyl  Alcohol,  626 
Penta-phenyl-guanidin,  104 
Pentamines,  113 
Pentol,  15 

Pentosides,  719,  723 
Pentylene-di-o-toluidin,  90 
Peonine,  593 

Perchlor-acroyl-acrylic  Acid,  47 
Perchlor-ethylene,  42 
Perchlorindone,  21,  647 
Perchloro-acetyl-acrylic  Acid,  48 

Chloride,  48 

Perchloro-cyclopentene,  14 
Perchloro-diphenyl,  552 
Perchloro-methane,  42 
Perchloro-naphthalene,  659 
Perchloro-vinyl-acrylic  Acid,  47 
Perhydro-diphenyl,  550 
Perhydro-fluorene,  696 
Peri-dioxy-naphthyl-ketones,  677 
Peri-naphthol-carboxylic  Acid,  679 
Perkin,  485 

Peroxide-phthalic  Acid,  356 
Persea  Cassia,  415 
Persio,  217 
Perylene,  68 1 
Petermann,  32 
Petroselinum  sativum,  412 
Phaseolus  vulgaris,  453 
Phellandrene,  494,  495 
Group,  494 

—  Nitrite,  494 
Phenacetin,  202 
Phenacetol,  191 
Phenacetyl-phenyl-alanin,  381 
Phenacyl-acetone,  375 
Phenacyl-anilide,  372 
Phenacyl  Bromide,  371 

—  Chloride,  371 
Phenacyl-cinnamic  Acid,  635 
Phenacyl-diacetyl-methane,  376 
Phenacyl  Iodide,  372 
Phenacyl-laevulinic  Acid,  396 
Phenacyl-phthalide,  630 
Phenacyl-succinic  Acid,  539 
Phenanthraquinone,  691 
Phenanthraquinone-monoxime,  692 
Phenanthrene,  50,  687,  689 
Phenanthrene-carboxylic  Acids,  690,  691    . 
Phenanthrene-dicarboxylic  Acid,  691 
Phenanthrene  Group,  687 
Phenanthrene-hydroquinone,  690 
Phenanthrene-quinone-sulphonic  Acicl,  693 
Phenanthrene-sulphonic  Acids,  690 
Phenanthridone,  560 
Phenanthro-anthraquinone,  719 
Phenanthrols,  690 
Phenanthrol-carboxylic  Acid,  691 
Phenanthrone,  690 
Phenanthrylamines,  690 

Phenates,  186 
Phenazin,  214 
Phenazone,  553 
Phene,  49 
Phenetetrol,  223 
Phenethyl-benzyl-ketone,  633 
Phenethyl-succinic  Acid,  397 
Phenetol,  190 


INDEX 


75i 


Phenetol-carbamide,  202 
Pheno-pentenal,  415 
Pheno-phenyl-triazin,  292 
Pheno-propyl-methylamine,  246 
Pheno-quinone,  227 
Pheao-triazin,  166 
Phenols,  30,  31,  183,  185,  187,  188 
Phenol  Acids,  327 

Alcohols,  187,  314 

Phenol-alcohol  Ethers,  189 
Phenol-aldehydes,  321 
Phenol-alkyl  Ether,  169 
Phenol-benzeln,  591 
Phenol-diazo-chlorides,  203 
Phenol  Ethers,  191 
Phenol-ethylene  Ether,  190 
Phenol  Haloids,  193 

Ketones,  325 

Phenol-methylene  Ether,  190 
Phenol-monocarboxylic  Acids,  327 
Phenol-naphthalein,  680 
Phenol-phenyl-ethane,  604 
Phenol-phthalem,  598 
Phenol-phthalem-anilide,  598 
Phenol-phthalem  Methyl  Ester,  598 
Phenol-phthalein-oxime,  598 
Phenol-salicylic  Ester,  330 
Phenol  Substitution  Products,  193 
Phenol-sulphonic  Acids,  178,  206 
Phenolates,  186 
Phenose,  454 
Phenoxalkylamines,  190 
Phenoxazin,  200,  214 
Phenoxethylamines,  190 
Phenoxy-acetaldehyde,  191 
Phenoxy-acetic  Acid,  191 
Phenoxy-aceto-acetic  Ester,  191 
Phenoxy -acetone,  191 
Phenoxy-acetyl  Chloride,  191 
Phenoxy-acetylene,  190 
Phenoxy-butylamine,  190 
Phenoxy-butyric  Acid,  191 
Phenoxy-cinnamic  Acid,  417 

Ester,  436 

Phenoxy-fumaric  Ester,  191 
Phenoxy-propylamine,  190 
Phenoxyl-diphenyl-phosphine,  1 69 
Phenoxyl-phosphazo-benzol,  93 
Phenyl- a-methyl-sulpho-hydantoin,  102 
Phenyl-acetaldehyde,  30,  31 
Phenyl  Acetate,  192 
Phenyl-acetic  Acid,  31,  276 

Azide,  284 

Ethyl  Ester,  278 

—  Hydrazide,  284 
Phenyl-aceto-acetic  Ester,  393 
Phenyl-aceto-phenone,  559 
Phenyl-aceto-succinic  Ester,  399 
Phenyl-acetyl-carbinol,  373 
Phenyl-acetyl  Chloride,  279 
Phenyl-acetyl-malonic  Ester,  399 
Phenyl-acetyl-thio-urea,  102 
Phenyl-acetylene,  407 

Alcohols,  414 

Aldehydes,  417 

Phenyl-acetylene-carboxylic  Acids,  431 
Phenyl-acetylene-copper,  407 
Phenyl-acetylene  Di-iodide,  405 

—  Ketones,  417 

Phenyl-acetylene-phenyl-carbinol,  630 
Phenyl-acetylene-silvef,  407 
Phenyl-acetylene-sodium,  407 
Phenyl-acrylic  Acids,  419,  425 
Phenyl-alanin,  98,  380 
Phenyl-alcohol  Aldehydes,  370 
Phenyl-alcohol-dicarboxylic  Acids,  397 
Phenyl-alcohol-ketone-carboxylic  Acids,  394 
Phenyl-aldehdye  Ketones,  373 
Phenyl-alkyl-ammonium  Bases,  88 
Phenyl-alkyl  Chlorides,  243 
Phenyl-alkyl-hydrazins,  151 
Phenyl-alkylamine,  87 
Phenyl-allophanic  Ester,  100,  193 
Phenyl-allyl-acetic  Acid,  426 
Phenyl-allyl-sulphone,  182 
Phenyl-allylene,  407 


Phenyl-amido-acetic  Acid,  379 
Phenyl-amido-carbonyl-chloride,  97 
Phenyl-amido-azo-benzol-[3]-sulphonic  Acid,  179 
Phenyl-amido-azo-benzol-[4]-sulphonic  Acid,  179 
Phenyl-angelica  Acid,  424 
Phenyl-anthracene,  704 
Phenyl-anthranile,  303,  570 
Phenyl-anthranilic  Acid,  306 

Formalide,  307 

Phenyl-anthranilido-acetic  Acid,  308 
Phenyl-arsenious  Chloride,  170 
Phenyl-arsinic  Acid,  170 
Phenyl-aticonic  Acid,  440 
Phenyl-azo-acetaldoxime,  165 
Phenyl-azo-aldoximes,  163,  165 
Phenyl-azo-amido-benzol,  140 
Phenyl-azo-benzaldoxime,  291 
Phenyl-azo-formaldoxime,  165 
Phenyl-azo-formazyl,  166 
Phenyl-azo-nitro-acid,  164 
Phenyl-azo-nitroso-benzol,  140 
Pheoyl-benzaldehyde,  559 
Phenyl-benzaldoxime,  260 
Phenyl -benzalsultime,  569 
Phenyl -benzamide,  281 
Phenyl-benzamidin,  290 
Phenyl-benzene  Sulphazide,  148 
Phenyl-benzo-hydrylamine,  565 
Phenyl-benzo-quinpne,  557 
Phenyl-benzoic  Acid,  559 
Phenyl-benzols,  549,  550 
Phenyl-benzol-sulphazide,  157 
Phenyl-benzyl-ketone,  613 
Phenyl-biguanide,  104 
Phenyl-biuret,  100 
Phenyl-boron  Bromide,  170 

Chloride,  170 

Compounds,  170 

Phenyl-bromacetic  Acid,  378 
Phenyl-bromo-acetylene,  407 
Phenyl-bromo-tetrahydro-naphthoic  Acid,  636 
Phenyl-butadiSne,  408 
Phenyl-butane-tricarboxylic  Acid,  400 
Phenyl-butylene-glycol,  368 
Phenyl-butyric  Acid,  277 
Phenyl -butyraldehyde,  256 
Phenyl-butyro-lactone,  608 
Phenyl-carbamic  Azide,  101 

Phenyl  Ester,  193 

Phenyl-carbaminate,  193 
Phenyl-carbaminic  a- Phenyl -hydrazide,  160 

Acid,  99 

Hydrazide,  100 

Phenyl  Ester,  193 

Thio-methyl  Ester,  101 

Phenyl-carbazinic  Ethyl  Ester,  160 
Phenyl-carbinol,  241 
Phenyl  Carbonates,  192 
Phenyl-carboxy-aconitic  Ester,  441 
Phenyl-carbylamine,  89,  97 
Phenyl-chloracetic  Acid,  378 
Phenyl-chloro-acetylene,  407 
Phenyl-chloro-fluorene,  697 
Phenyl-chloroform,  31,  297 
Phenyl-chryso-fluorene,  698 
Phenyl-cinnamenyl-acrylic  Acid,  635 
Phenyl-cinnamic  Acid,  608 

Nitrite,  621 

Phenyl-citraconic  Acid,  440 
Phenyl-cumalin,  437 
Phenyl-cumaran,  629 
Phenyl-cumarin,  622 
Phenyl-cyanamide,  106 
Phenyl-cyano-acetic  Acid,  396 
Phenyl-cyano-pyro-racemic  Ester,  399 
Phenyl-cyano-triazene,  136 
Phenyl -cyclo-hexane,  550 
Phenyl-cyclopentenone,  17 
Phenyl-diazo-methane,  248 
Phenyl-dihaloid-acryh'c  Acids,  422 
Phenyl-dihydro-resorcin,  459 
Phenyl-diketo-hexahydro-a-triazin,  158 
Phenyl-dimethyl  Carbinol,  242 
Phenyl-dimethyl-pyrimidin,  290 
Phenyl-dimethylamine,  79 
Phenyl-dinitro-methane,  257 


752 


INDEX 


Phenyl-diolefin  Aldehydes,  416 
Phenyl-diolefin-carboxylic  Acids,  433 
Phenyl-diolefin  Ketones,  417 
Phenyl-dioxy-olefine-carboxylic  Acids,  437 
Phenyl-disulphide.  209 
Phenyl-dithio-carbaminic  Methyl  Ester,  101 
Phenyl-dithio-carbazimic  Acid,  161 

Phenyl-hydrazin,  161 

Phenyl-dithio-carbonic  Ester,  208 
Phenyl-dithio-urethane,  101 
Phenyl-dithymol-methane,  590 
Phenyl  Esters,  181 
Phenyl-ethenyl-amidin,  97 
Phenyl  Ether,  191 
Phenyl-ethyl-alcohol,  30,  31 
Phenyl-ethyl-amine,  246 
Phenyl-ethyl  Carbonate,  192 
Phenyl-ethyl-nitrosamine,  119 
Phenyl-ethyl  Sulphide,  210 
Phenyl-ethyl-sulphone,  182 

Alcohol,  182 

Phenyl-ethylene,  404 

Oxide,  368 

Phenyl-fatty  Acids,  275 

Nitriles  of,  286 

Phenyl-fluorene,  697 
Phenyl-fluorone,  592 
Phenyl  Formate  192 
Phenyl-formic  Acid,  31,  273 
Phenyl-formyl-acetic  Ethyl  Ester.  387 
Phenyl-fumaric  Ester,  193 
Phenyl-glutaconic  Acid,  441 
Phenyl-glutaric  Acid,  397 
Phenyl-glyceric  Acid,  256 
Phenyl-glycerin,  367 

Aldehyde,  370 

Phenyl-glycidic  Acid,  386 

Ether,  190 

Phenyl-glycin,  97 
Phenyl-glycocoll,  97 
Phenyl-glycollic  Acid,  376 
Phenyl-glycols,  367 
Phenyl-glyoxal,  267,  373 
Phenyl-glyoxylic  Acid,  387 
Phenyl-guanidin,  104 
Phenyl-hexadiene,  408 
Phenyl-hexamethylene-carboxylic  Acid,  559 
Phenyl-hydantom,  100 
Phenyl-hydracrylic  Acid,  382 
Phenyl-hydrazi-methylene-carboxylic  Acid,  388 
Phenyl-hydrazide,  158,  287 
Phenyl-hydrazidine,  164 
Phenyl-hydrazido-acetic  Acid,  158 
Phenyl-hydrazido-acids,  Hetero-ring  Formation  of, 

158 

Phenyl-hydrazido-/3-butyric  Acid,  158 
Phenyl-hydrazido-j3-propionic  Ester,  158 
Phenyl-hydrazido-formic  ester,  160 
Phenyl-hydrazin,  145,  149 

Carboxylic  Acid  Derivatives  of,  157 

Chlorohydrate,  149 

Derivatives  of  Carbonic  Acid,  159,  161 

of  Inorganic  Acids,  156 

Group,  148 

Phenyl-hydrazin-p-sulphonic  Acid,  179 
Phenyl-hydrazin-phenyl-carbazinate,  159 
Phenyl-hydrazin-sulphinic  Acid,  156 
Phenyl-hydrazin-sulphonic  Acids.  156,  179 
Phenyl-hydrazin-urea,  160 
Phenyl-hydrazo-acetaldoxime,  165 
Phenyl-hydrazo-aldoximes,  163,  165 
Phenyl-hydrazo-formaldoxime,  165 
Phenyl-hydrazones,  152,  254,  322,  674 

Transformations  of,  155 

Phenyl-hydro-naphthalene,  684 
Phenyl-hydro-nitric  Ester,  138 
Phenyl-hydroxyl-thio-urea,  103 
Phenyl -hydroxyl-urea,  100 
Phenyl-hydroxylamine,  69,  78 
Phenyl-imido-carbonic  Phenyl  Ester,  193 
Phenyl-imido-carbonyl  Chloride,  105 
Phenyl-imido-formyl-chloride,  97 
Phenyl-imido-oxalic  Dimethyl  Ester,  108 


Phenyl  -  imido  -  phenyl  -  carbaminic    thio  -  methyl 

Ester,  103 
Phenyl-imido-thio-carboxylic  Acid,  101 


Phenyl-imino-benzo-phenone,  569 
Phenyl -indoxazene,  571 
Phenyl-iodo-acetylene,  407 
Phenyl-iodo-chloride,  61 
Phenyl-iso-amyl  Carbinol,  242 
Phenyl-iso-butyl,  242 
Phenyl-iso-crotone-phenone,  633 
Phenyl-iso-crotonic  Acid,  424 
Phenyl  Iso-cyanate,  104 
Phenyl-iso-cyanide,  97 
Phenyl-iso-phthalic  Acid,  560 
Phenyl-iso-propyl,  242 
Phenyl-iso-oxazolonimide,  393 
Phenyl-itaconic  Acid,  440 
Phenyl-itamalic  Acid,  398 

Phenyl-keto-pentamethylene-dicarboxylic  Acid,  21 
Phenyl-keto-tricarboxylic  Acids,  400 
Phenyl  Ketols,  371 

Phenyl-ketone-dicarboxylic  Acids,  399 
Phenyl-lactazame,  575 
Phenyl-lactic  Acids,  379,  382 
Phenyl-magnesium  Bromide,  171 

Iodide,  171 

Phenyl-maleic  Acid,  440 
Phenyl-malic  Acids,  398 
Phenyl-malonic  Acids,  396 
Phenyl-mesaconic  Acid,  440 
Phenyl  Metal  Derivatives,  171 
Phenyl-methane,  31 
Phenyl-methyl-acetylene,  407 
Phenyl-methyl-alcohol,  31 
Phenyl-methyl-butadiene,  408 
Phenyl-methyl  Carbinol,  242 

cyanamide,  106 

Phenyl-methyl-ethyl-propyl-silicon,  1 70 
Phenyl-methyl-ethylene  Oxide,  368 
Phenyl-methyl-formhydrazin,  164 
Phenyl-methyl-glycol,  367 
Phenyl-methyl-glyoxime,  375 
Phenyl-methyl  Ketone,  266 
Phenyl-methyl-nitramine,  120 
Phenyl-methyl-nitrosamine,  119 
Phenyl-methyl-oxy-pyrimidin,  290 
Phenyl-methyl-pentadiene,  408 
Phenyl-methyl-pseudo-thio-urea,  102 
Phenyl-methyl-sulphide,  210 
Phenyl-methyl-triazol,  165 
Phenyl-methyl-triketone,  375 
Phenyl-methylamine,  79 
Phenyl -methylamine  Chlorohydrate,  82 
Phenyl-methylol,  241 
Phenyl-monohaloid-acrylic  Acids,  421 
Phenyl-mustard  Oil,  106 
Phenyl-naphtho-xanthene,  682 
Phenyl-naphthyl-ketones,  677 
Phenyl-naphthylamines,  660 
Phenyl -nitramines,  120 
Phenyl-nitro-acetic  Ester,  378 
Phenyl-nitro-aceto-nitrile,  378 
Phenyl-nitro-ethylene,  405 
Phenyl-nitro-f ormaldehydrazone,  291 
Phenyl-nitro-isoxazol,  415 
Phenyl-nitro-methane,  244 
Phenyl-nitro-paraffins,  244 
Phenyl-nitrosamines,  118 
Phenyl-nitroso-hydrazin,  166 
Phenyl -olefin  Alcohols,  413 

Aldehydes,  415 

Phenyl-olefin-carboxyh'c  Acids,  418 
Phenyl-olefin-ketols,  436 
Phenyl-olefin  Ketones,  416 
Phenyl-olefin-tricarboxylic  Acids,  441 
Phenyl-opiazone,  352 
Phenyl-ortho-formic  Ester,  192 
Phenyl-oxalacetic  Ester,  399 
Phenyl-oxalic  Ester,  193 
Phenyl-oxalkyl-amines,  369 
Phenyl-oxamide,  107 
Phenyl-oxaminic  Diphenyl-amidine,  108 
Phenyl-oxanthranyl  Chloride,  707 
Phenyl-oxethyl-amine,  369 
Phenyl-oxy-ketone-dicarboxylic  Acids,  400 
Phenyl-oxy-olenn-dicarboxyh'c  Acids,  441 
Phenyl-oxy-propionic  Acids,  379 
Phenyl-p-toluidin,  92 
Phenyl-parabanic  Acid,  109 


INDEX 


753 


Phenyl-paraconic  Acid,  398 

Phenyl-paraffin  Alcohols,  239 

Alcohol  Acids,  376 

Phenyl-paraffin-aldehyde-carboxylic  Acids,  386 

Phenyl-paraffin  Amines,  245 

Phenyl-paraffin-dicarboxylic  Acids,  396 

Phenyl-paraffin  Diketones,  374 

Phenyl-paraffin-ketone-carboxylic  Acids,  387 

Phenyl-paraffin-tricarboxylic  Acids,  400 

Phenyl-pentadiene,  408 

Phenyl-phosphine,  169 

Phenyl-phosphorus  Compounds,  168 

Phenyl-phthalazone,  351 

Phenol-phthalol,  594 

Phenyl-piperidin,  60 

Phenyl-propargyl  Aldehyde,  417 

Phenyl-propenyl-ketone,  417 

Phenyl-propiolic  Acid,  431,  652 
Ethyl  Ester,  432 

Phenyl-propionic  Acid,  31 

Phenyl-propyl  Alcohols,  242 

Phenyl-propyl -aldehyde,  256 

Phenyl-pyro-racemic  Acid,  391 

Phenyl-salicylic  Acid,  330,  559 

Phenyl-semicarbazide,  100,  160 

Phenyl  Silicates,  192 

Phenyl-silico-chloride,  170 

Phenyl-sih'cpn  Compounds,  170 

Phenyl-stibinic  Acid,  170 

Phenyl -stibinous  Chloride,  170 

Phenyl-succinic  Acid,  396 

Phenyl-sulphaminic  Acid,  93 

Phenyl  Sulphide,  209 

Phenyl-sulpho-aceto-nitrile,  182 

Phenyl-sulpho-cyanide,  105 

Phenyl-sulpho-hydantolns,  102 

Phenyl-sulpho-semicarbazide,  161 

Phenyl-sulpho-urea,  101 

Phenyl-sulphone  Acetamide.  182 

Phenyl-sulphone-acetic  Acid,  182 

Phenyl-sulphonic  Ester,  191 

Phenyl-sulphoxy-acetic  Acid,  181 

Phenyl-sulphur-ethane,  101 

Phenyl-sulphuric  Acid,  191 

Phenyl-tartronic  Methyl  Ester,  398 

Phenyl-tetronic  Acid,  395 

Phenyl-tetrose,  371 
Phenyl-thio-acetyl  Bisulphide,  280 
Phenyl-thio-biazolone-sulphohydrate,  161 

Phenyl-thio-carbaminic  a-Phenyl-hydrazide,  161 

/3-Phenyl-hydrazide,  161 

Hydrazide,  103 

Phenyl-thio-carbonic  Chloride,  208 
Phenyl-thio-glycolic  Acid,  210 
Phenyl-thio-salicylic  Acid,  333 
Phenyl-thio-semicarbazide,  103 
Phenyl-thio-sulphonic  Aceto-acetic  Ester,  181 
Phenyl-thiuram-sulphide,  101 
Phenyi-tin  Compounds,  171 
Phenyl-tolyl-disulphone,  181 
Phenyl-tolyl-ketone,  568 
Phenyl-tolyl-propane,  610 
Phenyl-triazene,  134 
Phenyl-triazole,  158 
Phenyl-tricarballylic  Acid,  400 
Phenyl-trimethyl-ammonium  Iodide,  82 
Phenyl-trimethyl-hydrazin,  152 
Phenyl-trimethylene-carboxylic  Acid,  8 
Phenyl-trioxy-fluorone,  592 
Phenyl-urazol,  161 
Phenyl-urea,  99 

Chloride,  99 

Phenyl-urethanes,  99,  193 
Phenyl-valerianic  Acid,  277 
Phenyl-vinyl-amine,  406 
Phenyl-vinyl-ethyl  Ether,  413 
Phenyl-vinyl-ketbne,  417 
Phenyl-vinyl-methyl  Ether,  413 
Phenyl-vinyl-phenyl  Ether,  413 
Phenyl-xanthydrols,  591 
Phenyl-xylyl-propane,  610 
Phenylamine,  79 
Phenylamines,  Primary,  80 

Properties  and  Transformations  of,  82 

Phenylated  Fatty  Ketones,  267,  268 
Para-rosanilins,  589 

VOL.  II. 


Phenylated  Rosanilins,  589 

Phenylene,  602 

Phenylene-aldehydo-carbpxylic  Acids,  435 

Phenylene-alkylene-diamines,  116 

Phenylene-bis-diazo-chloride,  126 

Phenylene-bis-diazo-imide,  138 

Phenylene  Blue,  239 

Brown,  145 

Phenylene-carbyl-amine,  114 

Phenylene-diacrylic  Acid,  436 

Phenylene-diamido-monosulphonic  Acid,  178 

Phenylene-diamines,  114,  115 

Phenylene-dicarboxylic  Acids,  435 

Phenylene-dicarbyl-amine,  115 

Phenylene-disazo-m-phenylene-diamine,  145 

Phenylene-ketone-dicarboxylic  Acids,  402 

Phenylene-naphthylene,  695 

Phenylene-naphthylene  Oxide,  726 

Phenylene-oxy-dicarboxylic  Acids,  401 

Phenylene-oxy-olefin-carboxylic  Acids,  434 

Phenylene-oxy-olefin-dicarboxylic  Acids,  442 

Phenylene-sulphonylide,  207 

Phenylisuretin,  97 

Phloretic  Acid,  336 

Phloretin,  221,  336 

Phlorizin,  721 

Phloro-baphene,  343 

Phloro-glucin,  48,  221 

Phloro-glucin-aldehyde,  325 

Phloro-glucin-carboxylic  Acid,  341 

Phloro-glucin-dicarboxylic  Ester,  483 

Phloro-glucin-phthalein,  601 

Phloro-glucin  Trioxime,  222 

Phloro-glucite,  222,  453 

Phloxin,  601 

Phosph-azo-benzol  Chloride,  93 

Phosph-azo-benzol-anilide,  93 

Phosphaniline,  169 

Phosphenyl  Chloride;  169 

Sulpho-chloride,  169 

Phosphine-benzoic  Acids,  312 

Phospbino-benzene,  169 

Phospho-benzol,  169 

Phosphoro-phenylamines,  93 

Photo-santonic  Acid,  725 

Phthal-acene,  701 

Phthal-aldehyde  Chlorides,  352 

Phthal-aldehydic  Acid,  351 

Methyl  Ether,  351 

Phthal-amic  Acid,  356 

Phthal-ane.  344 

Phthal-azin,  346 

Phthal-azone,  351 

Phthaleins,  597 

Phthalic  Acids,  35,  36,  37,  354 

Acid  Aldehydes,  346 

Anhydride;  356 

Diamide,  356 

Phthalide,  347 

Phthalide-acetic  Acid,  401 

Phthalide  Anile.  348 

Phthalide-carboxylic  Acid.  401 

Phthalide  Chloride,  348 

Phthalide-propionic  Acid,  402 

Phthalide-tricarboxylic  Acid,  403 

Phthalideins,  597,  707 
Phthalidins,  597,  707 

Phthalimide,  356 
Phthalimidin,  348 
PhthaUmino-aceto-phenone,  372 
Phthalins,  597 

Phthalo-mono-super  Acid,  356 
Phthalo-nitrile,  358 
Phthalo-phenones,  576 
Phthalonic  Acid,  402 
Phthalyl-acetic  Acid,  442 
Phthalyl-alanin,  358 
Phthalyl  Chloride,  355 
Phthalyl-diacetic  Acid,  403 
Phthalyl-dimalonic  Acid,  403 
Phthalyl-glutaric  Esters,  642 
Phthalyl-glycocoll,  357 
Phthalyl-hydrazin,  357 
Phthalyl-hydroxylamine,  357 
Phthalyl-hydroxylaminic  Acid,  357 
Phthalyl-malonic  Ester,  442 

3C 


754 


INDEX 


Phthalyl  Peroxide,  356 
Phthalyl-phenyl-hydrazide,  357 
Phthalyl-phenyl-hydrazin,  357 
Phthalylene  Tetrachlorides,  356 
Piazo-selenols,  116 
Piazo-thiols,  116 
Picamar,  221 
Piceane  Ring,  13 
Picene,  693,  694 
Picene-fluorene,  695,  697 
Picene-ketone,  699 
Picene-perhydride,  695 
Picramic  Acid,  202 
Picric  Acid,  184,  196 
Picro-cyaminic  Acid,  197 
Picro-erythrin,  339 
Picro-toxin,  724 
Picro-toxinin,  724 
Picrotin,  724 

Picryl-anthranilic  Acid,  306 
Picryl  Bromide,  72 

Chloride,  184 

Picryl-malonic  Ester,  396 
Picylene-methane,  697 
Pimaric  Acid,  548 
Pimpinella  anisum,  410 
Pinane,  513 

Group, 515 

Pinene,  13,  515,  519 

Dibromide,  519 

Pinene-glycol,  516,  519 
Pinene  Hydrate,  520 

Hydro-bromide,  518 

Hydro-chloride,  518 

Hydro-iodide,  518 

Nitroso-bromide,  519 

Nitroso-chloride,  519 

Pinic  Acid,  13 
Finite,  454 
Pino-campheol,  520 
Pino-camphone,  519,  521 
Pino-camphylamine,  521 
Pino-carveol,  520 
Pino-carvone,  521 
Pinol-chloro-hydrins,  521 
Pinol  dibromide,  521 
Pinol-glycol,  521 
Pinol  Hydrate.  520 

Nitroso-chloride,  521 

Oxide,  521 

Pinolone,  521 
Pinonic  Acid,  516 
Pinoyl-formic  Acid,  516 
Pinus  Lambertiana,  454 
Pinus  maritima,  548 
Pinylamine,  519,  521 
Piperic  Acid,  433 
Piperonal,  324 

Chloride,  324 

Piperonoyl-carboxylic  Acid,  390 
Piperonyl  Acid  Dibromide,  386 
Piperonyl-acrolem,  416 
Piperonyl-acrylic  Acid,  430 
Piperonyl  Alcohol,  321 
Piperonylene-acetone,  418 
Piperonylene-malonic  Acid,  440 
Piperonylic  Acid,  338 
Pipitzaho'ic  Acid,  231 
Pittical,  594 

Poly-benzoyl  Cyanide,  388 
Poly-carboxylic  Acids,  354 
Poly-gonin,  723 
Poly-gonine,  717 
Poly-haloid  Phenols,  194 
Poly-hydric  Aromatic  Alcohols,  344 
Poly-phenyl-fatty  Hydrocarbons,  549 
Poly-phenylamines,  91 
Poly-quinoyls,  230 
Poly-quinoyl  Compounds,  231 
Poly-sulphonic  Acids,  176 
Poly-terpenes,  546 
Poly-thymo-quinone,  229 
Poly-valent  Ring-alcohols,  452 
Polymerisation,  44 
Populin,  720 
Potassium  Anilide,  85 


Potassium  Chloranilate,  230 

Diazo-benzol,  119 

Diazo-benzolic  Acid,  119 

Potassium-benzyl  Diazotate,  248 
Potassium  Euthio-chronate,  230 

Iso-diazo-benzol,  119,  127 

—  Iso-p-diazo-toluol,  127 

Myronate,  720 

Phenate,  186 

Phenyl-hydrazin,  150 

Phthalimide,  357 

Potassium-salicylic  Aldehyde,  322 

Prehnidin,  87 

Prehnitic  Acid,  366,  403 

Prehnitol  55,  58 

Primary  Potassium-iso-diazo-sulphonate,  178 

Prismatic  Scheme,  41 

Prom,  273 

Propene-pyrocatechin,  213 

Propenyl-anisol,  410 

Propenyl-benzol,  406 

Propenyl-naphthalin,  658 

Propenyl-phenol,  409 

Propiolic  Acid,  43 

Propionyl-iso-butyryl-phenyl-hydrrizide,  157 

Propionyl-phenpl,  326 

Propyl-acetanilide,  95 

Propyl-benzoic  Acids,  275 

Propyl-benzol.  30,  57 

Propyl-cyclo-hexane,  446 

Propyl-mesitylene,  59 

Propyl-phenol,  188 

Protea  mellifera,  338 

Proteaic  Acid,  338 

Proto-catechuic  Acid,  337 

Aldehyde,  323 

Proto-coto'in,  573 

Prulaurasin,  723 

Pseudo-cumenol,  188 

Pseudo-cumidin,  86 

Pseudo-cumol,  55,  57 

Pseudo-cumol-5-sulphonic  Acid,  175 

Pseudo-cumyl-hydrazin,  150 

Pseudo-diphenyl-thiohydanto'in,  103 

Pseudo-diphenyl-thiohydantoi'nic  Acid.  103 

Pseudo-ephedrin,  369 

Pseudo-ionone,  490 

Pseudo-opianic  Acid,  353 

Pseudo-phenols,  317 

Pseudo-phenol  Alcohol  Haloids,  317 

Pseudo-phenyl-thiohydantoin  ,103 

Pseudo-phenyl-thiohydantoinic  Acid,  103 

Pseudo-phthal-imidin,  348 

Pseudo-purpurin,  717 

Pseudo-saccharin  Chloride,  314 

Pterocarpus,  212 

Pterocarpus  erinaceus,  343 

Ptyalin,  720 

Piychotis  ajowan,  188 

Pulegenic  Acid,  508 

Pulegon,  507 

Pulegonamine,  504 

Pulegone,  508 

Pulvic  Acid,  637 

Purpur,  217 

Purpurin,  702,  716 

Purpurin-amide,  717 

Purpurin-carboxylic  Acid,  717 

Purpuro-xanthin,  715 

Pyranthrone,  718 

Pyrazoles,  155 

Pyrazolidones,  159 

Pyrazolins,  155 

Pyrene,  50,  695 

Pyrene-ketone,  695 

Pyrene-quinone,  695 

Pyrenic  Acid,  695 

Pyro-catechin,  35,  212 

Pyro-catechin-carbonic  Hydrazide,  213 

Pyro-catechin  Chloro-phosphine,  213 

Pyro-catechin-diphenyl  Ether,  213 

Pyro-catechin-methyl  Ether,  212 

Pyro-catechin-methylene,  213 

Pyro-catechin  Oxy-chloro-phosphine,  213 

Pyro-catechin-phenyl-phthalide,  596 

Pyro-catechin  Sulphite,  213 


INDEX 


755 


Pyro-catechol,  212 

Hetero-ring  Formations  from, 

Pyro-catechol-sulphuric  Acid,  212 
Pyro-condensation.  43,  51 
Pyro-gallol,  220,  340 
Pyro-gallol-aldehyde,  325 
Pyro-gallol  Carbonate,  221 
Pyro-gallol-carboxylic  Acid,  341 
Pyro-gallol-pheuyl-phthalide,  596 
Pyro-gallol-phthaleln,  601 
Pyro-gallol-succineln,  599 
Pyro-genic  Synthesis,  51 
Pyro-mellitic  Acid,  365 
Pyro-racemic  Acid,  164 
— —  Anilide,  98 

Chloride,  97,  98 

Pyro-terebinic  Acid,  518 
Pyro-traubem'c  Acid,  43 
Pyrones,  255 
Pyrrol,  633 


QUERCETRIN,  221 
Quercite  453 
Quercitrin,  723 
Quercus  infectoria,  342 

tinctoria,  723 

Quin-alizarin,  717 
Quina-aceto-phenone,  327 
Quinhydrone,  227 
Quinic  Acid,  226,  474 
Quinisatin,  395 
Juinisatinic  Acid,  395 

inite,  226,  453 

linizarin,  715 
}uinolene-phenylene-ketone,  649 

liiiols,  465 

inones,  115,  224.  671 

inone  Anilin-imine.  237 

Azine,  23 

Chlorimines,  235 

Di-anile,  238 

Diazides,  236 

Dichlorimine,  115,  235 

Di-imine,  115,  234 

Dimethyl-anilin-imine,  237 

Dimethyl-imine,  115 

—  Dioximes,  226,  233 
Quinone-dioxime-carboxylic  Ester,  482 
Quinone  Haloids,  229 

Imines,  233 

Quinone-methanes,  317 
Quinone  Mono-anil,  236 

mono-chlorimine,  235 

mono-imine,  234 

mono-methyl-imine,  234 

Quinone-monoxime,  199 
Quinone  Oxime,  226 
Quinone-oxime-hydrazone,  235 
Quinone,  Phenol  Addition  Products  of,  227 

Phenol-imine,  236 

Phenyl-di-imines,  237 

Quinone-phenyl-hydrazones,  235 
Quinone-phenyl  Mono-imine,  236 
Quinone  Semi-carbazone.  235 

—  Tetrabromide,  460 
Quinone-tetracarboxylic  Ester,  365 
Quinoxalins,  116 

Quinoyl,  226,  231 


Ranunculacece,  724 
Resaceto-phenone,  326 
Resaurin,  594 
Residual  Valences,  42 
Resins,  548 

Resorcin,  35,  48,  215,  217 
Resorcin-benzeln,  592 
Resorcin-dialdehyde,  346 
Resorcin-phthalem,  599 
Resorcyl-aldehyde,  325 
Resorcyl-maleinic  Lactone,  440 
Resorcyl-phenyl-phthalide,  596 
Resorcylic  Acid,  338 
Retene,  693 
Retene-diphenic  Acid,  693 


Retene  Dodeca-hydride,  693 
Retene-fluorene,  697 
Retene-glycollic  Acid,  693 
Retene-ketone,  693,  699 
Retene-quinone,  693 
Rhamnose,  723 
Rhamnosides,  723 
Rhamnus  frangula,  717,  724 
Rhelnic  Acid,  716 
Rhodamins,  601 
Rhodan-acetanilide,  103 
Rhodinal,  489 
Rhodinic  Acid,  490 
Rhodizonic  Acid,  231 
Rhus  coriaria,  342 
Ring-ketols,  458 
Ring  Olefins,  i 
Robiquet,  723 
Roccella,  217 

fuciformis,  339 

Rocellin,  668 
Romer,  149 
Rosamines,  592 
Rosamine  Chloride,  593 
Rosanilin,  585 

Rosanilin-sulphonic  Acid,  587 
Rosaniline,  91 
Roshydrazin,  589 
Rosoh'c  Acids,  590,  593,  594 
Rubeanic  Hydride,  164 
Ruberythric  Acid,  714,  722 
Rubia  ttnctorium,  714,  722 
Rungallic  Acid,  341,  717 
Rufiopin,  717 
Rufol,  705,  706 
Runge,  186 

SABATIER,  443 
Sabinane,  511 
Sabinene,  510 

Hydrate,  511 

Sabinol,  512 
Sabinyl-glycerin,  512 
Saccharin,  173,  314 
Safranins,  117 
Safrol,  368,  411 
Safrosine,  600 
Salicin,  720 

Salicyl-acetic  Acid,  330 
Salicyl-amide,  332 
Salicyl-amine,  315 
Sah'cyl-anilide,  332 
Salicyl  Chloride,  330 
Salicyl-hydramide,  322 
Salicyl-hydrazone,  322 
Salicyl-lactic  Acid,  381 
Salicyl-uric  Acid,  332 
Salicylates,  329 
Salicylic  Acid,  36,  328 
SaUcyu'c-acid  Azide,  332 

Hydrazide,  332 

Phthalide,  602 

Salicylic  Aldehyde,  322 

Salicylides,  331 

Salicylide  Chloroform,  331 

Salicylo-nitrile,  332 

SaUcylo-phosphoric  Chloride,  331 

Salicylo-salicylic  Acid,  331 

SaUcylous  Acid,  322 

Saligenin,  315 

SaUnetin,  315 

Sambunigrin,  723 

Santalene,  547 

Santalol,  547 

Santalum  album,  547 

Santene,  526 

Santoic  Acid,  724 

Santonic  Acid,  724 

Santonin,  724 

Saponaria  officinalis,  722 

Saponarin,  722 

Saponin,  722 

Sassafras  officinalis,  411 

Saytzew,  334 

Scammomn,  722 


756 


INDEX 


Schorleminer,  586 

Scyllite,  454 

Secondary  phenyl-alkylamines,  88 

Selenanthrene,  215 

Selenium  benzamide,  289 

Seleno-phenols,  211 

Seleno-phthalide,  348 

Sellner,  485 
Semicarbazone,  19 
Semidin  Transposition,  147 
Senderens,  443  '• 
Sesqui-terpenes,  546 
Shikimic  Acid,  474 
Shikimino-ki,  411 
Shikimol,  411 
Silico-benzoic  Acid,  170 
Silico-diphenylimide,  93 
Silico-tetraphenylamide,  93 
Silver  Benzamide,  281 

Formanilide,  95 

Sinalbin,  720 

Sinapin  sulphate,  720 

Sinapinic  Acid,  431 

Sinigrin,  720 

Slocum,  418 

Sobrerol,  520 

Sodium  Acetanilide,  95 

Sodium-acetic  Ester,  43 

Sodium-acetylene-tetracarboxylic  Ester,  653 

Sodium-benzaldehyde  Sulphoxylate,  257 

Sodium  Benzamide,  281 

Benzanilide,  282 

Sodium-benzyl  Iso-azotate,  248 
Sodium  Dibenzamide,  281 

Formanilide,  94 

Iso-p-nitro-diazo-benzol,  127 

Sodium-phenate,  186 
Sodium-phenol-o-carboxylic  Acid,  192 
Sodium-phenyl,  172 

Carbonate,  192 

Sodium-phenyl-hydrazin,  150 
Sodium  Salicylate,  192,  329 

Salol,  330 

Sozo-iodol,  207 
Spiraea,  721 

Spir&a  ulmaria,  322,  328 
Spiroytous  Acid,  322 
Stilbene,  27,  244,  258,  610 

Alcohol  Derivatives  of,  619 

Stilbene-carboxylic  Acid,  621 
Stilbene-diamine,  615 
Stilbene  Dibromide,  614 
Stilbene-dicarboxylic  Acid,  623 
Stilbene-dichloride,  614 
Stilbene-glycol  Diacetate,  619 

Dibenzoate,  619 

Stilbene  Hydrate,  613 
Stilbene-methyl-ketone,  622 
Stilbene-propionic  Acid,  622 
Stilbene-quinone,  612 
Stilbene-succinic  Acid,  623 
Storax,  241,  413 
Strecker,  123,  149 
Styceric  Acid,  384 
Styracin,  420 
Styrax  Benzoin,  273 
Styril-itaconic  Acid,  441 
Styril-succinic  Acid,  441 
Styrol,  30,  404 

Dibromide,  369 

Dichloride,  369 

Oxide,  368 

Styrol-pseudo-nitrosites,  404 
Styrolene  Alcohol,  367 
Styrone,  413 
Styryl-amine,  413 
Styryl-methyl-carbinol,  414 
Styryl-methyl-ketone,  416 
Styryl-phenacyl-propionic  Acid,  639 
Suberane,  23 
Suberane-acetic  Acid,  25 
Suberane-aldehyde,  24 
Suberane-carboxylic  Acid,  24 
Suberane-i,  i-dicarboxylic  Acid,  24 
Suberene,  23 
Suberene-aldehyde,  24 


Suberone,  24 
Suberyl-alcohol,  23 
Suberyl-glycolic  Acid,  25 
Suberyl-methylamine,  23 
Suberylene-acetic  Acid,  25 
Succin-anile,  108 
Succin-anilic  Acid,  108 
Succinic  Phenyl-hydrazilic  Ester,  163 
Succino-rhodamin,  602 
Succino-succinic  Acid,  481 

Diethyl  Ester,  481 

Succinyl-diphenyl-hydrazide,  163 
Succinyl-phenyl-hydrazin,  163 
Succinyl-succinic  Acid,  363 
Sulphamido-benzoic  Acid,  313 
Sulphanilic  Acid,  177 
Sulphanilide,  93 
Sulphinic  Acids,  179 
Sulphinides,  314 
Sulpho-anthranilic  Acid,  308 
Sulpho-benzide,  182,  251 
Sulpho-benzoic  Acids,  312,  313 

Anhydride,  313 

Anile,  314 

Sulpho-benzol  Disulphide,  181 

Sulphide,  181 

Sulpho-camphoric  Acid,  543 
Sulpho-camphylic  Acid,  543 
Sulpho-carbanile,  106 
Sulpho-carbanile-amide,  101 
Sulpho-carbanilide,  102 
Sulpho-carbizin,  161 
Sulpho-carbonimides,  314 
Sulpho-chloride-benzoic  Methyl  Ester,  313 
Sulpho-cinnamic  Acids,  424 
Sulpho-cyano-diazo-benzol  Chloride,  125 
Sulpho-hydrazin-cinnamic  Acid,  424 
Sulpho-o-phthalic  Acid,  359 
Sulpho-phosphazo-benzol  Chloride,  93 
Sulpho-salicylic  Acid,  333 
Sulpho-terephthalic  Acid,  362 
Sulphonation,  172 
Sulphones,  180,  182 
Sulphonic  Acids,  172,  663 
Sulphoxides,  181 
Sulphurised  Azo-dyes,  178 
Suprarenin,  370 
Sylvestrene,  495 
Sylveterpine,  496 
Sylveterpineole,  496 
Syringa-aldehyde,  325 
Syringa  vulgaris,  721 
Syringin,  721 


Taneceium  vulgar e,  510 
Tanacetyl-alcohol,  511 
Tannic  Acids,  342 
Tannin,  342 
Taurine,  177 
Teraconic  Acid,  518 
Teracrylic  Acid,  518 
Terebinic  Acid,  517 
Terephthalic  Acid,  36,  361 

Di-super-acid,  361 

Teresantaric  Acid,  526 
Terpadienes,  486 
Terpane,  486 
Terpenes,  443,  484 
Terpenogens,  487 
Terpenylic  Acid,  517,  518 
Terpin  499 

Hydrate,  499 

Terpinene,  493 
Terpinene-cineol,  500 
Terpinene-nitrolamine,  493 
Terpinene  Nitrpsite,  493 
Terpinene-terpin,  500 
Terpineols,  502 
Terpinolene,  492 
Tertiary  Amyl-phenol.  189 

Butyl-phenol,  189 

Phenyl-dialkylamines,  89 

Tetra-ami  do-benzol,  118 
Tetra-amido-diphenyl-p-azo-phenylene,  115 


INDEX 


757 


Tetra-bromo-cyclo-butane,  u 
Tetra-bromo-fluorescein,  600 
Tetra-bromo-phenol,  195 
Tetra-bromo-stilbene-quinone,  612 
Tetra-carboxylic  Acids,  402 
Tetra-chloro-acetoae,  48,  221 
Tetra-chloro-cyclopentane,  16 
Tetra-chloro-diketo-R-pentene,  18,  48 
Tetra-chloro-gallem,  601 
Tetra-chloro-p-quinone,  47 
Tetra-chloro-quinone,  47 
Tetra-chloro-stilbene-quinone,  612 
Tetra-ethyl-benzol,  59 
Tetra-ethyl-phenol,  189 
Tetra-hydro-acenaphthene,  683 
Tetra-hydro-aceto-phenone,  468 
Tetra-hydro-benzaldehyde,  466 
Tetra-hydro-benzoic  Acids,  471 
Tetra-hydro-benzols,  447,  448 
Tetra-hydro-carveol,  498 
Tetra-hydro-carvone,  506 
Tetra-hydro-carvylamine,  504 
Tetra-hydro-cprnicularic  Acid,  635 
Tetra-hydro-dicarboxylic  Acids,  478 
Tetra-hydro-diphenyl,  550 
Tetra-hydro-eucarveol,  514 
Tetra-hydro-eucarvone,  514 
Tetra-hydro-fenchene,  526 
Tetra-hydro-naphthalene,  685 

Derivatives,  685 

Tetra-hydro-naphthalene-dicarboxylic  Acid,  687 
Tetra-hydro-naphthoic  Acids,  687 
Tetra-hydro-naphthyl-phenol,  686 
Tetra-hydro-naphthylamines,  685 
Tetra-hydro-naphthylene,  684 

Glycol,  686 

Oxide,  686 

Tetra-hydro-phenol,  454 
Tetra-hydro-phenyl  Fatty  Acids,  472 
Tetra-hydroquinone,  460 
Tetra-hydro-terephthalic  Acids,  479 
Tetra-hydro-toluic  Acids,  471 
Tetra-hydro-toluols,  448 
Tetra-methoxy-diphthalyl,  621 


Tetramethyl-apionpl,  223 
Tetra-methyl-benzidin,  5; 


Tetra-methyl-benzoic  Acids,  275 
Tetra-methyl-benzol,  55 
Tetra-methyl  Derivative,  564 
Tetra-methyl-diamido-benzile,  619 
Tetra-methyl-diamido-azoxy-benzol,  140 
Tetra-methyl-diamido-phenyl-oxanthrone,  709 
Tetra-methyl-diamido-tetraphenyl-ethylene,  625 
Tetra-methyl-2,  4-diketo-tetramethylene,  12 
Tetra-methyl  Dioxime,  12 
Tetra-methyl-m-phenylene-diamine,  114 
Tetra-methyl-mmx-diamido-azo-benzol,  145 
Tetra-methyl-p-diamido-benzo-phenone,  90 
Tetra-methyl-phenols,  189 
Tetra-methyl  Violet,  588 
Tetra-methylene,  i,  3 
Tetra-methylene-carbinol,  1 1 
Tetra-methylene-carboxyh'c  Acid,  12 
Tetra-methylene-cyclo-butane,  ip 
Tetra-methylene-i,  i-dicarboxylic  Acid,  12 
Tetra-methylene-i,  2-dicarboxylic  Acid;  12 
Tetra-methylene-i,  3-dicarboxylic  Acid,  12 
Tetra-methylene-diethyl-glycol,  n 
Tetra-methylene-i,  3-diglyoxylic  Acid,  13 
Tetra-methylene-dimethyl-carbiuol,  n 
Tetra-methylene  Group,  10 
Tetra-methylene-methyl-carbinol,  n 
Tetra-methylene-methylamine,  1 1 
Tetra-methylene-methyl-ketone,  1 1 
Tetra-methylene-i,  2-tetracarboxylic  Acid,  12 
Tetra-nitro-anisol,  197 
Tetra-nitro-benzol,  71 
Tetra-nitro-diphenyl-acetic  Acid,  606 
Tetra-nitro-naphthalenes,  659 
Tetra-nitro-phenol,  197 
Tetra-nitroso-benzol,  77 
Tetra-oxy-benzo-phenone,  573 
Tetra-oxy-biphenyls,  557 
Tetra-oxy-cinnamic  Acids,  431 
Tetra-oxy-naphthalene,  671 
Tetra-oxy-quinone,  230 


Tetra-p-tolyl-hydrazin,  150 
Tetra-p-tolyl-oxamide,  108 
Tetra-phenyl-allene,  627 
Tetra-phenyl-benzol,  562 
Tetra-phenyl-butadiene,  633 
Tetra-phenyl-croto-lactone,  634 
Tetra-phenyl-cyclopentadiene,  16 
Tetra-phenyl-diethylene-diamine,  615 
Tetra-phenyl-dimethylene-quinone,  602 
Tetra-phenyl-ethane,  624 
Tetra-phenyl-ethane-dicarboxylic  Acid,  627 
Tetra-phenyl-ethylene,  624 
Tetra-phenyl-ethylene  Dichloride,  624 
Tetra-phenyl-ethylene-glycol,  625 
Tetra-phenyl-guanidin,  104 
Tetra-phenyl-hexatriene,  640 
Tetra-phenyl-hydrazin,  150 
Tetra-phenyl-methane,  27,  602 
Tetra-phenyl-octazone,  168 
Tetra-phenyl-pentamethylene,  14 
Tetra-phenyl-phenylene-diamines,  114 
Tetra-phenyl-piperazin,  615 
Tetra-phenyl-propinol,  630 
Tetra-phenyl-silicpn,  171 
Tetra-phenyl-succinic  Acid,  627 
Tetra-phenyl-tetramethylene-giycol,  633 
Tetra-phenyl-tetrazone,  167 
Tetra-phenyl-thio-urea,  102 
Tetra-phenyl-urea,  100 
Tetra-salicylide,  331 
Tetra-thio-ethyl-quinone,  231 
Tetra-tolyl-tetrazone,  167 
Tetramido-anisol,  203 
Tetramines,  118 
Tetrazanes,  167 
Tetrazenes,  167 
Tetrazones,  139,  167 
Tetroxy-terephthalic  Ester,  483 
Thebain,  689 
Thianthrene,  214 

Dioxide,  214 

Monosulphone,  214 

Tbio-acetanilide,  96 
Thio-Acids,  280 
Thio-aldo-aniline,  91 
Thio-anilides,  96 
Thio-anilines,  210 
Thio-anisol,  211 
Thio-benzaldehyde,  257 
Thio-benzamide,  288 
Thio-benzanilide,  289 
Thio-benzo-hydroxamic  Acid  294 
Thio-benzo-phenone,  568 
Thio-benzoic  Acid,  280 
Thio-borneol,  528 

Thio-carbaminic  a  Phenyl-hydrazide;  161 
Thio-carbanilic  Ethyl  Ester,  101 
Thio-carvacrol,  189,  208 
Thio-cresol,  208 
Thio-ctimarin,  428 
Thio-cumazone,  251 
Thio-cumo-thiazone,  251 
Thio-derivatives  of  Phenol,  208 
Thio-diglycol-anilic  Acid,  98 
Thio-diphenyl-amine,  92,  204,  211,  214 
Thio-diphenyl-imides,  211 
Thio-fonnanilide,  96,  97 
Thio-isatin,  390 
Thio-naphthene-quinone,  390 
Thio-naphthols,  671 
Thio-oxanilic  Acid,  108 

Thio-amide,  108 

Thio-oxanilide,  108 
Thio-phene,  633 
Thio-pheno-quinone,  227 
Thio-phenol,  208 
Thio-phenol-sulphonic  Acid,  178 
Thio-phenyl-acetal,  208 
Thio-phenyl-acetone,  208 
Tbio-phthalic  Anhydride,  356 
Thio-phthaHde,  348 
Thio-phthalimidin,  348 
Thio-resprcin,  216 
ThkHsalicylic  Acid,  313,  332 
Thio^salicylic-phenyl  Ester,  333 
Thio-urea  Derivatives,  116 


758 


INDEX 


Thionin  Dyes,  92 
Thionyl-aniline,  93,  156 
Thionyl-benzidin,  554 
Thionyl-benzol,  181 
Thionyl-phenyl-hydrazone,  156 
Thionyl-o-bromaniline,  93 
Thionyl-o-chloraniline,  93 
Thionyl-o-iiitraniline,  93 
Thionyl-o-toluidin,  93 
Thuja-menthol,  513 
Thuja-menthone,  513 
Thujane,  511 
Thujene,  511 
Thujone,  510,  512 
Thujone-oxime,  510 
Thujyl-alcohol,  511 
Thujylamine,  512 
Thymo-dialdehyde,  346 
Thymo-quinone,  228 
Thymoil,  228 
Thymol,  188,  505 
Thymotic  Acids,  335 
Thy  mo  tin  Alcohol,  316 
Thymus  vulgaris,  188 
Tin-diphenyl  Chloride,  171 
Tin-tetraphenyl,  171 
Tolane,  27,  613 

Dichloride,  619 

Tetrachloride,  618 

Tolidins,  147,  554 
Tolilic  Acid,  607 
Tolu  Balsam,  56 
Tolu-hydroquinone,  219 
Tolu-quinol,  320 
Tolu-quinone,  228 

Dioxime,  233 

Toluene-azo-naphthalene,  662 
Toluic  Acids,  274 

Aldehydes,  256 

Formaldehyde,  374 

Toluidin,  85 

Chlorohydrate,  82 

Toluol,  30,  54,  55,  56 
Toluol-disulphonic  Acids,  176 
Toluol,  Higher  Homologues  of,  59 
Toluol-sulphamide,  175 
Toluol-sulphinic  Acid,  181 
Toluol-sulpho-chloride,  175 
Toluol-sulphonic  Acids,  175 
Toluyl  Chlorides,  279 
Toluylene,  610 

Blue,  239 

Toluylene-diamido-sulphonic  Acids,  178 
Toluylene-diamines,  115 
Toluylene-glycol,  614 
Toluylic  Acids,  31,  35,  56 
Tolyl-acetic  Acids,  276 
Tolyl-aceto-nitriles,  286 
Tolyl-alcohol,  30 
Tolyl-aldehyde,  30 
Tolyl-azo-benzoic  Acid,  312 
Tolyl-glyoxylic  Acid,  390 
Tolyl-hydrazin,  150 
Tolyl-hydroxylamine,  78 
Tolyl  Isocyanate,  105 
Tolyl-isocyanide,  97 
Tolyl-methyl-triazene,  136 
Tolyl-nitro-methane,  245 
Tolyl-phenyl-hydrazin.  146 
Tolyl-phosphoro-chloride.  169 
Tolyl-semicarbazide,  160 
Tolyl-sulphaminic,  93 
Tolyl-trianilido-phosphonium  Chloride,  169 
Triaceto-phloro-glucin,  347 
Triacetyl-benzol,  347 
Triacetyl-gallic  Acid,  341 
Triacid  Menthane  Alcohols,  500 
Trialkyl-benzamidin,  290 
Triamido-azo-benzol,  145 
Triamido-benzoic  Acid,  310 
Triamido-benzol,  79 
Triamido-diazp-benzol,  114 
Triamido-mesitylene,  118 
Triamido-phenol,  202 
Triamido-toluol,  118 
Triamido-triphenyl-acetic  Nitrile,  609 


Triamido-triphenyl-carbinols.  584 
Triamines,  118 

Triamino-triphenyl-methanes,  579 
Trianisyl-carbinol,  593 
Trianisyl-methane,  590 
Trianthraquinone-di-imides,  712 
Trianthrimides,  712 
Tribenzal-diamine,  257 
Tribenzamide,  281 
Tribenzo-nitrile  Oxide,  295 
Tribenzoyl-hydroxylamine,  294 
Tribenzoyl-methane,  630 
Tribenzyl-amine,  246 
Tribenzyl-carbinol,  628 
Tribenzyl-sulphinic  Chloride,  244 
Tribenzyl-sulphinic  Iodide,  244 
Tribiphenyl-methyl,  627 
Tribromaniline,  no 
Tribromo-aceto-benzoic  Acid,  402 
Tribromo-benzol-diazo-cyanide,  128 
Tribromo-cyclo-butane,  10 
Tribromo-fluorene,  696 
Tribromo-hemimellithol,  66 
Tribromo-mesitylene,  66 
Tribromo-phenyl-nitramine,  121 
Tribromo-pseudocumol,  66 
Tribromo-reso-quinone,  558 
Tricarboxylic  Acids,  364,  402 
Trichlor-ethylidene-diphenyl-diarnine,  90 
Trichloraniline,  no 
Trichlor-ethylene,  47 
Trichloro-aceto-benzoic  Acid,  402 
Trichloro-acetyl-pentachloro-butyric  Acid,  48 
Trichloro-cyclopentane,  15 

Trichloro-cyclo-pentene-dioxy-carboxylic  Acid,  21 
Trichloro-naphthalenes,  659 
Trichloro-phenanthrene,  689 
Trichloro-pheno-malic  Acid,  46 
Trichloro-phenyl-nitramine,  121 
Trichloro-phosphanile,  93 
Trichloro-quinone  Chlorimine,  235 
Tricyclene,  525 

Tricyclene-carboxylic  Acid,  522 
Tricyclo-trimethylene  Benzol,  695 
Triethyl-benzol,  59 
Triethyl-phenyl  Silicide,  170 
Trihydrazin,  589 
Tri-iodaniline,  no 
Tri-iodo-2-chloro-benzol,  61 
Triketo-hydrindene,  649 

Triketo-pentamethylene-3,  5-dicarboxylic  Ester,  22 
Trimellitic  Acid,  365 
Trimesic  Acid.  364 
Trimesinic  Acid,  57 
Trimethoxy-benzaldehyde,  325 
Trimethyl-benzoic  Acids,  275 
Trimethyl-benzols,  55,  57 
Trimethyl-brasilin,  726 
Trimethyl-brasilone,  726 
Trimethyl-cyclo-hexane,  446 
Trimethyl-cyclopentanone,  17 
Trimethyl-dehydro-brasilone,  726 
Trimethyl-dihydro-resorcin,  460 
Trimethyl-ethyl-benzol.  59 
Trimethyl-homogallic  Acid,  342 
Trimethyl  -  keto  -  pentamethyleiie  -  dicarboxylic 

Ester,  21 
Trimethyl-oxy-tetrahydro-naphthylene-ammonium 

Hydroxide,  686 
Trimethyl-phenyl-allene,  408 
Trimethyl-quinol,  320 
Trimethyl-trimethylene,  7 
Trimethyl-triphenyl-para-rosanilin.  589 
Trimethylene,  i,  7 
Trimethylene-aldehyde,  8 
Trimethylene  Benzamidin,  290 

Bromide,  7 

Trimethylene-carbanilide,  100 
Trimethylene-carbinol,  7 
Trimethylene-carboxylic  Acids,  8 
Trimethylene- 1,  i-dicarboxyh'c  Acid,  8 
Trimethylene-i,  2 -dicarboxylic  Acid,  9 
Trimethylene-diethyl-carbinpl,  8 
Trimethylene-dimethyl-carbinol,  8 
Trimethylene-diphenyl-diamine,  90 
Trimethylene-ethyl-carbinol,  8 


INDEX 


759 


Trimethylene  Group,  7 
Trimethylene-isopropyl-carbinol,  8 
Trimethylene-methyl-ethyl-carbinol ,  8 
Trimethylene-methylainine,  7 
Trimethylene-phenyl-urea,  100 
Trimethylene-phenylimine,  90 
Trimethylene- 1,  2-tetracarboxylic  Acid,  9 
Trimethylene-i,  2,  3-tetracarboxylic  Acid,  9 
Trimethylene-i,  2-tricarboxylic  Acid,  9 
Trimethylene-i,  2.  3-tricarboxylic  Acid,  9 
Trimethylene-tricyano-tricarboxylic-acid  Ester,  10 
Trimolecular  Diphenyl-silicon,  171 
Trinaphthyl-carbinol,  682 
Trinaphthylene-benzol,  683 
Trinitraniline,  in 
Trinitro-azo-benzols,  142 
Trinitro-azoxy-benzols,  140 
Trinitro-benzaldehyde,  262 
Trinitro-benzoic  Acid,  299 
Trinitro-benzols,  70 
Trinitro-chloro-benzol,  72 
Trinitro-chloro-benzol-picryl-chloride,  72 
Trinitro-5-chloro-toluol,  74 
Trinitro-diphenyl-sulphone,  183 
Trinitro-ethyl-benzol,  73 
Trinitro-hydranthranol,  705 
Trinitro-m-xylol  73 
Trinitro-mesitylene,  73 
Trinitro-naphthalenes.  659 
Trinitro-nitroso-benzol,  76 
Trinitro-p-xylol,  73 
Trinitro-phenols,  196 
Trinitro-phenyl-carbinol,  582 
Trinitro-phenyl-hydroxylamine,  78 
Trinitro-phenyl-malonic  Ester,  396 
Trinitro-phenyl-methane,  577 
Trinitro-phenyl-nitramine.  121 
Trinitro-phenyl-phenyl-amine,  112 
Trinitroso-phloroglucin,  222 
Trinitro-pseudocumol;  73 
Trinitro-tolupl,  72 
Trinitro-v-trimethyl-benzol,  73 
Trinitro-xylidine,  in 
Trinitro-xylyl-phenyl-amine,  112 
Trioxy-alcohol  Acid's,  386 
Trioxy-anthraquinones,  716,  717 
Trioxy-anthraquinone-carboxylic  Acid,  717 
Trioxy-aurin,  594 
Trioxy-benzoic  Acids,  340 
Trioxy -benzol,  30 
Trioxy-cinnamic  Acids,  431 
Trioxy-dicarboxylic  Acids,  363 
Trioxy-hexahydro-cymol,  500 
Trioxy-methyl-anthraquinone,  717 
Trioxy-naphthalenes,  671 
Trioxy-phenanthrene,  690 
Trioxy-trinaphthyl-methane,  682 
Triphenyl-acetaklehyde,  608 
Triphenyl-acetic  Acid,  608 
Triphenyl-acrylic  Ester,  624 
Triphenyl-acyl-methyl-amine,  373 
Triphenyl-arsin,  170 
Triphenyl-benzols,  562 
Triphenyl-biuret,  too 
Triphenyl-bromo-ethanone,  624 
Triphenyl-bromo-methane,  580 
Triphenyl-butadiene,  633 
Triphenyl-carbinol,  580 

Chloride,  580 

Triphenyl-chloro-carbamidin,  100 
Triphenyl-chloro-methane,  580 
Triphenyl-croto-lactone,  634 
Triphenyl  Cyanurate,  105 
Triphenyl-cyanuro-triamide,  107 
Triphenyl-cyclopentadiene,  16 
Triphenyl-dimethyl-pentamethylene,  14 
Triphenyl-ethane,  623 
Triphenyl-ethanol,  624 
Triphenyl-ethanone,  623 
Triphenyl-ethyl  Silicide,  170 
Triphenyl-ethylene,  623 
Triphenyl-ethylene-glycol,  623 
Triphenyl-glutaric  Acid,  632 
Triphenyl-guanidin,  104 
Triphenyl-hydranthracene,  709 
Triphenyl-hydranthranol,  709 


Triphenyl-hydrazin,  150 
Triphenyl-indene,  645 
Triphenyl-iodo-methane,  580 
Triphenyl  Isocyanurate,  105 
Triphenyl-isomelamine,  107 
Triphenyl-melamine,  107 
Triphenyl-methane,  27,  577 
Triphenyl-methane-azo-benzpl,  581 
Triphenyl-methane-carboxylic  Acids,  594 
Triphenyl-methane  Group,  576 
Triphenyl-methane-hydrazo-benzol,  581 
Triphenyl-methyl,  14 
Triphenyl-methyl-amine,  581 
Triphenyl-methyl-aniline,  581 
Triphenyl-methyl-ethane,  624 
Triphenyl-methyl-hydrazin,  581 
Triphenyl-methyl-sUicide,  170 
Triphenyl-nitro-methane,  626 
Triphenyl-nitroso-methane,  626 
Triphenyl-oxy-ethanone,  624 
Triphenyl-para-rosanilin,  539 
Triphenyl-phosphine,  169 

Oxide,  169 

Triphenyl-propio-phenone,  629 
Triphenyl-propionic  Acid,  624 
Triphenyl-pseudo-thio-urea,  103 
Triphenyl-rosaniline,  92 
Triphenyl-rosanilin  Hydrochloride,  589 
Triphenyl-semi-carbazide,  160 
Triphenyl-silicane,  171 
Triphenyl-siKcp-chloride,  170 
Triphenyl-stibin,  170 

—  Sulphide,  170 

Triphenyl-tetrazolium  Hydroxide,  292 
Triphenyl-thio-urea,  102 
Triphenylamine,  79,  92 
Triphenylene,  695 
Triquinoyl,  231,  460 
Triresorcin,  215 
Trithio-vanillin,  324 
Tritoluol-sulphonamide,  175 
Tritolyl-amine,  92 
Trixis  pipitzahuac,  231 
Tropic  Acid,  380 
Tropilidene,  23 

Tropilidene-carboxylic  Acids,  24 
Tropafolum  majus,  286,  720 
Truxillic  Acid,  421 
Tuberosa,  302 
Turpentine,  515 
Tyrosin,  381 


UMBELLIC  Acid,  430 
Umbelh'ferone,  430 
Umbellulone,  513 
Urea  Chlorides,  99 
Urethano-phenyl-aceto-nitrile,  379 
Usnea,  727 
Usnic  Acid,  217,  727 
Uvitinic  Acid,  57,  360 


VALENCES,  Residual,  42 
Valero-hydroquinone,  327 
Vanillic  Acid,  337 
Vanillin,  324 
Vanillin-oxime,  324 
VanUlyl  Alcohol,  321 
Veratric  Acid,  338 
Veratroyl-carboxylic  Acid,  390 
Vesuvine,  145 
Vinaconic  Acid,  8 
Vinyl-benzoic  Acid,  418 
Vinyl-benzol,  30,  404 
Vinyl-naphthalin,  658 
Vinyl-phenol,  409 
Vinyl-phenyl-acetic  Acid,  418 
Vinyl-pyro-catechin,  410 
Vinyl-trimethylene,  7 
Violanthrenes,  719 
Virianin,  723 
Viridiflora,  727 
Vulpic  Acid,  637 


760 


INDEX 


WAGNER,  485,  516,  523 
Wallach,  485 
Wanklyn,  586 
Water  Blue,  589 
Werner,  259 
Winther,  669 
Wohler,  255 
Woskresensky,  226,  231 
Wurster's  Red.  234 


XANTHOGEN-ANILIDE,  101 
Xanthone,  330,  595 
Xylenols,  187 
Xylidic  Acid,  361 
Xylidins,  86 
Xylo-quinone,  228 
Xylol,  30,  54,  55,  56 
Xylol-disulphonic  Acids,  176 
Xylol  Hexachloride,  447 
Xylol-2-sulphonic  Acid,  175 


Xylol-3-sulphonic  Acid,  175 
Xylol-4-sulphonic  Acid,  175 
Xylorcin,  217 
Xylyl-acetic  Acid,  276 
Xylyl-hydrazin,  150 
Xylyl-hydroxylamine,  78 
Xylylene  Alcohols,  344 
Xylylene-diamine,  115,  344 
Xylylene  Oxide,  344 
—  Sulphide,  344 

Sulpho-hydrates,  344 

Tetrabromide,  346 

Xylylenimine,  344 
Xylylol  Tetrachlorides,  346 


YELLOW  Corallin,  593 


ZlNCKE, 46 

Zingiberene.  547 
Zulkowsky,  586 


END   OF  VOL.    II. 


PRINTED    IN    GREAT   BRITAIN    BY    NEILL    AND    CO.,    LTD.,    EDINBURGH. 


UNIVERSITY    OF    CALIFORNIA 
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